How can I get Saturn brighter?

[Doodles23 (Dave Bleser)]

I have a C11 and a DMK21AF04. I live in Miami and typically on a clear night there are only 5-12 stars visible to the naked eye. That said, I am having a rough time getting a blue filtered image of Saturn @ f/25 bright enough.
If I drop the frame rate to 7.5 frames/sec the image will be just bright enough, but I'd like to be able to get to 15 fps like I use for the Red and Blue images.

Now the question..

If I upgraded the c11 to a C14, and kept the imaging at f/25, the image size would be the same on the CCD. But would'nt the image be sufficiently brighter to be able to achieve a 15 fps capture rate?

What if I upgraded the camera to the more sensitive Skynyx?

What if I took the scope to a dark site where I don't have to deal with 3 magnitudes of dimming? Would that brighten the image even more?

Which of these 3 strategies would bear the most fruit?

Dave Bleser

[bird (Anthony Wesley)]

Dave, upgrading from a C11 to a C14 would give you 1.6x as much light, so if you leave the focal length the same as current (ie keep the image the same size) then you could increase your fps in all channels by 1.6x.

You don't want to keep the focal ratio the same - that would make the image larger but the same brightness, it's the focal length that you're really talking about here.

A more sensitive camera is also a good option - the DMK has 8 bit resolution whereas the SkyNyx and other modern cameras have between 12 and 14 bit resolution, this means you can fill less of the histogram and still get a good result. Filling less of the histogram means you can use a faster fps.

Also the modern cameras allow you to pick any fps, not just 7.5/15/30, so you can find the best match with your scope.

And finding a location where you're not looking through a lot of salt haze would help make the image brighter :-)

cheers, Bird