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Baader Mk.V and mirror T-2, part 1.

Started by rumpledoll, 06/01/2006 11:36AM
Posted 06/01/2006 11:36AM Opening Post
It has always been a small niggling concern of mine the Baader prism T-2 diagonal that came with my Baader Mk.V might be introducing a small bit of colour and spherical error when used with my f/6 130mm APO and f/5.8 105mm APO.

I saw that Baader has available a T-2 Maxbright mirror diagonal. Hmmm, I thought, let's get it and see.

Comparing it to the T-2 prism unit, it was a very little bit larger. It would not come to focus on an AP 130EDF and 24mm Pans. Uh-oh. A quick order to AP for their 2" thin adapter (ADA2013) did the trick.

Last night I used the 130EDF, 24mm Pans and 13mm Naglers with the Baader Mk.V and the mirror T-2 diagonal and thin adaptor. Before the mists rolled in the views of the Moon was very nice indeed. I was happy to be able to reach focus.

Next up is seing if I can reach focus without the 1.25" glasspath and seeing if I really notice any correction improvement from the mirror diagonal vs. the prism diagonal. I think it may be more a theoretical improvement rather than a practical, but we shall see.

Philip
Posted 06/03/2006 04:55AM #1
Hi Philip,

I was waiting to see if anyone else was going to respond to your post. You have some very nice equipment. Some of us wish we had your problems. grin

Please let us know if you do see any difference in color between the prism diagonal and the mirror diagonal. My gut feeling is that you will not but I would like to hear what you discover.

thanks,
Don Durbin
Posted 06/03/2006 08:49AM | Edited 06/05/2006 08:16AM #2
Philip Blanda said:

Next up is seeing if I can reach focus without the 1.25" glasspath and seeing if I really notice any correction improvement from the mirror diagonal vs. the prism diagonal. I think it may be more a theoretical improvement rather than a practical, but we shall see.

Philip

Hi Philip:

I have measured that I need to rack my focuser in an additional 18mm to reach focus after removing a 1.25x glaspath compensator.

I'm sure that the amount of necessary in focus travel is a very system dependent measurement, but my system is similar to yours (24mm pans, Mark V, 140mm f7 refractor).

The field of view without the 1.25x glaspath is really not that much wider, but it is nice to go to the maximum for open clusters and other big things like M31.

I can't see any aberrations at these super low powers with or without the glaspath. I do always use the various glaspaths and/or barcon combinations for planetary viewing though. I like being able to run the whole list of useable magnifications with just the 24 pans.

Jim