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Equipment Discussions >> Reflectors

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aatt
sage


Reged: 07/26/12

Loc: CT
Depressed-accident with my new mirror
      #5526419 - 11/18/12 04:26 PM

I was up till dawn the other night having a blast with my new week old 15" Discovery split tube and upon removing the upper tube assembly, one of the studs came loose unexpectedly and fell on the mirror....I am still cringing and totally upset by this stupid lack of foresight on my part.I could not believe the horrible sound of clinking metal followed by sound of the stud rolling back and forth across the formerly pristine smooth surface of the mirror. The mirror is damaged in four places. I took the cell out today and took a magnifying glass to the marks. The glass looks kinda crushed/cracked and the figure of the mirror seems to be distorted past the periphery of the worst divot by about 4 mm judging by the reflections. I can't see any spiderwebbing. Upon loosely measuring these areas my worst case scenario is 2% of the area of the mirror is compromised, but it is probably closer to 1%. Last night I took it out and it did not seem the same, but seeing was pretty bad or was it the damage? This accident is playing with my head and perceptions possibly. My collimation accuracy seemed about the same as before the accident-if not better. Does anyone have suggestions about how to evaluate this damage or what to do? I did a star test and if I tracked the defocused star across the FOV I could locate a couple of bullseyes that corresponded to the location of the strike points. Seeing was poor and the image was boiling-could not make out the rings with any consistency. This just sucks! I have had the scope a week. Hindsight is 20/20.

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Mirzam
Post Laureate
*****

Reged: 04/01/08

Loc: Lovettsville, VA
Re: Depressed-accident with my new mirror new [Re: aatt]
      #5526438 - 11/18/12 04:35 PM

Can you provide a picture? Most of the damage is probably superficial coating damage and will look a lot worse that it is. How heavy was the object that fell on the glass? If it was just a metal bolt, you may have a small crater somewhere, but I doubt that any important damage to the mirror figure would have occurred.

JimC


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aatt
sage


Reged: 07/26/12

Loc: CT
Re: Depressed-accident with my new mirror new [Re: Mirzam]
      #5526477 - 11/18/12 04:58 PM

Not at this time-my Digital camera is on the fritz and my phone is a dinosaur. I will look into it.The stud weighs less than half of a typical 10mm eyepiece-not heavy, but heavy and hard enough.

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dpwoos
Pooh-Bah
*****

Reged: 10/18/06

Loc: United States
Re: Depressed-accident with my new mirror new [Re: Mirzam]
      #5526495 - 11/18/12 05:12 PM

I don't think there is any reason to believe that the damage isn't localized to a very small area. Blacken out those spots and see how it performs. Too bad that it happened, but the actual impact will be very, very minor and in the dark only you will know.

Unless you are a "collector", I suggest that you view all of the dings and smudges and range marks that accumulate over time as signs that astronomy is going on - a sometimes messy endeavor!


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mayidunk
Don't Ask...
*****

Reged: 02/17/10

Loc: Betwixt & Between...
Re: Depressed-accident with my new mirror new [Re: aatt]
      #5526545 - 11/18/12 06:10 PM

Wow! That is horrible to hear, but I don't think it's as bad as you think it is... I believe that the major concern would be light scatter caused by the damaged areas, the mirror's figure itself is unlikely to have been affected. The MacDonald Observatory in Texas has a large reflector that has several repaired bullet holes in the primary! IIRC, I believe they painted the holes black in order to eliminate them scattering the light, resulting in the only negative affect being the overall brightness of the image having dimmed by an insignificant amount; as if the diameter of the mirror was decreased every slightly! As far as I know, they continue to use the repaired primary to this day.

That being said, you might first try calling Discovery and asking them what they would recommend you do. You could ask them about your dabbing non-reflective black paint on the damaged parts. Then, after the paint has dried, try doing a star test to see if the figure has been affected in any appreciable way. Chances are that you'll find that the star test looks just as good as it ever did. The paint dabs should no more affect the image than the secondary spot currently does. If, however, you find that the figure might have been affected, you could then determine if it appreciably affects your being able to see the objects you're looking at the most with that scope. If you do mostly deep sky, then it may not really affect it at all. If planets are your primary target, then only you can determine if the affect it has on the view is worth the cost of re-figuring or replacing the mirror. If you can afford it, perhaps it would be an opportunity to get a premium mirror, though from what I understand the mirror you already have is no slouch.

