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Posts Made By: Donald Durbin

December 5, 2006 02:19 PM Forum: Binoviewers

Eye-pieces for Denkmeier Binoviewers

Posted By Donald Durbin
Hi Hans,

I have the D21s, 19mm Panoptics, and 18mm Radians. I think the 18mm Radians get the most use. You also might want to look at the 24mm Siebert Ultras. They are a great EP for less than half the price of the others I mentioned and they give you more room for your nose. :>)

Don Durbin

December 6, 2006 04:34 PM Forum: Binoviewers

Anyone get a BO bino to work in a Klevzov?

Posted By Donald Durbin
Hi Louis,

Can you describe the Klevzov in more detail. I looked it up on the internet and it looked pretty much like an SCT. Most SCT's will focus binoveiwers without any corrector at all.

If you are seeing the scopes mirror in your EP's then it sounds like you have a hefty focal reducer somewhere in the light path.

Is it possible the Klevzov has a built in focal reducer? At F10 I would not think that was the case.

Don Durbin

December 31, 2006 03:47 PM Forum: Binoviewers

SV BV3

Posted By Donald Durbin
Hi Steve,

I did a quick search on the Stellarvue group for BV3 and got nothing. I did find them on the Stellarvue web site.

Looks like the EP holders are better than the standard for this type of binoviewer. They are still listed as 22mm Prisms.

These have the same light path as the other 22mm Prism binoviewers and to me that is a big plus. They are also light weight when compared to other binoviewers.

The adapter is listed as 1.95X. That is a lower magnification than you will get through your average Barlow, but not as low as the premium correctors.

The case, EPs, and corrector, while coupled with Stellarvue tech support should make this a good entry level package for anyone who does not have a binoviewer and wants to try them out.

If binoviewing is for you this package will greatly enhance your viewing enjoyment. The ease of two eyed viewing makes getting a comfortable chair a necessity.

Don Durbin

February 5, 2007 10:10 PM Forum: Binoviewers

Big Eazy on Tak

Posted By Donald Durbin
Alan,

You may need an OCS with your 2" diagonal. You might not need one if you use a 1 1/4" diagonal. I have a TAK FS-128 and I can focus my Denks, Black Knights, and Burgess binoviewers without any OCS if I use a 1 1/4" diagonal.

I would think that the NSV would have even more in-travel than my FS-128.

Don Durbin


February 27, 2007 05:14 PM Forum: Binoviewers

Getting a Denk to focus on a Newt

Posted By Donald Durbin
Hi George,

You may already have what you need to come to focus in your DOB.

The OCA or OCS is normally a combination of a Barlow and a Focal reducer lens. The Barlow goes in front of the focal reducer. (i.e. closer to the telescope objective) One rule is that the focal reducer cannot overpower the Barlow. Another variable in this is the distance between the Barlow and the focal reducer.

Your StarSweeper module is a focal reducer. Try plugging that into a Barlow and then put it in your DOB. You may need to slide the StarSweeper away from the Barlow to get your DOB to focus.

I did a little write-up about building your own OCA a while back. You can find it here.
http://www.astromart.com/forums/viewpost.asp?forum_post_id=313188&poll_id=&news_id=&page=6

Good luck,
Don Durbin

April 7, 2007 11:31 PM Forum: Binoviewers

Denkmeier and collimation

Posted By Donald Durbin
Hi Dave,

I think the binoviewer will result in a higher magnification and need a tighter collimation. The weight of the binoviewer may also flex the focuser slightly, so collimation with the binoviewer in place may compensate for that slightly.

Binoviewers magnify any type of optical problem. So a good collimation is good for them.

I do not believe that switching back to a 2" eyepiece will shift the collimation enough for you to notice.

Don

April 11, 2007 10:38 AM Forum: Binoviewers

B/V and small scopes??

Posted By Donald Durbin
I have used binoviewers on my ETX90-RA while it was tracking without any problem, but full Goto mode on an EC model would be a challenge.

I think your best bet would be to use one of the clone binoviewers. They weigh less than the Denk, Siebert, or Televue models.

The good new is that you will not need any type of OCA/OCS with these scopes. That also cuts down on the weight and makes the setup less awkward.

Binoviewers are really great for day time viewing of terrestrial targets with my ETX90.

Don Durbin

June 5, 2007 05:18 PM Forum: Binoviewers

Eyepiece recommendations?

Posted By Donald Durbin
When I first got into binoveiwers, I had an older 21mm TV Plossl. So I looked around and found another one to match it. TV maintains nice standards over long periods of time. The first 21mm had green lettering at the top and the second one had its lettering half way down the barrel but they are still exactly par focal.

They were one of my favorite pair until I got my 18mm Radians and 19mm Panoptics.

Don Durbin

September 20, 2007 12:23 PM Forum: Binoviewers

Denk Question

Posted By Donald Durbin
Hi Bill,

I know of two sources for binoviewer correctors for PST's. You can use the Denk corrector or you can use a Siebert corrector.

The PST is a strange beast. You do need a corrector to use a binoviewer with it.

Don Durbin

October 11, 2007 12:39 AM Forum: Binoviewers

SV3 for NHNG

Posted By Donald Durbin
Hi Steven,

I am not sure what a NHNG is. I am guessing it might be a Nighthawk.

I do not think you would go wrong with a pair of 18mm Radans or 19mm Panoptics. I prefer the Radians myself.

Don Durbin

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