Easy to make light and wind screen

Most of us are having to contend with worsening light pollution at our homes or other observing sites, and not just the overall sky glow, but nearby lights. Since LEDs became cheap and widely available, people just have to have more and more lighting. Many still think it deters crime (it doesn't), so they add lights, always brighter and rarely properly shielded. I can count at least nine lights, sometimes more, that are consistently in my eyes in my front yard, where I have to observe (trees in back). I also have cars stopped at a nearby traffic light whose headlights point directly at me.

But you can fight back, as I noted in my article on building a "Redneck Observatory," with stuff you have around your house or garage, if you have one. One of the items I used was an old PVC pipe target stand I used to use for .22 target practice out at an unsupervised public range. I added a wood frame and a blanket. I'll use that light screen more often than setting frames up against my garbage cans because I observe more now on a grassy strip on my front lawn and it's sometimes messy to roll the cans across the grass. I decided to make a second one to block out the lights across the street and the headlights and lights 90 degrees around from there.

Some people say they do fine just using a hood over their head, and I do use a hoodie to reduce light trespass into my eye and eyepiece, but I find it's just not very satisfying to see all those lights glaring at me as soon as I raise the hood. I also don't like being lit up like daylight and unaware of what's around me. If that works for you, though, no need to bother with a screen. But I think there is a primodial desire for shelter from outside intrusions that makes the screens, or an observatory, much more satisfying. It's kind of like a snow fort for amateur astronomers!

Light screen

The light screen consists of a base of 1-1/2" PVC pipe in two upside down "T" configurations that holds a taller frame of 1x2 or 2x2 furring strips (or fancier wood if the spirit and wallet moves you; that's a piece of old baseboard molding in the picture). Over that you drape a cheap moving blanket and use plastic spring clamps to hold it to the frame. The height depends on where the lights are in relation to your eyepiece height and how much room you want to maneuver. This one stands 72" tall to block out lights from right across the street. Do some measurements at night to be sure you end up with what you need.

Why the moving blanket? You could use a tarp, but I'm in a residential neighborhood and poly tarps tend to be noisy with any kind of wind. Moving blankets are cheap, they block out all the light, they are relatively heavyweight so they don't flap aound much, and when they do, they are quiet. You can also use them as blankets when observing from a recliner or to pack around your telescope.

Schedule 40 PVC pipe is generally sold in the United States in 10' lengths. My car can only fit an 8' length, so I used the self-cutting molding station in the store to cut off two feet of it. You could also bring a hacksaw and cut it in the parking lot, but then you'd be spreading plastic sawdust all over. Pine furring strips or their equivalent are usually 8', so no problem there. 

You'll use four PVC "T" fittings to make the joints. These are friction fit together so you can take it apart as needed.

The process, in a nutshell, is to cut the PVC pipe, assemble it, cut the furring strips, and assemble the frame. The frame just sits in the pipe openings.

Wind screen

The light screen can do double duty as a wind screen if you substitute 2x2s for the 1x2s and stake the feet into the ground or weight them down with something, which would be necessary if you set up on pavement. The  blanket shown is a small 72x40" (actual 70x39").

Depending on whether you sit or stand, and how tall your setup is, you may also want to lower the height, as shown at left.

You can adjust the width of the PVC feet by cutting different lengths for the cross piece. 

Note that  you'll want the side facing us in the image at left to be on the windward side so the blanket is blown against the frame. You can use additional spring clips to hold the lower part of the blanket to the frame if necessary.

Be realistic about how strong a wind it will be able to handle, and build accordingly.

Staking down the four feet will help keep the screen in place with some wind. I wouldn't set it up in wind over about 15 mph so you don't risk it plowing over your telescope if it lets go. You be the judge. (Put the stakes all the way in. I didn't bother for this picture but it'll keep it anchored better.)

If you're on pavement, use weights instead, but they have to be more than about 10 lbs. per side to hold it in any kind of wind. Leaving space below the blanket at the bottom will help it from becoming a sail. You want the protection at the level of the scope tube.

