Cheap telescopes: What to expect, what to look for

I spend time on several online astronomy forums and see this question all the time:

"What telescope should I get? I have $100 to spend."

Left: Too many super cheap telescopes end up in the thrift store. Sadly, they knew they would.

Constructive responses from amateur astronomers usually include one or more of the following:

• Clarifying questions: what do you want to see, what is your interest, how dark or light-polluted is your sky, etc.
• Save your money until you can spend more
• Find a used telescope
• Check out your local astronomy club
• Buy binoculars instead

All of these responses are quite valid and contain good advice. There is endless data online about recommended telescopes and equipment, which I won't delve into here. 

Most "experts" will tell you these cheap telescopes are all junk and are "hobby killers." However, I have seen many comments by avid amateurs who started with just such a telescope and the thrill of seeing craters on the Moon or Saturn's rings for the first time set them on a lifelong path as an amateur astronomer. I think a far more reliable determinant of whether someone will catch the astronomy bug is the person rather than the equipment. I think that's the case for most everything related to astronomy—or anything else, really. Nevertheless, if you can afford spending a bit more, you will likely get a better telescope and enjoyment for a longer period of time and without as much frustration.

You will see some reviews of ultra cheap telescopes saying how fantastic and awesome they are, primarily because most of the reviewers never looked through a telescope before and ANY view of the Moon's craters, for example, will elicit that type of response. If that's all you're after, then maybe dipping your toe in the cosmos like this is enough. But after that initial "wow" moment, the cons start stacking up. I think this quote from a $100 telescope five-star review on Amazon says it all:

"...if I could do it over again, I would've spent more and gone with a better one."

However, for various reasons, all of the above advice may not be feasible or practical for you. For example, maybe you just don't have $300 to spend on a telescope. While you are slowly saving money, the prices are slowly going up. You're not sure if your kid is going to use it and you don't want to spend hundreds of dollars finding out. You may not be comfortable looking for a used telescope, not knowing what's good and what isn't. You may not have a local astronomy club, or can't get to one. With binoculars, you're not going to see much detail on the Moon and none on the brighter planets—it's just not the same as the telescope experience.

If you don't follow the above advice, here's what you can expect, and here's what to look for. The key criterion is enjoyment, and that depends on the individual and your expectations.

What to expect from a cheap telescope

Most telescopes recommended by amateurs start at about $300 these days, although sometimes you can get one on sale for cheaper, especially in the used market. So we're talking about sub-$300 (new) telescopes. This is the total price for the optical tube assembly (OTA, the telescope itself), a mount that moves in two axes, and a tripod or base on which the tube and mount are placed. You also need at least one eyepiece (the lens that you look through), some type of lower power finderscope attached and aligned to the main telescope so you can find things in the sky, and some type of chart or software that tells you where those things are. Some telescopes come with all of these pieces, especially the ultra-low end scopes. That doesn't mean they all work well, or at all.

With a cheap telescope, you can expect the following:

• Shaky views. Manufacturers usually skimp on the mount and tripod. Your view in the eyepiece, especially the higher the power you use, will vibrate uncontrollably any time you touch any part of the telescope. So if you are trying to focus, you will have to move the focuser a little, wait several seconds for the view to steady, decide if it's better or worse, and repeat until you get it in focus. All the while, the object will appear to move out of the field of view because the Earth (with your telescope attached to it) is turning and the sky is not. When you move the telescope to get the object back in view, you will again have to wait for the scope to settle. This can be frustrating, but not necessarily terminal.
  
  
  
  
  
• Blurry views. Most cheap telescopes either have poor main optics (the refractor lens or reflector mirror), or poor eyepieces (the lens you look through), or poor mirror diagonals (for refractors, to bend the light 90 degrees so that you can look high in the sky at a reasonably comfortable angle), or all three. Some main optics are better than others, but the view will still not be as sharp as that of a higher quality telescope. Finer lunar detail available to a scope of that size may not be visible, the edges of the bright planets may not be well-defined, moon shadow transits of Jupiter are often difficult to make out, color fringes appear on the edges of bright objects, and stars may be misshapen blobs rather than pinpoints.
  
  IMPORTANT NOTE: These same effects may be the result of poor atmospheric "seeing." This is the case in the eastern U.S., for example, which is under or near the jet stream and is often subject to poor seeing. The view will appear be ripply as if viewing a stone in a shallow stream, or soft and blurry. If possible, observe objects when they are higher in the sky, where you are looking through less atmosphere. Also avoid viewing directly over pavement, rooftops, cars, or other objects that radiate heat at night. If the seeing is bad, switch to a lower power eyepiece where the effects are less noticeable. Or wait for a better night.
  
  
• Jerky movements. Going back to the mount and tripod or base, the movements of the axes (left and right, up and down) are usually not very smooth, so it becomes difficult to place an object in the center of the field of view, and then recenter it each time it drifts out of the field, sometimes overshooting it and then losing it completely.
  
  
• Difficulty finding objects. This is usually the most frustrating aspect and one which causes a lot of cheap telescopes to end up in the closet or the dumpster. The other defects above may still allow you to enjoy using the telescope if you have patience and reasonable expectations, but this one is terminal if not addressed. Most cheap telescopes come with very cheap finderscopes or red dot finders, and sometimes the design does not even allow you to easily replace them later on down the road. Also, if you don't know the sky, you will be limited to the Moon and maybe Jupiter and Saturn. You WILL need to learn the sky.

• No imaging capability. These cheap telescopes are not designed for imaging, which requires a tracking mount and a much more robust build. With some practice, you can hold your phone up to the eyepiece and snap a fuzzy view of the Moon. That's about it.
  
  

With these defects, or should I say challenges, in mind, you can usually work around most of them to be able to see craters on the Moon, the four brightest moons of Jupiter, the rings of Saturn, maybe some slight detail on these brighter planets, and brighter double stars. If you are in a dark enough sky, you can glimpse some of the brighter deep sky objects, such as star clusters and a few galaxies and nebulas. 

