Eyepiece cheat codes: Becoming a Lunatic

Most of us probably live in light polluted urban or semi-urban areas. My home usually exhibits a Bortle 8 sky at best (no hope of seeing the Milky Way and only the brighter constellations visible on a good clear night). We eagerly await the period around new moon so we can get somewhere darker and do some deep sky observing: galaxies, clusters, nebulae, hoping that we might have some clear nights.

We've all probably observed the Moon when it was up. But have we really observed it?

I am by no means an accomplished lunar observer, primarily because for many years, like many of us, I waited for new moon to do my observing. Now that I'm unable to get out to a darker sky as often, I have developed a new attitude toward our little rocky satellite, and I've discovered that lunar observing is pretty damn B A D A S S.

Having a 6-inch reflector as my current "go to" scope, I can't see many of the smaller features that someone with a 12-inch with consistently excellent seeing might see. Yet, given my limitations, I've found lunar observing to be something I look forward to as much, and sometimes more, than deep sky observing. 

[Want some Pink Floyd on YouTube to accompany you while you read this post? Click here.]

Catch the excitement

When I was much younger, the race between the U.S. and the Soviet Union to put spacecraft and eventually people on the Moon was exciting for the general population, and even more so for space nerds like myself, whose favorite movie then (and now) was 2001: A Space Odyssey. Say hello again to HAL 9000.

Now, with spacecraft once again landing on the Moon, some of that excitement is returning. Where are the landing sites? Where did the Apollo astronauts land? What are the various features visible in small telescopes? Can I see the flag on the Moon? (No, a flag is much too small to see in a backyard telescope. Buzz Aldrin saw the Apollo 11 flag blown over upon ascent from the lunar surface, but the other five flags planted in the Apollo program are still standing, although they may be quite faded and deteriorated from the ultraviolet light and temperature extremes. See this LROC explanation and this NASA evaluation for further discussion of the flags on the Moon.)

Above: The Apollo 11 landing site viewed by the Lunar Reconaissance Orbiter Camera showing the Lunar Module (LM) just left of center and several instruments left by the astronauts. The image is roughly 225 meters across, or about 738 feet. In comparison, an 8" telescope will only resolve details as small as about seven times the width of the image, or about a mile across, or half an arc second in perfect seeing. With a good Moon map, however, you can identify the general location of the various spacecraft landing sites. (NASA/GSFC/Arizona State University)

Get started being a lunatic

I recommend starting your lunar observing by simply perusing the surface, especially along or near the terminator—the line demarcating sunrise or sunset, where the shadows highlight the relief of the various features. Don't worry about names until you get curious. What is that crater with the long bright rays? How about that one with the straight radial line inside it? What is that U-shaped valley by that bright crater? What is that long cliff-like feature? How about that gap in that huge mountain range? Discovering these features on your own and then looking them up on a Moon map is part of the fun.

The ever-changing shadows

One of the many great things about lunar observing is that the view is continuously changing as the Sun's light marches across the Moon, with the terminator highlighting new vistas every night. One rule of thumb is that the period between new moon and full moon, centered on first quarter, will place the Moon best for observing in the evening sky, and the nights centered on last quarter will place the Moon best in the morning sky. First quarter in the first part of the night, last quarter in the last part of the night. In the evening, you'll be seeing sunrise marching across the Moon. In the morning, sunset.

You can look up the rise/set times and current phase of the Moon on many websites, including Time and Date. There are also many apps available, such as Moon Phase Calendar.

The importance of good seeing

With lunar observing, we really want to see detail as sharply as possible, with little to no blurring by the atmosphere. A night with steady air, or good "seeing," will yield more detail than a night of poor seeing when the Moon looks like it is rippling, undulating, or just plain fuzzed out. How do you know when the seeing will be good? Well, if you're like me and live under the jet stream, it won't happen very often that you get excellent seeing. But usable seeing can often be had. 

Check apps or sites like Astrospheric or Clear Dark Sky (R.I.P, Attilla Danko) for seeing predictions for your location, understanding that they are just predictions. Other factors can affect seeing, especially from urban locations where heat rising from streets, driveways, and roofs can turn an otherwise good night of seeing into churning soup. If your telescope needs some cool down time, typical for reflectors or SCTs, try to set it outside for at least 30 to 60 minutes and use a fan or insulation to reduce internal tube currents.

Charts and Moon map apps

While my favorite charting app, Sky Safari Pro, shows lunar features when zoomed in, I find it difficult to see in night mode, with the features just too dim. Since I do most of my observing of the Moon from home, I can hop indoors and check out the excellent (and free) Virtual Moon Atlas, which I highly recommend if you have a Windows or Linux operating system.  Once you set it up, it will show you where the terminator is currently, you can turn labels on or off, zoom in to an astonishing level of detail (thanks to Lunar Reconaissance Orbiter Camera imaging), look up information about various features, and even orient the view to match your telescope's. There are other apps available that you may prefer. Try Moon Globe for iPad, or the online Real Time Map of the Moon. 

Left: Virtual Moon Atlas showing the phase on a particular date and time and set up for a 180 degree rotated image with south up and astronomical west to the left, as seen in a reflector. The Moon is about 31 arc minutes in diameter, or half a degree as seen from Earth. On the other hand, the Earth is about 2 degrees in diameter as seen from the Moon.

Note that when describing directions on the Moon, we use the convention of east being toward Mare Crisium, the circular dark plain just below center near the left limb in the image. This conforms with how terrestrial maps work, and is opposite from directions described for the night sky and deep sky objects. The idea was that lunar explorers would not get confused by "backwards" maps of the surface, compared to terrestrial maps. The crater Copernicus is on the terminator just below center.

Right: Zooming in on the crater Copernicus, which is about 58 miles in diameter. 37 mile-wide Eratosthenes is the crater in the lower left. The image is about 3.5 arc minutes wide.