Parts list

• One 10" long 1-1/2" (inner diameter, it's marked on the pipe) Schedule 40 PVC pipe.
• Four PVC 1-1/2" Ts (S-S-S) for pressure applications. Make sure all three openings are 1-1/2" and smooth inside, not threaded. Don't get cleanout Ts, the pipe won't go in straight in the middle connection. The cleanout Ts to avoid have a slight curve to the outer contour.
• Three 8" long 1x2" furring strips (or 2x2" if  you want it to be sturdier to stand up to higher wind, at the expense of a bit heavier frame). Seems that the big box hardware store selection gets worse every year. Cull through the boards to find the least warped, twisted, split, and otherwise pathetic specimens you can find. Find a good lumber yard instead if you can. You can use treated or untreated wood. Treated will be more expensive and heavier. Unless you are leaving the screen out in the elements (not recommended) you really don't need treated.
• Eight wood screws. Make sure they are long enough to join the two pieces of wood together firmly without protruding out the back side. 1-1/4" should work for 1x2s (which are really 3/4x3/4) and 1x2s to 2x2s (which are anywhere from 1-1/4" to 1-1/2", pressure-treated being somewhat smaller), as long as you put them through the 1x2 first.
• Alternative to wood screws: Four 1/4-20 knobs and four 1/4-20 T-nuts (less than 3/4" long). This allows you to disassemble the frame for transportation.
• Cheap moving blanket or other blanket. A smaller size, like this 70x39" blanket (actual measurement) won't cover the entire frame from top to ground, but you probably don't need to, and it's lighter and less bulky than a larger blanket. Really, any blanket or tarp will work, depending on what you want. You can size the frame to fit whatever blanket works for you.
• Four steel nail-type stakes (such as these) or weights (bags of grass seed or soil work well on pavement).
• Four to six plastic spring clamps for holding the blanket to the frame.
  
  

Tools

• Wood saw of some kind
• Hacksaw or wood saw to cut the PVC pipe (unless you have a suitable pipecutter for 1-1/2" pipe).
• Electric drill, with a countersink bit that matches your wood screw size (size 6 or 8 should work) and an 11/16" bit for drilling the PVC pipe to accept typical steel nail peg stakes
• Phillips screwdriver
• Sandpaper
• Paint if you want to paint the wood

Build it

You can adjust any measurement as you see fit, especially if you plan on transporting it in your car, but these are my suggested dimensions.

Cut the following pieces of PVC pipe:

• (4 pieces) 16" each (these are the feet)
• (2 pieces) 9" each (these are the lower uprights)
• (2 pieces) 4" each (these are the upper uprights)
• (1 piece) 24 to 30" as you desire (this is the crosspiece and will determine the width of the frame uprights). The frame in the images at the beginning of the article has a 24" PVC crosspiece, for reference.

If you want the widest possible spread between uprights and you have to cut the pipe to fit it in your car on the way home from the store, cut a 30" piece off the 10' length in the store.  You can always shorten it, but that will allow  you to cut all the other pieces to the dimensions above for a total of 120". After each cut, use a small piece of sandpaper to clean the cut edges. Sweep or vacuum up all the plastic dust and bits. Wear a mask so you don't get plastic particles in your lungs.

Brace each foot piece in a vise, clamps, or wood, and carefully drill a hole just big enough for the stakes you are using through both walls of each end, about 3 inches from the ends. The stakes will go through these holes into the ground, if you use them.

Assemble the pipe frame as shown in the image at right.

Now, decide how high you need the wood uprights to be. You will be putting the wood uprights into the open pipe holes. I cut two 8" pieces of 1x2 and slip them into the pipes first. This allows the uprights to be shorter and still give me the height I want.

Left: An 8" piece of 1x2 dropped into the upright pipe from above will compensate for making the wood upright 8" shorter and easier to transport.

Cut the wood uprights from 1x2s (or 2x2s for a heavier frame). Cut a wood crosspiece to span across the two uprights as a brace. Cut a crosspiece for the top of the wood frame, over which you will drape or attach the blanket. This will probably be wider than the pipe base because you want good coverage with the narrowest base that will be stable. I used leftover wide baseboard molding for my top crosspieces, but you can use a piece of 1x2. 

If you use 2x2s for the uprights you will probably have to shave the four corner edges down some on the lower 8" of the upright so they'll fit snugly into the pipes. The 1x2s should fit without modification.

Left: I had to shave the ends of the 2x2 uprights down with an orbital sander so they would fit into the pipes. 

If you're making this more wind resistant, use 2x2s instead of the 1x2s for the uprights, but you can probably stick with 1x2s for the crosspieces. The lighter the frame is, the easier it is to set up, and the more likely you are to use it. The heavier it is, the more wind resistant. It's a tradeoff.

You can fasten the wood frame together with wood screws, two at each joint. However, to make it portable so you can take it to a darker site that maybe has an annoying light or two or is often windy, you can instead drill holes where the pieces connect, then insert knobs through the two pieces and fasten them with nuts or wingnuts. 1/4-20 threads should be fine.

