Tuesday, October 1, 2013

Indoor Astronomy

One thing you hear from time to time is: Astronomy can't be done indoors. Well, I say Bah Humbug! to that.

Well of course the quality of the images is better if you schlep yourself and your astronomical gear outside. First of all you don't have the window panes between your fine astronomical instrument and the astronomical object you want to observe. As you probably do not have windows made out of a multi-coated, λ/4 polished, BK7 glass (or better), the image will be somewhat degraded by the window panes. But even if you do open the window, the temperature difference between inside and outside will lead to thermal currents which can degrade the image. And of course the portion of sky one can see is limited.

Having said that, you can do astronomy from indoors. In summer I observed Saturn with its majestic rings from inside. I opened the windows half an hour before I started observing and I didn't notice any problems.

Then in the last month I observed through the closed window and got quite nice views of the Moon at around 60x magnification.

And on Sunday I saw the Pleiades just fine from inside at 12x magnification.

Of course, the fainter and the smaller something is, the less likely it is to be viewable from inside. Conversely the less difficult an object is, the more likely it is to be viewable from inside. If you can go outside to observe, than by all means do it! But sometimes there are reasons to stay inside (staying outside in the cold is not good my health) and then it is good to do astronomy from indoors.
    [Update 2013-10-23] I have to report that I tried yesterday to observe Jupiter from indoors, through the closed window and it was not good. The disc was not resolved sharply, and the two visible jovian moons were turned into smudges (the other two moons were transiting Jupiter, or close to the limb, I take it). So low magnification is OK from indoors (say for open star clusters, or the Moon), but trying to do any "serious" astronomy through a common window-pane is not the way to go :-D

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