Left: Zooming in further into the interior of Copernicus. This image scale and detail is beyond the capability of most backyard telescopes. The image is about 25 arc seconds across.

The central peaks are almost 4,000 feet high, ,while the crater wall at left is about 13,500 feet high. The detached part of the central peak just to the right of center is about 9 miles wide, or about 7 arc seconds in the telescope.

Lunar features and naming conventions

Features on the Moon are labeled in Latin (and you thought it was a "dead" language!). These are based on names first proposed by Giovanni Battista Riccioli, an Italian astronomer and Catholic priest (hence the Latin) who lived in the 1600s. His Moon maps were drawn by Francesco Maria Grimaldi, his colleague and fellow scientist/priest. They both have large walled plains, close to each other on the western limb, named after them. Many features, mostly craters, have been named since then. For more on naming, see the Smithsonian Magazine's How are Places on the Moon Named?

Some of the main types of features include:

Mare ("sea"): the expansive darker, smoother basaltic plains formed from molten rock that can be seen with the unaided eye. Examples: Mare Tranquilitatis (where the Apollo 11 astronauts landed), Mare Crisium, and Mare Imbrium.

Left: Mare Crisium (Virtual Moon Atlas. South is up.)

Sinus ("bay"): A smaller plain similar to a mare. Similar smaller "maria" include Lacus ("lake") and Palus ("marsh"). Examples: Sinus Aestuum, Sinus Iridum, Lacus Lenitatis. 

Left: Sinus Aestuum, with craters Eratosthenes below center and Copernicus at right edge (Virtual Moon Atlas. South is up.)

Crater: 95% of named features on the Moon are craters, almost all of which were caused by the impact of meteors or asteroids. They are named after dead scientists and explorers. Examples: Copernicus, Tycho, Clavius.

Left: Clavius, amid many other craters in the lunar southern hemisphere. This was the home of the fictitious moon base in the movie 2001: A Space Odyssey (Virtual Moon Atlas. South is up.)

Mons/Montes ("mountain/mountain range"): These can be individual mountains or massive mountain ranges. Examples: Montes Apenninus (named after the Apennines on Earth), Montes Alpes (named after the Alps on Earth), Mons Piton (named after a peak in the Canary Islands).

Left: Montes Apenninus (Virtual Moon Atlas. South is up.)

Vallis ("Valley"): Usually, but not always, named after a nearby crater. Examples: Vallis Schröteri, Vallis Alpes, Vallis Rheita.

Left: Vallis Schröteri. The deep crater to the left is Aristarchus. The valley's end points to the crater Herodotus. (Virtual Moon Atlas. South is up.)

Rima/Rimae ("rille/rilles" or narrow channels): These were mostly formed by lava flows, collapsed lava tubes, or grabens caused by the sinking of the surface between faults. Examples: Rima Hyginus, Rima Cauchy, Rimae Ariadaeus.

Left: Rima Hyginus. Crater Agrippa is in the upper left. (Virtual Moon Atlas. South is up.)

Rupes ("scarp" as defined by the IAU, but actually a fault looking like a huge cliff): Examples: Rupes Altai, Rupes Recta, Rupes Cauchy.

Left: Rupes Recta, the "Straight Wall,"  on the southeast edge of Mare Nubium (Virtual Moon Atlas. South is up.)

Dorsum/Dorsa ("ridge/ridges"): Tectonic features found in maria, these "wrinkle ridges" are long, thin folds formed by the cooled and solidified edges of lava flows. Examples: Dorsum Heim, Dorsa Smirnov, Dorsum Zirkel.

Left: Dorsa Smirnov, curving vertically down the center. The crater Posidonius is at bottom left. (Virtual Moon Atlas. South is up.)

Advanced lunacy

If you really want to get into all the details of the Moon's orbit, phases, libration, etc., check out NASA's Scientific Visualization Studio. 

For more ideas on lunar observing, and what others are looking at, see The Association of Lunar and Planetary Observers (ALPO) Lunar Section.

If you don't mind logging your observations in detail, you might consider joining the Astronomical League and trying out their Lunar Observing Program, which contains features to view with the unaided eye, binoculars, and a small telescope. Even if you don't log your observations to get the certificate, this gives you a list of prominent lunar features to observe.

Welcome to the lunatic asylum!

How much does amateur astronomy cost?

tl;dr: It costs whatever you have to spare that you want to invest in it.

I was recently reading a thread on the Cloudy Nights amateur astronomy forum in which the poster was complaining how some people are always claiming how expensive amateur astronomy is, when it "really isn't." These threads pop up periodically, and usually follow the same course. (Above: Andrew Magill from Boulder, USA, CC BY 2.0, via Wikimedia Commons; Astroboy by Astronomerica)

First, let me comment that many of the most frequent posters on Cloudy Nights seem to mostly be retired engineers, white collar skilled workers, or successful retired "boomers" (full disclosure: I am a retired "boomer") who have fairly large disposable incomes. Often someone will state that compared to expensive motorcycles, high end photography, golf memberships and green fees, high end gaming, skiing equipment and lift fees, and the like, amateur astronomy is cheap. Well, if you look at it that way, it is. Until you buy land out in the boonies and build your own observatory to house your 6" refractor imaging rig. But most of us will never have the money, opportunity, or life situation to do that.

But how about those people, and not just kids, who don't have thousands or even hundreds of dollars to spend on a hobby? I remember when I lived in a 24' travel trailer, had a minimum wage job, and thought that buying a 4.5" Tasco 11TR department store reflector for almost $200 was a huge splurge—and it was for me. By the way, I did start out with $20 Tasco binoculars before I could afford the telescope.

