Basic Astrophotography

I have a good amount of astrophotography experience. I just received my Nikon D100 (see D100 Images) in mid August, 2003, and I've started using it to shoot some astrophotos.
Update: 10/28/2005, I am shooting with a Canon EOS 20Da.

This page covers astrophotography basics, with some discussion of both film and digital imaging.

Star Trails

Take a camera, mount it on a tripod, aim it at the sky. Using a cable release, take a picture for 1 minute to 1 hour. Shooting really long exposure star trails is still best done with film. If all you want is star trails, you can use slow film like Velvia. Here's a 2 hr. job on 100 film; details on the page: "Sky glow" has to be accounted for in your film speed & aperture calculations. You don't need a fast lens, BTW. From suburban skies, try 5 minutes on 100 film at f4 as a start, and experiment.

Stars or planets from a tripod

Shooting stars without trailing is similar to the above, but you use faster film. 800 film or faster with exposures between 5 and 60 seconds are good. Shoot a roll bracketing from 4s, 8s, 16s, 32s, and 64s and see what you get. Use f2.8 or so to start. Similar digicam techniques will work, also. See examples of stars and planets from a tripod here. A new "Fixed Tripod Astronomy Pictures" page is here.

Telescope & Milky Way, fixed tripod, ~30 second exposure at f1.4, 50mm lens

Meteors

With regards to shooting meteors, there is a very specific technique where you expose for about 5 minutes on 800 (or any fast) film with a normal lens at f2.8 or so. You point at the part of the sky where there's likely to be the most activity, or perhaps frame a familiar constellation as my friend did. See pix, links, discussion: I've not this the above with a digital camera; but, due to the shorter exposure (3-7 min), it will work better than star trails (1 minute to all night) *very* long exposures.

Shooting from a mount that tracks the skies movement

It almost goes without saying that you need at least a sturdy tripod when shooting star trails or meteors. I shoot tripod camera lens stuff, but this gets limiting in a hurry. I also shoot through the 'scope ("prime focus"), as well as with cameras and lenses attached to a telescope mount ("piggy back" or "wide field"). See me and my scope/mount setup here: (bottom of page) and here: Scope Setup (this shows a camera and a film lens attached to a telescope mount.

Here's a link with one of my better wide field shots

Prime focus is very difficult and takes quite a while to master. Film choice here is very important, because some films are very poor performers. For both prime focus and wide field astrophotography you want to use film that's no longer sold (Kodak PJ400/LE400 and the old Supra 400). Now Kodak E200 slide film is the best sold that I know about. It's difficult to scan and several folks push it btw 1-3 stops to brighten it up. This is an always changing topic, as films get reformulated all the time now with little or no notice.

Digital SLRs, Digicams, and Astrophotography

The Canon 10D and related cameras were king of D-SLR astrophotography due to long-exposure noise characteristics. The Canon EOS 20Da is king now in 2006. There are still reasons to prefer film for astrophotography, cost being a primary factor. See my discussion here: Why Film Astrophotography?

One other point is that what people do with digital cameras is to take a large number of pictures that individually are under exposed, and then digitally combine them. Combining multiple images is required to create good pix of planets.

Most astro images benefit from extensive digital image manipulation as described here Photoshop Basics

There there are a couple of newsgroups relevant to this topic, the astro-photo@seds.org and http://groups.yahoo.com/group/digital_astro/

-Dick L.

p.s. Books: Covington's Astrophotography for the Amateur and Reeves' Wide-Field Astrophotography are indispensable.

The following question in a news group prompted me to scribe this page:

>I apologize for repeating a topic. I'm shooting with a D100. I use it for photo journalism and it is my best friend. I took my friends out the other night to shoot the rather unexciting meteor shower and set it up to take a long exposure of the sky in hopes of capturing one of those then illusive streaks of burning rock. I got the exposures right and I can see a nice smattering of stars all turning about one central point but there is a LOT of noise after the 20 minute exposure. I had NR turned on but its still there. Are there any tricks or general good practices that could help reduce the noise?

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