I use an ED80 to image, although i am looking at something additional for two reasons
1. the ED80 is widefield and i also need something with a smaller frame
2. I want something with a larger aperture to capture more photons!
and it got me thinking, i can work out the frame size with a CCD calc utility, but can someone give me a comparison, like for like, with exposures on two differing scopes?
Let me give you an example, would a 20 sec exposure of say, the Lagoon Nebula on an 8" reflctor, be about as bright as 60 second exposure on the ED80? i know the resolution, amount of info captured, and frame size would be different, but you can see what i am asking here, just for some general info on the differences with exposures lengths as a comparison.
its a bit covoluted i know.
thanks for any answers.