I grew up being frugal and I still am as a matter of principle. Even if I can afford something more expensive, I like to see how much enjoyment I can get out of a less expensive option. That extra 300% in price often only buys a 10% improvement in what really counts: enjoyment. Maybe 1000% will buy a 50% improvement, but that often takes the expense well out of a person's budget range. (Above: At Bull Creek Wildlife Management Area in Central Florida, 1993, with myTasco 11TR department store reflector. Some of the happiest nights of observing in my whole life.)

Hence, with Astronomerica I attempt to demonstrate that it doesn't take a lot of money—whatever that means to you—to enjoy amateur astronomy. We constantly read about "hobby killer" cheap telescopes. That's probably what my 4.5" Tasco was considered by many at the time, yet it helped me develop a hobby that I have enjoyed for the rest of my life, because if you don't approach it from an elitist perspective, it's not a bad scope. 

No one wants to buy crap, but even now there are some decent telescopes for $250 or even less. I just picked up a Svbony SV510 solar telescope (above) for less than $10 new that actually shows sunspots pretty well, even if it's on a very rickety tripod. If that's what you have to start with, then go for it. Just understand the limitations. "Perfect is the enemy of good" (Voltaire).

Many times I read posts where people say for $500 a particular piece of gear is too good of a deal not to buy, even if it's just to try it out. After all, it's "only" $500! Don't we all wish we had that kind of mad money? Others consistently recommend finding a higher quality piece of gear used. But most people don't want to wait weeks, months, or even years for that particular equipment to come up on the used market, just to see it sold to a retired "boomer" engineer before they can even get home from school or work to check the classifieds.

I know from experience that there are ways to get a lot of enjoyment out of amateur astronomy for very little cost.  But as you get more into the hobby it can cost you more. Want to get away from your Bortle 9 city lights out to the country? Better have a car and gas money, or a friend who has both and is also into astronomy (good luck with that). Want to buy that perfect beginner 8-inch Dobsonian? Better have $600, plus a phone with a charting app or money for a star charting book, plus a suitable observing chair, plus good cold weather gear, etc. 

It does get expensive by many people's standards. But do we really need that 8-inch dob as our perfect starter scope that will "serve us well for a lifetime?" No. You can get good binoculars for a third of that price, and "recommended" cheap binoculars for perhaps half of that. Cheaper if you get them on sale, or the price of club dues if you're lucky enough to have a local astronomy club that has some to borrow. (Above: Apertura 8-inch Dobsonian, the "perfect" starter scope for those with $600 to spare.)

While I love forums like Cloudy Nights, Stargazer's Lounge, and Reddit (r/telescopes), there is a strong tendency for the frequent posters to make it sound like if you don't get this or that recommended equipment, then you're making a huge mistake. "Better to buy once and cry once," is the mantra. Easy to say if you have the money on hand to do so. If not, they then suggest you wait and save your money until you can. Depending on your situation, that might take many months, if not years. There really is no reason not to start with whatever modest equipment you have, even if it's a cheap lawn chair, your own eyes, and a bottle of bug spray. (Left: Nikolay Andreyev, Public domain, via Wikimedia Commons, modified for amateur astronomy FOMO)

I recommend you read those forums but don't fall into the trap of thinking you have to have a pile of high quality equipment to enjoy amateur astronomy. Consider the situations of those making the recommendations, and consider your own situation. One user may have 20 telescopes, 50 eyepieces, and a fountain of experience (who is also the one that tells you "Better to buy once and cry once!"). You don't need to be that person. You aren't that person. You can enjoy the night sky the way you can, given your own means and situation. Don't feel like you're missing out. You're seeing the same things everyone else is. Someone will always have a better view. Don't let that keep you from looking up.

Enjoy the journey, wherever you start and wherever you wind up.

Taking an astronomy trip by air

Whether you're taking a trip purely for astronomy observing, or you'd like to do some observing on the side, having something to magnify your view can really add to the experience. Here I'm not talking about scopes that pack into the car for a drive but ones that you can carry with you on an airplane. That's a big difference. Your standard "grab 'n go" scope may not make a good airline travel scope once you try to put it in your luggage.

When to go

The Southern Cross from Florida in September?
Not gonna happen!
(Naskies at en.wikipedia, CC BY-SA 3.0,
via Wikimedia Commons)

The most obvious consideration for when to go is to plan it around new moon. Consult an app or website to see when it gets dark and when the Moon rises or sets. If you are likely only to observe during the early part of the night, go within the week before new moon, when the Moon rises in the early morning hours. 

Research your destination and find out what months have the best chances for good observing weather.

Consider what objects you would really like to see. For example, going to the Florida Keys to see the Southern Cross, Omega Centauri, and NGC 5128 won't work in September. Use a charting app such as Sky Safari or Stellarium to see what will be up throughout the night.

Choosing a destination 

First and foremost, you'll want dark skies that have frequent clear nights and good seeing. Harder than finding that, though, is finding a place where there are no local lights to ruin an otherwise great sky. Non-astronomy people will often rave about the great sky, with no attention paid to all-night lighting that would be a deal-killer for astronomers. Even a single LED on a nearby outbuilding can be incredibly annoying.

Unless those traveling with you are as excited about astronomy as you are, and even if they are, it's good to have alternate activities available so everyone is happy and you have some variety. If they aren't into nature and the outdoors, you'll probably be limited to a fairly mediocre sky with lots of lights. Most destinations also have a chance of cloudy nights.

I recommend a place that has a kitchen, so you can prepare your own meals. You won't spend as much money, you'll be able to be set up and ready at dusk, and you'll be able to plan the meals and snacks around your observing and sleeping schedule.

Excepting stays in really posh digs, the largest part of the budget will likely be the air travel. You might find dark skies closer than you think unless you're bent upon seeing the opposite hemisphere. After all, the constellations are the same until you change latitude significantly.

Access to a telescope at your destination

The most convenient travel solution is to have a telescope waiting for you at your destination. You could ship your equipment, but that could be expensive and any delay could ruin your chances to observe. I have read about some people doing this for very distant trips, and maybe that's a decent solution in that case.

