Quote:
Originally Posted by cometcatcher
Yes. A fast F4 system will capture nebula in much shorter time than an F10 system will. This is why fast scopes match DSLR's so well.
|
Thanks Kevin, that might explain why I've seen so many DSLR images on the cloudy nights forum taken with fast newts
Quote:
Originally Posted by raymo
For example here's one I took years ago. 1100D 10x45secs ISO 3200. 8" f/5.
Very simple unguided imaging, and just stacked in DSS, no separate darks, flats, etc: Far better images of M16 than this can be obtained with a DSLR.
raymo
|
Cheers Raymo, that's a great image you've got there!
Quote:
Originally Posted by RyanJones
Hi Evan
There is no doubt that the Astro cam image is clearer. I concur that the fact that it's a mono cam would help with that considerably. It's a good comparison to see. Often, as we all have different equipment, it's hard to tell what is causing what difference. Good on you for posting it.
As far as F ratio goes, lower f, lower required exposure time for the same data. That being said, I have an f10 SCT which is " slow " by AP standards and I live under skies that literally look like daylight when it's cloudy. The trick there is to trade in a good f ratio for some good old fashioned perseverance. |
Thanks Ryan, absolutely! Based the information contained in this thread I've now realised that it's not as simple as comparing the cameras. The telescope, f ratio etc. is also an important component.
I often find myself shooting at either f10 or f7. My favourite targets are galaxies so I prefer the longer focal lengths