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Equipment Discussions >> Cats & Casses

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cavefrog
Carpal Tunnel
*****

Reged: 11/11/08

Loc: loozyanna
large SCT badly damaged, can it be used? new
      #5793373 - 04/11/13 10:00 PM

as in title... this has a secondary with a 3/4 inch hole worn completely through the coating in the center, and working its way out toward the edge. this is a C-14, just for proportions sake.
the question is, would it be possible to collimate with this much damage? I cannot seem to get any movement out of the center spot while defocused. it always stays at about 7:00, and flattened in the same area. the primary is damaged also, but not as much in percentage as the secondary. I think if it was just the primary damage, it would be useable (to what degree I could not say), but the secondary damage has me wondering if anything at all could work. am I just wasting my time?

Theo


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cavefrog
Carpal Tunnel
*****

Reged: 11/11/08

Loc: loozyanna
Re: large SCT badly damaged, can it be used? new [Re: cavefrog]
      #5793572 - 04/11/13 11:45 PM

no answers... anyway, I don't know, it may have been pilot error, but I got the collimation in focus somewhat. I went to the other side of focus, and started to get some results.
I started with a 31mm, then a 20mm, then down to a 9mm. It still doesn't focus very well. judgement was made in a very low (may be the focus problem) Orion nebula. not much contrast. I think I may need to look at something else, but need to rest my back right now.


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Starhawk
Space Ranger
*****

Reged: 09/16/08

Loc: Tucson, Arizona
Re: large SCT badly damaged, can it be used? new [Re: cavefrog]
      #5793582 - 04/11/13 11:55 PM

Huh? Try a photo.

-Rich


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Steven
sage
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Reged: 01/06/04

Loc: Ontario, Canada
Re: large SCT badly damaged, can it be used? new [Re: Starhawk]
      #5793635 - 04/12/13 12:36 AM

What caused the damaged?

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tim53
Postmaster
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Reged: 12/17/04

Loc: Highland Park, CA
Re: large SCT badly damaged, can it be used? new [Re: Steven]
      #5793778 - 04/12/13 03:34 AM

By damage, do you mean the coatings are oxydized or coming off? If so, you should be able to still collimate and try the scope out. If that's what the damage consists of, you could send the mirrors for recoating. You might want to consult someone who's removed the primary from its mount, as it might be RTV'd in place. I don't know about the secondary.

-Tim.


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RogueGazer
super member


Reged: 06/10/12

Loc: Central Point Oregon
Re: large SCT badly damaged, can it be used? new [Re: tim53]
      #5793794 - 04/12/13 04:29 AM

I would think you could collimate this poor scope in theory. If it were my scope I would gently tighten the 3 collimation screws all the way down and then back them all off 1 half turn. This should tighten things up and remove any possible slop in the secondary. After that go ahead and collimate with a properly cooled down scope and without using any diagonal. The image may look like doo doo even after collimation but who knows.

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KerryR
Post Laureate
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Reged: 12/05/07

Loc: SW Michigan
Re: large SCT badly damaged, can it be used? new [Re: RogueGazer]
      #5794053 - 04/12/13 09:55 AM

Why not remove the secondary and send it in for a re-coat? Not all coaters will coat secondaries with the backing plate attached, but some will. I believe OWL does, as does, I think, Spectrum. The primary could be done, too, but I'm pretty sure you'd have to remove it from the carrier, which, because it's glued on, is a big deal...



Edited by KerryR (04/12/13 09:57 AM)


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cavefrog
Carpal Tunnel
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Reged: 11/11/08

Loc: loozyanna
Re: large SCT badly damaged, can it be used? new [Re: RogueGazer]
      #5794063 - 04/12/13 10:03 AM Attachment (83 downloads)

here's the photos. one can see what was the cause, and that it was not oxidation.

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cavefrog
Carpal Tunnel
*****

Reged: 11/11/08

Loc: loozyanna
Re: large SCT badly damaged, can it be used? new [Re: cavefrog]
      #5794066 - 04/12/13 10:05 AM Attachment (60 downloads)

I really wanted to cry when I saw this.

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cavefrog
Carpal Tunnel
*****

Reged: 11/11/08

Loc: loozyanna
Re: large SCT badly damaged, can it be used? [Re: cavefrog]
      #5794067 - 04/12/13 10:05 AM Attachment (64 downloads)

the culprit in shipping.

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cavefrog
Carpal Tunnel
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Reged: 11/11/08

Loc: loozyanna
Re: large SCT badly damaged, can it be used? new [Re: cavefrog]
      #5794102 - 04/12/13 10:21 AM Attachment (48 downloads)

now there was a few variables thrown in here. I did not have any means to cool the scope, but it was out a couple hours. it was very humid, and I had to use a hair dryer about every 15 mins or so. even though I did finally get it collimated with a 9mm EP, it still does not focus very sharp. the secondary is, well... shot. one can see a chunk 1" long on the left side gone, and dead center coating is gone. would this be a problem? . no really, could this cause bad focus? I am surprised this works at all, that is why when I first could not get collimation under control, I wondered if it was possible to collimate at all with this kind of damage. there is a chunk out of the primary too. it is mostly out of the backside (2" across), and some of the first surface. about 1/2" x 1/8 inch.

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cavefrog
Carpal Tunnel
*****

Reged: 11/11/08

Loc: loozyanna
Re: large SCT badly damaged, can it be used? new [Re: cavefrog]
      #5794110 - 04/12/13 10:26 AM

Tim... waddayathink? can it be recoated? I think I could file down that secondary enough to get some silver fingernail polish to stick!
seriously though, I did not have enough forethought to paint the crater in the secondary flat black. easily enough done though, it is fastar.

