Celestron Mini-Maks, et al (1 Viewer)

[Robert Ellis]

Do these types of scopes as marketed for birders present the image properly oriented left to right? It has been a long time since I gave a second look at astoronomical scope designs.

 

[Jay Turberville]

Do these types of scopes as marketed for birders present the image properly oriented left to right? It has been a long time since I gave a second look at astoronomical scope designs.

I believe that they do via the use of a 45 degree roof prism. At least all of my catadioptrics work that way. For better image quality, you can use a mirror finder that will erect the image but leave it reversed left-right. And in-between the two, you can use a Porro prism. But these are bulky and also only offer straight through (actually slightly off-center) viewing.

 

[Humboldt Jim]

The exception is the Maksutov-Gregorian design. Unfortunately the erecting prisms comonly used degrade the image and most mirror scopes have high focal ratios and narrow real fields of view. From an optical standpoint, however, good quality catadioptrics nearly equals the best refractors. Mirrors simply do not have chromatic aberation.

 

[Jay Turberville]

The exception is the Maksutov-Gregorian design. Unfortunately the erecting prisms comonly used degrade the image and most mirror scopes have high focal ratios and narrow real fields of view. From an optical standpoint, however, good quality catadioptrics nearly equals the best refractors. Mirrors simply do not have chromatic aberation.

That's correct about the Maksutov-Gregorian. My 40mm Lomo Captain uses that design.

http://www.jayandwanda.com/digiscope/digiscope_calc.html

Cats are an inexpensive path to very good optics. Though they tend to give up FOV (as you mentioned) and some image contrast. I think they are well worth considering for inexpensive digiscoping and maybe not so good for observing depending on your priorities. Though for very long distance observing, the larger ones may be the very best choice.