Results 1 to 7 of 7

Thread: 1.25" or 2" EP

  1. #1
    cablet's Avatar
    cablet is offline White Dwarf
    Points: 1,434, Level: 22
    Level completed: 34%, Points required for next Level: 66
    Overall activity: 0%
    Achievements:
    365 Days+ Registered Achievement!5 Threads Achievement!2 Posts Achievement20 Posts Achievement!First 1000 Experience Points
    Join Date
    Aug 2011
    Location
    Portland, OR
    Posts
    11
    Points
    1,434
    Level
    22
    Thanks
    2
    Thanked 8x 4 Posts

    Default 1.25" or 2" EP



    Hello,
    I just purchased a scope (Orion EON 120mm refractor) which can handle both 1.25" and 2" EPs. From what I can gather it looks like the 2" can handle larger FOV (if I have it right). I am now starting the process of purchasing just a couple of high quality eye pieces and I'm not sure if I should stick with the 2" EPs because my scope can use them or would one normally end up with a couple of each. I'd image getting all 2" would cost quite a bit more than the 1.25".

    Can anyone comment on this?
    Thank you very much.


    -cablet

  2. #2
    DaveW's Avatar
    DaveW is offline HYPER GIANT
    Points: 13,128, Level: 79
    Level completed: 8%, Points required for next Level: 322
    Overall activity: 0%
    Achievements:
    200+ Posts Achievement!First 1000 Experience PointsGhost Achievement! Averaging 5+ posts a day!365 Days+ Registered Achievement!100+ Threads Achievement!
    Join Date
    Jun 2010
    Location
    Saskatoon, Canada
    Posts
    1,792
    Points
    13,128
    Level
    79
    Thanks
    100
    Thanked 621x 447 Posts

    Default

    Generally, low power wide field eyepieces need a 2" barrel while higher magnifications won't require a bigger barrel.

    For instance, your scope has a focal length of 900mm. If you wanted 100x magnification, you'd need a 9mm eyepiece. Even for a really wide field 100 degree apparent field of view, there won't be a difference in performance between a 2" and 1.25" barrel because the bigger barrel isn't needed.

    There's a few less expensive eyepieces that are made in 1.25" sizes where they really should be 2" in order to get the whole field of view in, but generally if an eyepiece is offered in a 1.25" barrel by a good manufacturer it probably doesn't need a 2" barrel.
    Zhumell Z10,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    114EQ, 10x50 and 15x70 Binoculars
    Zhumell 2" UHC Filter
    Hyperion 8mm GSO Superview 30mm and a whole case full of Plossls

    Saskatoon, SK - 106W, 52N

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

  3. #3
    dmbryan's Avatar
    dmbryan is offline Super Moderator
    Points: 38,228, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 8.0%
    Achievements:
    First 1000 Experience Points200+ Posts Achievement!Got three Friends100+ Threads Achievement!365 Days+ Registered Achievement!
    Join Date
    Jun 2009
    Location
    b'ham alabama
    Posts
    5,576
    Points
    38,228
    Level
    100
    Thanks
    4,795
    Thanked 1,938x 1,521 Posts

    Default

    Lower mag eps benefit from the 2" format wheras higher mags work just as well in 1.25. It is personal preference to go all 2". I use all 2" eps simply so I don't have to add adapters between changing. I also like the wider lenses, but it is 6 to one regarding quality. Cheers.
    name: Derek

    Various
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    and such.

  4. The Following User Says Thank You to dmbryan For This Useful Post:

    GWING (08-13-2011)

  5. #4
    Bob327's Avatar
    Bob327 is offline HYPER GIANT
    Points: 41,366, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    10 Days registered200+ Posts Achievement!First 1000 Experience PointsGot three Friends365 Days+ Registered Achievement!
    Join Date
    Sep 2009
    Location
    Frederick Maryland
    Posts
    9,247
    Points
    41,366
    Level
    100
    Thanks
    19
    Thanked 4,039x 3,068 Posts

    Default

    Bottom line is that for high magnifications you do NOT need a wide FOV...

    Put it this way ..... Saturn when viewed at 300x will appear smaller in a wide field of view eyepiece then it will in a regular eyepiece...simply because you see a heck of a lot more of the sky....

    Now when you are looking at an open cluster ,,, which may contain hundreds of stars you generally use a low powered eyepiece since magnification is not important PLUS you would like as wide a view of the sky as possible...

    Best way to do this is with a 2 inch Wide Field Eyepiece....

    So in may case since I use 1.25 inch eyepieces for ALL my high powered viewing (8 thru 25 mm eyepieces) and 2 inch eyepieces for all of my low powered viewing (26-42 mm eyepieces)....

    BTW...I normally will be viewing with LOW POWER eyepieces the vast majority of the time...

    My personal problem is that I do not like 82 Ultra wide angle eyepieces which force me to shift my eyeballs all over the place to take in the entire FOV so I only use super wide field eyepieces of 68-70 degree FOV....No 100 degree eyepieces for me...

