Amateur astronomy things I've learned

• Someone always has a better view. Don't chase someone else's view.
• Your observing skill and enthusiasm are more important than the equipment you use.
• Knowing a little about what you are looking at makes it much more interesting.
• A dark sky is better than a big telescope. (But a big telescope in a dark sky is heavenly.)
• The best telescope is the one you are currently looking through.
• You can adapt your observing to any level of light pollution, no matter how bad.
• Aperture rules...until the spine, the spouse, and the savings account have their say
• Non-astronomers LOVE lights at night.
• Never sell a telescope unless you really hate it or need the money to buy a different one. Or need to eat.
• Amateur astronomy is a hobby.
• Pursue your passion but remember your family and friends may not share it.
• Outreach is great but there's nothing wrong with observing by yourself.
• Get used to clouds. According to NASA Earth Observatory, only 30% of land on Earth is completely clear of clouds at any given time. Cherish those clear nights.
• Apropos of the above, always acquire any new deep sky observing gear after new moon.
• If I don't write it down, I'll forget, or "misremember," most of what I observe. That's why I keep an observing log.
• If you're not enjoying it, don't do it. Take a break and come back later. That might be 5 minutes or 10 years.
• You are not weird for being into astronomy. The rest of the world is weird for not being into it.
• Collimation is not a four letter word.
• Comfort is king.
• Dress warmer than you think you'll need to.
• The universe is really big. We are an incredibly miniscule and short-lived part of it, but we're still significant.
• Your time on Earth is limited. Make time for the people and things you love.
  
  

Eyepiece Cheat Codes: Binocular astronomy

One of the common pieces of advice for amateur astronomers who are just starting out is to get binoculars. The reasons are that you can get a decent pair for less than a mediocre telescope, they are intuitive, compact, and easy to use, they help you learn the sky, and they will be useful no matter how experienced an observer you become. In addition, you can also use them for nature viewing, sports, and many other situations.

The main drawback to binoculars is that they don't magnify as much as telescopes and you can't change that magnification, at least for handheld binoculars. There are larger binoculars and  binocular telescopes that do both, but these tend to be very heavy and very expensive.

A second complaint is that it's difficult to take advantage of them fully for astronomy because holding them introduces shakiness and fatigue. Try keeping your hand on a telescope while you observe with it and you see how much it degrades the image.

But the beauty of binoculars are manifold. They allow you to use both of your eyes. They are eminently portable. They are uncomplicated: just point and focus. They have a wide field of view. They are inexpensive for the quality you get. They are widely available in many different size and magnification combinations. They are versatile. They are the ultimate "grab-n-go" astronomy gear.

Astroboy cartoon by Astronomerica.

Mounting binoculars

Besides learning how to hold it steady, you are going to get better views by mounting your binoculars in some way. For lower powered binoculars like 7x35 or 7x50 you can keep them pretty steady handheld, but once you get to around 10x50, even with a steady hold, you will still not get the good views that you would get if you mounted them. Also, any binoculars get tiring after holding them up with your arms for a few minutes.

For those reasons, many astronomers mount their binoculars. Most use a photo tripod or a monopod, but this limits the freedom of movement somewhat and certainly makes it uncomfortable to observe high in the sky, where the sky is usually darkest and most transparent. You can observe sitting down, but not in a reclining chair without difficulty. The best uses of a tripod are for objects lower in the sky, which is often the southern summer Milky Way for North American observers, and comets, which are often close to the Sun and visibly at their best shortly after sunset or before sunrise. I find a tripod very limiting overall.

Another option is the parallelogram mount. These are commercially available or you can build your own. I built one from plans in Astronomy magazine years ago, and while it worked okay, it was bulky and heavy. You have to adjust it if you move your chair to look at a different part of the sky. Commercial options are somewhat limited lately, and they are relatively expensive. Because I have to travel to observe in a darker sky, I don't have much room left after the Dobsonian telescope and other gear is loaded, so I don't want another big piece of gear and a tripod to mess with.

Some people don't bother with mounting and buy image stabilized binoculars instead. I've tried them and they're okay, but I get a bit dizzy using them. They are also quite expensive. You still have the fatigue of holding them up, and they are generally heavier than the same size non-stabilized binoculars.