So if you don't take the advice above and still end up buying a cheap telescope, with some patience and resolve, you might still get some enjoyment out of it. Just don't expect anything close to the images you see online. Not even close. Even big expensive telescopes can't compete visually with images from even mediocre telescopes.

Except for some stars that show subtle color, a yellowish or chalky gray color to the Moon, and some muted colors in the bright planets, almost everything else will be shades of white or gray. These objects can still be fascinating and quite beautiful, but you have to appreciate what you are seeing, not just what it looks like in the telescope. It's a thrill to see these incredibly huge and distant objects through your own telescope with your own eyes! If it isn't, then maybe a telescope isn't the right thing for you or your child. No problem, we're all different.

Cheap telescope as a toy

Do not give a child younger than about 8 years old a telescope. It's just not something most of them have the patience or understanding to operate and appreciate. Expect that you, the adult, will be the one having to learn the sky and find objects for young children. A cheap telescope will stretch your own limits of patience.

A telescope given as a toy is just that—a toy, and won't function as a precision instrument. Telescopes make bad toys. A $30 pair of binoculars would make a better gift once the child is old enough to know not to look at the Sun, and is also a functioning instrument that's a lot easier to use, for a lot less money. 

What to look for

• The most critical part is the mount and tripod. Thicker, adjustable legs on the tripod, a heavier mount, and a spreader to keep the tripod legs from collapsing are all good. Most cheap telescope tripods are not tall enough to allow an adult to observe without bending over. But that's okay, because sitting is more comfortable and allows for a steadier view at the eyepiece. Look for 1/4-20 mounting threads on the telescope tube assembly so that you can upgrade to a better photo tripod. Many of these, whether new, used, or from a thrift store, will be better than what comes with the telescope. 
  
  Above: Many cheap scopes come on wobbly pan-tilt photo-style tripods such as this one, but if the thread on the top is the standard 1/4-20, you can upgrade it to a heavier photo tripod at a later date.
  
  
• Ignore claims of what power a telescope can give you ("High powered telescope!!"). The power, or magnification, is determined by the combination of the focal length of the telescope and the focal length of the eyepiece. Most cheap telescopes, and some good telescopes, will not give you any kind of clear, bright view over about 100x, often much less (x is the power). That is still enough to see many objects within range of the telescope fairly well. In fact, some large objects are better in lower power.
  
  
• Assuming equal quality, the most important optical characteristic to consider is the size of the aperture. The larger the aperture, the more light the telescope collects, making typically very faint celestial objects a little brighter and detail a little easier to see, even on brighter objects like the Moon and Jupiter.
  
  
• For cheap reflectors, parabolic mirrors are generally better than spherical mirrors. That doesn't mean a spherical mirror can't produce a decent image, at least in the middle of the field of view, but it is a cost-saving measure, not a feature, and it's best to avoid it.
  
  
• Eyepieces and barlow lenses that, combined, give no more than 150x, and often even that is way too high. For example, many telescopes come with 25mm and 10mm eyepieces. For a scope with a 700mm focal length, those eyepieces will give you 700/25=28x and 700/10=70x, which may be reasonable. If you put the eyepiece into the included 3x barlow (tripling the magnification at the loss of a lot of sharpness and brightness), you would have 84x (still possibly okay) and 210x (too high for pretty much all of these telescopes). What happens with too much magnification? It dims the view down, it becomes very blurry, it magnifies the scope's jitters, and it becomes even more difficult to track an object as it speeds through the tiny field of view.
  
  In my opinion, the maximum usable power for a cheap telescope with a cheap eyepiece is about equivalent to the aperture in mm. This is under perfect conditions (very steady atmosphere), which may not happen very often depending on where you observe. So for a 70mm telescope, 70x; a 90mm telescope 90x. This is about half of the generally recommended 50-60x per inch (25mm) of aperture for higher quality telescopes. Under perfect conditions. Divide the number in half and you're probably closer to typical effective use.
  
  
  
  
  
• A red-dot finder. In most cases, a magnifying finderscope that looks like a mini-telescope attached to the main telescope will be too small and dim to see anything well through it. A red-dot finder, however, allows you to point the dot at what you want to view and, if aligned properly, you can then view it in the main telescope. It's very intuitive. If the telescope comes with a magnifying finderscope, it will likely be a 5x24, which is frustrating to use and you won't see many stars at all in it. A 6x30 is better. A red-dot is probably best for a beginner.
  
  
• Generally for small refractors and reflectors, a shorter tube (shorter focal length of around 300-800mm) for a refractor or reflector means lower power, wider views, better for dark skies and viewing larger star clusters and galaxies. A longer tube (longer focal length of around 800mm or more) will generally give a more magnified view using the same eyepiece, but with a narrower field, better for the Moon, bright planets, double stars, and smaller objects.
  
  Note: If you see a short tube reflector and it has a long focal length listed, this may be a Bird-Jones design, with a spherical mirror and corrector lens, which is almost always poorly rendered in cheap telescopes. The infamous Celestron Powerseeker 127mm reflector is a good example.
  
  
• Many cheap telescopes now come with cell phone adapters, remote shutter buttons, cheap barlow lenses, and moon filters. Ignore these mostly useless accessories when you first start out. You can probably take cell phone photos of the Moon through the eyepiece easier without the cell phone adapter. Barlows that come with these scopes are generally too cheap to be satisfying long term and give dim, blurry views, but may be exciting at first. If the scope comes with one or two, try them out and decide for yourself, but get the object in view in a low power eyepiece first, remove it, insert the barlow, then insert the eyepiece into the barlow.
  
  
• For a refractor, make sure it has a 90 degree diagonal. Many only come with a 45 degree diagonal, which is fine for terrestrial use, but unsuitable for observing high up in the sky, where the sky is usually darker and steadier. The 90 degree diagonal lets you place your head and eye at a more comfortable position, which is key for observing.
  
