hi,
I'm looking at getting a relatively inexpensive fast doublet to do widefield narrowband and was wondering if the skywatcher 102mm F5 scopes are any good.
I have a mono sbig with a filter wheel and I will be re-focusing between filters so would that be sufficient to remove CA?
What sort of flattener/reducer will I need?
I really want it below F4 but I can't find an inexpensive one that's native F5 or below.
I'm looking at either
http://www.skywatcher.com/product.php?cat=3&id=39 or
http://www.skywatcher.com/product.php?cat=3&id=38
Will this reducer/flattener work with either of these scopes?
http://www.bintel.com.au/Astrophotog...oductview.aspx
This would drop both F5's to F4 which is what I like to image at.
I'm using an STF8300m with an OAG and lodestar and the sharpsky focus controller.
Cheers
Alistair