My own preference is to build and use the compact, simple, and inexpensive Bino Body Mount (left), which you can use to observe anywhere in the sky (best up high) in a zero gravity chair for maximum flexibility and comfort. This lets you keep your elbows down by your side and transfers most of the weight to your shoulders directly, rather than through your eye sockets and arms. It preserves the freedom of motion of handheld binoculars and you can get views so steady that only your heartbeat is discernible.

What other equipment do I need?

Binoculars are the only essential equipment. There are many articles and videos about choosing binoculars. Generally, the higher the power the narrower the field of view. The larger the objective lens, the fainter and finer detail you will be able to see.

My recommendation is 7x50s if you are in the first half of your life and just beginning. They are easier to hold steady, have a wider field, lower power, big exit pupil (second number divided by the first, i.e., 50/7=7.1mm exit pupil) that young eyes can fully take advantage of. I recommend 10x50s, 15x70s, or 20x80s especially if you are older or interested in viewing more than starry vistas and want to locate individual objects like smaller star clusters, globular clusters, some nebulas, galaxies, and the like. These are the binoculars I recommend for my binocular audio guides "Space Walk Among the Stars."

But you'll really improve your observing and comfort with a reclining chair. A zero gravity chair is best because, unlike most other recliners, you don't need to manipulate the arms with both hands to change the reclining angle. Instead, you just transfer your weight between your feet and shoulders to change the angle, or altitude. The only drawback is the same as any chair: you have to get up and move it to view a different part of the sky. This leads some DIYers to build rotating platforms for their chairs. I recently built one, although I haven't got it quite right yet.

Left: Reader Mike (Telescope Guy) using his homemade rotating chair mount with his Bino Body Mount. Can't get much better than that!

For cold or cooler nights, besides dressing appropriately, a blanket laid on the chair will help insulate you from the cold air between the underside of your chair and the ground. I like to use a cheap moving blanket, but any blanket will do.

Unless you are just casually scanning the sky only, you will need some type of star chart, planisphere, or app. I use an app (Sky Safari Pro) with night vision turned on. Some will argue that this little bit of red light still disturbs your night vision, but I haven't found that to be the case unless I am observing in a super dark location, which doesn't happen very often. You'll have the same issue if you use a dim red flashlight and a paper chart, which to me is way too fussy for observing with binoculars. Even if  you don't have a specific observing list in mind, it's nice to be able to look up something you spotted to see what it is. I just attach my phone to the arm of my chair so I know where it is and it doesn't end up on the ground.

If you observe where dew is prevalent, you can add a pair of USB dew heaters made for camera lenses and power them with a phone power bank, which I recommend you carry in a pouch around your neck. If it's really dewy, and I've experienced this, or you are sweating from setting up, you can use a small battery operated pocket fan to clear the eyepiece lenses periodically.

What to look at

Well really, the sky's the limit. You can look at anything you want. But some things are too small and dim and are best left to telescopes.

The "Space Walk Among the Stars: Binocular Edition" audio guides are a great way to learn different areas of the sky and what objects are there. I suggest that you start with them.

Besides the Space Walks, here is a list of the types of objects you can view well in binoculars, with some examples for Northern Hemisphere observers. It's difficult to simulate the binocular view for each, other than adjusting the scale and dimming it down some from images, which I have done just to try to give you an idea of scale and brightness. But images just can't capture the sparkling beauty, color, and contrast with the sky that stars show visually. You'll find that these objects will appear much more entrancing in your binoculars, and you may end up staring at them longer than you expect. 

I've compiled an observing list of all the named objects below plus a few more, except comets and asteroids, in .skylist format for Sky Safari Plus and Pro. Download to your phone or tablet and import into Sky Safari Pro or Plus. Do this by emailing the .skylist file to yourself, open the email on your device, download it, then select the file, select "open with" and choose Sky Safari. You'll get an acknowledgment that it was imported. The list will show up as "Imported List" followed by the date and time. You can rename it in Sky Safari. 

1. Comets. I think brighter comets are best viewed in binoculars. The really good ones require a large field of view, larger than most telescopes, the tail shows best, and they're easiest to find quickly in binoculars. These tend to be brightest, with the longest tails, when they are closest to the  Sun. Therefore, low in the west in the evening and in the east in the morning is where you'll often be looking. The window for best viewing in these situations is often fairly short, so you want to be able to hop out before or after work or school and catch them.

