Results 1 to 5 of 5
  1. #1
    MrKb's Avatar
    MrKb is offline White Dwarf
    Points: 6,539, Level: 55
    Level completed: 95%, Points required for next Level: 11
    Overall activity: 0%
    Achievements:
    First 1000 Experience Points365 Days+ Registered Achievement!750 Days+ Registered Achievement!2 Posts Achievement1000 Days+ Registered Achievement!
    Join Date
    Mar 2010
    Location
    San Francisco
    Posts
    12
    Points
    6,539
    Level
    55
    Thanks
    5
    Thanked 3x 3 Posts

    Default Binocular Telescope magnification



    Hello all!

    Quick question for you guys . . . . how much magnification do you think you can get out of a pair of 100mm binocular telescopes (Orion or Garett Optical) by changing the eyepieces before the view becomes not so good? I love binos . . . . don't want a telescope just yet . . . and want some more satisfying views of the planets.
    Thanks in advance

  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
    6,921
    Points
    56,828
    Level
    100
    Thanks
    743
    Thanked 5,863x 3,113 Posts
    Blog Entries
    1

    Default

    Probably 40X - 45X...

    I've experimented with my Oberwerk BT-100's (25/40x100) over time, and find that beyond 45X there is very little usable magnification gain, and excessive narrowing of the field of view such that one loses that "floating in space" binocular experience.

    The maximum theoretical value would be nominally 200X - in my case, (600mm f/l), I could stuff the oculars with 3mm eyepieces to push the binos that high. That being said I doubt that this would be useful due to the chromatic aberration and narrowing of the FOV to something less than 1 degree.
    CGEM 800 HD, NexGuide, Orion XT8 Limited Edition, Oberwerk BT-100, Canon 20D/20Da/T3i/60D/5D Mk III, various eyepieces, adapters, geegaws, widgets, and tiddlybits

  3. The Following 2 Users Say Thank You to AustinPSD For This Useful Post:

    MrKb (03-28-2010),sxinias (03-26-2010)

  4. #3
    MrKb's Avatar
    MrKb is offline White Dwarf
    Points: 6,539, Level: 55
    Level completed: 95%, Points required for next Level: 11
    Overall activity: 0%
    Achievements:
    First 1000 Experience Points365 Days+ Registered Achievement!750 Days+ Registered Achievement!2 Posts Achievement1000 Days+ Registered Achievement!
    Join Date
    Mar 2010
    Location
    San Francisco
    Posts
    12
    Points
    6,539
    Level
    55
    Thanks
    5
    Thanked 3x 3 Posts

    Default

    Austin,
    Thank you for your insights, I really appreciate it. Sorry for the late reply, I just wanted to have one more night of observing before I asked my next question. I understand that I will lose a great deal of the "floating in space" with greater magnifications, but i guess my thoughts and questions boil down to this. I know I can use the binos with the proper eyepieces to enjoy more "traditional" views of deep space objects (say about x20). But if I find and center Saturn (for example), and want to bump the view up to x100, or even x150, just to view the planet, will I be dissapointed with the view? I love scanning the skies to find DSOs, but I also would like to be able to swap out the eyepiece on a fixed object and get a good look. I saw Saturn tonight (very cool) but I would like to not have to use my imagination so much.
    Thank you again,
    Kb

  5. #4
    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
    6,921
    Points
    56,828
    Level
    100
    Thanks
    743
    Thanked 5,863x 3,113 Posts
    Blog Entries
    1

    Default

    The term "disappointed" is subjective and personal - here is a more objective way to gauge what you might experience:

    Simulated Telescope Planet Images

    It is reasonable to think of the binocular telescope as a pair of 100mm achromatic telescopes with image-erecting diagonals. The Garret, Orion, and Oberwerk binos have reasonably high-quality optics, and relatively large aperture (100mm = 3.93 inches). Their focal lengths are similar, 600mm - 609mm.

    You can push the magnification to around 200x with a 3mm - 3.5mm eyepiece, which is consistent with realistic seeing conditions (good to excellent). The chroma defect shouldn't be too bad, because Saturn isn't terribly bright.
    CGEM 800 HD, NexGuide, Orion XT8 Limited Edition, Oberwerk BT-100, Canon 20D/20Da/T3i/60D/5D Mk III, various eyepieces, adapters, geegaws, widgets, and tiddlybits

  6. The Following 2 Users Say Thank You to AustinPSD For This Useful Post:

    admin (03-28-2010),MrKb (03-31-2010)

  7. #5
    MrKb's Avatar
    MrKb is offline White Dwarf
    Points: 6,539, Level: 55
    Level completed: 95%, Points required for next Level: 11
    Overall activity: 0%
    Achievements:
    First 1000 Experience Points365 Days+ Registered Achievement!750 Days+ Registered Achievement!2 Posts Achievement1000 Days+ Registered Achievement!
    Join Date
    Mar 2010
    Location
    San Francisco
    Posts
    12
    Points
    6,539
    Level
    55
    Thanks
    5
    Thanked 3x 3 Posts

    Default

    Austin,

    Thank you again! I think you've helped me make up my mind. I'm going to get them in about 6 weeks . . . . I think. (geez thats a lot of money)
    http://www.astronomyforum.net/images/smilies/cool12.gif

    Best,
    Kb

 

 

Similar Threads

  1. What is the maximum magnification of a radio telescope?
    By mangosmoothie in forum Telescope Forum
    Replies: 3
    Last Post: 05-27-2008, 03:20 AM
  2. Replies: 1
    Last Post: 04-16-2008, 01:35 AM
  3. About Telescope magnification?
    By Xanox in forum Telescope Forum
    Replies: 0
    Last Post: 04-04-2008, 02:50 AM
  4. Telescope magnification question
    By Neil W in forum UK Astronomy Forum
    Replies: 7
    Last Post: 03-20-2008, 08:57 AM
  5. Telescope magnification - common misconceptions
    By Malcolm Stewart in forum UK Astronomy Forum
    Replies: 12
    Last Post: 10-11-2004, 07:55 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 10:25 PM.