SIMPLE COMET PHOTOGRAPHY
The appearance of a graceful comet hanging in the sky will certainly stir your
imagination and you will want to capture this photographically.
Todays digital cameras are a revelation over the old film-based cameras.
The advantage of imaging is that it is much more sensitive to colour and light than your eye, hence you can capture the comet in all its colourful glory as well as pick up fainter parts of the tail that are not seen visually.
It is rather simple to take successful night sky photographs and these are the basic requirements:
You will need to use a manual Digital SLR camera capable of taking long time
These cameras have a B setting on your exposure control.
If you use an automatic SLR camera, be aware that it will use battery power when the shutter is open, so carry a spare battery, or use an AC adaptor.
Those fortunate to own high end digital cameras are able to take excellent quality images.
The lower the shooting speed the less grainier the image (noise).
If using a digital camera, I would recommend using the ISO1600 setting to reduce noise.
Take several exposures and stack them together using software. Don't forget to subtract dark frames of same exposure length.
The better the lens quality, the better the result.
I would suggest spending as much for the lens as you paid for the camera.
Pick a lens in the 28 to 50mm range and open the lens to its widest focal ratio (usually f/1.8).
The smallest f/ratio the better, as it allows more light into the camera.
Lenses over 50mm usually are too slow for standard tripod photography and you will need to mount the camera onto a equatorial tracking telescope.
Should be sturdy enough so as not to shake during the exposure.
5. DIGITAL TIMER
Is used to prevent the camera from jarring while starting and ending the
exposure. You can take multiple exposures with time delay intervals.
6. EXPOSURE TIME
Because of the Earth’s rotation, exposure times longer than 30 seconds with a 50mm lens will show trailed star images. Experiment for best results.
7. PROCESSING IMAGES
There are several freeware programs available on the web. Try deepskystacker or fitswork,
One final note. You might think it unwise to take photographs during moonlit periods. True, the end result is a blue background sky giving the appearance that the photo was taken during the daytime. However, should the comets be sufficiently bright enough, you can use moonlight to your advantage by having a foreground object such as a building, mountain, tree ect. add to the aesthetics.