Above: Comet C/2023 A3 (Tsuchinshan-ATLAS) by Kevin Gill, via Flickr, CC by 2.0.

2. Star fields. One of the truly amazing sights in amateur astronomy is getting out to a dark sky and just scanning the Milky Way with binoculars. Sometimes that's all I do, and I may not even set up my telescope. Binoculars (and the unaided eye in a dark sky) are the best instrument for these wide field vistas. A wide field refractor can be great, too, but being able to lie back, using two eyes, and the freedom to move around the sky easily with an orientation matching your unaided eye are huge advantages for binoculars. Check out M24, the Small Sagittarius Star Cloud, the area around Sadr in Cygnus, and the Belt of Orion for some standouts.

Above: Simulated binocular view of a star field in Sagittarius (adapted from Aladin Lite)

3. Open star clusters. There are many larger and brighter open clusters that are easily visible in even small binoculars. Some of the best are the Hyades and the Pleiades in Taurus, the Double Cluster (NGC 869 and 884) and M34 in Perseus, M35 in Gemini, IC 4756 in Serpens (Cauda), M44 (the Beehive) in Cancer, M23 in Sagittarius, M7 in Scorpius, NGC 752 in Andromeda, NGC 7209 in Lacerta, NGC 6940 in Vulpecula, M46 in Puppis, and NGC 2360 in Canis Major. Many globular clusters can also be spotted in binoculars, but they invariably look like little fuzzballs unless you have very large binoculars.

Above: M35 in Gemini. (Astrophoto Andy, via Flickr, CC by 2.0, brightess/contrast adjusted, cropped and rotated)

4. Asterisms. These are groups of stars that form patterns even if they may not be actual gravitationally bound clusters. You can probably find your own by scanning the sky, and many of them are best seen with the naked eye (Big Dipper or the Plough in Ursa Major, the Backwards Question Mark in Leo, the Keystone in Hercules, the Teapot in Sagittarius), but a couple of the most famous ones for binoculars are the Coathanger (Collinder 399) in Vulpecula, and Kemble's Cascade in Camelopardalis.

Above: The Coathanger asterism. Simulated binocular view.

5. Nebulas. You need a darker sky to view most nebulas in binoculars. Some of the brightest are the Orion Nebula (M42), which will show up even in bad light pollution, the North American Nebula (NGC 7000) and the Veil Nebula (NGC 6992 and NGC 6960, etc.) in Cygnus, the Helix Nebula (NGC 7293) in Aquarius, the Lagoon Nebula (M8) in Sagittarius, and the Dumbbell Nebula (M27) in Vulpecula. If you're in a really dark sky, you might also be able to pick out dark nebulas, which are clouds of obscuring dust that make it seem like there is a ragged black hole in the star field.

Above: The Helix Nebula, NGC 7293. Simulated binocular view adapted from Aladin Lite.

6. Galaxies. Most galaxies are relatively small objects, and some of the smaller but brighter ones can be seen in binoculars. The bigger, brighter ones are the Andromeda Galaxy (M31) in Andromeda, M33 in Triangulum (need a pretty dark sky), and NGC 5128 in Centaurus (if you're far enough south).

Left: Galaxy M33. Simulated binocular view adapted from Aladin Lite.

7. Interesting stars. Many double stars, variables, and colorful stars are good for binoculars. A very steady hold with 10x or higher binoculars will split the colorful double Albireo. Any stars with reasonably close magnitudes with a separation of about 30 arc seconds or more are fair game for binocular observation. You might do better or worse, but that's about the practical limit for most people with 10x binoculars.

Above: Double star Nu Draconis (Kuma). Although this simulated binocular view adapted from Aladin Lite makes it look very difficult to split, at 62.3 arcseconds separation, mounted or steadily held 10x50s can do half that.

8. Asteroids. Asteroids look like stars except they appear to change position over a matter of hours or days, depending on the magnification you are using. Binoculars can be used to view stars and asteroids to approximately 11th magnitude, depending on your sky, your binoculars, your observing experience, and the density of the star field. Here's a list of 25 asteroids that are often viewable in binoculars. Magnitudes of asteroids do vary as they orbit the Sun, so sometimes you can catch dimmer ones during a favorable apparition. Sketch their position from one night to the next to verify you have the right "star." Apps like Sky Safari Pro let you do a canned search on the night's brightest asteroids. I looked at tonight's list, and there are 14 asteroids brighter than 11th magnitude, however not all of them are well placed in the sky to view at any given time.

