Results 1 to 7 of 7
Like Tree3Likes
  • 1 Post By OttoMann
  • 1 Post By TCampbell
  • 1 Post By TILLIBOBS

Thread: Eyepiece locating query on 6SE and focussing accuracy

  1. #1
    Mystery57's Avatar
    Mystery57 is offline Main Sequence
    Points: 2,814, Level: 34
    Level completed: 43%, Points required for next Level: 86
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!Gallery Achievement!Album Achievement!5 Threads Achievement!
    Join Date
    Jan 2014
    Location
    North Devon
    Posts
    72
    Points
    2,814
    Level
    34
    Thanks
    47
    Thanked 3x 3 Posts

    Default Eyepiece locating query on 6SE and focussing accuracy



    I've been trying out my DSLR attached to the 6SE i got last week, and connected it up to my laptop so I could check the accuracy of focussing the telescope lens better.

    Got the image onscreen pinsharp which was pleasing.

    I disconnected the camera from the scope and put the Diagonal as supplied with the scope back on, and also the supplied 25mm lens - when I looked at the target image this time it was not as pin sharp as I got on the laptop view.

    I pulled the eyepiece up about 1/4 inch in the mount, and the image became sharp.

    Is this normal - is there something else I should be looking into

    thanks
    Andrew

  2. #2
    OttoMann's Avatar
    OttoMann is offline HYPER GIANT
    Points: 18,224, Level: 93
    Level completed: 31%, Points required for next Level: 276
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!Got three Friends
    Join Date
    Jan 2013
    Location
    Mars Hill, NC
    Posts
    1,535
    Points
    18,224
    Level
    93
    Thanks
    298
    Thanked 464x 410 Posts

    Default Re: Eyepiece locating query on 6SE and focussing accuracy

    It's normal.
    The focusing point will be different between a DSLR and an eyepiece.
    Mystery57 likes this.
    Kurt
    Telescope : Celestron C6-N 6" Newt, AVX Mount,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    5SE
    Imaging : Canon Rebel T4i 650D , Neximage 5,
    Accessories :
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    MMAG, Celestron f 6.3
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    , BackyardEOS, DSS, PIPP, Registax, StarTools

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

    Mystery57 (01-22-2014)

  4. #3
    Mystery57's Avatar
    Mystery57 is offline Main Sequence
    Points: 2,814, Level: 34
    Level completed: 43%, Points required for next Level: 86
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!Gallery Achievement!Album Achievement!5 Threads Achievement!
    Join Date
    Jan 2014
    Location
    North Devon
    Posts
    72
    Points
    2,814
    Level
    34
    Thanks
    47
    Thanked 3x 3 Posts

    Default Re: Eyepiece locating query on 6SE and focussing accuracy

    Thats a relief thank you for that

  5. #4
    TCampbell's Avatar
    TCampbell is offline HYPER GIANT
    Points: 13,047, Level: 78
    Level completed: 85%, Points required for next Level: 53
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!200+ Posts Achievement!365 Days+ Registered Achievement!
    Join Date
    Apr 2012
    Location
    Dearborn, MI
    Posts
    1,798
    Points
    13,047
    Level
    78
    Thanks
    4
    Thanked 759x 569 Posts

    Default Re: Eyepiece locating query on 6SE and focussing accuracy

    Each eyepiece will usually require re-focusing -- as well the focus difference of a camera. In fact each camera will have a different focus (the difference is the number of millimeters from the point where the camera "seats" on to the telescope and the actual sensor/imaging chip.)

    Sometimes eyepieces are designed to have the same focus distance (deliberately) and they call these "parfocal" (e.g. if your eyepiece manufacturer claims that their 25mm eyepiece is "parfocal" with their 15mm eyepiece (i'm just making this up as an example), then what it means once you focus the scope for one eyepiece, you should be able to remove it, insert the other eyepiece and notice that it's still in focus.)

