Page 1 of 5 123 ... LastLast
Results 1 to 10 of 41
Like Tree40Likes

Thread: ^%$##%$#%#$!!!!! Something fell on my mirror!

  1. #1
    aatt's Avatar
    aatt is offline Main Sequence
    Points: 5,816, Level: 52
    Level completed: 33%, Points required for next Level: 134
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!365 Days+ Registered Achievement!
    Join Date
    Aug 2012
    Location
    ct
    Posts
    176
    Points
    5,816
    Level
    52
    Thanks
    0
    Thanked 13x 13 Posts

    Default ^%$##%$#%#$!!!!! Something fell on my mirror!



    I just got a Discovery split tube 15" last week. So far it has been really great, but the night before last night, when I packed it up, one of the metal studs that anchors the upper tube assembly came loose and fell on the pristine primary when I was pulling the top off....I almost cried...it rolled back and forth along the ultra smooth face of the mirror before coming to a stop.I think this horrible sound was permanently imprinted onto my brain.... I star tested it last night and could see the defects in the mirror-they were three contact points, or at least I think I could see them, as a small bullseye that would track with the motions of the scope along the defocused star disc. Seeing was atrocious last night so I can't tell from the images I saw during my observing session, if the overall image is compromised. The mirror is not cracked and the coating is intact, but from off angle, there are three little bowls where the blasted stud hit the mirror.One of them is 4-5mm in diameter. I am not an optical expert-do mirrors need refiguring with this kind of damage in general or can they take a little abuse and still perform? I am really depressed about this accident-any feedback or reassurance would be most welcome.

  2. #2
    skcusfa's Avatar
    skcusfa is offline Banned
    Points: 1,815, Level: 26
    Level completed: 15%, Points required for next Level: 85
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!Got three Friends200+ Posts Achievement!
    Join Date
    Nov 2012
    Location
    usa
    Posts
    494
    Points
    1,815
    Level
    26
    Thanks
    25
    Thanked 108x 100 Posts

    Default Re: ^%$##%$#%#$!!!!! Something fell on my mirror!

    Ouch,, sorry to hear this

  3. #3
    santosh83's Avatar
    santosh83 is offline Main Sequence
    Points: 3,922, Level: 41
    Level completed: 82%, Points required for next Level: 28
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!Ghost Achievement! Averaging 5+ posts a day!
    Join Date
    Nov 2012
    Location
    Madras, India
    Posts
    110
    Points
    3,922
    Level
    41
    Thanks
    148
    Thanked 29x 17 Posts

    Default Re: ^%$##%$#%#$!!!!! Something fell on my mirror!

    Hi aatt,

    So sorry to hear about your misfortune. This is one of the worst things that can happen to a reflector telescope owner I think. What I don't understand is why the manufacturers don't design some sort of retractable lid right next to the mirror to prevent exactly this kind of thing from happening. It shouldn't be too difficult to engineer it so that it retracts to the tube's walls during use and covers the mirror after viewing.

    If the stud has managed to excavate a 4-5 mm depression then certainly I think you should get the mirror re-figured for best performance. I suppose if you explain what happened to your manufacturer they can cover this in the warranty. If a stud falls lose during routine disassembly, they are as much to blame for designing such a system as you, I'd say.

    Hope everything works out with minimal cost/trouble to you.

  4. #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
    6,923
    Points
    56,828
    Level
    100
    Thanks
    743
    Thanked 5,861x 3,115 Posts
    Blog Entries
    1

    Default Re: ^%$##%$#%#$!!!!! Something fell on my mirror!

    I will offer a counter to the refiguring thought.

    One of the telescopes here at McDonald, the 107" / 2.7M has seven bullet holes, and a hatchet 'hit' on its surface. In the '70's, an employee here went crazy and shot the telescope - when it failed to shatter, he took a hatchet to the mirror.

    We use flat black paint, carefully covering each bullet hole and the hatchet mark - the flat black paint stops off-angle, random reflections from the defects from scattering light into the secondary.

    I doubt you need to take this action with your mirror - my point is that the M1 primary on most telescopes can take a lot more abuse, contamination, and degradation than most of us would ever dream possible, and still perform acceptably. In the 107" case, even this kind of tremendous damage causes loss of less than 1% of its total reflectivity...