Left: Using knobs instead of wood screws to attached the frame crosspiece. I have the pieces labeled with painter's tape so I can reassemble it easily. The hole in the side of the upright was a mistake. It's easy for a bumbling woodworker like me to not to get the hole straight, so I had to redo it on the other face of the 2x2. 

Right: Close up of the knob attachment point. Use a flat washer on both sides, and a nut or wingnut on the back side. These are all 1/4-20 size threads.

Here is the finished frame for the transportable wind screen. You can drill additional sets of holes in the uprights for a variety of heights.

To pack the screen in a car, you detach the center cross pipe in the base and the crosspiece or pieces of the wood frame. Consider the length of the uprights in this case so they fit comfortably in your car (maybe with ends in the passenger seat footwell, extending through the gap between front seats, and across the tops of the back seats). This is why I like the 8" pieces of wood inserted into the pipes first. That allows you to use shorter uprights.

Once you have everything cut, sand the wood so you don't get splinters and paint it if desired, mostly to smooth the surface further and protect it from dew and other moisture. Bare wood and the white PVC pipe will show up well at night, but if you use it as a wind screen in a really dark sky, you might want to sew or tape some white fabric or tape to parts of the blanket so no one walks into it in the dark. If you have a site that dark, I envy you!

Why not make the whole screen frame with PVC pipe? I used to have one I designed that used 3/4" pipe, shown at left, and it worked well for a while, but after some years the pipes were either too loose or too tight and setting it up and taking it down became a chore. My wife sewed the fabric with pockets to slip the pipes into and velcro tabs. The wind would often pop it apart and eventually broke a couple of pieces. So I recommend a hybrid PVC and wood frame. It's also lighter and cheaper. PVC pipe has gone up a lot in price.

The quest for perfection

As with any pursuit, amateur astronomers wonder, "What would perfection look like?" With amateur astronomy most people realize nothing is perfect, yet there is an underlying current of constant comparison of equipment to see what is the "best." I'm sure if you are an experienced observer you can tell the difference, however slight, between a high end eyepiece, for example, and a value eyepiece, maybe somewhere in the mid-range. But how much does it really matter? If a little coma, for example, bothers you that much, maybe you're looking in the eyepiece for the wrong things.

Connoisseurs

Like wine, some people have cultivated a finer sense of the subtle differences between high end astronomy equipment and the rest of it, which the majority owns and uses. The most prolific posters online often tend to be those who fall into the former category. The result ends up being a constant chase by the rest of the group to try to keep up with "the best," even if it sometimes really doesn't matter, or is even detrimental, to the enjoyment of the hobby.

Above: Diamond by Nikilok, CC by 2.0.
Right: Wine taster by William Lawrence, CC by SA 2.0, cropped.

I remember when I attended my first astronomer gatherings and star parties how I was a bit put off by the emphasis on discussing equipment versus what we were looking at in the sky. I gravitated towards those individuals who were quietly observing while others spent most of their time discussing this or that mount or eyepiece. Now I understand. I believe this is because a lot of technical and engineering people are attracted to a scientific hobby like amateur astronomy. It's also because people just tend to compare themselves to others. We're in competition even when we don't need to be. I guess it's in our DNA.

It's a different facet of the hobby that most of us do at some time partake, but often the main purpose gets lost in all the focus on equipment and the manipulation thereof. Truthfully, it's a lot easier to blog or v-log about equipment because there's an endless supply of material and it's easy to comment about it. I'm guilty of that myself. After all, that's what we use to do our observing.

Tell me what you want

It goes off the rails somewhat when someone is convinced they have to have something because others have it and they gush about how good it is. It's fear of missing out (FOMO), of course. I read about how great the new line of Houdini eyepieces are, and I try to find reasons why I should buy one. A new telescope is praised as such a great value that everyone should have one. You can't stop it, but you can resist it.

What do you really want out of amateur astronomy? For some, there's certainly a component about getting the best equipment, the largest scope in town, etc. I think the majority of us just want to observe the night sky because we find it fascinating and mindblowing. What do you need for that?

Above: Montparnasse trainwreck, 1895, Public Domain.

Now tell me what you need

Actually, very little. The most important thing is a clear, unobstructed sky, hopefully without a ridiculous amount of light pollution. That's becoming more difficult to find. Another thing is time. You have kids, you start school, you take a new job, and all of a sudden you have no more time for astronomy. Health. An understanding family. A safe place to observe. You can't buy your way past those hurdles.

You can, however, buy your way into dissatisfaction or disillusionment with the hobby. It's easy. You just bought this telescope, but now you're thinking a bigger one would show you more. Maybe you buy the bigger one and you're happy as a clam. 

