Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Announcements and News >> Discussion of CN Articles, Reviews, and Reports

Pages: 1
Charlie HeinAdministrator
Postmaster
*****

Reged: 11/02/03

Loc: 26.06.08N, +80.23.08W
Mirror vs. Dielectric vs. Prism Diagonal Compariso new
      #6435649 - 03/29/14 07:32 AM

Mirror vs. Dielectric vs. Prism Diagonal Comparison

By William Paolini


Post Extras: Print Post   Remind Me!   Notify Moderator  
davidpitre
Post Laureate
*****

Reged: 05/10/05

Loc: Central Texas
Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: Charlie Hein]
      #6436828 - 03/29/14 08:24 PM

The best comparison and review of diagonals I've ever read.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Daniel Mounsey
Vendor (Woodland Hills)
*****

Reged: 06/12/02

Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: davidpitre]
      #6436919 - 03/29/14 09:34 PM

Bill, has helped make observers aware that prisms are unquestionably the best diagonal for planetary observation in scopes more dedicated for that application. This is why Thomas Back of TMB Optical preferred them. I use prisms for deep sky as well. Prisms and silver coated diagonals are my favorite diagonals hands down.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Scott in NCAdministrator
80mm Refractor Fanatic
*****

Reged: 03/05/05

Loc: NC
Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: davidpitre]
      #6437040 - 03/29/14 11:24 PM

Quote:

The best comparison and review of diagonals I've ever read.




+1

Excellent job, Bill!


Post Extras: Print Post   Remind Me!   Notify Moderator  
roadi
Pooh-Bah
*****

Reged: 08/18/07

Loc: Great Grey Spot "Denmark"
Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: Scott in NC]
      #6437331 - 03/30/14 08:09 AM

Very interesting reading! thanks Bill
It also confirms my own experience with prism vs mirror diagonals.
My beloved 1.25" takahshi prism diagonal will never leave my home, It has proved its worth many times against some highend dielectric mirror diagonals

I do disagree a litle about the issues on the compression mechanics on the Takahashi 1.25" prism!! IMO and Experience the issues simply lies in the old fasioned and conservative undercut on many EP's and not on the compression mechanics on the Takahashi diagonal.
To name one, as much as I love TV products I find these undercuts on their Ep's and barlows realy annoying! fortunately the are "slowly" stearing away from it with their newer Ethos wich has tapered barrels like others!


Post Extras: Print Post   Remind Me!   Notify Moderator  
BillP
Postmaster
*****

Reged: 11/26/06

Loc: Vienna, VA
Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: roadi]
      #6437408 - 03/30/14 09:28 AM

So true. If manufacturers didn't add the undercut, which was never needed or asked for, then we wouldn't have problems like this. It goes further too. If you examine it the undercuts and compression ring interactions often result in misalignment. Truly a BAD idea the undercut.

Post Extras: Print Post   Remind Me!   Notify Moderator  
roadi
Pooh-Bah
*****

Reged: 08/18/07

Loc: Great Grey Spot "Denmark"
Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: BillP]
      #6437418 - 03/30/14 09:35 AM

I fully agree

Post Extras: Print Post   Remind Me!   Notify Moderator  
Roy McCoy
Pooh-Bah
*****

Reged: 10/13/05

Loc: Glendale, AZ
Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: Daniel Mounsey]
      #6437670 - 03/30/14 12:22 PM

Quote:

Bill, has helped make observers aware that prisms are unquestionably the best diagonal for planetary observation in scopes more dedicated for that application.




+1

Quote:

Quote:

The best comparison and review of diagonals I've ever read.




+1

Excellent job, Bill!




Bill's reviews, as he might say about the gear itself, are "in a different league".

Thanks a lot Bill!

Edited by Roy McCoy (03/31/14 12:10 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Bill Steen
member


Reged: 12/15/12

Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: Roy McCoy]
      #6438474 - 03/30/14 09:02 PM

Thank you for the very enlightening report! I have often wondered about what the real differences between the two types were. I have, however, been using Meade, Celestron, and Astro Visioneer prism diagonals. These lower levels did not seem to measure up as well. I did notice that the Celestron diagonal tested was 1980s vintage. I have noticed improvement in eyepieces over the years, or at least I think I have. I am wondering if there have been improvements in the mass produced prism diagonals as well. Naturally, I would like to think so.

Again, thanks for all of your hard work that you have graciously shared with us!