Yeah, it'll look ugly! But if you're lucky it'll still work fine. And now you have a war story that you can tell the kids, and the newbies here on CN! Plus you've had the worst thing you could ever imagine happening to your scope happen... and you lived to tell the tale! So has the scope.

I recall a story about a guy who, when he bought a new guitar, the first thing he would do would be to open the case, and drop his keys on it! When asked why he did such a thing, he replied that it was so he wouldn't have to continue worrying about when the first scratch would happen. He figured that by doing it himself, he got it out of the way, and was then able to just enjoy the guitar!

Good luck.


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aatt
sage


Reged: 07/26/12

Loc: CT
Re: Depressed-accident with my new mirror new [Re: mayidunk]
      #5526766 - 11/18/12 08:18 PM

Thanks-I will have to try the paint thing out. You are right-this mirror is no slouch my first star test was textbook. That makes this all the more upsetting.

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dan_h
Carpal Tunnel


Reged: 12/10/07

Re: Depressed-accident with my new mirror new [Re: aatt]
      #5526767 - 11/18/12 08:18 PM

Sorry to hear of your misfortune. I too have done some things that left me feeling totally depressed and I was not the first.

If you don't want to paint the damaged spot in the glass, you could cut a small circle of peel and stick flocking material and just cover it it up. Ugly in daylight but effective at preventing light scatter and easy enough to remove if ever needed.

good luck,

dan


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panhard
It's All Good
*****

Reged: 01/20/08

Loc: Markham Ontario Canada
Re: Depressed-accident with my new mirror new [Re: dan_h]
      #5526889 - 11/18/12 09:24 PM

I say use it on a good night before you do anything to the mirror.

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Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Depressed-accident with my new mirror new [Re: panhard]
      #5527095 - 11/18/12 11:50 PM

Yes, a bummer fersure! Had a few minor boofs myself, a few scratches on my primary (coatings only, not into glass) resulted. But have found the views are entirely unaffected. Likely yours will be, also.

Since then, i no longer feel the urge to offer gravity free-shots at my mirror! I've even heard of folks tying a thread around their tools & looping it over their wrist while adjusting collimation, etc., to prevent accidental drops.

Let us know how views turn out the next steady night! And always remember- if the good folks from MacDonald Observatory should come by for a look, make sure they keep their safeties on!


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mayidunk
Don't Ask...
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Reged: 02/17/10

Loc: Betwixt & Between...
Re: Depressed-accident with my new mirror new [Re: aatt]
      #5527122 - 11/19/12 12:07 AM

Practically speaking, unless the pin hit it in such a way as to cause a crack to form (a pretty remote chance), you'll soon be glued to the eyepiece once again.

Where do you go for a dark sky site?


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Binojunky
Carpal Tunnel
*****

Reged: 12/25/10

Re: Depressed-accident with my new mirror new [Re: mayidunk]
      #5527538 - 11/19/12 09:25 AM

Its like the new car and waiting for the first stone chip or shopping cart dent, I remember years back getting a 10" Meade dob and the first night out dripping coffee on to the sonotube and staining the white paint, recently I bought a high end expensive watch, within a week I,d managed to put a couple of scuffs on the bracelet, the mirror damage is what it is, its done and you can,t turn back the clock however don,t let it eat you up, go out and enjoy the scope, sorry to here about your accident,DA.

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csrlice12
Postmaster
*****

Reged: 05/22/12

Loc: Denver, CO
Re: Depressed-accident with my new mirror new [Re: Binojunky]
      #5527624 - 11/19/12 10:21 AM

Don't feel bad. First Light with my 10XTi about a year ago: I was carring the OTA to the mount; I had picked it up by the two ends. The front cover came off and the Secondary end of the scope took a nose dive to the dirt (luckily there was some grass there). Also, luckily, my collimation wasn't off, a slight tweek to the primary, and off I went....still dreading my first mirror ding. I've already had to blow off a couple of mosquitos. Now when I store the scope in the shed, I put it horizontially.

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killdabuddha
Pooh-Bah
*****

Reged: 08/26/11

Re: Depressed-accident with my new mirror new [Re: Binojunky]
      #5527633 - 11/19/12 10:27 AM

I can't find the link, but there was a guy who posted his ordeal at his blog...He was usin large magnets as counterweights when, a little too close to horizon, one came unstuck and bounced off his new Zambuto mirror. He sent it to Carl for examination and about a quarter-sized spot had stress-fractured beneath the coating, makin that bit unusable. Carl's advice to him was to just cover that spot, as others here have suggested. The amount of light loss was negligible.