But maybe later in the back of your mind you're thinking how much easier it was to observe with that little telescope, and you're sorry you sold it. So you buy another one to replace it. And another one because you don't have one of that type. And...

You're encouraged because you see all the online people with their ever-growing lists of equipment under every post they make. Your eyepieces are breeding in their box, which now no longer holds them all. 

Eventually nothing is enough, you give up, and you admit you're addicted to buying things. You've become a consumer more than an observer. But you comfort yourself with the thought that now you are an "expert," having tried most everything that's out there! You decide to start your own social media channel and monetize it all to buy more stuff.

By CusterDome, Public Domain

There's nothing wrong with wanting good equipment. It makes observing more enjoyable. It's when the reason for consuming is more about FOMO than it is about making the experience better for you that the problems arise. What can you do?

Dance with the one that brought you

Get out and observe. Try going out with just a chair and a pair of binoculars. Or even just a chair. Do you still enjoy that? Try taking your old small scope out and seeing what you can observe with it. Do you still know the constellations, or have they missed you? Get back in touch with what got you started in the first place. Do some outreach, if you're so inclined. 

When you do that, you'll get a lot more enjoyment out of that big Dob you bought because you're actually using it for what it was intended: to give you a great look at the sky. And maybe you can share that with others.

Dancing under the Moon by Yusuf Gönenli, CC by 2.0.

Learning to use your first telescope

The internet is bursting at the seams with telescope reviews, which is why I try not to add to that. However, it is harder to find some comprehensive advice regarding what to do when you get that package in the mail, put it together, wait two weeks for the sky to clear (the "curse" of buying a new telescope), and are ready to start observing.

Learning the telescope

Of course you will be eager to start observing, but before you put your new telescope outside under the stars, make sure you read the instructions, whether included with the telescope or found online. Put it together properly and understand what each part does. If you don't, you might end up frustrated that you can't find anything or wondering why everything just looks like a blob.

DO NOT start tweaking collimation, if your telescope allows it, until you know what you are doing. I can't count how many times beginners go online saying they can't see things well in their telescope and because they've heard about collimation they immediately think that's the problem and hopelessly screw up the telescope's alignment. Most telescopes are reasonably well collimated out of the factory and won't be out of alignment so bad that it will even be noticeable to a beginner. They also tend to hold collimation extremely well, so while it's something you will need to learn to do eventually, it's not something I recommend a beginner start messing with. That's a rabbit hole you don't need to go down when you are starting out.

Tripod and/or mount

Steady views are good. Most inexpensive telescopes that beginners buy, except for Dobsonians, tend to be undermounted, giving shaky and frustrating views. That's why advanced amateurs, especially imagers, spend gobs of money on big heavy mounts and tripods. The tripod is the three legged stand that holds the mount, which holds the telescope optical tube assembly (OTA). The mount provides movement in two axes, either in altitude and azimuth or right ascension and declination. Either system allows you to point the telescope tube anywhere in the sky.

Hopefully your telescope's mount is reasonably sturdy. If not, it's not the end of the world. You simply wait a few seconds after touching it (moving the tube to an object, focusing, etc.) for the vibrations to die down. If it's windy and you have a shaky mount, try to get behind a car or the side of a building to minimize the effect. Or just wait until it's not so windy. 

Left: The Explore Scientific FirstLight 102mm refractor, with main parts labeled.

A far greater impediment to observing is if the mount is difficult to move smoothly. This is where Dobsonians shine. You simply push the tube where you want it to go. I recommend putting one hand up on the lip of the aperture and the other near the back of the tube. This gives you more precise control and leverage.

Right: A Dobsonian reflector, such as the Apertura AD8, is a simple design that maximizes aperture and stability per dollar spent.

For tripod-mounted scopes, a lower quality mount will really become an issue when you try to move the scope to center an object and track it manually. Some just aren't designed well or are cheaply manufactured, making these operations incredibly frustrating. This is why I like slow motion controls. These are semi-flexible cables with a knob on the end that you turn to allow you to move the scope in finer increments than by just pushing the tube around. 

Main optics

Telescopes work by collecting as much light as possible using a larger aperture than the pupil of your eye. Refractors do this using a set of lenses. Reflectors use a large parabolic-shaped mirror. Catadioptrics (Schmidt-Cassegrains, Maksutov-Cassegrains, for example) use a combination of lenses and mirrors to create a light path that folds back upon itself. The larger the aperture, the more light the telescope collects. 

