Results 1 to 2 of 2
Like Tree10Likes
  • 9 Post By kanadalainen
  • 1 Post By Gabby76

Thread: Star Testing a Telescope

  1. #1
    kanadalainen's Avatar
    kanadalainen is offline HYPER GIANT
    Points: 28,800, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!First 1000 Experience Points
    Join Date
    Feb 2017
    Location
    Winnipeg
    Posts
    2,941
    Points
    28,800
    Level
    100
    Thanks
    2,941
    Thanked 2,392x 1,050 Posts

    Default Star Testing a Telescope



    This is a really handy guide to teach yourself how to star test a mirror/objective and interpret what you see.

    https://www.bbastrodesigns.com/JoyOf...g.html#Overall

    I enjoyed it so much so that I decided to put it up here. Useful for studies of scope performance at the eyepiece.

    Example:

    The perfect star test.

    "Slide or rack the focuser with a high power eyepiece giving 1-2mm exit pupil back and forth about an eight of an inch [3mm]. If the mirror is nearly perfect, you will see a bright ring emerge from the focused star image followed by an inner ring that is the diagonal shadow. Between these two bright rings are fainter thinner interference rings. As you slide the eyepiece further out of focus these rings turn into a smooth disc of light with a centered diagonal shadow."





    Regards - I hope you find it as useful as I did,

    Ian
    Last edited by kanadalainen; 02-28-2019 at 06:15 AM.
    Ian
    Scopes Celestron - Vixen 80 f11.3 on a Vixen alt/az mount and an Orion dob XT10i f4.7
    Binoculars Asahi Pentax 7x35 and 7x50, Beck Kassel 8x30 and Celestron 15x70 Camera Nikon D90 with Rokinon 10mm
    Eyepieces: Leitz Periplan GF, ES68s, ES82s, TV Naglers, Meade 4000 super plossl, Nikon CFI, Olympus FK, Paracorr I, Abbe Orthos: Carl Zeiss Jena K7x (35mm), K10x (25mm)
    M110: 110 Herschel 400: 90 Comets: 2 Planets: 6

  2. The Following 8 Users Say Thank You to kanadalainen For This Useful Post:

    Bigzmey (02-28-2019),bladekeeper (02-28-2019),burris (02-28-2019),Gabby76 (04-13-2019),ic_1101 (03-01-2019),j.gardavsky (04-14-2019),ozeclipse (03-01-2019),TheFatKitty (04-13-2019)

  3. #2
    Gabby76's Avatar
    Gabby76 is offline Super Moderator
    Points: 80,899, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 74.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!Gallery Achievement!Album Achievement!50 Posts Achievement!
    Awards:
    Activity & Post & Thread Master
    Join Date
    Jan 2016
    Location
    Live: Slovakia Work: Canada
    Posts
    18,728
    Points
    80,899
    Level
    100
    Thanks
    3,590
    Thanked 5,886x 4,936 Posts
    Blog Entries
    4

    Default Re: Star Testing a Telescope

    Thank you for the link Ian, if you really want to learn how to evaluate a star test, this is a perfect place to start.
    https://www.willbell.com/TM/tm5.htm
    kanadalainen likes this.
    Refractors: Antares 105 f/15, Celestron 150 f/8, Stellarvue NHNG 80 f/6.9, TAL 100RS f/10, TS 102 f/11, UR 70 f/10, Vixen SD115s f/7.7
    Mounts: Celestron SLT w/ pier mod & EQ-3 tripod, Celestron hypertuned CG-5 w/ tracking motor & Argo Navis, Manfrotto 028B w/ Stellarvue M2C, Manfrotto 055PRO w/ 128RC, TAL-1 HD EQ, Vixen SXP w/ HAL-130 SXG & half pier Diagonals: 2" Astro-Physics MaxBright, 2" Zeiss/ Baader prism, 2" Baader Herschel Wedge (Photo Version), 2"
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Amici prism, 2" Stellarvue Dielectric, 2" TeleVue Everbrite Eyepieces: A-Z

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

    The weakest link in the optical chain is the large nut located directly behind the eyepiece/ camera. - Gabrielle
    Ya gotta keep this Apo/
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    thing in some balance of perspective. Apos are awesome, but long focus Achros aren't that far behind them - Siriusandthepup (CN)

    Refractors kick arse precisely because they don't hide behind excuses. That is, they have no obstructions to hide behind. - Jon Isaacs (CN)

  4. The Following User Says Thank You to Gabby76 For This Useful Post:

    kanadalainen (04-22-2019)

 

 

Similar Threads

  1. Hubble Optics 5-Star Artificial Star for Testing and Collimating Telescopes
    By michael131313 in forum Astronomy Beginners Forum
    Replies: 4
    Last Post: 05-28-2017, 01:32 AM
  2. Star Testing
    By Just A Simple Guy in forum Astronomy Beginners Forum
    Replies: 6
    Last Post: 10-28-2015, 05:56 AM
  3. star testing
    By PostalTwo in forum Astronomy Beginners Forum
    Replies: 15
    Last Post: 10-26-2013, 08:07 PM
  4. star testing
    By MrMan in forum Astronomy Beginners Forum
    Replies: 1
    Last Post: 09-29-2011, 04:47 PM
  5. Star Testing
    By mrmojorisin04 in forum UK Astronomy Forum
    Replies: 3
    Last Post: 09-17-2004, 11:08 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 09:35 PM.