As for cars, I always put an extra ding in the fender before someone else does. First got the idea from Sheldon Vanauken's "A Severe Mercy."

A cruce salus. Absit invidia.


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Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: Depressed-accident with my new mirror new [Re: killdabuddha]
      #5528150 - 11/19/12 03:07 PM

I dropped a 2.5 lb counterweight on the mirror of my Discovery many years ago. It fell from the height of the top of the UTA!
It landed flat (fortune smiles on the idiot) and didn't bounce, and it hit hard enough to slightly flatten the edges of the counterweight.
It left two scuff marks in the coating, with no obviously fractures leading away from the scuff marks (lucky, I know), about 12mm x 1-2mm wide. I was going to paint them black, then decided to test the mirror to see if those marks were visible either in the out-of-focus star image or in-focus as scattered light.
Nope. No effect on anything except my ego for having been so stupid, stupid, stupid
We worry a lot about such things, but the truth is that such minor scratches and scuff marks are really not very important.
If your marks are larger and you CAN see them in the out-of-focus star image, just paint them in with flat black paint and ignore them. [I know, it's hard.....]


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frito
Pooh-Bah


Reged: 10/05/12

Loc: Fremont, CA
Re: Depressed-accident with my new mirror new [Re: Starman1]
      #5528197 - 11/19/12 03:29 PM

I feel your pain. Last Friday I was installing a bracket for my new finder scope and dropped the steel reinforcement plate on my XT8 mirror. My heart sank but the only damage was a small maybe 1/8th inch diameter surface chip and so far it looks like I won't even need to black the spot out

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Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Depressed-accident with my new mirror new [Re: frito]
      #5528238 - 11/19/12 03:43 PM

Gravity is a harsh & unforgiving master! It neither takes account of kings, nor suffers fools with tools (like me).
Our Dob's may be optical configurations first, but are secondarily anti-gravity devices.


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csrlice12
Postmaster
*****

Reged: 05/22/12

Loc: Denver, CO
Re: Depressed-accident with my new mirror new [Re: Mike B]
      #5528263 - 11/19/12 03:53 PM

"Gravity is a harsh & unforgiving master!"



Edited by David Pavlich (11/19/12 10:05 PM)


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dvb
different Syndrome.
*****

Reged: 06/18/05

Loc: Vancouver, Canada
Re: Depressed-accident with my new mirror new [Re: csrlice12]
      #5528388 - 11/19/12 04:53 PM

I try to never do any maintenance on my scope - including collimation - unless the tube is horizontal

But that isn't always possible, and I've had a few "D'Oh"! moments myself.


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frito
Pooh-Bah


Reged: 10/05/12

Loc: Fremont, CA
Re: Depressed-accident with my new mirror new [Re: dvb]
      #5528419 - 11/19/12 05:15 PM

Quote:

I try to never do any maintenance on my scope - including collimation - unless the tube is horizontal

But that isn't always possible, and I've had a few "D'Oh"! moments myself.




Yeah i do the same thing normally and when i was removing the old finder mounting bracket i did so horizontally. the problem was putting the new one back in with the reinforcement bracket was proving to be hard in that position and i didn't want to drop it onto the secondary it was right above so i thought hmm ill do it with the scope vertical and gravity will hold it in place till i get the first nut on and it did the first time i put it on. then i realized i put it on backwards and it all went downhill from there


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Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Depressed-accident with my new mirror new [Re: frito]
      #5528430 - 11/19/12 05:22 PM

Quote:

...and it all went downhill from there




Ayup, gravity will do that.


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Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Depressed-accident with my new mirror new [Re: csrlice12]
      #5528438 - 11/19/12 05:27 PM

Quote:





You, sir, are a brave soul to enter that end of the pond.

Yet typically, when gravity is mixed with levity in THAT arena, it leads to brevity... of the mixer's tranquility!

Edited by David Pavlich (11/19/12 10:24 PM)


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stratocaster
sage
*****

Reged: 10/27/11

Re: Depressed-accident with my new mirror new [Re: Mike B]
      #5528847 - 11/19/12 09:26 PM

I got bummed out when I was removing my finder bracket and dropped one of the teeny tiny nuts holding the bracket. I could hear it bouncing around on the mirror. Perhaps not surprisingly there was absolutely no visible damage at all. But I still had a coronary when it happened.