  
• If shopping used, avoid older telescopes with .965" focusers and eyepieces. The standard today is 1.25" and many better scopes come with 2" focusers with 1.25" adapters. There may still be a few cheap new telescopes using the .965" size. These are narrower eyepieces, and options to replace cheap ones with better ones are very limited. You can sometimes use a 1.25" eyepiece with an adapter in a .965" focuser, but it won't work well, if at all, in many telescopes. Go with 1.25".

If you must buy a cheap telescope, I recommend first reading the telescope rankings on Telescopicwatch.com, which start with the cheapest at the top.

Let's look at a sample listing

Here's the Celestron Travel Scope 70, a 70mm (diameter of the main lens) refractor with a basic tilt/pan camera type mount on a tripod, with a 400mm focal length. It has a list price of $119.99, but it was on sale on Amazon for "Prime Big Deal" days in October 2025 for $99.99 and around $75 on Black Friday 2025. 

I have not used this particular telescope, so I am going only by the specs and the reviews of other users. I can therefore not say whether I personally would recommend this telescope or not versus others in its price range. This is just to illustrate how you would go about assessing the telescope for your own needs from an online listing. If you are interested in a particular telescope, read the reviews and ask others who have it on astronomy forums such as cloudynights.com or Reddit r/telescopes. See the review of this scope on Telescopicwatch.com.

The specs:

It's a 70mm refractor, with a 400mm focal length, making it a focal ratio of f/5.7. Let's break that down:

70mm - This is the aperture, which determines how much light the telescope collects. The more the better. 70mm (2.8") is relatively small, so only brighter objects will show up and the resolution, or the fineness of detail, that you can see through it will be relatively low. Hint: getting any telescope to a dark sky will let you see much more!

400mm - This is the focal length of the telescope. Divide by the aperture to get the focal ratio (400/70=5.7).

f/5.7 - An f/5.7 telescope is on the "fast side," providing lower power views and wider fields, but still "slow" enough to forgive some optical defects in the eyepieces.

The good (maybe):

• Celestron sells astronomical telescopes and gear. They don't make any of it themselves, but they are one of the most well known companies selling astronomical gear. That doesn't mean all their telescopes are good, but they know when they are selling crap. The low price provides a clue on this one, but some crap is better than others.
• Appears to have a 1/4-20 attachment point, allowing you to upgrade to a better photo tripod.
• 90 degree diagonal, suitable for astronomy, although it will mirror-reverse your view, which is normal. It also comes with a 45 degree correct image diagonal if you want to view nature or other terrestrial scenes.
• No cheap barlow. You can buy a better one anyway for less than $20 if you need it. The backpack is more useful.
• Decent eyepiece focal lengths, giving 20x and 40x. This is very low power for an astronomical telescope, but okay for a scope of these specs. The Moon will easily fit in the field of view and Jupiter and Saturn will be quite small, with surface detail very difficult or impossible to discern. Saturn's rings will be visible when tilted at an angle (right now they are almost on edge). Jupiter's moons will be visible. Larger, brighter deep sky objects like the Pleiades and M31, the Andromeda Galaxy, and M42, the Orion Nebula, will be framed fairly well. Smaller objects will be very dim and tough or impossible to see unless you are in a nice dark sky. Hint: for deep sky, start out looking at open star clusters, which will show up better. Skip most of the galaxies and nebulas until you have more experience and can observe in a dark sky.
• Lightweight and portable for camping, hiking, etc.

The okay.

• Small 70mm aperture and short focal length limit you to low power, wide field views and low resolution.
• Backpack is useful if you want to hike to a darker, more open site and protect the scope during transport. 
• Starry Night software for the computer is fine, but there are other good cheap or free options,  including mobile versions (Sky Safari, Stellarium) for easier use at the telescope.

The bad.

• Tripod is rickety, although it has a spreader, and is adjustable for sitting height only. Views will be jittery and bounce around a lot.
• Altitude/azimuth mount like a cheap camera tripod (tilt/pan). Not easy to position objects and tends to be jerky when trying to move the view around.
• 5x24 finderscope is small and dim. It will be difficult to find objects by looking at a chart and "starhopping" to the right location.
• No idea about the quality of the eyepieces. Likely low quality but usable.

Upgrading

Sometimes it's worth upgrading certain parts of the telescope, usually the eyepieces, diagonal, finder, and/or tripod/mount. This may be a good strategy if you like the scope but find some parts are annoying. It can help you spread the cost over time and still be enjoying the scope from the get-go.

Here are some cost estimates for minor upgrades, i.e., parts that are a bit better but not overkill for a cheap telescope:

• Eyepiece: Different focal lengths allow you to achieve different powers. Don't go overboard with high power. Views get dimmer and blurrier beyond a certain point. (Recommended price range: around $35 per eyepiece. Often recommended: Svbony "redline" series)
  
  
• Finder: Red-dot finders do not magnify and are more intuitive. Just point the dot where you want to look (after making sure it is aligned to the view in the eyepiece). Make sure the finder bracket will fit the mounting bracket on your telescope! (Recommended price range: $15-30)
  
  
• Barlow lens: A barlow lens adds magnification. You put your eyepiece into the barlow, then insert the barlow in the telescope focuser. 2x, or at most 3x, will give you higher magnifications. Again, don't go crazy with high power. (Recommended price range: $15-25. I have the Svbony SV137 2x barlow and find it to be a great value for the price.)
  
  
• Tripod: Sometimes the optical tube assembly is pretty decent, but the mount and tripod are almost always too unstable on these cheap telescopes, which leads to frustration. Your best bet is to look in a thrift store for a working photo tripod. You can get them online, too, but it's harder to tell how sturdy it is. Just make sure it's an improvement over your current one and that your telescope or mount has a 1/4-20 thread so you can mount it on a standard photo tripod. (Recommended price range for new: $30-50, but only if it's sturdier than what came with the scope and it fits.)