Bill Steen


Post Extras: Print Post   Remind Me!   Notify Moderator  
Ed D
Carpal Tunnel
*****

Reged: 04/30/10

Loc: Sunny South Florida
Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: Bill Steen]
      #6439047 - 03/31/14 09:10 AM

Excellent and detailed article. I really enjoyed reading it and found the information very useful.

Ed D


Post Extras: Print Post   Remind Me!   Notify Moderator  
Littlegreenman
Post Laureate
*****

Reged: 05/09/05

Loc: Southern California
Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: Ed D]
      #6440545 - 03/31/14 10:25 PM

Excellent article! But I do have a complaint: now I have to upgrade my diagonal.

My experience with a TV Everbright diagonal with a compression ring and a Panoptic 35, with an undercut, is a great example of how not to do things: it frequently required removing the diagonal from the tube and then some minor 'surgery' to extricate the eyepiece.

Of course, you can't expect every diagonal to be include. I've had a couple of Lumicon 1.25" Enhanced over the years. These are aluminum mirrored. Mine were set screw types. The ergonomics were a high point for me. They came with a larger than usual brass set screw.

Thanks again,
LGM

LGM


Post Extras: Print Post   Remind Me!   Notify Moderator  
davidpitre
Post Laureate
*****

Reged: 05/10/05

Loc: Central Texas
Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: Littlegreenman]
      #6444068 - 04/02/14 07:13 PM

Anyone know much detail about the Stellarvue Diagonal? 2" Mirrored . I had one for years and felt it gave as good images as my Everbright.

Post Extras: Print Post   Remind Me!   Notify Moderator  
azure1961p
Postmaster
*****

Reged: 01/17/09

Loc: USA
Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: davidpitre]
      #6448358 - 04/05/14 01:40 AM

An excellent article Bill that was technically well covered with very honest impressions conveyed. Superb.

Pete


Post Extras: Print Post   Remind Me!   Notify Moderator  
cjc
sage


Reged: 10/15/10

Loc: Derbyshire, England
Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso [Re: azure1961p]
      #6452866 - 04/07/14 02:04 PM

A very clear very useful review!

I am particularly struck by the minimalist conclusion that: "In assessment of scatter around Jupiter and bright stars, straight-through observing without any diagonal was very clearly and distinctively better, perhaps showing only half as much scatter as the best diagonal."


Post Extras: Print Post   Remind Me!   Notify Moderator  
Ed D
Carpal Tunnel
*****

Reged: 04/30/10

Loc: Sunny South Florida
Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: cjc]
      #6648108 - 07/22/14 11:55 PM

It was thanks to Bill's article that I recently made the decision to get the Baader/Zeiss prism diagonal for planetary observing. It really is the best choice for the dedicated planetary observer, and not super expensive. The fine focuser lets me rotate my binoviewer a bit to find the most comfortable position.

Thanks Bill,
Ed D


Post Extras: Print Post   Remind Me!   Notify Moderator  
ehallspqr
member


Reged: 07/30/09

Loc: Port Townsend, WA. USA
Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: Ed D]
      #6648841 - 07/23/14 01:20 PM

Quote:

It was thanks to Bill's article that I recently made the decision to get the Baader/Zeiss prism diagonal for planetary observing. It really is the best choice for the dedicated planetary observer, and not super expensive. The fine focuser lets me rotate my binoviewer a bit to find the most comfortable position.

Thanks Bill,
Ed D




Ditto. Great article and confirms what I have always thought. I'm on my 3rd Baader prism diagonal, the Zeiss version. Tried the latest greatest mirror prism's over the years but have always returned to the Baader Zeiss. There are a number of reasons why I prefer them. No doubt they are the best for planetary observing, at least to my eye's. There is a certain vibrancy and "pop" to the image. Hard to describe except to say I Like it! Not bad on deep sky either. Again great review thanks for posting.


Post Extras: Print Post   Remind Me!   Notify Moderator  
combatdad
professor emeritus


Reged: 12/28/12

Loc: Culpeper, VA
Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: ehallspqr]
      #6650135 - 07/24/14 08:08 AM

Very thorough and balanced assessment. Thanks for taking the time and for sharing.

Dave


Post Extras: Print Post   Remind Me!   Notify Moderator  
Daniel Mounsey
Vendor (Woodland Hills)
*****

Reged: 06/12/02

Re: Mirror vs. Dielectric vs. Prism Diagonal Compariso new [Re: Littlegreenman]
      #6653706 - 07/26/14 02:08 PM

Quote:

Excellent article! But I do have a complaint: now I have to upgrade my diagonal.





I like this


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1


Extra information
0 registered and 1 anonymous users are browsing this forum.

Moderator:  droid 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 2057

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics