4 ms·
Not at all, my 9.25” telescope has a focal length of about 2.4 metres - a focal ratio of f/10. You’ll recognise f/x from camera lenses and such. The diameter
by carl_dr 5y ago
Not at all, my 9.25” telescope has a focal length of about 2.4 metres - a focal ratio of f/10.
You’ll recognise f/x from camera lenses and such.
The diameter does control how much light the telescope “swallows” though, you’ll need a larger telescope to see less bright objects (or longer exposures, although when you are using your eye, that has a limit of course!)
So in this case, the post about is saying you’ll need something about 200mm diameter to see the comet. Anything smaller, and you’re just not getting enough light to see it.
- SAI_Peregrinus 5y agoThat said, if you don't care about seeing it in real time you can use a MUCH smaller lens and stack exposures. You'll likely want a star tracker (MASSIVE decrease in effort) to go with your camera, lens, tripod, intervalometer, and Bahtinov mask (cheap, makes focusing MUCH easier). https://www.youtube.com/watch?v=iuMZG-SyDCU https://www.youtube.com/watch?v=iuMZG-SyDCU is an excellent tutorial on how to do this without the tracker.