If you upgrade all of the above parts, you'll end up spending at least $95. Consider that you might just want to buy a better telescope from the start, if that's possible.

Bottom line: Take the advice at the top of this post. If you just can't, then approach a cheap telescope with very low expectations and a large amount of patience, learn the sky, and get as much enjoyment out of it as you can. But don't say I didn't warn you!

SAFETY NOTE: Never point a telescope at the Sun, even when no one is looking into it, without a full aperture reputable solar filter designed for visual observation securely fastened over the aperture and the finderscope capped. Supervise children and don't leave the scope unattended when the Sun is up. For terrestrial viewing with small kids around, it's best to set it up in the shade. If your telescope comes with a little solar filter that screws onto an eyepiece, smash it with a hammer and throw it away, it is dangerous to use!

Astroboy cartoons by Astronomerica.

Equipment Tip: Stop your dovetail clamp from marring your dovetail

There's a joke somewhere in the title of this tip, I just know it. Not sure what it is, though. Anyway, here's one for those who have a dovetail clamp on their mount that has a rounded screw tip or tips that hold the scope to the dovetail. 

The problem is, the screw is steel and the dovetail is aluminum, so it leaves dimple marks in the dovetail. If this doesn't bother you, problem solved. But for others, it's a little irksome. It's kind of like focusers with thumbscrews that mark up your eyepiece barrel. It doesn't affect the function at all, but we'd rather keep the eyepiece clear of marks.

Some people just buy a new dovetail clamp that has a flat contact surface, such as the Svbony medium dovetail clamp shown at left. But something like that will cost you around $25-40, and Astronomerica is not about wasteful spending.

Instead, get a 1/2" x 1/16" thick flat bar of aluminum, cut it to length easily with a hacksaw, file and sand the edges smooth (be careful, they will be sharp!), and use double-sided tape to stick it to your dovetail. Problem solved and you didn't have to buy a new dovetail clamp. Now the clamp only mars the aluminum piece.

I found just such a piece of aluminum for a few bucks at my local home improvement store. It's three feet long, so enough to protect the dovetails of even a very large family of amateur astronomers!

Downsizing again: The Sky-Watcher 102mm Mak

I'm not one who tends to buy a lot of telescopes. I started in 1991 with a 4.5 inch Tasco 11TR reflector on a German equatorial mount and a tripod. I used that regularly for 13 years, so if you think you'll outgrow a small telescope quickly, think again.

Then I decided to go for a Dobsonian because the 4.5 inch's tripod had literally fallen apart from use. I built a Dobsonian mount for the tube and it worked great. But I wanted more aperture, so I went as big as I could comfortably go, physically and financially, and got a 10 inch GSO Dob. I used that regularly for 20 years. 

Nine months ago, as a result of declining health, I could no longer manage the 10 inch. I separated the base into two parts that could be easily reassembled with four knobs, and I devised a simple rope harness to go around my shoulders to help carry the tube, but that wasn't enough. Very reluctantly I realized it was time to start downsizing. 

I chose the Sky-Watcher Virtuoso GTi 150P 150mm (6 inch) f/5 tabletop scope with a go-to/tracking base. I figured the tracking might help soften the blow of the loss of 4 inches of aperture. It helped a little, and I've gotten used to it, but the views in the 10 inch are just so much better. You do what you have to do.

As my health continues to decline, I can sometimes no longer even set up the 6 inch comfortably, so I decided I would need to downsize again, this time to a true "grab and go" telescope. My requirements were:

• 15 lbs. max total weight
• Carryable out the door in one piece (it's okay to come back for the observing stool)
• Good on the Moon, bright planets, and double stars because I would be using this from my light polluted home, reserving the 6 inch for any dark sky forays
• No cool down required

I settled on a Sky-Watcher Skymax 102mm (4 inch) Maksutov-Cassegrain. This scope, made by Synta, is an F/12.7, with a 1300mm focal length. The optical tube assembly (OTA) weighs less than five pounds.

This means my Svbony SV135 6-element 7-21mm zoom is all I need, giving me 62-186x in a single eyepiece, with exit pupils (aperture in mm / magnification or eyepiece focal length in mm / telescope focal ratio) of 1.6 to 0.5, good for seeing detail in bright objects.

Now I have the smallest telescope I've ever had (not counting the little Svbony dedicated solar scope), but...and this is the key...I can use it! 

I mounted it on the Svbony SV225 alt-az mount that I used on my trip to Arizona in 2024. I had bought this as an alternative to the go-to/tracking mount that came with the 150P. I can mount the 102 on the Virtuoso mount if I want tracking. In fact, Sky-Watcher sells a Virtuoso package with a 127mm Mak.

I don't really like tripods, but decided a tripod was the way to go with this setup for several reasons:

• With a tripod, I can lift the telescope and bring it in and out of the house without bending over or crouching down. Those of you with bad backs, bad knees, or similar issues will relate. This makes a big difference.
• The tripod is adjustable to match the height of the very lightweight GCI PackSeat observing stool I've been using with the tabletop scope. I can easily pick up that stool with one hand under the seat. It weighs about a pound. My homemade adjustable observing chair weighs around 15 lbs.
• I can mount other small telescopes on it as long as they have a standard Vixen style dovetail to fit the SV225 dovetail clamp. That includes my 150P.

I chose the Sky-Watcher Star Adventurer tripod. It's pretty sturdy for being inexpensive and I like that it has a tray for my eyeglasses, since this is my "quick look" scope and I don't want to have to put my contact lenses in for very short sessions. To fold up the legs to get through the door and around objects more easily, I can easily take off the tray with a simple twist, then put it on again outside.

I took the Svbony SV182 6x30 right angle correct image (RACI) finderscope off my 4.5 inch and put it on the Mak in place of the red dot finder that came with it (image at left). I can't do the contortions necessary to use straight through finders anymore. I wasn't using the 4.5 inch much anyway. It uses .965 eyepieces, and although I have some decent ones from Orion, they just aren't as nice as my 1.25" eyepieces.