    You can buy something called a "parfocal ring" which goes on the eyepiece barrel. This is just a simple ring (collar) with a set-screw on the side. You slide the eyepiece and up and down until you find the point where it's focus matches that of another eyepiece, then tighten down the ring. Now you can swap between eyepiece and the ring will rest on the eyepiece seat at the correct parfocal distance.
    Mystery57 likes this.
    Tim Campbell


    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    : PlaneWave 12.5” CDK - Meade 14" LX-200 ACF - TeleVue NP101is - Lunt LS80T Ha/PT/DSII
    Mounts: Losmandy G11 &
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    2 - Losmandy GM8 & Gemini 2 - Meade LX80
    Cameras: ZWO ASI128MC-Pro - ZWO ASI174MM-Cool - Canon 60Da

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

    Mystery57 (01-22-2014)

  7. #5
    Mystery57's Avatar
    Mystery57 is offline Main Sequence
    Points: 2,814, Level: 34
    Level completed: 43%, Points required for next Level: 86
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!Gallery Achievement!Album Achievement!5 Threads Achievement!
    Join Date
    Jan 2014
    Location
    North Devon
    Posts
    72
    Points
    2,814
    Level
    34
    Thanks
    47
    Thanked 3x 3 Posts

    Default Re: Eyepiece locating query on 6SE and focussing accuracy

    wow thats some useful information there Tim, thank you

  8. #6
    TILLIBOBS's Avatar
    TILLIBOBS is offline HYPER GIANT
    Points: 93,552, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    5 Threads Achievement!50 Posts Achievement!2 Posts Achievement20 Posts Achievement!First 1000 Experience Points
    Awards:
    Social Group Award!
    Join Date
    Mar 2012
    Location
    gomersal UK.
    Posts
    9,730
    Points
    93,552
    Level
    100
    Thanks
    2,769
    Thanked 1,760x 1,566 Posts

    Default Re: Eyepiece locating query on 6SE and focussing accuracy

    My C6S is the same model as yours apart from my tube being black whilst yours is orange. To the best of my knowledge ( which isn't much ), the diagonal is used to make observing at the eyepiece comfortable. I never use the diagonal when I am imaging.
    Mystery57 likes this.
    ,Lunt60,BF1200. Quark Chromo, Lunt Herschel solar wedge, DMK21.
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Evostar 80mm with Moonlite focusser DMK51.
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    href="
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    rel="lightbox[signatures]">
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Celestron SCT8SE
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

  9. The Following User Says Thank You to TILLIBOBS For This Useful Post:

    Mystery57 (01-23-2014)

  10. #7
    Mystery57's Avatar
    Mystery57 is offline Main Sequence
    Points: 2,814, Level: 34
    Level completed: 43%, Points required for next Level: 86
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!Gallery Achievement!Album Achievement!5 Threads Achievement!
    Join Date
    Jan 2014
    Location
    North Devon
    Posts
    72
    Points
    2,814
    Level
    34
    Thanks
    47
    Thanked 3x 3 Posts

    Default Re: Eyepiece locating query on 6SE and focussing accuracy

    The only time I have put camera on so far, was without the diagonal mainly because the T-adaptor was a 2" given to me

    How would you manage if you were using a Barlow, would you use the diagonal then or buy a larger barlow ?

 

 

Similar Threads

  1. zooming and focussing
    By shashi2408 in forum Astronomy Beginners Forum
    Replies: 4
    Last Post: 11-20-2013, 09:53 PM
  2. Focussing issue
    By md1542 in forum Telescope Forum
    Replies: 4
    Last Post: 11-15-2012, 05:18 AM
  3. Question about focussing
    By epeddy1 in forum Astronomy Beginners Forum
    Replies: 8
    Last Post: 01-18-2012, 10:37 PM
  4. Afocal focussing
    By jimg@sonic.net in forum Astro Imaging Forum
    Replies: 1
    Last Post: 11-23-2011, 07:22 PM
  5. RCX not focussing
    By SRBell in forum Meade LX200 Telescope Forum
    Replies: 4
    Last Post: 09-14-2009, 10:01 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 12:25 PM.