• Afocal Photography

• Wide-Angle Piggy-Back Photography

• Telephoto Piggy-Back Photography

• Prime-focus

• Telecompressor / Tele-extender

• Eyepiece Projection

For intermediate astrophotography, we'll start easy at first, with bright subjects and relatively short exposures so that tracking is not that important. Focus, however, will now get more critical as we start shooting with longer focal lengths.

The Learning Curve

• Learn how to critically focus your camera.
• Begin shooting wide-angle shots with a simple barn door mount or equatorial mount.
• Start seriously researching in-depth which telescope and mount to buy.
• Perfect your wide-angle technique.
• Decide which telescope and mount you want, and buy them.
• Learn how to use the new scope and mount.
• Master the art of drift polar alignment.
• Learn how to guide.
• Start shooting piggy-back photos with telephoto lenses on top of your new telescope.
• Perfect your piggy-back technique.

After you have mastered some simple time exposures on a tripod, you may be feeling more adventurous and want to take some longer exposures that track on the stars as the Earth rotates below. Longer exposures can reveal much fainter stars as well as nebulae and other interesting deep-sky objects.

Many of today's modern telescope mountings that feature computerized Go To capabilities use altazimuth mountings. These mountings are not polar aligned, and although the computer allows tracking of an object over long time periods, the field that contains the image will rotate around the center of the frame, causing "field rotation". This makes the stars in the image almost look like star trail pictures. with a computerized altazimuth mounting your maximum exposure will be limited to about 30 seconds.

You can take deep-sky images on an altazimuth mounting if you keep your exposures short and stack a lot of frames as seen in the astrophotography of John Ambrose. Depending on the speed of your optical system, it can be difficult to get the image data up out of the camera noise with these kinds of short exposures though.

To shoot exposures longer than 30 seconds will require some type of equatorial tracking platform. This can be in the form of an German-equatorial telescope mounting or inexpensive "barn-door" mount. These must be correctly polar aligned.

Many modern equatorial mountings come with a accessory polar axis alignment telescope. This is a small telescope that slides into the hollow polar axis of the telescope. This alignment scope contains a reticle for finding the north celestial pole. This type of alignment is usually accurate to a couple of arcminutes and close enough for exposures of several minutes without field rotation.