By concentrating and focusing this larger amount of collected light into a spot roughly the size of your pupil, a telescope allows you to see dimmer objects and more detail in even bright objects like the Moon or Jupiter. You look through an eyepiece inserted into the telescope where the light comes to focus. The eyepiece contains multiple lenses to magnify the image. In short, the telescope collects and concentrates the light, the eyepiece magnifies it.

Redirecting the light path for comfortable viewing

If you have a refractor or catadioptric ("cat") telescope (like a Schmidt-Cassegrain or a Maksutov-Cassegrain), you will first insert a diagonal, usually containing a mirror tilted at 90 degrees, and insert the eyepiece into that. The diagonal ensures that you have a comfortable position for viewing high up in the sky. If your scope comes with a 90 and and 45 degree diagonal, use the 90 for astronomy and the 45 for terrestrial viewing.

Because the diagonal is usually held in by a couple of thumb screws, you can rotate it to position it more comfortably for viewing. This will change the orientation of the view in the eyepiece, like tilting your head, but you learn to know which way is which after a while. There's no law saying you have to have it set vertically and look straight down into the eyepiece.

A reflector has a diagonal of sorts, too, but it's built into the upper part of the telescope tube. It's called the secondary mirror, and like the mirror diagonal, it's a flat mirror that redirects the focused light path 90 degrees so you can view in a comfortable position, either on the left or right side of the front of the tube.

Generally, a refractor or catadioptric will mirror-reverse the view. A Newtonian reflector will simply rotate it 180 degrees. Understanding directions in your eyepiece will help you make sense out of what you are seeing compared to a chart or image.

Changing magnification

Eyepieces, what some people call "lenses" (or "oculars" for the more esoteric term), are how you change magnification, or power. Except for specific eyepieces with a rotating barrel that actually are zoom lenses, each eyepiece will give you a fixed power depending on its focal length and that of the telescope. You change magnification by changing eyepieces. 

The standard eyepiece barrel diameter is 1.25". However, many telescopes have 2" focusers, allowing for larger eyepieces with 2" barrel diameters. Most of these come with a 1.25" adapter so you can use both, or you can buy one.

Magnification (or power) = telescope focal length / eyepiece focal length. So a 750mm focal length telescope with a commonly included 25mm eyepiece will give you 30 power (30x)—magnifying 30 times what your unaided eye sees. Place the eyepiece in the focuser or diagonal, making sure it's seated all the way in, and use the thumbscrews to clamp it tightly so it won't fall out. It doesn't matter how it's rotated. 

It's best to remove an eyepiece before you move the telescope to prevent it from falling out if the thumbscrews aren't tight. Get in the habit of frequently checking the tightness of all thumbscrews for eyepieces, diagonals, and finderscopes. After 30+ years with no incident, I recently had an 8x50 finderscope fall from the upright tube of my 10-inch Dobsonian onto the cement floor of the garage. Surprisingly, no damage, but it does happen. (Most finderscopes have a tab on one side of the base of the bracket, however the ones I've seen are always toward the back, where they don't help to prevent the finderscope from sliding out on a reflector, as mine did. Makes more sense to me to have the tab in the front, but it's a refractor thing.)

Taking a seat

Although I stood the first dozen or so years when observing with a telescope, I highly recommend finding a good seat and sitting while you observe. You will be more comfortable, you will get a steadier view, and you won't tire so quickly.

The longer the tube of your telescope, the more variation there will be in the height of the eyepiece as you view objects around the sky. You can get by with a stool or chair for a shorter tube, and for telescopes that use a diagonal you can rotate it to make up some of the difference, but longer tubes such as larger Dobsonians will require an adjustable chair. 

You can decide later if you want to spend the money on a commercially available observing chair, such as the Starbound, Vestil, Catsperch, or build your own. Some people also buy and use drum thrones with varying degrees of success. 

I built my own Denver Observing Chair, a popular option, for my 10-inch Dobsonian but I often use a collapsible stool for my 6-inch tabletop Dobsonian and 102mm Maksutov-Cassegrain.

Right: My homemade Denver Observing Chair that has served me well for over 20 years.

Finding objects

Your telescope should have some sort of finderscope, either what amounts to a tiny refractor mounted on the main scope that magnifies the view or a red dot or red circle finder that projects a dot or circle on a tilted glass or plastic surface and makes it look like the dot is projected onto the sky with no magnification. In either case, it is absolutely critical that you align the finder with the telescope. The finder has a low power (in the case of a red dot, 1x) and wide field so it's easier to find objects than looking directly in the main telescope.