Above: The non-profit Reach for the Stars in Tucson, AZ, rents telescopes. Check for telescope stores or astronomy clubs at your destination that might be able to set you up with a telescope.

Some astronomy-suitable vacation rentals (dark sky, minimal light pollution) come with telescopes, but while I was doing research I found that most don't. I think trying to maintain them is more of a hassle than it's worth, except for a very few number of places dedicated to astronomy observing. Most places cater to a wider variety of interests because, let's face it, the market for astronomy vacation rentals is pretty miniscule.

Above: The Marathon Motel Sky Park in Marathon, TX, provides nightly observing programs with their 20" and 24" Dobsonians, as well as powered telescope pads if you bring your own.

Still, if I had a rental property where I knew astronomers would be staying, I would probably have an 8 or 10-inch Dob available because there's not much you could do to break one of those. However, then you have to have a chair and eyepieces and a finder and all that kind of stuff that can be broken, lost  stolen, or ruined fairly easily. So I understand the lack of available equipment.

As a renter, you don't know what kind of shape the equipment is in, or what comes with it. So it's good to bring, at the very least, binoculars, and if you can manage it, a small telescope and a small collection of eyepieces.

On my recent trip to Arizona Sky Village, I had arranged several options for on-site telescopes in advance, including observing with somebody who lived in the area and renting a telescope from a place near the airport. In the end we just used what I had brought with me. I couldn't have even rented an 8 or 10-inch Dob because it would not have fit in the rental car with three of us and all of our luggage!

What makes a good air travel scope

I'm not a refractor guy, not because I don't like them, but because refractors have never really fit into my style of observing. Many people use wide field refractors, for example 80mm refractors, as travel scopes. It seems like a good idea because they're small and relatively lightweight, and many people go that route. Little Maksutovs are also a popular choice, and although they have a limited field of view, they can double as a terrestrial scope with an erecting prism.

For me, it makes more sense to bring a good pair of binoculars than a wide field refractor or "Mak" of small aperture. Binoculars can be used for birding and nature watching in addition to astronomy and don't require much else. And what can be better than lying back while you're observing? See my Bino Body Mount post for a great lightweight mount for binoculars, pictured at left, that you can easily break down and pack in a suitcase.

Therefore, If I'm going to bring a telescope, I want something with as large an aperture as possible because I already have the low power/wide field experience covered with the binoculars. But it's problematic when you have to pack a telescope for a plane trip. 

Do-it-yourselfers have built some pretty incredible travel telescopes with larger apertures. But most of us don't have the skills, the time, or the money for that. Commercial versions are pricey. So we look for mass-produced telescopes that are lightweight and small but pack as much aperture as possible. 

Can a 6-inch be a travel scope? 

I can definitively say yes. I took my collapsible Sky-Watcher Virtuoso GTI 150P (6-inch) optical tube assembly (OTA) off its bulky go-to mount and built a travel mount for it. The entire setup weighs about 25 lbs. I took it with me from Virginia to Arizona and back by air and rental car, and was really glad to have that much aperture to appreciate the dark Arizona skies. 

If you want to go with a refractor or Maksutov, fine. You'll need that, a tripod, and some eye pieces, at a minimum. If you want to sit, you'll need some sort of chair you put outside and move around. 

I don't recommend a high-end scope or even a medium-end scope for air travel, because you may never see your luggage again, it may get broken, and even if you carry on the OTA, you still have to pack it well and there's a chance you may end up having to gate check it. 

I packed my OTA in a 22-inch hard shell carry-on suitcase, packing all my warm jackets around it, and it did fine. The mount, tripod table, and associated gear all fit in a 26-inch checked roller suitcase. My wife and I carried on the eyepieces, finderscope, and two pairs of binoculars (15x70 and 10x56) in a case and a small bag that fit under the seats. You can't put lithium batteries in your checked bags, so I carried them in my "personal item" bag that fits under the seat.

For eyepieces, I brought a Celestron Xcel-LX 25mm (30x), an Astro-Tech UWA 10mm (75x), a Svbony 7-21mm zoom, and a Svbony 2x barlow, giving me a range of powers from 30x to 214x, plenty for a 6-inch.

My Sky-Watcher 150P came with a go-to mount, which I wasn't about to take apart, and it was too big to fit in any kind of suitcase I want to be lugging on a plane. I decided to put together a new mount for it, and chose the Svbony SV225 alt-az mount. It's relatively inexpensive, weighs a bit more than 5 lbs., it's sturdy, and can be compacted into a pretty small form factor. I fit it in a plastic shoebox with foam padding. I also built a tripod table which could be broken down flat, upon which I bolted the mount.

The biggest challenge was finding a chair that I could bring with me that was the right height for the telescope. I do not like observing standing up, especially for many hours at a time. The chair I usually use is a big heavy Denver style adjustable chair, which is too big and heavy for airline travel. 

I looked online and finally found a folding tripod chair where each leg folds in half, making it even more compact. It's called a GCI PackSeat. It weighs just over 1 lb. I stuck tennis balls on the bottoms of each leg to keep it from sinking into soft ground, and that worked great. It was just the right height, about 18", for my telescope once I added a stool cushion, fastening it to the chair seat with sheet stays.

Your rental may not have any outdoor chair suitable for use with the telescope, so if you're planning a trip and planning on sitting at your scope, make sure you know what height chair you need, and what they have at your destination, or bring something the right height to sit on.

Don't forget to inquire about reclining chairs if you plan on doing binocular observing. Some people use tripods or monopods, but for me they are tough on the neck for more than a few quick looks well below the zenith. The place I recently rented had Adirondack chairs that worked well.