A 6x30 finderscope is not ideal for a light polluted sky, but good enough for quickly finding the Moon or bright planets and stars. There just aren't that many stars bright enough to be visible in a 30mm finder in bad light pollution.

The 102 is designed to be mounted on top of a mount, not side-mounted, as I would have to do with the SV225 mount. I wasn't sure it would work, but it does. I just rotate the diagonal off to the left side a little and I can use both the main eyepiece and the finder well at any altitude setting. I had to partially take apart the mount to free up the setting circles so I could adjust them as needed, but now I can find anything using them and the finderscope.

The whole setup weighs about 15 lbs. I can move it easily in and out of the house for quick looks at Jupiter, Saturn, the Moon, or maybe some double stars or brighter deep sky objects. That's all I can see from my light polluted neighborhood anyway. It is truly "grab and go."

Avoiding cool down thermals

My fourth requirement was that no cool down be required, because I wanted to be able to pop outside with it to take advantage of a break in the clouds or just a quick look. But it's a Mak, which needs cool down, right? How can that work?

A few years ago, Cassegrain users started wrapping their telescope tubes in an insulating material, usually Reflectix, which is basically bubble wrap with a reflective layer on both sides. This prevents the scope from cooling unevenly and developing internal heat plumes as a result, which ruin seeing.

The wrap will slow this cooling down and keep the remaining heat distributed more evenly thoroughout the interior of the tube as it slowly cools. This allows observing immediately without waiting for the scope to cool down. It won't fix bad seeing (rats!), but it will make sure the scope is not to blame.

I got a 16" x 5' roll of Reflectix and found that 16" is a great length for the wrap on this scope. This includes about five inches of overlap in front for an integrated dew and glare shield, with adhesive-backed black craft felt such as this lining the inside to avoid reflections. Attached to itself with adhesive-backed Velcro, the "jacket" can be removed easily. Some say it looks ugly, but I say it makes it look like I'm observing with the Hubble Space Telescope!

I've had it out a lot already, and although it appears to be very slightly out of collimation, it's not enough for me to start fiddling with it. On nights of decent seeing (about the best we get here), I can see the five brightest moons of Saturn and detail on the planet. Stars in high power are nice and sharp with crisp Airy disks. 

For example, Alpha Piscium (4.1 and 5.2 mag at 1.8" separation) splits cleanly in 7/10 seeing, although component B is right on the first diffraction ring. That's about the practical resolution limit of the scope. I'm happy. 

Above: Simulated view of Alpha Piscium in the 102mm scope at about 170x.

Note: I noticed in writing this that a lot of what I have bought lately is either branded Svbony (products manufactured in Mainland China) or Sky-Watcher (a distribution company for Synta products of Taiwan). While I'm not beholden to either of them (I buy my own stuff with my own money and don't have any brand loyalty), they seem to be among those offering some of the better quality inexpensive astronomy products lately, with the caveat that most inexpensive gear requires some tweaking or modifying to work to its fullest potential.

(Human evolution silhouettes by M. Garde after José-Manuel Benitos, Wikimedia, CC By-SA 3.0, modified with telescopes by Astronomerica)

New Binocular Space Walk - Cygnus Milky Way

I've added another Binocular Space Walk audio guide, this one looking at a variety of objects and the beautiful Milky Way star fields of the constellation Cygnus. I found some of the objects pretty challenging from a Bortle 4.5 or so location, but I could find most of them even from my Bortle 8-ish home with my 15x70s.

I used 15x70s to create the Space Walk, so I recommend something close to that, or at least 10x50s. 7x50s may be a good challenge, too. A darker sky always helps.

Because each Space Walk includes helper charts and you may need to refer to them in the field, I have converted all the Space Walk charts to white stars on black background to help keep your vision reasonably dark adapted. However, I'm hoping you can review the charts in advance and then just lie back and listen while you follow along in your binoculars. I also darkened the Space Walk Among the Stars logo background (see above) to go easier on your night vision.

In addition, I added a transcript of the entire Space Walk at the end, in case you find that useful.

Click here to go to the Binocular Space Walk - Cygnus Milky Way page.

Equipment Tip: Add a cell phone holder to your observing chair

More and more I find I like to observe with my binoculars, using my Bino Body Mount. The problem with binocular observing is it takes two hands. I like to use Sky Safari on my phone as my charting app, and I got tired of my phone sliding off of my ever-expanding belly onto the dewy grass in the dark. It's uncomfortable to constantly be reaching over for the phone on a fold up table, so I needed something else.

A cheap gooseneck cell phone holder came free with something else I bought, so I use that, but there are plenty of similar ones such as this one you can buy. I recommend a clip rather than a clamp just for ease of use in the dark, although a clamp might work better for certain chairs. I clip it onto the arm of my zero gravity chair and I have my chart right there at hand, easily using the app with one hand while the Bino Body Mount is perched on my shoulders.

I did find that, at least on my chair, I had to clip the holder behind the locking knob (some chairs have a lever) or the arm would slide past the knob when I leaned the chair back and knock the holder off the chair. Behind the knob there is no obstruction, so I can adjust the chair in any position and the holder will stay on.

Yeah, they wobble like crazy, but when you're using your phone you're holding it steady in your hand. The holder is just to keep it handy within easy reach so you know where it is.

Observing with bad vision

I've worn glasses for about forty years, and my vision has been getting progressively worse, as it usually will. It has stabilized in recent years, but now without my glasses, everything is a blur. I started out with hyperopia (farsightedness) which was joined later in life by astigmatism (irregular curvature of the cornea or lens) so, close or far, it's now all blurry. About 15 or 20 years ago I decided to try contact lenses, and now my typical observing session requires I put them in before going out. I don't wear them regularly, only while observing.