Before searching for anything, focus your finderscope if you have one. This is usually done by loosening a ring near the objective lens and screwing the lens housing in or out, then retightening the ring. Also put your lowest power/widest field eyepiece in the telescope's main focuser and focus on any random stars. Focusing tips are covered later in this article.

Above: Simulated view of the field for the Owl Nebula, M97, in an 8x50 straight-through finderscope on a Dobsonian telescope in a light polluted sky. The view will be rotated 180 degrees from the naked eye view, which matches the view in the eyepiece.

Left: Screenshot from Sky Safari Pro showing the 8x50 field of view, rotated to roughly match the finderscope view above. You can customize the field of view to match your own equipment, which helps to match what the chart is showing to what you are seeing in the finderscope and eyepiece. The small circle around the planetary nebula symbol is the eyepiece filed of view. You can see how much more difficult it is to find something in the eyepiece without first centering it in the finderscope.

Sometimes the labels and other clutter can obscure some of the stars, so be careful. Zoom the screen in and out to see what might be hidden.

Below: Simulated view of the same field for the Owl Nebula, M97, in a red dot finder, also in a light polluted sky. The brightest star in both views is Merak, or Beta Ursae Majoris, magnitude 2.3. The view is the same as your naked eye view, with fewer stars visible than in a magnifying finderscope. 

In neither finder will M97 be visible, so you need to aim based on the location in relation to the star patterns from a star chart and what you can see in the sky. Without the magnification of a finderscope, the red dot loses a lot of precision, so it's critical that you use the lowest power/widest field eyepiece that you have once you are pointed in the right general direction. 

Sometimes, especially if the object is very dim and you may not recognize it right away, it's better to start by pointing the red dot at the nearest bright star, Merak in this case, then switching to the eyepiece and starhopping your way to the object by comparing the star patterns in your eyepiece to those on the chart. This sounds simple, but it's often difficult to be sure exactly where you are pointing, and it's easy to get lost along the way. It still happens to me all the time. It takes practice and, even with experience, patience.

It's easiest to do the finder rough alignment in the daytime. Find a distant fixed object, like the top of a telephone pole. Put your lowest power eyepiece in (the one with the highest mm number) and center the object in the telescope. Then, without moving where the scope is pointing, look in the finder and use the little thumbscrews on the side of it to put the same object in the center or crosshairs. Do this a couple of times, even using a higher power eyepiece for more accuracy, until you are sure they match.

Each time you go out observing, check the finder alignment on a bright object like the Moon, Jupiter, or a bright star, something you'll be certain you are pointed at. First in the main telescope, then in the finder and adjust the finder as needed.  Then when you use the finder to locate an object, it will show up in the main telescope eyepiece. Depending on how accurate the alignment is and how well you positioned the object in the finder, you may need to look around in the main telescope eyepiece a little to find it. Use low power when searching. You can always switch to higher power later.

Some telescopes have a go-to computerized mount, which requires battery power and must be leveled and aligned prior to observing. These aren't as foolproof and simple as they sound, and they often don't work right. They will have tracking, though, which keeps an object more or less centered in the eyepiece. These usually come with a hand controller or are controlled via an app. 

Another computerized navigation system is a variation of a push-to configuration, where an app guides you with arrows to manually push the telescope to the location of an object. Again, this must be aligned or calibrated. The Celestron StarSense app is a good example. It takes pictures of the sky and matches them to an internal database. A freeware push-to app is AstroHopper, which requires frequent recalibration but otherwise is a good alternative to pure starhopping or expensive commercial push-to systems.

Focusing

The basic rule for focusing is to slowly turn the focusing knob, or the focuser itself in the case of the helical focuser found on many tabletop telescopes, until the object gets as small and sharp as it can be. If it does so, but then gets larger and fuzzier as you keep turning the knob, then you know where the point of focus was and that you have passed it. Just go back slowly and find it. You may have to tweak the focus in very small increments back and forth until you get the best focus possible for the seeing conditions. Usually you will have to let the scope vibrations settle after each tweak. This is normal unless you have an exceptionally sturdy mount. If your telescope has a dual-speed focuser, you can use the smaller knob for fine focus adjustment, much the same for focusing as slow motion controls on a mount are for centering and tracking objects with more precision.

Stars should look like points in low power. However, in high power, you may begin to see the "Airy disk," which is the tiny disk of light that the star is spread out into due to the optics in your telescope, its size dependent upon the aperture of your telescope. Dimmer stars will still look like points in high power, but the brighter ones should look like tiny disks surrounded by a thin circle or two, called diffraction rings. This is what you want in a well focused and collimated telescope.