Sizing it up 

The three main rules for traveling by air are keep it light, keep it compact, and make it easy to assemble and disassemble. If you already have some luggage, it may be fine for your scope and mount/table/tripod. Otherwise buy luggage that will fit what you're designing or buying. I found that a 22-inch hard shell carry-on roller suitcase was the perfect size for the 6-inch collapsible 17-inch long OTA with suitable padding, namely my ski pants, a hoodie, a light down jacket, some gloves, and a hat. 

Try to use stuff you're going to bring anyway for padding rather than packing a lot of foam and dedicated padding. Just make sure it's packed well enough that it's not likely to receive damage under normal handling. 

Someone on Cloudy Nights mentioned they packed their OneSky 5-inch tube in their checked baggage in a duffel bag filled with clothes, and it made it fine. It depends on your own risk aversion how you want to handle that. I feel much more comfortable carrying the OTA on.

Watch your baggage weights and sizes and make sure you stay within the airline's limits. My 26-inch roller suitcase (above) that held the scope mount, table, bino mounts, observing stool, tools, windscreen, and other gear was pretty close to the max limit of 50 lbs. 

Disassembly and assembly

You want to make sure you have all the tools and bolts and other things that you'll need to assemble and take apart your gear. I found it was a good idea to go through the whole disassembly and reassembly process once I had collected all my tools and equipment, using just those things that I would be packing. That way I would immediately recognize if I was missing some key tool or item. 

Bring a few extra critical bolts, screws, washers, and other items in case you drop them and lose them. A single bolt could shut you down if you lose it. If you need a wrench, bring a compact 3/8 inch socket wrench and bring sockets in the right sizes that you'll need. Get a cheap stubby screwdriver if you need one.

Plan for the weather at your destination

Research the environment you're going to be in. For my trip to Arizona Sky Village in late October/early November, I realized based on my research that it was likely to be quite cold at night, possibly going into the mid-30s. Therefore, I made sure I brought plenty of warm layers, wool gloves, headband, hand warmers, and anything else I would normally wear for winter observing. It rained on the last night, and the nearby mountains (left) were covered with snow in the morning. 

I recently got a heated vest that's powered by a pocket power bank. It took up very little space but kept me very warm along with a hoodie and a light down jacket. Use several layers instead of bringing one huge bulky coat. You can add layers as it gets colder.

Even if it's nice and warm during the day, it may get quite cold at night, depending on where you're observing. So do your weather research in advance. 

The Arizona high desert can have some pretty strong winds, so when I went there, I brought a privacy screen I found at a Lidl grocery store (similar to this one) and used that. It worked very well, but I had to replace the cheap steel wire shepherd's hook stakes with aluminum gutter spikes. They were lighter and a bit stronger than the shepherd's hook stakes, which bend if you just look at them wrong. I used a local rock to pound in the stakes. I set the screen up at my local observing site first (above), so I knew how to do it and could evaluate the components.

A wind screen can also double as a light screen in case you encounter some unexpected all-night lighting, or a steady stream of car headlights.

If you will be observing in cold weather, your Mukluk or Sorrel boots are great, but they take up a lot of space in your luggage. Instead, bring chemical hand warmers, for example Hot Hands, and slip one under your toes in each shoe. Unless you're observing in sub-freezing weather, they will keep your toes warm all night. If the warmers are still hot and soft when you're done observing, put them into a Ziploc sandwich bag to cut the air off, and you'll be able to reuse them the next night. I used one pair of hand warmers three consecutive nights doing that, wearing them for probably a total of 12 hours.

Observing

Bring whatever charts you're going to need, whether on an app or if you use paper charts. Don't forget a red light for when you're moving around or reading at night. Pack some spare batteries and a small charger if you think you'll need one, as well as wall chargers and charging cables. Even a non-electric setup probably has some requirements for juice. 

If you're going to be going in and out of a brightly lit house, room, or cabin, you can get a pair of red goggles that are used for laser work to protect your night vision when you go in for a snack or go to the bathroom. The darker the sky, the more important it is to protect your night vision.

What finder scope are you going to use? I packed my RACI finder with my eyepieces in a carry-on bag. I wrapped each one in bubble wrap.

Make a list of those objects that you really want to see. Maybe they're ones that you can't see from your light polluted home or typical observing site, or ones that are perhaps further south than you can ever view from home. Make sure they're reasonably high above the horizon at some point during the night from your destination location.

Above: Sky Safari Pro allows you to make your own observing lists. I made one for my recent trip to Arizona. Easy to load it in the app and cruise around to view your "must see" objects.

Dealing with an "oops"

It's a good idea to bring a small bottle of alcohol or lens cleaner and some q-tips and lens tissues. You might end up dropping an eyepiece in the dirt, as I did, and it's great to be able to just clean it right off and go right back to observing. See Televue's instructions on cleaning optics.

I brought a roll of white duct tape. I flagged the guy lines for the windscreen with them, which allowed us to see them easily at night so we didn't trip over them. I also made a repair to a plastic box that got broken on the outbound flight. 

There is no "now" in the night sky

Above: An illustration of the time lag in viewing an object, in this case, the Moon, from Earth, caused by the finite speed of light and the great distance between the two bodies. (James O'Donoghue, CC BY 3.0, via Wikimedia Commons)

One of the more fascinating things about visual astronomy is that we are literally time travelling when observing. Although the speed of light is fast—nothing can go faster than the speed of light in a vacuum—there is still a long time lag because of the tremendous distances light travels across the universe. 

On Earth, everything seems to happen instantaneously. I can talk to someone in Tokyo about 6,800 miles away and there is only an imperceptible lag to our conversation because the electromagnetic waves of our transmission are going through a conductor that won't let them travel as fast as light in a vacuum, maybe 50 to 90% of it. But it seems instantaneous or close to it because that's still really fast in our limited experience. So we think of everything on Earth as happening "now," and for all practical purposes there is a "now."