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frito
Pooh-Bah


Reged: 10/05/12

Loc: Fremont, CA
Re: Depressed-accident with my new mirror new [Re: stratocaster]
      #5528873 - 11/19/12 09:40 PM

Quote:

I got bummed out when I was removing my finder bracket and dropped one of the teeny tiny nuts holding the bracket. I could hear it bouncing around on the mirror. Perhaps not surprisingly there was absolutely no visible damage at all. But I still had a coronary when it happened.




after what i did i'd be overjoyed if all i dropped was a small nut hehe


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azure1961p
Postmaster
*****

Reged: 01/17/09

Loc: USA
Re: Depressed-accident with my new mirror new [Re: Mike B]
      #5528896 - 11/19/12 09:51 PM

Wow OK. Blacken the dings but be careful here. You don't want a reaction with the paint versus coatings and this foggy apron of fog around the paint. My knee jerk thing said use a Sharpie its got acetone but mirrors sometimes are cleaned with acetone. I suggest staying well away from lacquers and outgassing enamels.

Good luck. Sounds like the real damage here is to your Psyche and I'm sympathetic here but don't let it precede the benefit of what might be at least a good mirror.

Pete


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frito
Pooh-Bah


Reged: 10/05/12

Loc: Fremont, CA
Re: Depressed-accident with my new mirror new [Re: azure1961p]
      #5528928 - 11/19/12 10:04 PM

Quote:

Wow OK. Blacken the dings but be careful here. You don't want a reaction with the paint versus coatings and this foggy apron of fog around the paint. My knee jerk thing said use a Sharpie its got acetone but mirrors sometimes are cleaned with acetone. I suggest staying well away from lacquers and outgassing enamels.

Good luck. Sounds like the real damage here is to your Psyche and I'm sympathetic here but don't let it precede the benefit of what might be at least a good mirror.

Pete




yeah my first thought of blacking out the small chip on mine was to use a sharpie as well but then i thought about it more and decided it was probably a bad idea if it had a reaction with the aluminum or SiO2 coatings around it and have not done anything to mine yet and its looking like i won't need to either because i can't see it at the eyepiece yet but the weather has been really bad for observing lately so i have not done any good tests yet.


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whirlpoolm51
professor emeritus
*****

Reged: 01/05/12

Loc: pittsburgh,pa
Re: Depressed-accident with my new mirror new [Re: frito]
      #5528974 - 11/19/12 10:24 PM

Feel your pain!!! When i had my orion xt12i awhile ago i was collimating and getting everything ready before i took it out for a good nights observing , i went into my kitchen to make a cup of coffee and all of a sudden........i hear a pings of somthing smacking of an aluminum tube and a loud smack!!! To my dismay , my little brother decided to see how fast a hot wheels car could go down the tube of my scope!!!!!!!! Lucky for that little bugger i love him or i would be an only child hahahaha 2 little chips in my mirror that had my head spinning for days!!!

This hobby will drivce you crazy if you fall in love with it as much as we do hahaha


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killdabuddha
Pooh-Bah
*****

Reged: 08/26/11

Re: Depressed-accident with my new mirror new [Re: whirlpoolm51]
      #5529215 - 11/20/12 12:32 AM

We were draggin our scope sled-style across uneven ground, then we weren't, cus it tipped over and crashed before we could catch it. The mirrors spilled out onto the square tubes and my first thought was, "I shoulda used round." And yeah, the sound is even worse. Got 'em inside, blew them off, and looked really hard for the damage. It showed up days later as a little abraded smear at the edge where the coating left. Glad we got that over with.

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RussD
member


Reged: 04/20/06

Loc: Minnesota
Re: Depressed-accident with my new mirror new [Re: killdabuddha]
      #5531936 - 11/21/12 10:49 AM

I feel your pain. I once dropped a 2" adapter on my full thickness 10" mirror, it bounced (tink) and bounced (tink,tink) and bounced (tink,tink,tink,tink...)then rolled around.

There were several scratches in the coating and other minor marks. Other than the coating scratches there was no real damage to the mirror.

At one of our club star parties once a friend was looking through his scope and suddenly though it had clouded over because the stars faded away. He looked at the sky only to see it was clear. He finally looked down at his mirror to see a stray cat had climbed into his rocker box for a nap on the nice smooth mirror!

