What on Earth, for viewing off the Earth?

[Scottie]

Hi All,

Someone complained recently to me how some Astro mags compare different scopes on the notion that it wasn't quite fair play or truelly informative.

It is rare, ( unless I've missed it ) for mags to compare say a plain 8" SCT and a plain 8" Newt. Not that this would be necessarily fair to either setup. People choose scopes for different reasons or what they intend to do with their personal observing... photography being a real passion these days.

I still cannot make up my mind over reflectors or SCT's.

What say you all ?

[Scottie]

Hi Again Good People,

After weeks of thought I am still weighing up the develoment plan for an observatory set-up. So here goes. Please do reply with insight if you feel inclined.

I may spend up to 5K on equipment but leaving aside the observatory build costs later. (Yep I am lucky being a pro joiner for a living so the observatory build should be a snip)

14" f 5 hand-built Newtonian, low profile focuser, on a Losmandy G11 mount with Gemini GoTo. Main steel support pier.

I have thought of having an interchangable larger secondary mirror should CCD imaging require it, taking the scope towards Astrograph territory.

I have heard the main issue with Newtonian photo imaging quality is the importance of rock solid mount support for long exposure sessions. Some superficial research tells me a few things about SCT's and Newts and the influence of the secondary obstruction in observing and astro imaging.

For example; 11" SCT secondary obsrtuction by diameter 34% (Celestron) Havn't found values for Meade.

10" Newtonian Reflector secondary obstruction 19%

10" Astrograph (Orion optics UK) secondary obstruction 40%

Some suggest that the human eye can detect a difference of 0.1 magnitude in reality more like 0.2 and above, so anything under say 30% obstruction by diameter may be undetectable. The big question is does the camera care?

Larger obstructions in larger apertures do create slight loss in contrast and visual softness, yet Newts stay ahead of this issue by having as much as one third less obstruction than SCT's.

Do we want bright and accurate Astro images?

Do we want portability first?

Tell me what I have missed out or mistaken please.