Above: One man's visualization of electromagnetic waves, slightly more poetic than current theory. (Attributed to Vittorio Matteo Corcos, 1859-1933, Public domain, via Wikimedia Commons)

Earth is tiny. The world of our immediate experience is tiny and our lifespan is an incredibly small fraction of the age of the universe. (To visualize the events on Earth, just one third the age of the universe, on a relative scale of one year, see this fascinating article in The Conversation.) To us there is a "now." But look out into space, into the night sky, and "now" becomes a very parochial term. Light travels at about 186,000 miles per second in a vacuum. Our view of the Moon is about 1.2 seconds old, viewed from Earth. That's almost "now." Light from the Sun, 93 million miles away, is about 8.2 minutes old when I observe it in my telescope with a solar filter. That's not "now," but fairly close.

The Einstein Cross is the image of a quasar 8

billion light years away broken up into four images

by a foreground galaxy 400 million light years away

through a process known as gravitational lensing.

(NASA Hubble, CC BY 2.0, via Wikimedia Commons)

Just within our solar system, we see or hear things as they were minutes or even hours ago. Currently any radio signal from the spacecraft on Mars is about 6 minutes old, as is my view of the Red Planet in my telescope. At opposition, our view of Jupiter is about 32 minutes old.  At its farthest, our view of Jupiter is about 54 minutes old. 

Because everything is moving, the age of our view changes. Neptune is so much farther out that we see it as it was pretty much four hours ago, give or take 8.2 minutes depending on which side of the Sun we are from it. It doesn't even make a complete orbit, 165 years, in a person's lifetime. Signals from Voyager 1, out in interstellar space now, beyond the influence of the Sun, take around a day to arrive here in Earth. Our view of M31, the Andromeda Galaxy, is about 2.5 million years old. Our view of M104, the Sombrero Galaxy, is around 30 million years old. If I can find Quasar 3C 273 in my telescope, I view it as it was 2.4 billion years ago.

But it's a hodgepodge. Let's look at the belt of Orion, the stars Zeta (Alnitak), Epsilon (Alnilam), and Delta (Mintaka). They are all about the same brightness and they're in a roughly straight line. Simple, huh? But no, depending on the source, the middle star, Alnilam, could be nearly three times farther than the other two. (Left: Orion by Tsuruta Yosuke, CC BY 2.0, via Flickr)

When we look up at the sky or in our telescopes, we are looking at a nearly endless number of "nows." Stars at different distances, clusters, nebulae, galaxies...viewed all at the same time, our "now," but all as they appeared at greatly varying times in the past. How confusing, yet how exhilarating! We're looking at a very jumbled canvas on which history is painted at wildly varying intervals. Fascinating!

This all brings up an interesting thought. If electromagnetic signals and light take so long to get to us, does anything really ever cease to exist? Does history every completely vanish? We can see history, and in fact can "now" see way back billions of years to just a couple hundred million years after the Big Bang with instruments like the James Webb Telescope.

Turn it around. Do we ourselves ever totally disappear from the universe? Let's face it, we're probably not as advanced as we could be. Hopefully we've got a long way to go before we realize our full potential in observing and understanding our universe, but there's no guarantee of that. However, if someone well beyond our level of development on a planet orbiting another star had an instrument powerful enough to detect us, we might well have been dead for thousands of years before they do. 

(Cheesy alien image created using Microsoft Copilot. 2025)

We could all be, in a sense, immortal, at least the record of our existence might well be. Yet it all depends on some sentient form, creature, or machine being sophisticated enough to detect the signs and signals of our existence. The pursuit of scientific knowledge and its application to cosmology, throughout the universe, may be our true Fountain of Youth.

How far is it? How astronomical distances are described

Light-year, megaparsec, astronomical unit...what does all that mean, and is there any way we can really understand how far away astronomical objects are?

Distances in the universe range from the Moon, averaging about 239,000 miles from Earth, to the farthest galaxies billions of light-years away. A light-year is almost 5.9 trillion miles. Already you can see the problem. Even 239,000 miles, about 30 Earth diameters, is difficult to comprehend, but for even a close galaxy like M31, the Andromeda Galaxy, the distance in miles becomes such a ridiculously large number as to be meaningless.

Above: The Earth and Moon photographed by the Nozomi spacecraft, launched in 1998 but failed to achieve Mars orbit. (NASA/NSSDC-KSC, Public domain, via Wikimedia Commons)

Units of measurement

A light-year is the distance light travels in a vacuum in the course of one Earth year, traveling at a speed of about 186,000 miles per second. This is a somewhat arbitrary and Earth-centric unit, being partially based on our little planet's movement around its star. Still, for most of us, this is about the best we can do to comprehend what is essentially incomprehensible.

Professional astronomers use the astronomical unit (AU) to describe closer distances in space, such as those within the solar system or around other stars. An astronomical unit, another Earth-centric measurement, is the mean Earth-Sun distance, or just under 93 million miles. (Diagram: nagualdesign, CC BY-SA 4.0, via Wikimedia Commons)

They use the parsec to measure larger cosmic distances. A parsec is the distance at which one astronomical unit subtends an angle of one arcsecond. A megaparsec (mpc) is a million parsecs. Easy to visualize, huh?

While none of these can really give us a true sense of the vast distances in the universe, I think most amateur astronomers and regular folks are better off using light-years, primarily because it introduces the element of time into the equation, which makes it relatable both spatially and temporally. But you'll find various measurements used in the literature. For example, Sky Safari Pro, my preferred star charting app, shows the distances to galaxies in megaparsecs (Mpc) and megalight-years (Mly). Mega=million.

My recommendation? Stick to light-years and just use the measurements to compare distances or the visual time delay between objects. For example, the Pleiades star cluster is listed in Sky Safari at 430 light-years and the Hyades cluster at 147 light-years, or almost three times closer to Earth. Aldebaran, which appears to be part of the Hyades but is actually a foreground star, is listed at 66.6 light-years, more than two times closer than the Hyades.