(Image by JSB Co. via Unsplash.)

Vision correction

There are nearly as many degrees and kinds of bad vision as there are observers. Most bad vision can be corrected at least to the point where observing is possible, and the telescope focuser takes care of any basic refractive errors in your vision. That's my case. While I have +6.5 and +7.0 corrective lenses that also help correct for astigmatism, the correction is not perfect. Nevertheless, for me progressive lenses correct enough for me to get through life. I don't recommend trying to use progressive lenses at the eyepiece.

Contacts don't do quite as well for me but they work better at the eyepiece. Although I have toric lenses, the astigmatism is still pretty strong, and I've gotten used to the idea that my views of astronomical objects are not going to be ideal—one of the reasons I don't spend a fortune on eyepieces! I have what's called monovision contacts. My left side focuses at about three feet to infinity and my right side focuses around reading distance. It takes some getting used to after wearing glasses, but within half an hour or even less I'm fully functional. 

(Star images rendered from AladinLite.)

Glasses on

Some people just observe with their glasses on. This requires you to have eyepieces with long eye relief, such that you can have your glasses in between your face and the eyepiece lens and still see the whole field of view, or at least most of it. 

Eye relief is the distance in millimeters from the closest your eye can get to the lens to the furthest point you can pull it back and still see the entire apparent field of view (you can see out to the circular edge of the eyepiece field). For eyepieces with very short eye relief, usually in the smaller focal lengths, this may be the same distance, and your eye has to be almost touching the lens. This can force you to strain and your eyelashes will deposit oil on the lens. 

When using glasses, this point may be closer to the eyepiece than you can actually place your eye, and in that case you will never be able to see the full field of view. Eye relief that is too long may require you to move your head around to catch the sweet spot and can be equally frustrating as the view blacks out when you move your head slightly out of position. Eye relief is also dependent upon the shape of your eye socket and your glasses.

I have yet to find an eyepiece with enough eye relief that works with my prescription, and I have progressive lenses anyway, so I don't wear my glasses when looking through the telescope. I can, however, use various binoculars with long eye relief.

Observing without glasses. Notice how close the eye can get to the lens, making longer eye relief unnecessary to be able to see the full apparent field of view of the eyepiece, which in this case is 82 degrees, nice and wide. Contact lenses require no additional eye relief.

Observing with glasses on. Compare to previous image, noting the much greater distance from the top surface of the eyepiece to the observer's eye. Long eye relief when wearing glasses is critical to being able to see most or all of the eyepiece field of view. This Astro-Tech UWA 10mm eyepiece has only 10mm of eye relief. Not long enough for eyeglass wearers, who need a minimum of about 17-20 mm.

(Images by Astronomerica.)

According to Don Pensack's 2025 Eyepiece Buyer's Guide, eyepieces currently available range in eye relief from a mere 1 to 3 mm for the Harry Siebert Optics Planesphere series to a whopping 46 mm for the Masuyama 60mm 2-inch eyepiece. The caveat on any eye relief figure is that the numbers often only count the measurement from the glass surface not including additional inset or eyecup. So if anything, the effective eye relief may be shorter than the advertised eye relief. This thread from Cloudy Nights discusses some of the better eyepieces for eyeglass wearers. Scroll to post 14 to bypass some rather less useful posts.

Glasses on and off

Another way to cope is to use your glasses when reading a chart or looking up at the sky and then taking them off each time you put your eye up to the eyepiece. This may work especially if you have a relatively mild prescription and maybe only use glasses for reading. For us hardcore Magoos (link provided for younger folks who have no idea), this is fraught with danger. 

(Superman image by DC Comics)

Let me relate my experience in that regard. Before I switched to contacts, I thought I would just swap my glasses on and off when observing. While annoying, this did work to some extent. Until one night, when I placed my glasses atop the roof of my car. They slid off with the heavy dew, and here I was with no way to search for them. Oh, I had a red light, but everything was blurry. I was afraid to move, but I took one step in the direction I thought would be away from the glasses and, you guessed it, heard and felt a sickening crunch underfoot. I managed to drive home that night using an older pair of glasses I had kept as a backup, but that was it for me, and I got contacts shortly thereafter. 

If it works for you, go for it, but be careful. Sometimes I still do use this technique (with my backup glasses!) when I'm just out for a quick look in the backyard or I'm taking a quick look in my solar scope. I recommend velcroing a soft case to your scope or table so you can slip the glasses in there, rather than trusting to a pocket that could contain who knows what that could scratch your lenses or just laying them on a table. I've tried keeping them on eyeglass retainers around my neck but the constant bumping and scraping as I leaned over the telescope was annoying and made me worry about scratches.

No glasses

You might be lucky enough to still be able to read or look at the sky without your glasses and still see reasonably well. In that case, just put your glasses away and use your uncorrected eyes. I did this until the stars just started looking like fuzzy blobs and I was straining to read charts with a magnifier in the dim red light of my flashlight. A man's got to know his limitations, and I had reached mine.

Contact lenses

For me, contacts are really the best solution. With my monovision lenses I can read reasonably well up close, I can drive, I can see the stars reasonably well when I look up, I can see pretty well with any eyepiece, and I've gotten used to using one eye for each. Another benefit is at public star parties, where I can focus an object in the telescope and know that people with reasonably good vision will get a decent look. But a tweak of the focuser will work for most people with uncorrected vision issues, other than astigmatism. I usually encourage people to take off their glasses to observe and just refocus, as long as they don't have bad astigmatism.

There are a few downsides, though. Especially if you don't wear them often, contacts can be itchy, scratchy, and blur out sometimes, especially as your eyes get tired. I sometimes struggle to get them to stay in at first, although other times they just slide right onto my eyeballs and stick. I've had them get stuck under my eyelid when I rubbed my tired eye, and I've even put two in at once, thinking the first one didn't stick and had dropped on the floor. 