Above: If you look closely, the Airy disks and diffraction rings of the two brightest stars are visible in this simulated high power telescope view. Too often Airy disk images are blown way up in scale so you don't know what you should be seeing.

What if things don't look sharp?

Assuming thin clouds aren't obstructing your view and your focus is the best it can be, then by far and away the likeliest culprit is atmospheric turbulence, or what astronomers call "poor seeing." This is what causes bright stars to "twinkle." The seeing changes based on your location, night to night, and even minute to minute. Some places in the world frequently have very good to excellent seeing, or steadiness. Examples in the United States include much of the western U.S., as well as Florida. The northern, eastern, and midwestern U.S. are often under the jet stream, meaning nights of very good or excellent seeing are rare. 

Below: Jupiter and its Galilean moons in good seeing (L) and bad seeing (R). (Jupiter images by TheWitscher via Flickr, CC By 2.0, modified to simulate seeing conditions in eyepiece.)

You'll get used to knowing what's good and bad seeing through experience. When Jupiter, Saturn, or the Moon look like they are sitting in the bottom of a clear flowing stream, you have very poor seeing. Stars will look like undulating blobs. The view will shimmer and boil as waves of thermals pass in the atmosphere. You may not be able to make out a bright star's sharp Airy disk or diffraction ring in high power. Every object will just be a moving mess. 

Don't give up just because the seeing isn't great. It's not uncommon to have very brief moments when the air steadies out despite bad seeing. It might only be a split second every few seconds, but you can see a lot in those short bursts of good seeing.

Extended objects like galaxies and nebulae are less obviously affected by seeing, so if you have a very clear night but poor seeing (a common combination), go for those types of objects. 

At the other extreme, excellent seeing means you see stars as steady points or Airy disks, bright planets seem to be much larger than you remember and show a lot more detail to an experienced eye. You can see tiny craterlets on the Moon, the shadows are sharply defined with no double-edges, and you see little or no shimmering.

Seeing is also affected by thermal currents within the tubes of some telescopes, mainly reflectors and catadioptrics. Refractors not so much, if at all. This is why you will see some Dobsonian owners with fans installed to blow air through the tube, or "cat" owners who wrap their tubes in Reflectix or other insulating material. It's all to make sure the scope design is not contributing to poor seeing. In the former case, they are trying to cool the mirror down to ambient temperature or remove thermal layers inside the tube. In the latter, they are trying to slow down and distribute the cooling so there are no big temperature differentials or plumes inside the tube to cause poor seeing. 

In most cases. setting a reflector or "cat" outside for an hour or so before observing will help, but it's not always possible, given your situation. Just be aware that it may take time for the scope to "settle."

What about collimation?

Rarely is it the case where collimation, the alignment of the telescope's main optics, is so bad that it spoils the view as much as bad seeing. There are tools you can use to check and adjust collimation, but you're better off leaving those alone until you can recognize what is bad seeing versus bad collimation. With bad collimation, you'll often see one side of an object always fuzzier than the other. Stars may look asymmetric, like little bumblebees. On nights of excellent seeing you will still have a "soft" view that you can't quite focus. But don't assume it's bad collimation until you've ruled out bad seeing, poorly made optics, or even the nature of the type of optics. 

For example, a "fast" reflector with a small focal ratio, for example f/5, will normally show "coma" at the outer edges of the field, an abberation that makes stars near the edge look like comets. Same with achromat refractors and "chromatic abberation," where you may see blue or yellow color fringing along the edges of bright objects at higher powers, an indication that the focus is going to be a bit soft. These abberations are inherent in the design. Because most everything in life is a compromise.

Learning the sky

Using a telescope is like driving a car. You can learn to drive it, but if you don't know where to go or how to get there it won't do you much good. Even if you have a go-to telescope, the equivalent of an autonomous-driving car, knowing what you want to see, when is a good time to see it, and knowing what to look for are important for enjoying your observing.

Many experienced amateurs recommend buying a book to start learning. That's fine if you are a book-learner, but with so much information available on the internet, with options to ask questions and interact with other people, I wonder if starter books aren't a little obsolete. With younger people especially, I don't think learning from a book is a very appealing process. I think it just depends on the individual.

I did start with some books, but most of my actual learning came from simply getting out and observing, and then reading about the objects I saw. Back then, the charts in the book were most important for me, but with charting apps that's changed. Unlike paper charts, apps are flexible, can be zoomed in and out and filtered and manipulated however you want. So many nights I wished my paper charts went deeper than what they showed. And don't get me started on trying to find the right chart late at night for the area I wanted to observe!