Above: The bright foreground star Aldebaran in the lower left, superimposed over the more distant Hyades cluster, with the hot blue stars of the Pleiades (upper right) three times farther away than the Hyades. (Jiří Bubeníček, CC BY-SA 4.0, via Wikimedia Commons) See also Taurus in 3D.

Arriving at an actual number

Once you have some idea of the measurement units used, then you have to try to understand how astronomers come up with the numbers for each object. This can vary considerably, and is why you often see quite different distance estimates from different sources. 

Let's take the galaxy M81 in Ursa Major as an example. Sky Safari lists its distance as 12 Mly. Wikipedia says 11.8 Mly, citing several technical studies, and the NASA/IPAC Extragalactic Database (NED) says 11.98. As you get farther away, the numbers tend to diverge even more. So who is right?

Left: Galaxy M81. (KeithSteffens, CC BY-SA 4.0, via Wikimedia Commons)

It depends on how it was measured. There's a lot of information out there, much of which is outdated, and that includes a lot of the information in apps like Sky Safari. Refinements of distances are continually being made, as scientists conduct research and obtain new data, as well as reinterpret older data. 

NED lists some of the methods used to determine distances to galaxies, which include the redshift—the amount light from the galaxy is shifted into the red part of the spectrum because of the expansion of the universe, 10 primary non-redshift methods, and 26 mostly lesser known and highly specialized methods. For M81, the database includes 67 measured redshifts and 99 distances measured by non-redshift methods. No wonder we can't agree! 

I won't go into all the different methods for measuring cosmic distances, but some of the most common include parallax, the shifting of a relatively close object's position relative to the background at different points in the Earth's orbit; luminosity of objects considered "standard candles," such as stars known as Cepheid variables, X-ray bursts from neutron stars, Type Ia supernovae; and calculations such as the Tully-Fisher relation, a correlation between the luminosity and rotational velocity of spiral galaxies. 

Left: Henrietta Swan Leavitt, who discovered the relationship between the period and luminosity of Cepheid variables and first used that to determine the distance to galaxies. (William Henry credited as photographer in the Woman Citizen issue where this photo appeared, Public domain, via Wikimedia Commons)

The lesson here is that science is a dynamic process and our knowledge and understanding of even apparently simple things, like distance, changes depending on how we observe it and what we use to measure it. So we take the commonly accepted number and run with it. For now.

Practical application

Long ago I gave up trying to conceptualize cosmic distances. Instead, I look at them relative to each other and try to get a sense of perspective that way. 

For example, when viewing Saturn and its largest and brightest moon, Titan, in the telescope, I consider that Saturn orbits the Sun about 9.6 times farther out than the Earth, and as I write this, sunlight reflecting off the top of its outer layer of gas takes about 77 minutes to reach our eyes. Titan averages about 746,000 miles from Saturn in its orbit, so that gives me a relative sense of the distance I am looking at between Saturn and Titan in the telescope when it is at its furthest from Saturn in my line of sight (greatest elongation). (Image: Saturn with Titan to the upper right; Kevin M. Gill, CC BY 2.0, via Wikimedia Commons)

You can also look at distance as a function of time, which is why I like to use light-years as the measuring unit. The farther away an object is, the farther in the past you are looking at it, and the number is the same. Right now, if it were clear, I would see the Moon as it was about 1.2 seconds ago (1.2 light seconds away), the Sun 8.2 minutes ago, Jupiter about 35 minutes ago, the Pleiades about 430 years ago, and galaxy M81 about 12 million years ago. Visual time travel.

Above: Supernova in M101. Seen by us in 2023. Actually happened about 21 million years ago. (Kheider, CC BY-SA 4.0, via Wikimedia Commons)

My point is that you don't have to do more than look at a couple of numbers and do simple arithmetic to understand the distance and time relationships between astronomical objects and appreciate what you are seeing when you observe.

Build an air travel table mount for a tabletop dobsonian

A tabletop dobsonian is a great inexpensive but capable and portable telescope. The mount is a single arm hybrid dob base. The basic ones can be disassembled for air travel, and reassembled at the destination with a screwdriver, but you still have to have a suitable table at your destination to set it on.

However, the scope that I have, the Sky-Watcher Heritage GTi 150P (6-inch), has an electronic go-to mount that I would be very hesitant to try to take apart and reassemble. It's too big to fit in an average suitcase, but I wanted to take the telescope on a dark sky vacation via airline. What to do?

The optical tube assembly (OTA) can go in a 22-inch carry-on hard shell roller suitcase as long as it's well packed. The base that I built, consisting of a mount and table or tripod, would need to be disassembled to fit in a checked suitcase. I have a 26" roller suitcase that I used for this. 

The total weight of OTA, mount, and table is about 25 lbs.

While you may not want or need to build this entire table mount, I hope this will give you some ideas if you are putting together your own travel setup.

Why not a tripod?

Some people use a sturdy photo tripod for their travel scopes, such as the Innorel RT90C, a carbon fiber tripod that is often recommended for light travel scopes. I have a few problems with that, though. First, I don't like standing when observing, which would be the case if mounting my 6-inch Newtonian on one. It gets tiring very quickly if  you're out observing for several hours or more, and it's difficult to keep your eye steady at the eyepiece when standing. Second, I was concerned with the stability. Third, and you knew this was coming, a good, light tripod is not inexpensive, especially after buying a mount to put on it. 

Choosing the mount

I decided I would buy a lightweight mount and build a custom table for it. I chose the Svbony SV225 alt-az mount. It's relatively inexpensive and sold without a tripod. It handles the 10 lb. weight of the 6-inch tube with accessories very well. The SV225 is just over 5 lbs, so it's the heaviest piece of the table mount, but still quite manageable for air travel. The motions are smooth and the slow motion controls partly make up for the tracking I'd be missing by not having the go-to mount.