Russ


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GeneT
Ely Kid
*****

Reged: 11/07/08

Loc: South Texas
Re: Depressed-accident with my new mirror new [Re: aatt]
      #5531953 - 11/21/12 10:54 AM

You need to get it out for a few more viewing sessions. What matters is how the views are affected. Put Jupiter under a little magnification and move the image around various parts of the field of view to see if there is a sudden change in image quality.

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Asbytec
Guy in a furry hat
*****

Reged: 08/08/07

Loc: La Union, PI
Re: Depressed-accident with my new mirror new [Re: GeneT]
      #5532083 - 11/21/12 11:48 AM

You know, it sucks. We care so much for our instruments, and we should. We've all dinged them and cringed mightily.

Truth is, a little ding will not likely have the proper surface correction to send an errant ray or two anywhere near focus. So, you will likely not even notice any scatter, or turned edge, or anything like that. I seriously doubt such an impact changed its figure to below diffraction limited. That would take a truly freak accident. I am pretty sure your glass didn't shatter like a car window.

Paint it over, feel good...smile. Be happy, well, when you find closure - probably during your next viewing session. Soon enough, someone else will have an accident, and you will have a story to tell them.


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JasonBurry
sage


Reged: 04/27/12

Loc: Cape Spencer, NB, Canada
Re: Depressed-accident with my new mirror new [Re: Asbytec]
      #5532149 - 11/21/12 12:21 PM

Another one here who's dropped an object on his primary mirror, in my case my 12.5mm plossl fell from my shirt pocket as I bent over the scope.

Mine suffered a 2X1mm ding in the coating, and no detectable effects at the eyepiece. Live and learn.

J


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csrlice12
Postmaster
*****

Reged: 05/22/12

Loc: Denver, CO
Re: Depressed-accident with my new mirror new [Re: JasonBurry]
      #5532402 - 11/21/12 02:34 PM

That's the sky goddess's way of telling you you need a bigger scope.....

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Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Depressed-accident with my new mirror new [Re: csrlice12]
      #5532623 - 11/21/12 04:43 PM

.... or else just messin' with our heads...


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ed_turco
Pooh-Bah
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Reged: 08/29/09

Loc: Lincoln, RI
Re: Depressed-accident with my new mirror new [Re: Mike B]
      #5532676 - 11/21/12 05:13 PM

I pulled this stunt with a very early 12" f/4. Diagonal loosened and fell on mirror. Damage, yes! Busted diagon. Marks on mirror.

But it still worked fine. Yours will too.


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smee
super member


Reged: 10/19/10

Re: Depressed-accident with my new mirror new [Re: Mike B]
      #5533879 - 11/22/12 12:31 PM

Quote:

Quote:

...and it all went downhill from there




Ayup, gravity will do that.





I heard once a guy tried to dodge a speeding ticket blaming gravity on a downhill stretch made him go 50% over the limit!


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Slow Astronomer
member


Reged: 05/01/10

Loc: Milky Way Galaxy
Re: Depressed-accident with my new mirror new [Re: smee]
      #5545892 - 11/29/12 05:38 PM

Sorry to hear about your mirror damage. Hopefully the damage won't affect the scopes use. Looks like you have rec'd some good advice above so I'll just leave you with this:

"Watch out for those gravity storms!" - Jimmy Buffett

Clear skies, Dave


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aatt
sage


Reged: 07/26/12

Loc: CT
Re: Depressed-accident with my new mirror new [Re: Slow Astronomer]
      #5546229 - 11/29/12 08:51 PM

Thanks to all the folks offering their reassurances and personal horror stories. I have never had to contend with a damaged scope in my 14 years of dabbling in this hobby as an adult-go figure that a new scope would "break" a perfect record within a week of getting it! Seeing here has been mostly mediocre, but the scope seems to be o.k. I can't tell if it is damaged, so I am encouraged by that.Conditions have been too poor for a good star test.When the seeing clears I have had some pretty amazing moments at the eyepiece. The visible detail on the moon and Jupiter this week are way beyond what my modest 6"has been able to show. So all-in all, I think the scope is working well enough to keep me pretty happy. A horrible moment, but no real obvious compromise in performance.