Theo


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cavefrog
Carpal Tunnel
*****

Reged: 11/11/08

Loc: loozyanna
Re: large SCT badly damaged, can it be used? new [Re: cavefrog]
      #5794123 - 04/12/13 10:32 AM

Hey Chris! ya out dere listenin'? I thought just too dang late about trying the laser for rough collimation. it wasn't utill I almost had it done , that I thought about it.
it would have been an opportune time to try out what we discussed. It fer sure couldn't of hurt anything.

Theo


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tim53
Postmaster
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Reged: 12/17/04

Loc: Highland Park, CA
Re: large SCT badly damaged, can it be used? new [Re: cavefrog]
      #5794153 - 04/12/13 10:45 AM

Yikes! Was the scope insured in shipping? At the least, both mirrors need to be refigured. The chip at the edge of the primary isn't too bad, but the one in the secondary is so big it could have affected the figure. And the scratches can only come out by refiguring. If you're covered by insurance, I would contact Celestron a out replacing the optics.

Tim


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Starhawk
Space Ranger
*****

Reged: 09/16/08

Loc: Tucson, Arizona
Re: large SCT badly damaged, can it be used? new [Re: cavefrog]
      #5794160 - 04/12/13 10:50 AM

Is this a new OTA? Any warranty option? The damage looks pretty bad. Yes, it could be collimated, but it will take fair amount of Tamiya XF-1 to keep this from playing merry heck with your contrast.

I agree, though- truly heartbreaking.

The Celestron option will be a new optics set at the bulk of the cost of a new OTA.

Otherwise, this one needs some earnest TLC to make it whole.

-Rich


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cavefrog
Carpal Tunnel
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Reged: 11/11/08

Loc: loozyanna
Re: large SCT badly damaged, can it be used? new [Re: Starhawk]
      #5794197 - 04/12/13 11:15 AM

yes, it was insured. just for grins and giggles, I called the "Tron". They said they need to examine the patient before they could give a prognosis. They would not give either a low or high estimate at the replacement cost of the optics. I know it would cost somewheres around $150.00 for one way shipment, so... end of inquiry.

Second hand purchase, but in brand new condition before shipping.

Theo


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cavefrog
Carpal Tunnel
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Reged: 11/11/08

Loc: loozyanna
Re: large SCT badly damaged, can it be used? new [Re: cavefrog]
      #5794204 - 04/12/13 11:20 AM

Tamiya XF-1 ? had to go look that up. you think I should paint the center too , along with the big chip? not a joke...serious question.

Theo


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cavefrog
Carpal Tunnel
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Reged: 11/11/08

Loc: loozyanna
Re: large SCT badly damaged, can it be used? new [Re: KerryR]
      #5794218 - 04/12/13 11:29 AM

Quote:

Why not remove the secondary and send it in for a re-coat? Not all coaters will coat secondaries with the backing plate attached, but some will. I believe OWL does, as does, I think, Spectrum. The primary could be done, too, but I'm pretty sure you'd have to remove it from the carrier, which, because it's glued on, is a big deal...






glued on?? wow. I would think that would cause some problems with a mirror that big. however , I have never pulled a primary on an SCT, let alone a C-14. Think I'll leave that for when it really needs to be done, and there is no other way out.

as far as the secondary is concerned, it is a loss. any respectable recoater would laugh at this.

Theo


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EFT
Vendor - Deep Space Products
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Reged: 05/07/07

Loc: Phoenix, AZ
Re: large SCT badly damaged, can it be used? new [Re: cavefrog]
      #5794236 - 04/12/13 11:37 AM

No way insurance is going to cover that. Even when the corrector is smashed they say it wasn't their fault and in this case, the secondary let loose and they will not consider that to be their fault.

Best bet is going to be optics replacement by Celestron, but it may not be cost effective.


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KerryR
Post Laureate
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Reged: 12/05/07

Loc: SW Michigan
Re: large SCT badly damaged, can it be used? new [Re: cavefrog]
      #5794392 - 04/12/13 12:58 PM

Quote:

Quote:

Why not remove the secondary and send it in for a re-coat? Not all coaters will coat secondaries with the backing plate attached, but some will. I believe OWL does, as does, I think, Spectrum. The primary could be done, too, but I'm pretty sure you'd have to remove it from the carrier, which, because it's glued on, is a big deal...






glued on?? wow. I would think that would cause some problems with a mirror that big. however , I have never pulled a primary on an SCT, let alone a C-14. Think I'll leave that for when it really needs to be done, and there is no other way out.

as far as the secondary is concerned, it is a loss. any respectable recoater would laugh at this.

Theo




The primary is held on to the carrier by the threaded central post that slides on the baffle (to allow focusing). A retainer threads onto that, pinching the primary between the 2 parts. The glue is used to hold the primary in collimation. As far as I know, all Celestron ota's are done this way. Meade's are not, or at least that used to be the case, which made re-coats and cleanings far easier.

Like the others, I think it's unlikely you're going to see insurance compensation because the issue was probably not due to mishandling, unlike, say, a crushed box and dented tube; this could have happened no matter how well the tube was packed. Sad, but I don't think the optics are ever going to work very well. At least Celestron can replace them with a new (matched) set, but that's going to be very expensive...

Not sure who should be saddled with this, you or the person you bought it from. Doesn't seem like you should have to eat all this-- none of it was your fault, and it sounds like the secondary may not have been tightened down sufficiently before shipping-- new scopes ship all the time without loosing the secondary. This would suggest a fatal error on the part of the previous owner... Yuck. I wouldn't want to have to deal with this.


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