Camera advice for C14 SCT requested

The best camera I’ve ever had is the ASI2600MC Pro. But with your light bucket, maybe a 6200 would be better.

A lot depends on what you want to image. When I use my C14 for small planetary nebulae and small galaxies, I will use a 585 based camera since I don’t need to record all the black space around the main object. For lunar and planetary “lucky imaging” I use a QHY5III715C. For large nebulae, I use a QHY268C (same chip as the ASI2600C suggested by @SonnyE above) and an ASI6200. An important thing to remember, is that unless you are doing lucky imaging, you will rarely have conditions good enough to use a C14 at its native focal length. Assuming you use a camera with 3.76u pixels (2600 or 268C), under average seeing conditions of 2” - 4” FWHM, an image scale of 0.67” - 2” per pixel is adequate to achieve all the resolution you will get for the conditions. At 3910mm focal length, this setup gives you 0.2”/px resolution. This is way over-sampled! You are limiting your light through-put, taxing your mount and requires excellent guiding all for no increase in detail than what you will get at a lower pixel scale. With a 0.7x reducer, you are still over-sampled at 0.28”/px. Even with a 0.33x reducer you are slightly over-sampled at 0.6”/px, but not by much.

If you have good seeing (1” - 2” FWHM, 0.33” - 1”/px resolution), the 0.33x reducer is perfect, the 0.7x reducer is still slightly over-sampled and with no reducer you still have significant over-samling. With excellent seeing (0.5” - 1” FWHM, 0.17” - 0.5”/px resolution) both the 0.7x reducer and the native focal length are properly sampled, while the 0.33x reducer results in slight UNDER-sampling. So which focal length you use depends on what your average seeing conditions are.

This is not to say that you shouldn’t try imaging at higher focal lengths. You may get lucky and have a rare night of exceptional seeing and get fantastic results with this scope. I have had a few at a high altitude dark sky site I go to. But at home, unless I am doing lucky imaging, I just leave the 0.7x reducer on all the time (I don’t have a 0.33x reducer, although maybe I should get one!), knowing that some images will have better detail than others. For the ones with less than ideal detail, I down-sample than during post processing and they still look great, just smaller!

Arnie

Hello. For three years I have been observing with a Celestron 14 Edge, from the beginning I have been doing it with an ASI 2400MC. My observation site has a Bortle 6/7. At first I used a focal reducer of X 0.7.

For a year and a half, I have been taking images at primary focus, that is, focal 11. To achieve good tracking I use a 90 mm diameter refractor and 900 mm focal length as a guide telescope with an ASI 678MM camera.

On good seeing nights, I have reached AR and Dec corrections of 0.16”.

In general I am satisfied with the equipment I now have.

Health and good skies.

2400 would be a perfect match for the 14.

Thanks to all for the advice. I’m part of a small group of fellows who have a C14 OTA available as part of our club inventory. One of our group is going to sell us his Paramount MX+ with 3 cw for a greatly reduced cost. We have some other donated items to work with and the rig will be sited at our club observatory facilities with remote operations being discussed.

I use an ASI678MC with my C14 non edge scope. It matches the focal length without using a barlow or reducer. I have got some really good planetary images with it. For DSO I use an ASI2600MM with a .80 focal reducer.