Start with things that are easy to find: the Moon, the bright planets, M42, the Orion Nebula (winter), or M8, the Lagoon Nebula (summer), and brighter star clusters. 

We measure the brightness of celestial objects primarily by "magnitude," with higher numbers meaning dimmer, and lower numbers, including negative numbers, meaning brighter. The magnitude scale is reverse logarithmic, therefore a difference of five magnitudes is 100 times brighter or dimmer and each difference of 1 magnitude is about 2.5 times brigher or dimmer. 

Venus varies from magnitude -3 to almost -5. The bright star Vega is a reference at magnitude 0.0. The limiting magnitude of the unaided eye (dimmest you can see) in a transparent, dark sky is around magnitude 6 or 7. A typical 3-inch (80mm) telescope can reveal stars to about magnitude 12. A 6-inch (150mm) to about 13.5 magnitude. An 8-inch (200mm) to about magnitude 14. This doesn't sound like much of a difference, but it makes a big difference in what you can see when so many stars and deep sky objects are at these threshold levels for seeing details, or just seeing them at all.

Extended objects like larger nebulas and some more diffuse galaxies will appear dimmer than their listed magnitudes might indicate, in which case we say they have "low surface brightness." This is one of the reasons a larger aperture that collects more light can show many deep sky objects better than smaller ones. 

Once you are familiar with using the telescope and have seen some of the brightest objects, observing the rest of the Messier Objects is a good next step. Some of them are more challenging than those in the much larger NGC catalog, but the rest are some of the biggest and brightest. Be realistic in what you try to observe, but once you gain experience, don't be afraid to try for something normally just out of reach if you have a great sky. That's part of the fun of observing!

Navigating the sky

Learn how to navigate with your telescope, depending on what assistive equipment it has. Regardless, learn how to starhop. This means comparing the patterns of the stars you see in your finder or eyepiece with those on a chart and moving the scope to the object you want to see. Unless your go-to or push-to system is really precise and functions flawlessly every time (ha!), you will still need to recognize star patterns and be able to hop to the object from where your navigation system takes you. Knowing how to starhop will also ensure you can continue observing even if your electronic system fails or runs out of power—not an uncommon occurrence.

Observing

Don't expect deep sky objects to look anything like the images you see online or in books. Your eyes, even with the help of a telescope, can't gather as much light or see most of the wavelengths represented in images. So most objects will be white or gray and look rather like dim fuzzy blobs or patches, if you can glimpse them at all. Star clusters on the other hand, at least the ones your telescope can resolve into individual stars, will look like sprinklings of beautiful points. 

Once you learn how to observe and spend 10 minutes or more viewing an object, very subtle detail will eventually start to reveal itself on clear and steady nights. Learn to appreciate what you are looking as much as how it looks.

Except when viewing the Moon or bright planets, let your eyes get accustomed to the dark, which takes about 20-30 minutes for full dark adaptation. Use a dim red light when you need light.

As you observe more, you will learn what different objects look like, what to expect, what to look for, and how to improve your observing skills. Astronomerica has articles on using averted vision, understanding distances and directions in the sky, observing the Moon, observing the brighter planets, and observing galaxies, to name a few. The internet has a huge amount of resources.

Modifying and tweaking

Even a high end telescope may require some modification and tweaking by the user, if only to customize it to your own satisfaction. Inexpensive telescopes will almost always require some modifications to get the most out of the equipment, so expect that and don't be afraid to experiment. 

Right: I added the right angle bracket and 6x30 finder to my 6-inch tabletop telescope. I also added the light-blocking craft foam, a hose clamp and extra long focuser thumbscrews to improve the helical focuser. These are all reversible mods.

However, don't start making changes until 1) you're sure you are going to keep the telescope, to avoid return or warranty issues, and 2) you've tried it as is and determined there is a modification that you can do yourself that will likely make it better. Mods for specific telescopes are abundantly available online, often offering multiple options to solve common problems. The safest mods are those that can be undone to return the scope to its original condition.

Don't rush to upgrade

Once you're comfortable with all of the above, then you can think about upgrading. Or not. You really don't need a lot of gear to see a lot. You mostly need clear dark skies, good seeing, time, patience, enthusiasm, and experience. You can't buy that. 

Unless you are missing a critical piece of gear or it just doesn't work, upgrading equipment should be the last thing on your list. You might find yourself buying a lot of stuff you don't need, won't use, or will have to rebuy once you determine what items you really want or need after observing for a while.

The important thing is to get out under the stars.

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)

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.