Jump to content


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Mark Vs on C5...

  • Please log in to reply
3 replies to this topic

#1 Eddgie



  • *****
  • topic starter
  • Posts: 17246
  • Joined: 01 Feb 2006

Posted 06 December 2012 - 09:57 AM

Ok, I already knew that Maxbrights made the C5 a lot of fun to use, but with the Mark Vs, the Joy-Joy factor jumped up quite a bit.

The Binoviewer, T2 Diagonal, and 24mm Hyperions seem to weight almost as much as the OTA! Scary to have all that money hanging off of the back!

I put my AP 2" adapter on the back of the C5 and this is actaully only 1/2 inch longer than the standard SCT 1.25" visual back, but more an that later. Anyway, the back focus is about 10mm more, so a minor impact, but the light path though the bino is also about 10mm more, so the back focus is likley close to 200mm, and the focal lenght as a result is going to be more like 1550mm or 1600mm than the stated. This would give a bit higher magnificaition than the Maxbrights, but of course this is offset by the ability to use eyepeices with a much larger field stop.

So, with the 24mm, I figure the field was about one degree and the magnification was about 65x or so.

As compared to my EdgeHD or C14, this is a huge true field!

I was out with the C14 mostly, but I had some dew formation and while I was waiting for the dew strip to cook it off, I went in for the C5 and move the binoviewers over to it.

I reallly didn't spend long with it, but I did have a chance to sweep through Orion and what a great sight! The 24mm Hyperions are maybe not the best eyepeices (though they are better than I had hoped) but they did an excellent job in the Mark Vs. The field was rich everywere. Just delightful. I do miss wide field viewing, and even the 6" APO was not able to give a field this big when binoviewed, so this was a delight.

And then I got to M42. Terrific. Just terrific! Trapezium was soooooo good that I could have sworn that I was catching hints of the "E" component. Seeing was not great though so it held me back from confirming this.

But the Nebula was enormous in the eyepice(s) and was beautifully renderd, with lots of detail and lots of extension. The wings spread far out into the field, and the big lagoon at the core was very black agiant the billows and stratus of the nebula itself.

The Trapezium was blazing. Brighter than I would have thought given the binoviewers and the aperture. And the area around the nebula was well populated.

This has me considering getting a better mount for the C5. Maybe an Alt Az mount. I used the Polaris, but there is a lot of interference, but I was using it in Polar mode, so maybe I just need to flip it into Alt-az. I worry about my home made modificatoin though. I cut a dovetail notch into the mount and that was fine for the C5 alone but with the Binovieres, the load is kind of heavy and I worry about the torque perhaps causing the metal to fail.

I had expected that the C5 would be even more fun with the Mark Vs than it was with the Maxbrights, and my brief expereince did indeed shot that to be the case.

As for the 2" back, I am thinking of going to the Televeu "Shorty" back. The noze on the T2 diagonal is actually very short and the short Televue back might be a better match, and could save me maybe 10mm of back focus. I know I sound anal about it, but back focus is the number one enemy of binoviewer usage for SCTs and refrectors that need GPCs to reach focus, and this is an inexpensive update. I worry about clearance though.

Anyway, this is a fun, fun, fun setup, and it is making me want to use the C5 more and more. And this is a scope that was gathering more dust than photons (just too small, but the binoviewers are making it a great wide field scope).

So, a great result. Better than I expected. The view seemed quite bright and the field was very wide.

What fun.

#2 prestonrich


    Viking 1

  • -----
  • Posts: 636
  • Joined: 01 Dec 2007
  • Loc: Washington DC Mayland suburbs

Posted 08 December 2012 - 04:24 PM

Can't use my Hyperions w/my C5 and binos because of IPD issues...wide nose (on my face ;-) . Have to stick w/the Plossls on that combo which is fine for me.

#3 RAKing


    Fly Me to the Moon

  • *****
  • Posts: 6971
  • Joined: 28 Dec 2007
  • Loc: West of the D.C. Nebula

Posted 08 December 2012 - 04:41 PM


Are you using the T2 mirror diagonal, or the T2 prism? The prism is slightly shorter, if that helps.

Also, the Televue Shorty VB is an excellent match for the Baader diagonal and either the A-P or Baader T2 nosepiece.

I'm glad you are having fun with your binos. :waytogo:



#4 Eddgie



  • *****
  • topic starter
  • Posts: 17246
  • Joined: 01 Feb 2006

Posted 08 December 2012 - 10:59 PM

Using the T2 Standard Prism.

I have a post already on Cats and Casses to see if the diagonal will clear the focuser if you use the Shorty TV back on a C5. Haven't had an answer yet.

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics