Wednesday, May 19, 2010

Ghetto Astrophotography

Do not try this at home, I am a professional.
Okay, not really.
If you do though, don't blame me if you see some UFOs.
Or something.
Way back in another life, I wanted to get into astrophotography, but as you can imagine, it's sort of an expensive hobby.
If you want to go after really big game, it gets, well, astronomical!
Get it? Astrophotography? Astronomical?
Anyways, you start off with a telescope:

I won't get into the particulars about the telescope for there are like a GAGILLION types out there. I will say that if you are thinking of getting one, don't get a cheap department store scope. Do some research; Sky and Telescope(link on right) has some good articles on buying into this hobby. My scope is about fifteen years old and is still in fairly good shape although it could use a good cleaning.
Focal length of my scope is 480mm, on the small side, but it has a wide field of view. Most refractors will be longer.
The diagonal is where the good stuff happens:

This is a 2" diagonal which is capable of handling 1.25" and 2" eyepieces. More on that later. The diagonal is where your image is corrected to right side up. If you look straight through a refractor, without a correcting diagonal, the image is not only mirrored, but upside down.
That's not too important for astronomy, but it sucks if you plan to use it for terrestial viewing.
The eyepiece(EP) is where you, well, look into with your eyeball:

The eyepiece is just as important as your scope! Don't be frugal here either. They come in all different sizes and the focal lenght determines your magnification.
For instance, that's a 13mm EP and a 480mm scope for a magnification of around 37X.
Of the EPs I've bought and sold, I kept this one for it was one of the last of this particular design that was made in Japan. I believe Televue makes their EPs in Taiwan now.
There are a whole bunch of things to consider when purchasing an EP so again, do some research before you jump.
Now, your mount is important too. What you don't want is something that will jump around or vibrate a lot. Let me tell you, that's not good at 100X.
So what about the pictures?
Okay, so let's put this together.
If you were serious, you'd remove the diagonal, get a T mount and attach a DSLR or something. This in effect turns your scope into a large telephoto lens.
You also need an equatorial mount, a mount that tracks the sky as the earth rotates. It centers on Polaris, the North star and tracks celestial objects.
This is important for you are probably going to take long exposures; over a minute is the norm.
I have a simple Altitude-Azimuth mount; a cradle mount that lets me move the scope side to side and up and down.
I'll try to get some Milky Way shots and come back to this later.
Now for the Moon, because it's so bright, you can get away with 'normal' camera settings. The pics from last night were shot with a shutter speed of 1/125 at f2.7.
Being the poor person I am, I can't afford all that fancy smancy stuff.
I gotta make do with what I got.
So I just hold the camera to the EP and shoot away:

No, the camera isn't small, the EP is huge. A little smaller than a beer can.
Anyways, you get the idea.
Astrophotography ain't cheap, but it certainly doesn't have to be out of reach.
The thing is, people tend to get bored with astronomy pretty quickly, so there's always a good supply of used stuff out there.
In fact, if you just want to kind of look around, binoculars do fine.
So now that I kinda sorta know what I'm doing, I want to get more shots of the Moon behind some clouds.
Dramatic effect, don't you know.
There you go!
Shoot the Moon on the cheap!
Sort of.

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