Above: Asteroids vary tremendously in shape and size. This diminutive walnut-shaped asteroid, Dinkinesh, shows a typically irregular shape. Only the largest asteroids become somewhat spherical, and they are some of the brightest, consistently visible in binoculars, unlike this dinky guy. (NASA/Goddard/SwRI/Johns Hopkins APL/NOIRLab/Brian May (yes, the Queen guitarist)/Claudia Manzoni). This is a parallel view stereogram. How to view.

9. The Moon and planets. All eight planets can be spotted in binoculars at different times of the year. You won't see any details (except for Earth!), but Saturn looks oblong when the rings are tilted and you can see up to four of the moons of Jupiter, depending on where they are in their orbits. The Moon supposedly shows 100 craters in binoculars, but I haven't counted, and I think it would drive me crazy trying to sort out the ones in the southern hemisphere. Larger objectives may blow out your vision on the Moon. I can't take the full Moon in my 15x70s without some kind of filter.

Above: Jupiter will show up as a tiny disk with no detail. Up to four moons can be seen, depending on their positions in orbit around the planet. Simulated binocular view.

While some people may observe the Sun with proper filters on their binoculars, I don't recommend it because you are looking in its direction and you can be blinded if you pull the binoculars away from your eyes even momentarily.

Technique

Advanced binocular observers often say you can get steady views and reduce fatigue with proper handheld technique (the way you cup your hands around the binoculars and rest them on your eye socket bone structure, etc.), but most people intuitively gravitate to a technique that works for them. That's the beauty of binoculars. But you still won't get the steadiest views without some kind of mounting (see above). 

Some people also say that they rest their arms on the chair arms to steady the view. Well, I don't know what kind of chair they are using, but for every chair I've ever used, the arms are way too low for that and I end up scrunching way down so my head is where my butt should be. Not comfortable or healthy!

Most multipurpose binoculars have a center-focus wheel that you turn with one or two fingers to focus both eyepieces at the same time. This allows you to quickly refocus for terrestrial viewing and is best if your binoculars are not strictly for astronomy. They will have a diopter adjustment on the right eyepiece that allows you to turn a ring to adjust for the inevitable difference between how your two eyes focus. 

Right: The diopter adjuster ring is usually on the right eyepiece. In the case of these 8x42s, adjustment marks are molded into the rubber armor just below the ring. This binocular also has eyecups that adjust by twisting them in or out for the desired eye relief, great for glasses wearers or to get just the right eye placement.

To use the diopter, first find a bright star field, close your right eye, and use the main focus wheel to focus for your left eye only. Stars should be pinpoints, or at least as small as you can make them. Then, close your left eye and using only the diopter ring, focus for your right eye only. Then look with both eyes and tweak the adjustment as needed.

Left: My 15x70s have individually focused eyepieces.That's true with many larger binoculars made for astronomy or long distance viewing only.

For astronomy, many binoculars focus each eyepiece individually, because once you are focused at infinity, you shouldn't need to refocus. You just turn the ring on the outside of each eyepiece and you shouldn't need to mess with it again. In my experience, individual focusing eyepieces hold their focus better and prevent my obsessive-compulsive tendencies from causing me to be continuously tweaking focus, so I like them better for astronomy.

When viewing a specific object, first look at it or the area with the unaided eye, facing it straight on, then without moving your face or gaze, bring the binoculars up between your eyes and the object. If you consistently have your binoculars too high or too low, make the adjustment until you typically have them right on the object each time. With practice you'll find objects more reliably this way, although it can still be frustrating even with practice. Don't get bent out of shape if you can't find something the first time. You can always scan around and compare the view to a chart to see where you are. Especially in a dark sky, it's easy to get lost among the stars. But that's kind of the point, isn't it!

Reducing glare

Unfortunately, we often have to observe with lights around us, not just skyglow. You can set up some screens or other objects to block out the lights (I'm working on an article for a DIY light screen), but you can't always block all of them. Even in a dark sky there's usually some light somewhere and the general glow from parts of the sky or the Moon.

