DSLR Astrophotography Tutorial

A Look Ahead To The Higher Levels Of Astrophotography

If you are hooked, you are going to want to shoot deep-sky objects like galaxies and nebulae and use more advanced techniques. With a telescope, and a camera with a lens (not your basic digital camera) you will be able to shoot the Moon, including close-ups of the craters!

This will require learning about attaching your camera to a telescope that has a motorized   mounting  that tracks the stars. Your camera will ride “piggyback” on top of the scope. If you have a DSLR camera, you will remove the camera lens hook it up directly to your telescope. The telescope becomes the camera lens.

There are a few pieces of equipment you will need in order to progress at this level

• You will need a telescope on an equatorial mount to track the stars so you can use the long exposures required for these faint objects.
• You can also use a computerized altazimuth mount to shoot brighter deep-sky objects.
• You really need something like a German-equatorial  mounting  with motor drives on both axes to do any kind of serious long-exposure deep-sky astrophotography.

If your telescope only has an altazimuth  mounting  that you use for tracking the stars as well as compensating for the Earth’s rotation, then your timing for exposures will be limited to no more than 30 seconds. Any exposure that goes beyond 30 seconds will suffer from “field rotation”. The stars end up rotating around the center of the frame, and so will look pretty odd. To shoot pictures of the night sky that have over 30 second exposures you must use an equatorial  mounting  that whose polar alignment is accurate.

Advanced astrophotography levels will show you how to shoot Raw file-format images and separate dark, flat-field and bias support frames. These are used to calibrate and improve light images.