Or maybe you just don't like touching your eyeball? Ewwww! (Image by Moist.acuvuehk via Wikimedia, public domain)

I always take a second pair of contacts with me in case I get a tear in one, it just feels crappy, or I somehow lose one out of my eye. Also bring eyedrops to rewet them if they get too annoying. The lens solution bottle won't help unless you want half the bottle all over your neck and down your shirt. Trust me on that one.

Televue DIOPTRX

Televue makes a device they call DIOPTRX that can help with mild astigatism. It looks like a filter with a fold-down eyecup attached that you can thread onto a variety of Televue eyepieces. I've read some accounts that all say it works well. If your astigmatism is relatively mild, but bad enough that correction would make it worth the cost, and you have Televue eyepieces, you might want to check it out.

Eyepiece cheat codes: Angular distances in the sky

In a previous post, we looked at cosmic distances and how they are measured. In this post, we'll look at angular distances as objects appear in the sky, and how to apply this to your observing. For this we use a system of degrees, minutes, and seconds of arc.

There are many resources on the internet that describe this system, so I'll only cover the basics. What we're interested in as visual observers is being able to translate numbers given to us in an app, article, or data source to what we see in the sky, especially in the telescope.

Because there are 360 degrees in a circle, the sky as we see it is always half of that, or 180 degrees. We are standing on the other half, as if we are standing in the middle of a globe. The zenith is 90 degrees overhead, so if the altitude of Jupiter is 45 degrees for our location at a given time, it will be halfway up the sky and good for observing if it's clear with steady air (seeing). At 20 degrees, things are a bit low and murky, subject to poor seeing and probably horizon light glow. 

Left: If we are using an altitude-azimuth mount like a Dobsonian, a degree in altitude is the same no matter how high we point our scope because all the circles of altitude are the same size. Think of these as lines of longitude.

But only if the scope is horizontal and pointed at the horizon is a degree of azimuth the same distance as a degree of altitude, because it's the only full diameter horizontal circle. As we point the scope higher up in the sky, the circles of azimuth, similar to lines of latitude, get smaller as we approach the zenith, so the apparent distance in the sky for the same number of degrees of azimuth is shorter. The higher we point the tube of the telescope, the smaller the arc it describes as it swings in the same number of degrees of azimuth.

As a result, we use a standard angular measurement of apparent distance essentially equal to degrees, minutes, and seconds of arc equivalent to any altitude circle (like a meridian of longitude, or our azimuth circle at the horizon only—essentially both great circles), regardless of what direction we are moving in, and we call them degrees, arcminutes ('), and arcseconds ("). 

Practical application

Left: At the scale of the unaided eye and binoculars, we usually use degrees. 

An easy rough estimate can be done with your outstretched hand.  

1 degree is about the width of your pinky 

5 degrees is about the width of your three middle fingers 

10 degrees is about the width of your fist 

20 degrees is about the width of your outstretched hand. 

This can vary considerably depending on the size of your hands and length of your fingers, but it's close enough for rough estimates. You can check how your own hand measures up by looking up the distances between bright stars that fit these measurements using an app such as Sky Safari Pro, Stellarium, or Cartes du Ciel.

When looking in binoculars or a telescope, your best bet is to know the field of view (FOV), or diameter of the portion of sky that you can see in your particular instrument, measured in degrees for binoculars and widefield eyepieces, and in arcminutes in higher power eyepieces. This will be fixed in non-zoom binoculars and will change depending on what eyepiece you use in the telescope. This is called the "true field of view" (TFOV) (or "actual field of view" in Stellarium), as opposed to the "apparent field of view" (AFOV), which is the angle of  "wideness" of your view based on the optics you are using. 

Left: The circle represents the true field of view (TFOV) in typical wide angle 10x50 binoculars. This diameter represents about 6.5 degrees of angular distance in the sky. (Chart adapted from Cartes du Ciel).

Left: The circle represents a true field of view (TFOV) of 35 arc minutes, or a little over half a degree in the sky, that is viewable in the combination of my 10-inch GSO Dobsonian with a particular 13mm focal length eyepiece. The apparent field of view (AFOV) for this particular eyepiece is 57 degrees. (View of globular cluster M13 adapted from Stellarium)

Left: A simplified diagram showing the apparent field of view (AFOV), which is determined by the lens configuration of the eyepiece and the eyepiece field stop or opening usually at or near the bottom. This does not change if you put the eyepiece in a different telescope. Manufacturers and vendors will state the AFOV in the specifications for the eyepiece.

Some eyepieces have a narrow AFOV because of their design, and it's like looking down a tube, whereas others have a wide, sometimes very wide, field of view, described as like looking through a "porthole" or on a "spacewalk," where you can't see the interior edge of the eyepiece, the field stop, at all without peering into the eyepiece almost sideways.

To recap, the AFOV is the apparent angle of wideness that you experience, but the TFOV is the actual angular measurement of distance in the sky that you are able to see, and that is what we're more concerned with here. Knowing this makes it easier to compare what you are seeing in your binoculars or telescope to your chart or unaided eye view.

Calculating TFOV in the telescope

TFOV must be calculated for each combination of telescope and eyepiece. You can use a variety of methods to calculate TFOV, with varying degrees of accuracy:

The easy calculated method

This method gives you a rough estimate because it is dependent upon the manufacturer specs being exactly correct, which is not always the case.

AFOV (provided by manufacturer or vendor) / MAGNIFICATION = TFOV (in degrees; multiply this by 60 for arc minutes)

Example: 60 / 30 (*see below for this calculation) = 2 degrees or 120 arc minutes

The published AFOV is often not completely accurate but usually fairly close.

*Magnification is calculated as follows:

FOCAL LENGTH OF TELESCOPE (in mm) / FOCAL LENGTH OF EYEPIECE (in mm)

Example: 750 / 25 = 30x

Both of the focal lengths above are provided by the manufacturers or vendors and are usually marked in millimeters somewhere on the telescope near the focuser and on the barrel of the eyepiece. 

