Results 1 to 6 of 6
  1. #1
    somecdnguy's Avatar
    somecdnguy is offline SUPER GIANT
    Points: 15,062, Level: 84
    Level completed: 61%, Points required for next Level: 138
    Overall activity: 0%
    Achievements:
    10 Days registered200+ Posts Achievement!First 1000 Experience Points365 Days+ Registered Achievement!100+ Threads Achievement!
    Join Date
    Sep 2009
    Location
    Peel Region, Ont, Canada
    Posts
    1,163
    Points
    15,062
    Level
    84
    Thanks
    62
    Thanked 618x 366 Posts

    Default Dielectric Diagonals, Worth it?



    Seeing after the holidays I've decided to put the new scope idea on hold for a while and try and get the most out of my current scope. So all the cash I've saved up is going towards new accessories. I've been looking at getting a William's Optics dielectric diagonal and have read quite a few reviews (including the ones on this forum). So far it seems 50% say there is a noticeable difference, the other 50% say not really. I'm really just looking for a diagonal and other accessories that will compliment my set of hyperion's very nicely. So what do you guys think? Any suggestions would be greatly appreciated.
    Name: Jason
    Member of the Royal Astronomical Society of Canada - Mississauga Centre & Stj÷rnusko­unarfÚlag Seltjarnarness (Iceland)
    Orion Atlas EQ-G, ES 152mm Mak-Newt, Canon 5DMkll, Canon 60D, EF 70-200mm f/2.8L MkII, EF 24-105mm f/4L, EF 50mm f/1.4

  2. #2
    AustinPSD's Avatar
    AustinPSD is offline Super Moderator
    Points: 56,828, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 2.0%
    Achievements:
    200+ Posts Achievement!First 1000 Experience PointsGot three Friends20+ Friends Achievement!5+ Referrals Achievement!
    Join Date
    Sep 2009
    Location
    McDonald Observatory, Mt. Locke
    Posts
    6,923
    Points
    56,828
    Level
    100
    Thanks
    743
    Thanked 5,865x 3,115 Posts
    Blog Entries
    1

    Default

    The main advantage of a dielectric coating is that it won't degrade via oxidation over time.

    Most of the diagonals out today run from 1/4 wave / 96% reflectivity to 1/10 wave / 99% reflectivity (dielectric).

    The human eye's logarithmic response and sensitivity to light, along with its integration capability make the visual distinction of 96% vs. 99% diagonal almost impossible.

    While you could measure the difference with appropriate instrumentation, you are unlikely to visually detect it between well-made 96% vs. 99% dielectric diagonals. From a pragmatic view, the dielectric coating will be easier to clean, if that becomes an issue than a less expensive coating. That's about it.

    I've heard people claim contrast differences ("blacker" black/dark sky) with dielectric diagonals, which may be true for "younger" eyes, but I can't see a difference with fifty-year aged eyes.
    CGEM 800 HD, NexGuide,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    XT8 Limited Edition, Oberwerk BT-100, Canon 20D/20Da/T3i/60D/5D Mk III, various eyepieces, adapters, geegaws, widgets, and tiddlybits

  3. The Following User Says Thank You to AustinPSD For This Useful Post:

    admin (12-30-2009)

  4. #3
    Hal the Elder's Avatar
    Hal the Elder is offline Banned
    Points: 11,650, Level: 74
    Level completed: 67%, Points required for next Level: 100
    Overall activity: 0%
    Achievements:
    10 Days registered200+ Posts Achievement!First 1000 Experience Points5+ Referrals Achievement!365 Days+ Registered Achievement!
    Join Date
    Sep 2009
    Location
    Apple Valley, CA
    Posts
    366
    Points
    11,650
    Level
    74
    Thanks
    1
    Thanked 98x 72 Posts

    Default

    I realize that the human eye cannot detect the difference in reflectivity between a 96% claim and a 99% claim, so I just buy WO dielectric diagonals simply because it says "Dielectric" on 'em, and that makes me feel comfortable!