I chose not to adapt my existing table for the mount because I wanted to save a bit of weight and would also need to raise the mount so that the mirror end of the tube would clear the table when pointed at the zenith. With a spacer block raising it thus, the eyepiece still sits 2-1/2 " lower than with the stock Virtuoso GTi go-to mount. Also, at 20" in diameter, my existing table would not fit in the suitcase. Case closed.

Building the table

Instead, I built a new table out of 3/4" pine plywood in a triangle shape with the corners cut off, a pretty common design to save weight. for the center spacer block I used two pieces of 3/4" plywood and one piece of 1/4" plywood. This raises the mount just enough, 1-3/4", for the mirror end of the scope, including the adjustment screws, to clear the table at the zenith. The block is on the left in the image. The edges of the top pieces are rounded to provide clearance for the OTA. 

I inset 1/4-20 T-nuts into the top of the table, same as my previous tables. The legs have hanger bolts screwed into one end, so they just screw into the T-nuts from underneath. See my previous article on building a table for details. The paper azimuth circle is glued to the tabletop with contact cement and sprayed with a clear matte sealer.

Making the table triangular instead of round allows for a wider footprint for the three legs for greater stability, with a smaller width to fit in the suitcase. Instead of the corresponding circle's diameter, the width of the table is the measurement from the center of one side to the opposite corner, which is further decreased by nipping off the corners. So a triangle cut from a theoretical circle of a larger diameter can fit where that same circle wouldn't, if you follow me. Basically, you have three legs at the same distance as you would for the circle, but with a smaller width for packing (reduced by the width of the blue arrow in the diagram). I cut the triangle from a theoretical 20" circle. The width in green is 15-1/2", so I reduced it by the 4-1/2" in blue by making it a triangle with cutoff corners.

The problem with a typical alt-az mount like the SV225 is that it must be mounted in the center of the table, which then puts the center of gravity of the scope well away from center and makes it easier to tip over, especially when the back of the scope is positioned over a side without a leg immediately behind it. This would be the same if it were mounted on a tripod. To account for this, I angled the legs a little more this time, about 15 degrees versus 10 degrees, to make a larger footprint and give it more stability. The legs are also a little longer to make up for the difference in height of the go-to mount versus the SV225. I made the legs out of 2x2 balusters, just like my other table. They screw into T-nuts hammered into holes in the tabletop 13-1/2" apart.  

While it is more stable, it's still not as stable as I would like. The solution is to add weight below the mount. Yet I wanted to keep it light for travel. I'll get to the that in a minute.

The hardest part of this project was figuring out how to cut the triangular tabletop out of a piece of plywood without first cutting a circle and wasting a lot of the wood. After wrestling with the geometry of it all, I finally figured it out and made the cuts. Whew, I don't like my brain to have to work that hard.

Back to adding the weight for stability. Since I had my original 18" tabletop made from 1/2" plywood that had eyepiece holder holes already drilled into it, I decided it would make a great lower level rack for the table. Not only would it help stabilize the legs, but it would also provide a place to put a large rock (or bag of rocks, or some other "found" objects). Weight really does wonders for the stability of tripods, which is why they sell stone bags for them. Same for this arrangement. It would also give me a place to put eyepieces while observing, since the small amount of clearance of the OTA over the tabletop would not allow for storing eyepieces in holes there. It just fits in my 26" suitcase.

The next problem was how to attach this 18" circular eyepiece/weight rack to the three table legs below the main tabletop. I solved this by wrapping a cam buckle strap around the outside of the legs (the orange strap visible in the image above). The circular board sits nicely on the strap, leaving the eyepiece holes clear. Easy to set up and break down with no tools, screws, bolts or nuts.

I don't use straight-through finders, so I have a right angle correct image (RACI) finder mounted on the OTA's dovetail bar. I've been adding azimuth circles to all of my scopes, so I added one to this table, too, printing an 8" outer diameter circle from Blocklayer.com. See my article on adding an azimuth circle for details. I use the same magnetic digital angle gauge for all of them. The azimuth pointer is a long strip about 1/2" wide cut from a piece of aluminum roof flashing. It had to reach from the rotating top part of the SV225 base down to the tabletop, while clearing the spacer block. I attached it to the SV225 with Velcro so it is movable when aligning the table mount in azimuth at the beginning of an observing session. The SV225 has altitude and azimuth scales (the black circle below the slow motion cable in the image), but they are very small and pretty much impossible to view while observing.

The legs are 14-1/4" long, cut from 2x2 treated deck balusters, with the ends cut at 15 degree angles. I used a cheap plastic protractor to mark the angles and a mitre box with bar clamps to cut them with a hand saw. This puts the table height at 14-5/8" and the max eyepiece height around 42". 

The whole table mount setup breaks down and fits with a bunch of other gear in a 26" suitcase. I do set the arm of the SV225 in the more compact position that it came shipped in, and that requires an Allen wrench that comes with the mount. I also need a small socket wrench with a 3/8" socket to remove the 3/8" center bolt holding the mount and spacer block to the table. It screws in from underneath. This is not something I would want to do every night, but for air travel to and from my destination it's fine. 

Finding a suitable chair

You really have to consider everything when traveling for astronomy. One of the biggest issues was not having a suitable observing chair. Regular folding chairs are too big and heavy for a suitcase. The place I was staying at didn't have any suitable chairs. I normally use a Denver style adjustable observing chair, but an adjustable chair isn't necessary for a scope this small and there's no way I would try to take one on a plane. So I found a small folding tripod chair with the sitting height that I wanted, and added a round stool cushion, fastened to the seat with sheet stays, as well as tennis balls to the legs so it wouldn't sink into soft ground. The stool is only 1.4 lbs. and folds up to into a 17" bag. It's going to be great for short sits while birding and hiking, too (minus the cushion and tennis balls).

This setup worked great on my trip to Arizona Sky Village, and my brother and I were really glad to have the 6-inch along!