Wellington Astronomical Society

Wellington Astronomical Society

Observing tips

By Mike McGavin

As an astronomical society, we often have observing sessions outdoors. Sometimes these are for specific events, such as watching for meteor showers, and sometimes it's general observing. All members are invited to come along. You're also welcome if you're thinking of joining, or just want to get an idea of what it's like.

Whether you're going out observing on your own or with a group, it's useful to be prepared. Having everything ready will often make the whole thing more enjoyable. If you have time, please take a look at this page for some hints about getting ready to go observing.

The problems with light

Direct light

Firstly get away from any direct lights, such as streetlights and roads with car headlights. One flash of a light can destroy up to an hour's worth of dark adaptation to your eyes, and then you'll see fewer meteors. Of course, if you're unable to get somewhere really dark in the first place, you'll have some flexibility, as it will take less time for your eyes to re-adapt to the conditions.

One particular thing to watch out for are interior car lights that automatically switch on when the car door opens, so make sure they're properly switched off in advance. Even flashing a light on a wristwatch to check the time can be blinding under dark-adapted circumstances.

Unless it's extremely dark, the adaptation of your eyes will usually compensate for tasks like walking around, that would normally require some artificial light. Sometimes you'll still need some artificial help for various tasks, though. When you need extra light for something like checking your watch, use a red filtered torch. Red light has less effect on human eyes' dark adaptation than any other colour, but still don't aim it directly into anyone's face. Putting some red cellophane over a torch usually works for this, and in the past I've even used a plastic red shopping bag that came with the torch. Make sure it's a cheap torch, though, in case it accidentally melts the cellophane.

If there are other astronomers around and you need to turn on a light that's not red-filtered, please check with everyone first. This will at least give them the chance to shut their eyes.

Sky glow

The other type of light pollution to escape from is called sky glow, which is caused by badly directed light from cities, suburbs and anywhere else being shone up into the sky. Sky glow blots out large amounts of celestial and other objects in the night sky, including meteors. There are long term efforts to encourage city planners and private citizens to cut down on light pollution such as that by the International Dark Sky Association as well as local campaigns, but for now the general rule is to get as far away from cities and suburbs as possible.

The Moon is the only natural form of sky glow, and this is why you might often see star parties and get-togethers arranged at times when the Moon won't be in the sky.

Groups are good

While some people prefer observing on their own from time to time, it's really good to go observing with other people. Usually it's more fun, and it's more motivating when other people are enjoying themselves, too.

Stay warm

Most of the best observing nights are freezing cold, so if you're anticipating a good display you should also anticipate warm clothing. You might spend several hours sitting outside at night without moving much, so even if you aren't wearing them straight away, have lots of clothes nearby to put on later if you need to. Having several layers of clothing is good, because the air pockets between the layers double to insulate from the cold. Also take a warm hat, a scarf, and gloves.

Take a thermos and put a hot drink in it. Hot water for making tea and coffee is always a good idea, as long as you remember the dry ingredients. Also, don't forget to bring some food. Try to stay away from any alcohol, because having it in your bloodstream causes you to lose body heat faster.

Get comfortable and prepared to watch

If things work out, you'll be spending a lot of time looking up at the sky. If you're not using a telescope, then binoculars are still great if you can get hold of them. Binoculars are good for being portable and they take in a much wider field of view over the sky than most telescopes normally can. If you're using them, it's much easier with something to lie back on. Deck chairs and rugs usually work nicely, and don't forget a pillow. This way you can lie back and watch without straining your neck. If you're in a group, arrange for someone to pour a bucket of water over you if you fall asleep.

Also, if you see clearer with glasses or contacts, have them available. Even if you can see okay without them, the sky looks much better when it's sharp.

Have a plan

If you're with a group of experienced astronomers then it won't be so bad, because they'll be able to show you around the sky themselves. If you're on your own or with people who aren't very experienced though, it's a good idea to have some idea of what you're going to look for and where to find it before you go out.

There are lots of beginners' astronomy books available in the library and in bookshops, and most have recommendations of things to look for. Constellation identifying is a good place to start, since usually it doesn't require any optical aid. When looking for books, one thing to be careful of is that it has lots of information about southern hemisphere objects. Unfortunately many astronomy books that are published in Europe and the USA fail to give much detail about what can be seen in the southern hemisphere sky.


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