Above: The Bino Bandit glare shield.

I find the Bino Bandit binocular glare shield to be a worthy investment, despite the relatively high cost for what it is. I've tried making something similar and failed miserably. It's made of neoprene and has two holes in it that stretch over your binocular eyepieces. You can get rubber eyeguards, but the Bino Bandit blocks the light from all angles. In addition, it leaves a little more air around your eyes so the lenses won't fog up as easily, and works with eyeglasses. It's easy to switch it from one pair of binoculars to another. I find it great for daytime viewing, too.

Using filters

Filters have limited use for binoculars, but they can help on certain nebulas. The problem is that they are designed to be fitted at the bottom end of the eyepiece, but with binoculars they must be threaded in front of the eyepiece, if the binoculars even have threaded eyepieces. This degrades the view, but can still help in some cases. I wouldn't buy a filter just for binocular observing, but if you have one for your telescope you might try it out.

If your eyepieces aren't threaded, you can try holding a filter between your eye and the eyepiece, which is not easy to do. A 2" filter is easier. 

Left: A UHC (Ultra High Contrast) type filter on one eyepiece will enhance a bright nebula, and the non-filtered eyepiece will still give you the full star field: the best of both worlds.

If you do have threaded eyepieces, use a UHC narrowband filter and thread it on one of them. This will give you a filtered view that enhances the nebula but dims down the stars in one eye, and gives an unfiltered, fully illuminated view in the other eye. 

I find a UHC filter helps on the larger and brighter binocular nebulas such as the North Ameircan Nebula, the Helix Nebula, and some of the brighter summer southern Milky Way nebulas. I don't have an OIII filter, but you might try that on the Veil Nebula or Helix Nebula if your sky is relatively dark. I can usually see the Eastern Veil from a Bortle 4 or 5 sky without any filter.

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.

Eyepiece cheat codes: How to use setting circles on an alt-az mount

I remember when I got my first telescope over 30 years ago, a Tasco 11TR 4.5 inch Newtonian reflector on a cheap equatorial mount, I looked at the setting circles and then ignored them, never bothering to polar align the scope and use them. Probably a good idea at the time, because the mount was not very sturdy, and I was able to quickly find things with a straight through finderscope and starhopping, without polar aligning the scope.

Fast forward to today, and manual setting circles are my go-to method for locating objects. 

What are setting circles?

Setting circles can be used on an equatorial or an altitude-azimuth (alt-az) mount to find objects in the sky. As noted, I don't have any experience with using them on an equatorial mount, but the concept is similar, only you use coordinates of declination and right ascension that don't change for an object. In this article, I am not going to get into equatorial or digital setting circles, but rather those that the observer lines up manuallly by eye on an alt-az mount.

Each axis, in this case altitude and azimuth, moves in a two-dimensional plane: altitude up and down in the sky from the horizon to the zenith, and azimuth in a 360 degree circle parallel with the horizon.

As in the diagram at right, it is convenient for us to look at the sky as a celestial dome, with altitude, graduated from 0-90 degrees, and azimuth from 0-360. A setting circle is a circular scale placed on each axis with the mount leveled and aligned so that 0 corresponds to the actual horizon (for altitude) and 0/360 corresponds to true north (for azimuth). 

Once the mount itself is aligned and leveled, you can move the scope to the coordinates of an object, obtained in real time from an app, and your telescope will be pointed at it. 

The accuracy depends on the construction of the mount and setting circles, and the accuracy of your alignment and leveling. You might get the object right in the center of your eyepiece or it might be out of the field of view but within your finder's field of view, and you'll have to starhop or adjust a little to find it.

For an alt-az mount on a tripod, the azimuth circle will be physically located at the point where the upper part of the mount rotates against the fixed base that is attached to the tripod or pier. 

The altitude circle will similarly be mounted at the point where the movable arm that holds the telescope tube rotates against the fixed part that holds the arm to the mount. 

On a Dobsonian, you typically have to create your own azimuth circle, as shown at right, because manufacturers haven't caught on to the usefulness of setting circles and would rather sell you fancy go-to or plate solving systems. See this post on creating your own azimuth circle. Instead of an altitude setting circle, most people use a digital angle gauge, like this one that I use, sitting on the tube.