    HAL
    Attached Images Attached Images

  5. The Following User Says Thank You to Hal the Elder For This Useful Post:

    admin (12-30-2009)

  6. #4
    Lenbo's Avatar
    Lenbo is offline SUPER GIANT
    Points: 12,882, Level: 78
    Level completed: 38%, Points required for next Level: 218
    Overall activity: 0%
    Join Date
    Feb 2009
    Location
    Cochranville Pa.
    Posts
    1,445
    Points
    12,882
    Level
    78
    Thanks
    239
    Thanked 336x 271 Posts

    Default

    I have the WO dielectric for my refractor. It was a good deal at the time so I went for it. Since I was upgrading from 1 1/4 to 2 inch anyway I decided to go a little more for the dielectric. Really didn't see any difference to be honest. I figure even if it isn't a noticable improvement, it looks like a well made diagonal and feel confident it doesn't add any issues to the mix. Kind of like Harold says I guess.
    Len
    Astro Tech 150mm mak f/12 -
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    8 inch reflector f/4.9 - VRC8 (RC Mod for Mallincam)
    Orion Atlas EQ mount - EQMOD
    TV Radian 6 mm / Baader Hyperion Eyepieces 8,13,17,24 mm / Meade SWA 28,34 mm/ES 82 11mm

  7. The Following User Says Thank You to Lenbo For This Useful Post:

    admin (12-30-2009)

  8. #5
    somecdnguy's Avatar
    somecdnguy is offline SUPER GIANT
    Points: 15,062, Level: 84
    Level completed: 61%, Points required for next Level: 138
    Overall activity: 0%
    Achievements:
    10 Days registered200+ Posts Achievement!First 1000 Experience Points365 Days+ Registered Achievement!100+ Threads Achievement!
    Join Date
    Sep 2009
    Location
    Peel Region, Ont, Canada
    Posts
    1,163
    Points
    15,062
    Level
    84
    Thanks
    62
    Thanked 618x 366 Posts

    Default

    Thanks for the info guys. Probably will end up buying one next week when I can make it to the scope store. I do like the idea of being easy to clean and no degradation. Currently I'm using a pretty basic 1.25" Orion diagonal that came with the scope when I bought it.
    Name: Jason
    Member of the Royal Astronomical Society of Canada - Mississauga Centre & Stj÷rnusko­unarfÚlag Seltjarnarness (Iceland)
    Orion Atlas EQ-G, ES 152mm Mak-Newt, Canon 5DMkll, Canon 60D, EF 70-200mm f/2.8L MkII, EF 24-105mm f/4L, EF 50mm f/1.4

  9. #6
    Ghostryderflyby's Avatar
    Ghostryderflyby is offline SUPER GIANT
    Points: 17,687, Level: 91
    Level completed: 97%, Points required for next Level: 13
    Overall activity: 1.0%
    Achievements:
    10 Days registered200+ Posts Achievement!Got three FriendsFirst 1000 Experience Points365 Days+ Registered Achievement!
    Join Date
    Aug 2009
    Location
    SW Idaho
    Posts
    727
    Points
    17,687
    Level
    91
    Thanks
    652
    Thanked 429x 223 Posts

    Default

    I recently purchased a Stellarvue 99% 1/10th wave length diagonal and love it. There is a DRAMATIC difference between it and the POS diagonal that came with the telescope. Couple that with the lack of degradation, easier cleaning and it was money very well spent. The Stellarvue is also very reasonably priced at $189.00 and is made in North America (USA). A rarity these days!

    They are also a smaller company with excellent customer service and that personal touch missing from the giants. Great service, great warranty, great product. (Sorry if I sound like an advertisement. I just like to reward great service with some props! )
    -C6-RGT refractor w/JMI EV-1r focuser & Orion 80mm guide scope on CGEM mount. Orion 10" Dob
    -Canon 1000D, StarShoot Autoguider & Blue Fireball Elim-T 2"
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    adapter
    -Televue Delos 12mm & 17mm, Baader 5mm, 10mm, 36mm & 8-24mm zoom & Orion 20mm centering


    I gravely give my profound thanks to those that have died in the name of liberty, that I might live free! - B.J. (My name)

 

 

Similar Threads

  1. Meade 5000 Dielectric
    By replicant in forum Astronomy Beginners Forum
    Replies: 11
    Last Post: 12-24-2010, 03:00 AM
  2. dielectric diagonals ?
    By dmbryan in forum Telescope Accessories Forum
    Replies: 6
    Last Post: 08-19-2009, 01:21 PM
  3. Dielectric Coatings
    By RussL in forum Telescope Accessories Forum
    Replies: 1
    Last Post: 05-14-2009, 03:10 AM
  4. Dielectric Diagonal
    By Nodgiles in forum Astronomy Beginners Forum
    Replies: 6
    Last Post: 01-15-2009, 11:00 PM
  5. Burgess Optical Dielectric Diagonals $99
    By JJ in forum Amateur Astronomy Forum
    Replies: 0
    Last Post: 06-21-2006, 01:43 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBulletin« Version 4.2.0
Powered by vBulletin«
All times are GMT. The time now is 05:01 AM.