    Get into the habit of covering the mirror before assembly/disassembly, and this will be less of an issue in the future.
    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

  5. The Following 9 Users Say Thank You to AustinPSD For This Useful Post:

    boardtrackbob (11-26-2012),fmhill (11-17-2012),les_robot (11-18-2012),Melissa 44th Lat NY (11-18-2012),not_Fritz_Argelander (11-17-2012),olddogg60 (11-17-2012),santosh83 (11-17-2012),Starprober (11-17-2012),Voyager3 (11-17-2012)

  6. #5
    KT4HX's Avatar
    KT4HX is online now HYPER GIANT
    Points: 99,566, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 13.0%
    Achievements:
    365 Days+ Registered Achievement!First 1000 Experience Points750 Days+ Registered Achievement!1000 Days+ Registered Achievement!200+ Posts Achievement!
    Join Date
    Dec 2008
    Location
    Virginia
    Posts
    11,710
    Points
    99,566
    Level
    100
    Thanks
    1,393
    Thanked 8,019x 4,327 Posts
    Blog Entries
    200

    Default Re: ^%$##%$#%#$!!!!! Something fell on my mirror!

    Sorry to hear that. Hopefully it isn't as bad as you initially suspected, and you can still observe without issue. Things like that are exactly the reason that I keep my dobs angled more to horizontal when I do anything with them that has even the remotest possibility of resulting in anything dropping or sliding towards the primary.
    santosh83 likes this.
    Alan || My DSO Blog:
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    ---------------------------------------------------------------------------
    Astro Sky 17.5 f/4.5 Dob || Apertura AD12 f/5 Dob || Zhumell Z10 f/4.9 Dob
    ES AR127 f/6.5 and ES ED80 f/6 on Twilight-II Mount
    ES 82° 24mm thru 4.7mm
    ---------------------------------------------------------------------------
    Astronomers: We look into the past to see our future.

  7. #6
    Voyager3's Avatar
    Voyager3 is offline HYPER GIANT
    Points: 14,604, Level: 83
    Level completed: 30%, Points required for next Level: 246
    Overall activity: 0%
    Achievements:
    Ghost Achievement! Averaging 5+ posts a day!200+ Posts Achievement!400+ Posts AchievementFirst 1000 Experience Points50 Posts Achievement!
    Join Date
    Jul 2011
    Location
    Montreal
    Posts
    2,211
    Points
    14,604
    Level
    83
    Thanks
    1,226
    Thanked 849x 646 Posts

    Default Re: ^%$##%$#%#$!!!!! Something fell on my mirror!

    Quote Originally Posted by AustinPSD View Post
    I will offer a counter to the refiguring thought.

    One of the telescopes here at McDonald, the 107" / 2.7M has seven bullet holes, and a hatchet 'hit' on its surface. In the '70's, an employee here went crazy and shot the telescope - when it failed to shatter, he took a hatchet to the mirror.

    We use flat black paint, carefully covering each bullet hole and the hatchet mark - the flat black paint stops off-angle, random reflections from the defects from scattering light into the secondary.

    I doubt you need to take this action with your mirror - my point is that the M1 primary on most telescopes can take a lot more abuse, contamination, and degradation than most of us would ever dream possible, and still perform acceptably. In the 107" case, even this kind of tremendous damage causes loss of less than 1% of its total reflectivity...

    Get into the habit of covering the mirror before assembly/disassembly, and this will be less of an issue in the future.
    What an amazing story. And very instructive.
    All of a sudden, I'm not that worried about any dust or minor crud that might mar my primary.

    Thanks for that.
    olddogg60 and santosh83 like this.
    C-800 Edge HD |TV 101| ES ED80 | WO ZS66 SD | Coronado PST | SW 130 Dob | B & L 8080 | ST-80 |
    Nexstar 8SE l EQ-5 l EQ3-2 l EQ-1 l AZ-3 | Vixen Mini-Porta l
    ES 7.6mm & 16mm | Nagler 9mm | Panoptic 24mm | TV 32mm & 40mm Plössl |

    “The history of astronomy is a history of receding horizons.”
    ― Edwin Hubble

  8. #7
    Newt Reno's Avatar
    Newt Reno is offline SUPER GIANT
    Points: 4,848, Level: 47
    Level completed: 49%, Points required for next Level: 102
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!200+ Posts Achievement!
    Join Date
    Sep 2012
    Location
    Minnesota
    Posts
    706
    Points
    4,848
    Level
    47
    Thanks
    19
    Thanked 165x 131 Posts

    Default Re: ^%$##%$#%#$!!!!! Something fell on my mirror!

    Sorry to hear that aatt, makes me cringe to think of it.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    :
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    XT8; Orion 150mm Maksutov; ES AR102; Celestron C90s
    Cyclops Eyepieces: Q70 32mm, GSO superview 20mm, Baader Hyperion 13mm with tuning rings, (ES 11mm 82, 18mm 82, 9mm 100), Orion Edge-on Planetary 6mm
    Other: OIII, Lybar chair, binoviewers with 25mm Orion plossls and 15mm GSO superviews, Orion Skyview Pro mount

  9. #8
    KathyNS's Avatar
    KathyNS is online now Super Moderator
    Points: 171,408, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 50.0%
    Achievements:
    200+ Posts Achievement!Ghost Achievement! Averaging 5+ posts a day!First 1000 Experience Points400+ Posts AchievementGot three Friends
    Awards:
    Reply Award
    Join Date
    Nov 2010
    Location
    Nova Scotia
    Posts
    25,045
    Points
    171,408
    Level
    100
    Thanks
    6,647
    Thanked 14,937x 9,508 Posts
    Blog Entries
    3

    Default Re: ^%$##%$#%#$!!!!! Something fell on my mirror!

