Astrophotography

Using telescopes for astrophotography or a spotting scope for digiscoping is something we are often asked about.

For astrophotography, and even for some wildlife photography, it can be more economic to use a telescope rather than a telephoto lens with a teleconverter attached.

The exact method of mounting a telescope depends on your camera and telescope combination. Most SLRs can be attached to a telescope via a T-mount adapter.

With the eyepiece of a telescope removed, the T-mount adapter screws on to either the rear of the telescope or the eyepiece thread. In turn, the T-mount adapter needs to fit the body of your camera. This is the same adapter you would use if you were fitting a T-mount lens.

There are other adapters, specifically designed for compact digital cameras.

The smaller size of compact cameras makes them easier to use when coupled with a telescope, as they are lighter and more manoeuvrable when trying to track a moving subject or find a particular astronomical target. Compact cameras also don’t suffer from mirror slap, the slight vibrations of which can affect image sharpness.

To help steady a camera and scope it is vital to use a sturdy tripod and mounting system. This is further complicated by the long exposures needed for astrophotography. As the earth rotates, it appears as if stars are moving across the sky. Over a long exposure this causes light trails in the sky.

To prevent these trails, or blurring caused by this movement, an equatorial telescope mount should be used. This compensates for the Earth’s rotation by using a motor to rotate the telescope at the same speed as the Earth is turning, helping to prevent star trails and blurring.

For more on astrophotography visit www.astropix.com, or for digiscoping visit www.digiscoping.co.uk.

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