Nikon D90 Digital Slr Camera Kit / Nikkor 18-105mm F/3.5-5.6

I think I paid close to a $1000 on a sale a few years back.

Been drooling over a D-90 for astrophotography since they came out. I almost jumped on it when they were on sale recently, until I looked at it's replacement, the D-7000. And I believe it has already been replaced, a D-7100 I think.

Just like when I bought my D-70 in 04 once you buy one of these pricey cameras in 6 months it will be obsolete/discontinued. But I still want one, it's a great camera for space pics.

Rick

The large screen and live display make focusing the rig much easier in the dark. On my D-70 I have to focus through the viewfinder as best I can on a bright object, like the Moon or a planet, take a shot then view it on the laptop to insure it's in perfect focus, and then repeat until it is. Then I slew the scope to the object I want to shoot.

What's in focus for my eye isn't exactly in focus for the camera/telescope. I now use a knife edge focuser but it's still a pain.

And astrophotos require sharp focus, especially if you're stacking a bunch of them.

And the high ISO is desirable for some but I like it a little lower, I usually shoot 800 or less. A lot of guy's shoot 1600 or 3200 and then process out the graininess.

There are a few other considerations that deal with noise and dark frames. Dark frames are required when stacking a lot of exposures to cancel out noise.

And of course twice the pixels of my D-70 is a big plus, the self cleaning sensor also.

The newer D-7000 has 18 mega pixels and dual card slots. This is a huge plus as taking long exposures in RAW format eats up some card space.

Rick

Unless I'm attempting very high magnification shots, which require shooting through a telescope eyepiece (a real PITA) I mount the camera to the telescope focusing tube with a 2" T-ring. Focus is achieved by focusing the telescope, it acts as the camera lens. This is called "prime focus".

I also have a 2X and a 4X multiplier that I can stick in the mix for double or quadruple the prime focus magnification. These two pieces are pretty pricey themselves. So by using the shoot and view method or the knife edge focuser it's no problem to get focus at infinity. Even on wide angle shots I've made with regular ED lenses I never had any trouble focusing at infinity.

Not sure what you mean by removing the AA, that's a new one for me. Some people do remove the IR filter that does filter out Ha and Hb wavelengths, and those are important wavelengths for shooting nebula, glowing space gas. But by removing this filter the camera becomes pretty much worthless for terrestrial photography.

Canon once made a camera with the IR filter removed strictly for astrophotography, the 20DA I think it was.

I shoot through a 178mm f9 APO refractor so it's not a very fast lens, but you can't beat the crisp, sharp details and contrast you get from a refractor over a reflector. Just viewing Saturn though this scope will knock your socks off.

Apologies to the OP for drifting off course.

Rick