Typically, a manual alt-az mount that is designed to be attached to a tripod, such as the SV225 that I use, will have setting circles on it from the factory. However, these may be quite small, making them less precise, and depending on the telescope tube you mount on it, may not be easily visible for the observer. In the case of the SV225, I had to take a few pieces apart to loosen the setting circles enough to be able to rotate them to line them up accurately for each observing session. I put my own pointer marks using blue painter's tape where I could more easily see them instead of the light gray, hard to see, markings that came from the factory. Sometimes I think manufacturers put these things on just for looks and marketing, but you can actually use them!

You can also add a vernier scale to smaller setting circles in place of a pointer mark. This allows you to accurately set them in smaller increments. In the case of the SV225, the circles' smallest increment is 5 degrees, but adding the vernier scale allows you to set to single degrees. I was skeptical that it would help, but found it actually does—a little. Plus it looks more scientific and makes me look like I know what I'm doing! (The setting at left is 273 degrees.)

Adjustable for accuracy

The mount must be leveled as accurately as possible and lined up so that the azimuth circle is aligned with the proper compass directions. You can either make the setting circle rotatable to line up with a pointer, or make the pointer movable. The pointer will show you what the current setting is, for example, once aligned, if the pointer on the azimuth circle is at 270, the scope is pointed due west. 

Regardless, you want the pointers to be within easy view from your observing position. A mount with setting circles built in should have the pointers already well-placed, but as noted, the type of scope tube you use on it may require moving the pointer. 

With a rotatable setting circle, you can position your mount close enough that you only have to rotate the setting circle slightly to get it as accurate as possible. With a movable pointer, you also have to place your mount as close to the correct position as possible and then move the pointer slightly to improve accuracy.

Sequence for alignment:

Here are my recommended steps for aligning your setting circles. Details below.

1. Rough align the mount for azimuth

2. Level the mount for altitude

3. Do a fine alignment on azimuth

4. Rinse and repeat

1. Rough align the mount for azimuth

It's better to do the rough azimuth alignment before you level the scope, because if you have to move the mount it may change the level adjustment needed and you'll have to do it over. If your scope tube is heavy, do your alignment and leveling before mounting the tube.

Because altitude and azimuth coordinates of a given object are continuously changing as the Earth rotates, you will need a charting app, such as Sky Safari, that will tell you the coordinates of objects viewed from your specific location and time, updated continuously. Make sure alt-az coordinates are selected in the settings. Your phone does not have to be connected to a network or wifi.

In Sky Safari, go into Settings > Coordinates and select "Horizon." Rather than futzing with degrees/minutes/seconds, I like to have them set as decimals. Go to Settings > Formats, then under "Azimuth, Altitude" select "DDD.DDDDDD, DD.DDDDDD." Now the alt-az coordinates of any object you select and center will show up in the upper left of the screen. You have to center the object or you won't see its correct coordinates. See the screenshot at left. In the example, 59.2 is the azimuth (toward the northeast) and 68.3 is the altitude of the centered item, M51, the Whirlpool Galaxy.

In Stellarium Mobile, you just tap an object, tap the info box at bottom for details and you'll see the alt-az coordinates.

Once it is dark enough, pick a bright object that's easy to find by sighting along the mount or tube by eye, such as the Moon, Jupiter, Saturn, or one of the brightest stars. Look up the azimuth of the object and move the mount so that the azimuth pointer is on the correct number, as close as you can eyeball it when the mount is lined up as if you had the scope on it. It won't be exact, but close enough that you can adjust the circle or pointer for more precise alignment later without moving the mount. Now you can go ahead and level it.

2. Level the mount for altitude

Leveling the mount will take care of the altitude alignment. The idea is to have the pointer at the 0 mark on the altitude setting circle when the telescope is exactly horizontal, and at 90 when it is pointed exactly at the zenith. Any bubble level will get you there. I use a phone app and it's close enough. Just put it on a flat horizonal surface somewhere on the mount. 

Some tripods have a small bubble level built in or you can add one. With a tripod, you can adjust the length of the legs until it reads level. 

Left: The Sky-Watcher Star Adventurer tripod, like many, has a built in bubble level.