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frito
Pooh-Bah


Reged: 10/05/12

Loc: Fremont, CA
Re: Depressed-accident with my new mirror new [Re: aatt]
      #5546329 - 11/29/12 09:55 PM

you should be fine. the very small chip i put in my XT8's mirror i have determined to be not visible at the eyepiece so i'm leaving it alone and not even painting over it. i still know its there but i still enjoy the performance of my scope and thats what matters the most!

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nirvanix
Carpal Tunnel


Reged: 06/07/07

Loc: Saskatoon, SK
Re: Depressed-accident with my new mirror new [Re: frito]
      #5547736 - 11/30/12 07:26 PM

Life is messy. The winners clean up and move forward.

My dob is an Antares (GSO). In their infinite wisdom the manufacturers hard-slapped and glued the secondary to its mount. Had it out in -40C and the glue failed. Big whack, little whack, tiny whack. Coating scratches on the mirror. Secondary had a 1/2 inch chip out of it. After my tantrum I blackened the rough spots on the secondary, remounted it with silicone dabs and to this day, even though I've replaced the mirrors with premium ones, that injured scope gave me the best view of Jupiter I ever had. For 5 seconds it looked like a Hubble photograph. I still have that secondary tucked away in the ods and ends drawer and would have no trouble calling it out again if the need arises.


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Mirzam
Post Laureate
*****

Reged: 04/01/08

Loc: Lovettsville, VA
Re: Depressed-accident with my new mirror new [Re: nirvanix]
      #5547748 - 11/30/12 07:34 PM

FWIW -40 C and -40 F are the same temperature. (Some of us may not be metric savy).

http://www.csgnetwork.com/tempconvjava.html

At that temp I'd be more worried about some body part falling off. CCD's cameras should have very good signal to noise though.

JimC


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nirvanix
Carpal Tunnel


Reged: 06/07/07

Loc: Saskatoon, SK
Re: Depressed-accident with my new mirror new [Re: Mirzam]
      #5548118 - 12/01/12 12:28 AM

Quote:


At that temp I'd be more worried about some body part falling off. CCD's cameras should have very good signal to noise though.




I always do a body part count after coming in from observing in such weather. As far as I know I've still got all my bits and pieces.


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Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Depressed-accident with my new mirror new [Re: nirvanix]
      #5548870 - 12/01/12 02:10 PM

Quote:

I always do a body part count after coming in from observing in such weather.




Good plan! Still, at my house, that's just the initial phase. A subsequent measure that's generally advisable is to exercise caution with said parts when crawling into bed at 0:dark:30, lest they come into contact with a sleeping spouse prior to reaching ambient temps...

Feet & toes are particularly hazardous in this regard.


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JohnMurphyRN
sage
*****

Reged: 09/09/12

Loc: Near St Louis
Re: Depressed-accident with my new mirror new [Re: Mike B]
      #5548875 - 12/01/12 02:13 PM

Quote:

A subsequent measure that's generally advisable is to exercise caution with said parts when crawling into bed at 0:dark:30, lest they come into contact with a sleeping spouse prior to reaching ambient temps...

Feet & toes are particularly hazardous in this regard.




I thought pressing said parts against sleeping spouse was the preferred method of rapidly reaching temperature equilibrium....


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Mike B
Starstruck
*****

Reged: 04/06/05

Loc: shake, rattle, & roll, CA
Re: Depressed-accident with my new mirror new [Re: JohnMurphyRN]
      #5548887 - 12/01/12 02:24 PM

As they say on the crazy video shows:
"Do not attempt this at home! Leave to the professionals"


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Scanning4Comets
Markus
*****

Reged: 12/26/04

Re: Depressed-accident with my new mirror new [Re: Mike B]
      #5550814 - 12/02/12 06:40 PM

Quote:

I can't find the link, but there was a guy who posted his ordeal at his blog...He was usin large magnets as counterweights when, a little too close to horizon, one came unstuck and bounced off his new Zambuto mirror. He sent it to Carl for examination and about a quarter-sized spot had stress-fractured beneath the coating, makin that bit unusable. Carl's advice to him was to just cover that spot, as others here have suggested. The amount of light loss was negligible.




I remember reading that article a few years ago! it was none other than TOM HOLE himself! I stumbled upon his blog a few years ago and I have read MANY of his articles which are EXCELLENT by the way!

If you read the link to the article below he was sent a brand NEW SHINY ZAMBUTO MIRROR !!!!

http://www.tomhole.com/Starmaster%2011%20EL.htm


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