Posts Made By: Donald Durbin

I think any given EP should vignette less when Barlowed. You are tightening the cone when you Barlow.

Don Durbin

For Siebert 45mm Elites, I always found that the best EP's were the Siebert 2" 36mm Observatory EP's.

Don Durbin

Just don't lick your new ED scope and you will be fine. You should probably avoid using your tongue to clean any optics in general.

D3

What is the Harbor Freight item number. I got on their web site but did not see any monocular listings.

I know that sometimes a low power view can help you locate an elusive object. I often use the Blue Planet opera glasses for that.

Don Durbin

I know some people who have a Televue 102is and a Burgess 24. I am not sure if they have a 45 degree diagonal, but I will ask them to try to focus their Burgess and see how much travel they have left using an 1 1/4" diagonal. The Burgess is one of the Chinese binoviewers with a 101mm light path.

I have always been a fan of scope with enough in-travel that they do not need an OCS/OCA or barlow to focus. I have a Meade SN-8 and a Meade SN-10 that I installed low profile moonlite focusers on to achieve this.

My TAK FS-128 can focus one of the short light path Chinese binoviewers without needing any help. I have even gotten my Denk and my Siebert Blacknight to focus in it with the right eye-pieces. My Nephew's Televue proved a bit too much (130mm light path) for even it to focus. This was also done with a 1 1/4 Lumibrite 90 degree diagonal.

The 210mm refractor that I am building will have a shortened tube capable of focusing my Siebert 2" binoviewers. It will also have a screw on extension made for the length of the 2" binoviewer light path for normal use.

Don Durbin

I was wrong my friends have the Televue 101is f/5.6.

We could not reach focus on the moon using just a 1 1/4" diagonal and a Burgess 24 (101mm light path) binoviewer. It looked to me like we needed another 10mm or 15mm of in-travel. We had to use an OCA.

Don Durbin

When you say you upgraded to 2", do you mean you have switched to a 2" nose on the Denks? Do you have a 2" OCS?

Can you supply a picture of yur binoviewer setup?

Don

I love using my binoviewer on my refractors, however some refractors do not have enough in focus travel to use with a binoviewer without also using some type of OCA/OCS or Barlow. The down side to that is you can end up with more magnification than you want. The ideal setup is a refractor that can focus without all the expensive add-ons.

The style of binoviewer also matters. The cheaper Chinese binoviewers only need 4 inches of in-travel. The Televue needs a little more than 5 inches. Everything else is in between except for 2" binoviewers.

My advice would be to check through different refractors using an eyepiece you want to use in the binoviewer. Bring a celestial object into focus and measure to see how much further you could have racked in the focuser. You can gain a lot by not using a diagonal, but it is a real pain in the neck at night.

My TAK FS-128 is a good example of a refractor that can focus most binoviewers except the Televue without needing additional correctors.

Don

I admit that I have too many to count. I will say that if I am not using a binoviewer, I prefer 2" over 1 1/4". Although that being said, I still have a 2" binoviewer. I like the combination of 24mm Hyperions in my Burgess 24mm bino. I have compared the 24mm Hyperions to 24mm Pans and the Pans are just a tad better but they do not justifiy the cost. My denk 21mm are also pretty nice in the Burgess. I also prefer using the 18mm Radians over the 19mm Pans in the same unit. Then of course it also varies with the scope I am using. I have too many of them to count too.

Hi John,

Welcome to the wonderful world of two eyed viewing!

Using both eyes provides a greater clarity of the image. You get a built in magnification that provides more detail. You can prove this by simply closing one eye and then opening it while looking through your binoviewer. The object you are looking at will appear to increase in size by 20% or more when using both eyes. For me there is actually less eye strain when using a binoviewer. I have noticed that back and neck strain may be more prevalent due to longer observing sessions and angles caused by the use of binoviewers.

When not using a scope with tracking and using a little imagination, a high magnification view of the moon results in a fantastic flight over the lunar landscape.

Enjoy,
Don