    Ouch! I can see why you would say "^%$##%$#%#$!!!!!"

    If it is affecting the optical performance, then a tiny bit of flat black paint, as AustinPSD suggested will take care of it. Any time you work on the scope, it should be horizontal, to prevent mirror strikes.
    santosh83 likes this.

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


    DSO AP:
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,LRGB filters; KWIQ/QHY5 guide
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome;
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    (pier);
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    .

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

  10. The Following User Says Thank You to KathyNS For This Useful Post:

    Melissa 44th Lat NY (11-18-2012)

  11. #9
    Starprober's Avatar
    Starprober is offline SUPER GIANT
    Points: 8,927, Level: 65
    Level completed: 59%, Points required for next Level: 123
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!200+ Posts Achievement!
    Join Date
    Aug 2012
    Location
    39.7597 N, 121.6208 W (Northern California)
    Posts
    1,166
    Points
    8,927
    Level
    65
    Thanks
    161
    Thanked 244x 235 Posts

    Default Re: ^%$##%$#%#$!!!!! Something fell on my mirror!

    Very sorry to hear of your misfortune. Indeed this is the stuff of my nightmares.

    From what is being said, hopefully other than the trauma associated with having to see such a thing happen, the damage wont be that bad.
    Will

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

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    tweaked,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    SpaceProbe 130ST EQ, 9x50 RACI finder, Telrad, Rigel Quickfinder.
    ES 18mm 82* 2-inch, ES 9mm 100* 2-inch , Superview 30mm 2-inch, Baader 13mm Hyperion, 32mm HighLight Plossl, 5mm and 10mm
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Plossl,
    9 mm Super Plossl, 7mm Celestron X-Cel LX, 25mm, 9mm and 4mm OR series Meade circa 1980.
    Orion 2x Shorty
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    lens. Orion 10x50 UltraView binoculars.

  12. #10
    Blackhorse11th's Avatar
    Blackhorse11th is offline Bright Giants
    Points: 8,013, Level: 62
    Level completed: 55%, Points required for next Level: 137
    Overall activity: 0%
    Achievements:
    2 Posts Achievement5 Threads Achievement!20 Posts Achievement!50 Posts Achievement!200+ Posts Achievement!
    Join Date
    Sep 2012
    Location
    Woodbury, MN
    Posts
    412
    Points
    8,013
    Level
    62
    Thanks
    47
    Thanked 111x 88 Posts

    Default Re: ^%$##%$#%#$!!!!! Something fell on my mirror!

    I can feel your pain!!! I dropped a sec mirror adjusting screw when changing out the philips head for a socket head so I don't need a screw driver to adjust it. Luckily it slid down the tube and missed my mirror but the thought of it almost made me sick. I'd say check it out visually as best you can to determine if the marks are an issue you can live with, then if you can't, the paint idea sounds great.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    :
    Zhumell 12"Newt/Dob.

    FINDERS: Zhumell 8 x 50 RACI scope,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    EZ Finder Red Dot .

    EP.s: Russel 2"- 10, 13 and 19mm Super-Wide Konig XL, andl 25mm Super Plossl; Zhumell 9mm & 30mm and 2X
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    .

    OTHER: Orion Laser Collimator , Zhumell 2" filter kit, Turn Left at Orion".
    HOMEMADE: Mobil Scope base, Various
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    tubes, larry-rigged chair.
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

 

 
Page 1 of 5 123 ... LastLast

Similar Threads

  1. Tripod fell over
    By canidae in forum ETX Telescope Forum
    Replies: 3
    Last Post: 09-05-2012, 08:35 PM
  2. Telrad battery cap fell under mirror!
    By mantra in forum Dobsonian Telescopes Forum
    Replies: 2
    Last Post: 09-26-2011, 03:32 AM
  3. Nearly fell off my seat!
    By Iceman1976za in forum Astronomy Beginners Forum
    Replies: 6
    Last Post: 07-21-2009, 08:15 PM
  4. Something fell off from the rover?
    By Alexander Avtanski in forum Amateur Astronomy Forum
    Replies: 5
    Last Post: 08-09-2005, 03:12 PM
  5. Be sad if the albatross fell out of orbit
    By RichA in forum Amateur Astronomy Forum
    Replies: 0
    Last Post: 03-18-2005, 05:32 AM

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 05:25 PM.