The more precise calculated method

This method relies upon the manufacturer or vendor to provide the field stop diameter. Unfortunately, aside from Televue eyepieces, these are not easy to find (check out Don Pensack's 2025 Eyepiece Buyer's Guide, which lists many, or it can be calculated or measured with calipers). If you have it, here is the formula:

EYEPIECE FIELD STOP DIAMETER / TELESCOPE FOCAL LENGTH x 57.3 = TFOV (in degrees;  multiply this by 60 for arc minutes)

Example (for the Celestron Xcel-LX 24mm eyepiece pictured above and a 750mm focal length telescope):

25 (provided by manufacturer) / 750 = .033 x 57.3 = 1.89 degrees or 113 arc minutes

The drift method

This one must be done in the field with the telescope - eyepiece combination for which you wish to find the TFOV. Rather than go into the details, David Knisely provided an excellent description in this post from the Cloudy Nights forum. He also provides descriptions of some of the other methods.

The app or chart method

This one is also accomplished in the field and is another rough estimate. Again, With the telescope - eyepiece combination for which you wish to find the TFOV, locate any two easily identifiable stars that just fit on the edges of a full diameter of the eyepiece field of view, and measure the distance between those stars in the app. This is inherently inaccurate because you have to eyeball it, but it will give you a number close enough for casual observing.

Using TFOV in starhopping

Fortunately, apps like Sky Safari Pro, Stellarium, and Cartes du Ciel let you specify the custom TFOVs for various combinations of telescopes and eyepieces. Once you've set those up, it's easy to starhop around by moving the background behind the TFOV indicator in the app and seeing how far you need to move from one object to another in the telescope. 

For example, "I need to move two-and-a-half fields of view in my 750mm 6-inch telescope using the Celestron Xcel-LX 24mm eyepiece (1.89 degree TFOV as calculated above) to get to M13 from Zeta Herculis." (Chart adapted from Cartes du Ciel)

Once you're comfortable with this, your navigation skills will improve immensely.

Can I take pictures through my telescope with my phone?

The short answer: Yes, but prepare to be underwhelmed. My question to you then would be: Why? If the answer to that is you just want something to text or post to show what you were looking at, go for it, but you're really not going to impress anyone. I have people at public events always wanting to take a picture of the Moon through the scope, and I usually oblige them by taking the picture for them, but it slows the line down and won't impress anyone but total non-astronomy folks (maybe). Still, I get it. People want something besides a memory to take home. Frankly, I'm happy with the memories.

Confession: Against all logic, I sometimes try to take pictures through my telescopes with a cell phone at the eyepiece, knowing it is probably a waste of time. The only decent pictures I've ever gotten were of the Moon, which are still far below almost any image I can find on the internet and the detail I can see visually, and some pretty cool images of Spica and Arcturus with an apodizing mask on my 10-inch. Otherwise, the images suck. Granted, I am using a Pixel 6a, which isn't exactly cutting edge now, so if you have a newer phone, or the latest and greatest (for now) iPhone, then you might have better luck. 

Anyway, here is a gallery of images I took through my 10-inch and 6-inch Dobsonians with the Pixel 6a, as a baseline for what you might expect to get, depending on your phone's camera. I will say it is difficult to get the phone's camera lens lined up with the eyepiece while still being able to snap an image before the object drifts out of view. Although I have no experience with eyepiece phone adapters, the general consensus appears to be that they are fiddly and mostly a waste of time and money. If you do get one, the Celestron NexYZ is often recommended. The images I've seen from them, however, are no better than my handheld images. Phones seem to be much better at getting non-optically magnified images like the Milky Way, or a lunar eclipse over some scenery using their night vision mode, or whatever they call it. Bright comets can be kind of nice.

Left: The Moon rising over the hills. This was so cool that I wanted to take a picture to put in my log for that unique sight, just to remember it better. To me, this is the best kind of use case for taking an image through the eyepiece. 10-inch dob.

Left: The gibbous Moon, zoomed in and cropped to show the level of detail, which is nowhere near what I could see visually. 6-inch tabletop dob.

Left: Spica with the apodizing mask. Pretty psychedelic, but rather pointless. Well, there actually are a lot of points. 10-inch dob. Apodizing masks are used on larger telescopes to negate some of the effects of poor seeing for splitting double stars and seeing more planetary detail. I didn't notice any improvement on my scope, as expected, although the kaleidoscope effect is interesting.

Left: Arcturus with the apodizing mask. Far out, man! 10-inch dob.

Left: Comet C/2023 A3 (Tsuchinshan-ATLAS) through a 6x30 finder. The shot through the eyepiece was too awful even to post here as a bad example.

Left: The same comet using the phone's "night vision" capability, without magnification. Especially with distinctive scenery, this can bring back the memory of the night much better than an eyepiece shot can.

So there you have it. Casual photos? Maybe. Anything more, get a SeeStar or go down the imaging rabbit hole and be prepared to spend some money and a lot of time learning processing. If you want to do planets and the Moon, a basic planetary camera might work for you, but you have to seriously ask yourself why you are wanting to do imaging. It's not for everyone but some people just love it, and it's more forgiving of light pollution.

Astro imaging is indeed a different hobby entirely from visual observing. I remember photographing Comet Hyakutake on a homemade barn door mount with a poorly functioning stepper motor and a film SLR camera. I don't even know where the picture is now, but it was so much less inspiring than the actual view of seeing the comet from that dark sky, stretching overhead like a flashlight beam. 

After that, I decided not to waste good observing opportunities trying to capture something mediocre to take home with me, unless I spend less than a couple minutes doing so out of the apparently primal urge for a tangible keepsake of everything to post on social media.

For me, give me visual every time. I'll find the pretty pictures on the internet—and I do, for placing in my log or notes to go along with my visual descriptions, or just to see what an object can look like to an imaging chip with a lot of computer manipulation.