36 replies to this topic

[Dave1066]

I'm no expert, but isn't polish the overwhelmingly most important factor in controlling scatter in an eyepiece?

 

 

Clear skies!

Thomas, Denmark

 

I guess so, but glass choice contributes to that as well? I think? Polish is very important to overall performance, Brandon eyepieces are suppose to be very good in this regard.  

Edited by Dave1066, 19 March 2018 - 01:37 PM.

[Levine]

I hate it when Bill P. is right, only because it makes me want to purchase what I don't have, I really really, REEEEEEALLY want the TAK Abbe's. Problem is I need them like I need a hole in my head and according to some that hole is already there.

"They do show less scatter" (compared to other Ortho's) - I know they do. Amazing how that little detail can make me want them with a desire that burns like Arizona asphalt on a hot summer day.

PM Sent.

[John Huntley]

Thanks John. So the CZJ Ortho's would still be rated above the Tak Ortho's?

Atleast now I now the different terminology and which eyepieces is referring to which.

I don't know, I've not compared them. Somehow I suspect that the more up-to-date coatings of the Tak Abbe Orthos might given them the edge perhaps ?

 

I have owned and used a TMB Supermonocentric and a ZAO though. Not at the same time unfortunately !

 

I'm not a big ortho user these days. I prefer the comfort of things like the Pentax XW. Must be getting old

Edited by John Huntley, 19 March 2018 - 03:21 PM.

[Peter Besenbruch]

BTW, if you want to find out, whether your diagonal is worth anything or not, try comparing it with a view straight through. The difference can be shockingly obvious.

This. Straight through vs diagonal is the best test. Have you done any viewing with the Baader 32mm prism?

[Joe1950]

The Baader/Zeiss prism (1-1/4) used to run about $450 (365€) sold as one unit. I don't see it sold like that, at least where I looked. It is sold as a prism housing and the eyepiece tube and nose piece are sold separately.

 

Buying it that way appears to cost about $405 (328€). Which, if it is as good as everyone says it is, it is certainly worth the price.

 

However, not having that available for equipment, I'll have to opt for the stiff neck with an extension tube method.

 

Confucius say: Better to have stiff neck than empty, floppy wallet. 

[Astrojensen]

This. Straight through vs diagonal is the best test. Have you done any viewing with the Baader 32mm prism?

No, I've not tested the 32mm version. But I've tested the T2 amici diagonal version and it's very good, too, if you can unsee the diffraction spike on bright stars. It is certainly worth the money if you want to make starhopping easier on yourself. I do recommend getting a normal diagonal for planetary observing. Lunar observing seems to be just as good as with a normal diagonal. 

 

 

Clear skies!
Thomas, Denmark

[Astrojensen]

I don't know, I've not compared them. Somehow I suspect that the more up-to-date coatings of the Tak Abbe Orthos might given them the edge perhaps ?

 

I have owned and used a TMB Supermonocentric and a ZAO though. Not at the same time unfortunately !

 

I'm not a big ortho user these days. I prefer the comfort of things like the Pentax XW. Must be getting old

One thing to be aware of, is that not all CZJ orthos are created equal. I have two versions, one older one, with chromed brass barrel and two newer ones, with aluminum barrels. The old one is noticeably sharper and cleaner on lunar details. The field stop is also sharper. 

 

 

Clear skies!
Thomas, Denmark

[Dave1066]

One thing to be aware of, is that not all CZJ orthos are created equal. I have two versions, one older one, with chromed brass barrel and two newer ones, with aluminum barrels. The old one is noticeably sharper and cleaner on lunar details. The field stop is also sharper.


Clear skies!
Thomas, Denmark

I've also read else where the older ones are suppose to be better.

Dave

[Astrojensen]

And I can confirm that they are.

 

 

Clear skies!

Thomas, Denmark

[Astrojensen]

I forgot to mention (and can't edit now) that it is the 10mm that I have in both old and new versions and is the one I compared. I also have old and new versions of the H-25 and O-16, but haven't done a detailed comparison. 

 

 

Clear skies!
Thomas, Denmark

[earlyriser]

Thanks for the feedback. Well given the design of Brandon and the fact they use 2 high index glasses, and 2 very high index glasses, I was lead to believe they didn't need a multi coating to control the scatter. That's why Brandon eyepieces are so expensive because of the glasses used. See in my telescopes being at least F15 I don't think being sharp to the edge of the field is going to be a problem. 

 

Certainly is food for thought, I seriously have to think now which route I am going to go. 

I believe the theory behind the Brandon's using fewer coatings is that as the layers (and thus total thickness) of the coatings increases, their effectiveness in reducing reflections of light increases for light orthogonal to the coating, but decreases for light incident on the coatings beyond a certain angle. So, the Brandon prioritizes consistency of transmission across a range of angles of incidence over total transmission throughput. 

[nicoledoula]

At F/15, for planets, I'd choose Brandons. For other objects I might choose an EP with newer coatings and a wider field....