Quote:
Originally Posted by gregbradley
Herein lies the problem of using just one scope. No scope is ideal for all uses it seems. Some are more flexible than others. They tend to sit in either wide field, medium field or narrow field.
Wide field tend to be your 4 inch type refractors, medium field large refractors, Newts and narrow field are your RCs Dall Kirkhams.
Some APOs have multiple accessories to allow a bit of each world and so can Newts. RCs though tend to only be long focal length.
The Ceravolo 12 inch astrograph is an attempt to be both wide field and narrow field. AP Honders probably is another one.
Its better to have larger aperture and a faster F ratio like F5 or better and use size of sensors to gain the desired image scale. For example 12 inch F3.8 should be a fairly wide field scope and Mike uses both 16803 camera (gives a wide view) and a 694 chipped camera (gives a galaxy type field of view). That way you don't even need barlows etc and retain the F3.8.
So 900 to 1260mm focal length and 2 sized sensors is quite a flexible approach for fairly wide (not FSQ106 wide though) and for galaxies.
In other words, concentrate on aperture and F ratio at the highest level of optics you can afford.
Greg.
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Hi Greg,
Surely if Mike used the ASA 1.8 x barlow here:
http://www.teleskop-express.de/shop/...low--1-8x.html
He'd get more detail from small galaxys?
cheers
Allan