Quote:
Originally Posted by Shiraz
if you can get up to 60 minute subs, you will make a signifcant difference Paul - the read noise component will drop to about 0.6 of the level at 20 minutes.
from a sensitivity perspective, your scope is functionally equivalent to Mike's, with the same aperture and roughly the same sampling.
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Ah ok, 60 minutes ought not be a problem but I would need to do this on nights when I can be assured of no cloud. Worth a try though to see what results could be obtained.
Quote:
Originally Posted by Atmos
Depending on your filter passband (3,5,7nm) you'd be looking at somewhere between 1-5 hour subs to be read noise limited if you have 12e- RMS read noise; also depends on the exact numbers I use in the iPhone calculator 
I'd say that it is the camera that is the biggest link in the chain. Focal ratio doesn't mean anything as long as you have pixel sizes to match. Mike is using 4.54 micron pixels at F/3.8, you'd have the same pixel scale with 9.55 micron pixels at F/8 (~0.8"/pixel).
Of anything however, a lower read noise than the KAF-11002 would make the biggest difference. |
Yes our image scale is very similar. And, I am contemplating a new camera as an new solution to the problem.
Band pass on the Ha is 5 nm , SII 5nm and 3nm on OIII, if that helps with your calculations. OIII on this object extends a little way around the object from the main ring. Deeper subs would be required to show it further out I suppose.
Quote:
Originally Posted by DaveNZ
Have you looked at focal reducers ? Im not sure what will work well with the GSO RC. So perhaps a new camera and a focal reducer.
Cheers Dave
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Thanks Dave, actually this has been the line of development I have looked at the most, it is the most cost effective. Reducing the focal length down and using a new sensor to match the existing scale or thereabouts is going to work better for me at present and it will eliminate issues with my current camera, which is unreliable. I am making changes at the observatory to an existing pier this weekend to allow me to put the big scope in the roll off roof. This will give me some flexibility to house a large Newtonian or a large RC. If I use a reducer and newer sensor with smaller pixels at first that will help determine whether I need to go further and buy a fast Newtonian. A large Newtonian would not fit in the dome, but it will fit in the ROR.