With a Dobsonian, place the bubble level somewhere on the base and level it before you place the tube on it. Inside the box works if you can see it well enough. The simplest method is to use a set of shims under the three feet to level it. You can buy plastic or wood shims. I also have 4-inch squares of 1/2 inch plywood for more uneven ground. You can stack them as needed. Just don't forget to pick them up when you pack up for the night. White tape on them will make them more visible on the ground. You can check the level again once the tube is placed on the base, but I've found it doesn't usually change.

Above: Leveling a tabletop Dob table/base using a bubble level app and a piece of plywood. The plastic shims on the table are for finer adjustments. I put a piece of tread tape on the plywood for better grip on the feet.

3. Do a fine alignment on azimuth

Now that you have the mount roughly aligned in azimuth and leveled, you can mount the tube if it's not already mounted and do the fine azimuth alignment. This is where it's important to either have a movable azimuth setting circle or movable pointer.

Below: My DIY tabletop Dob design uses Velcro for a movable pointer. Most use a magnet, but in this application Velcro works better for me so I don't knock it out of place with my hand when I'm fumbling for eyepieces in the dark.

Again, find a bright object and look up its azimuth and altitude. Usually something about 30-60 degrees up will give you a good calibration. It really doesn't matter what direction it is. It's not necessary to use Polaris for an alt-az mount. Move the scope until the circles show the correct azimuth setting and then the altitude setting, without disturbing the azimuth position. Look along the tube to see that it's roughly pointing at the object. Now look in your finderscope. If you were pretty accurate in your rough alignment, you should see the object in your finder. If not, move the scope around until you do.

Put in a low power eyepiece, find and center the object. Next, line up your finderscope so that it matches the eyepiece view, with the object in the center of both. Adjust the finder with the adjustment thumbscrews to match the eyepiece. You should perform this alignment at the beginning of any observing session regarless of whether or not you are using setting circles. 

Next, look at the alt-az coordinates of the object again in your app and compare them to those on your setting circles. They will likely be a little off. Just move your circle or pointer to match the coordinates from your app while keeping the object centered. The higher power the eyepiece you use, the more accurate it will be, but that level of accuracy is usually not necessary. The closer you can get the match between the listed coordinates and those on your circles, the more accurate your subsequent pointings will be.

Your altitude might be slightly off, too, so adjust that as necessary. 

4. Rinse and repeat

Now you can look up the coordinates of any object and dial them in on your mount. Depending on how well you aligned everything, you may see the object immediately in a low power eyepiece. However, don't be surprised if it's off enough that it's not in the field of view, and you can only see the object, or the correct location, in the finderscope. If that's the case, just use your charting app and starhop to the correct location. You'll be close enough that you should be able to find the object every time. 

I find the greatest challenge when I have to starhop to the exact location is when the sky is either too light polluted to see many stars in the finder, or if the star field is difficult to match to the chart. This is often the case with Sky Safari, as I have to have it rotated correctly to match what I am seeing, it's often very cluttered with objects, and the star magnitude settings don't really make the brighter ones stand out enough from the dimmer ones, making the patterns somewhat confusing. Don't worry, have patience, and you'll find your object. You'll get better with practice.

An added benefit, and the reason I personally went with setting circles, is you don't have to crane your neck to look through a straigh-through finder. You can use one with a 90 degree diagonal (right angle correct image, or RACI). Occasionally I'll try to look through the red dot to get an initial fix, but I usually can't even manage that anymore. Getting old ain't for rookies, as my brother likes to say!

Additonal tips:

• Have a red light handy so you can read the setting circles
• Use a low power eyepiece when you are first locating an object, then move to higher power as desired
• It's not uncommon to have to re-calibrate if you find the settings are off a bit, especially in a different part of the sky. Just adjust the circle or pointer to match the coordinates of a centered object.
• If you're having trouble finding a faint object, look up a nearby bright star and see if you perhaps moved the circle or pointer by accident, then re-calibrate on the star and try again. You can also just starhop from that star if it's close enough.
• If you don't like where the pointer is placed on a commercial mount, simply put a little triangular piece of tape or other marker in the location you prefer.
• If you find you don't have setting circles, don't want to make them, or just don't like using them, try the free AstroHopper phone app. I use both, and I find I like setting circles better. But you're not me.

Below: An alternative solution, the AstroHopper app, in use.