The good news about winter is that the skies are dark longer than they are bright (for those of us north of the equator); the bad news about winter is that it cold, often frightfully so, at night. More good news: when a cold front blows through, sometimes accompanied by bad weather, it’s not uncommon to have very clear skies behind the front. Astronomers say that the ‘transparency’ of the sky is good. What’s often not good is the steadiness of the air in the atmosphere, which astronomers call the ‘seeing’. Poor seeing makes stars look like blobs and planets look like bigger blobs.

By Bill Pellerin, Houston Astronomical Society

The good news about winter is that the skies are dark longer than they are bright (for those of us north of the equator); the bad news about winter is that it cold, often frightfully so, at night. More good news: when a cold front blows through, sometimes accompanied by bad weather, it’s not uncommon to have very clear skies behind the front. Astronomers say that the ‘transparency’ of the sky is good. What’s often not good is the steadiness of the air in the atmosphere, which astronomers call the ‘seeing’. Poor seeing makes stars look like blobs and planets look like bigger blobs.

For me, living in the southern United States, the cold is a challenge. I can be driven inside by the cold temperatures faster than anything. In fact, it doesn’t need to be that cold to be a problem. Astronomical observing does not require a high level physical activity. I’m either sitting at a map table (often with a computer-based map) or sitting at the eyepiece, or transitioning between the two. Much more of the time is sitting than transitioning.

What are some things you can do to make the cold weather tolerable?

If it’s seriously cold outside, you shouldn’t have the expectation that you’re going to be able to stay out for all night or even several hours. There are the hearty souls who can do this, but for most of us observing in very cold weather is an exercise in futility. The coldest night on which I had scheduled an observing session was in New Mexico, some years ago, over a Thanksgiving weekend. It was 8 degrees F outside. I don’t remember how many observations I made or what I observed, but I do recall spending a lot of time in the warming room at the site drinking coffee and trying to steel myself against the cold so I could go outside again. It didn’t work.

The common advice is to dress in layers, and I suppose that’s good advice. Wear everything you have because, as they say, it’s the space between the layers that captures the warmth.

I have a ski suit that I bought at one of the sporting goods supply stores in January of 2009. The jacket consists of two pieces, an inner jacket and an outer jacket. These can be separated if using the two jackets simultaneously makes you too warm. I also have a pair of ski pants that I can pull on over my blue jeans and keep the lower half of my torso warm. In addition, I have a ‘mad bomber’ hat available from many sources. Just search for ‘mad bomber hat’ on the Internet and you’ll find plenty of them.

Covering the ears is a problem for me because I need glasses to read star charts, but avoid glasses when looking through the telescope. The glasses are more difficult to take off and to put on with ear flaps. By the way, it’s easy to tune-out the focusing problems of my eyes by adjusting the telescope, but if you have astigmatism you’ll need a corrector on your eyepiece to deal with that. TeleVue is the only company that sells these, as far as I know and whether you need one or not depends on the size of the exit cone of your eyepiece. If stars have horizontal lines going through them on one side of focus and vertical lines going through them on the other side of focus, you likely have astigmatism. Check with your eye doctor or read your prescription.

I use mittens that have the tips of the fingers open so I can feel small parts (eyepiece screws, etc.) when I’m outside. The mittens have a fold-over pocket for the exposed fingers when the fine-touch capability isn’t needed. The final piece of clothing I (sometimes) use is called ‘moon boots’ — very warm and furry inside and generally water resistant outside. Not good for doing a lot of walking, however. Some nice wool socks help.

I also use the chemical hand warmers, available from a sporting goods supply store. These are activated by contact with the air and they stay warm for several hours. I put them in the pocket of my jacket and put my hands in those pockets as needed to absorb the warmth. It feels good to wrap my hands around those warmers; they provide a good bit of relief from the cold. There are also chemical warmers for boots, but I haven’t used them.

Walk around. It’s always a good idea to get out of your chair and go for a brisk walk. Doing so will loosen you up and warm you up a bit. Worth the effort. You can take a break as well. At the Texas Star Party there’s a snack booth that serves hot food and drinks all night. This isn’t an endurance contest. Go inside a warm space to thaw out and have a warm beverage.

Another approach — (imagers only) — once you set up your telescope and camera and autoguider, etc., you can walk away from your setup and connect to your near-telescope computer from another computer (in a warm place). Software that does this is typically called ‘remote control’ software. These warm places could be your travel trailer, your car, your warm-room or even your house if your house and observatory are co-located. Some versions of Windows has the ability to be remote controlled built-in and there’s a lot of software you can find that provides this functionality. You can always go to the telescope site if there is an adjustment that needs to be made or there is a problem that requires your intervention.

I heard of a guy who used a remote USB port device and moved his computer to his warm trailer. Using this remote USB capability he could control the telescope pointing, the imager, the guider, and the focuser.

Yes… doing one of these ‘remote control’ capabilities gets you out of the dark sky, but it also gets you into a warm place.

One thing that’s getting more common these days is scripting your observing session and monitoring (or not) the operation of the script from your house or over the Internet from anywhere. Several commercial telescopes are online that allow you to script your targets, your exposure times, your filters, etc. and pick up your images in the morning. Hey, this approach lacks the ‘romance’ of being out at the telescope under the dark sky, but it also lacks the discomfort of being too cold.

I’m seeing more online telescopes, too. Many of these are much more capable than the setup I own. So, for a fee, I can use a high-end telescope on a high-end mount to capture some images of the sky. I use these to get data (images) on variable stars. While I can get down to about 15^th magnitude with my setup, I can do much better with some of these remote telescopes. Again, you’re not spending time under a dark sky, but you’re getting the data or the images you want without owning the setup and without suffering through a cold night.

Keep warm, but keep observing.