    I'm not alone with this problem BUT I admit I am in the minority ....

    Bob G
    CPC1100 housed in a slotted domed observatory (Exploradome) 4 and 5 inch refractors for use from the lawn, a 8" Sct (NS 8i) for star parties...
    I Hate the winter so I use heated Motorcycle clothing to stay warm while observing in winter
    Retired, also have 2 other hobbies
    1. tinker with older Corvettes (6 in garage)
    2. make a heck of a lot of sawdust in my wood shop.

  6. The Following User Says Thank You to Bob327 For This Useful Post:

    Cladinator (08-13-2011)

  7. #5
    jimt's Avatar
    jimt is offline Super Moderator
    Points: 37,302, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    200+ Posts Achievement!First 1000 Experience PointsGot three Friends20+ Friends Achievement!5+ Referrals Achievement!
    Join Date
    Jul 2009
    Location
    North Georgia
    Posts
    5,715
    Points
    37,302
    Level
    100
    Thanks
    1,338
    Thanked 2,734x 1,769 Posts

    Default

    For me my eyepieces 25mm and under are 1 1/2 in, over 25 mm are 2in. Same reason Derek and Bob stated. With the exception of some star clusters, Planets and the Moon, I use the low power eyepieces 99% of the time.
    I haven't had the opportunity to use the huge fov eyepieces, but I am happy enough with my 65deg ones.

    Jim
    Celestron C9.25. Atlas EQG mount. Canon 500D unmodded, Celestron ST80 guide scope, SSAG, Meade 6.3 FR, Thousand Oaks dew control with Dewnot straps. Zhumell 8/24mm Zoom, 2"Gso Superview 42mm, Meade 2"QX wide angle 30MM, Meade 1.25 EP and filter set. Tasco 10x50 Zhumell 20x80 bino and a few other odds and ends.
    Now where did I put that clear sky button!

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

  8. #6
    TH0MAS's Avatar
    TH0MAS is offline Bright Giants
    Points: 4,091, Level: 42
    Level completed: 94%, Points required for next Level: 9
    Overall activity: 0%
    Achievements:
    200+ Posts Achievement!365 Days+ Registered Achievement!First 1000 Experience Points50 Posts Achievement!5 Threads Achievement!
    Join Date
    Jan 2011
    Location
    Gatineau, Quebec, Canada
    Posts
    220
    Points
    4,091
    Level
    42
    Thanks
    21
    Thanked 107x 67 Posts

    Default

    I have both 2" and 1.25" eyepieces. I use an Antares 2" to 1.25" centering adapter for my 1.25" eyepieces so I don't need to change adapters.

    You'll find that some 2" eyepieces are really 1.25" eyepieces housed in a 2" barrel like my T4 12mm Nagler and I believe all the Baader Hyperion eyepieces as well.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    12” Collapsible
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Dob w/Telrad, Astrozap Light Shroud, iOS Skywire

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    130 SLT
    Celestron 76mm Dob (First
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    )
    Tele Vue Panoptic 27mm, T4 17mm and 12mm Naglers, 2" 2x Powermate, Meade 8-24 Zoom

  9. #7
    GRB1984's Avatar
    GRB1984 is offline SUPER GIANT
    Points: 4,695, Level: 46
    Level completed: 73%, Points required for next Level: 55
    Overall activity: 0%
    Join Date
    Mar 2011
    Location
    Britsh Columbia
    Posts
    881
    Points
    4,695
    Level
    46
    Thanks
    250
    Thanked 254x 189 Posts

    Default

    I agree with all the above advice, 2"low power 1.25" high power. It is however, a personal choice. Best thing to do would be to try and view at a local astro club, see how you like them in comparison.
    Josh L.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    8" Traditional Dob, TeleVue X2
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    , ES 82* 14mm, Baader Hyperion 17mm, GSO Superview 20mm and 30mm, Antares w70 25mm, Antares variable
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    filter

    "I was born not knowing and have had only a little time to change that here and there."
    Richard Feynman

 

 

Similar Threads

  1. Replies: 27
    Last Post: 03-24-2011, 12:40 PM
  2. "Science" Lightweight Addresses "Global Warming" (and Chinese Food)
    By John Steinberg in forum Amateur Astronomy Forum
    Replies: 3
    Last Post: 06-21-2006, 09:33 PM
  3. need email addresses of "Emil Bonnano" and "Perry Remaklus" (MEGASTAR)
    By Michael Feiler in forum UK Astronomy Forum
    Replies: 2
    Last Post: 12-16-2004, 08:21 PM
  4. need email addresses of "Emil Bonnano" and "Perry Remaklus" (MEGASTAR)
    By Michael Feiler in forum General Astronomy Forum
    Replies: 0
    Last Post: 12-14-2004, 07:23 PM
  5. MEBAY: "Space Frontiers," "Shuttle/Comet," "Secrets of Space"
    By Scott Lowther in forum Space Exploration History Forum
    Replies: 8
    Last Post: 11-15-2003, 09:41 PM

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 05:47 PM.