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How bad is this corrector haze?

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#1 Michael Rapp

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Posted 10 September 2013 - 06:44 PM

I was inspecting my C9.25's corrector plate this afternoon and I noticed that there seems to be quite a bit of haze on the underside of the corrector!

When I got my C9.25 two years ago, I did notice a smudge mark on the underside of the corrector, but as I was going to use the scope for planetary imagine/video work, I ignored it.

Now however there seems to be a layer of haze, concentrated on the upper half of the corrector plate that seems to be the same "type"/opacity as the smudge, but a little more rarified than the smudge. What is most interesting is that it seems to have a wavy pattern to it.

Here, take a look:

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#2 Michael Rapp

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Posted 10 September 2013 - 06:45 PM

Here's a view from the other side. Do you see the wavy and criss-crossed pattern?

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#3 Michael Rapp

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Posted 10 September 2013 - 06:46 PM

Here's a view of the smudge.

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#4 Michael Rapp

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Posted 10 September 2013 - 06:48 PM

Obviously my first question is, is this haze opaque enough to noticeably reduce contrast/brightness at my sea level viewing location?

The next question is....where the heck did it come from? It is inside the scope! The primary mirror seems just fine, nearly pristine.

My OTA is stored in my garage to keep it acclimated, but the cap is always on both over the corrector plate and the diagonal.

Living along the Texas Gulf Coast, I deal with a lot of dew in all seasons. I always use a heated dew shield for that reason. Still.....must something have condensed in the tube?

Have yall seen something like this before?

#5 telescopeguy238

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Posted 10 September 2013 - 07:23 PM

Looked at a used C8 and passed because of the same thing. Seller called me back a month later and made a great offer. Took it home and cleaned the FRONT and it was good as new. Could have sworn it was on the back. Try that.

#6 tonyt

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Posted 10 September 2013 - 07:41 PM

its not uncommon for this haze inside celestron scopes. I've had two SCT's with the same issue. All you can do is pull the corrector and clean it. Celestron has never issued a statement defining the cause, but I guess it's some type of outgassing from paint or grease.

#7 brianb11213

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Posted 11 September 2013 - 04:48 AM

its not uncommon for this haze inside celestron scopes. I've had two SCT's with the same issue. All you can do is pull the corrector and clean it. Celestron has never issued a statement defining the cause, but I guess it's some type of outgassing from paint or grease.

Yup. :grrr: Though TBH the effects of the haze on the performance of the scope are a lot less than a casual inspection of the contaminated surfaces would indicate.

#8 mayidunk

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Posted 11 September 2013 - 06:10 AM

Apparently, it has to do with something inside the OTA out-gassing, and precipitating on the corrector. I bought a C6 a couple years ago that had a lot of haze on the inside surface of the corrector plate. Bummed me out, at first! However, it all came off quite easily using unscented, white Kleenex (brand name) tissues, and original formula Windex window cleaner. The corrector is now crystal clear, and the scope is a gem!

#9 bob midiri

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Posted 11 September 2013 - 07:11 AM

Yup, my Celestron SuperC8 had had the beginnings of some haze. Pulled out the corrector and cleaned, now she looks brand new. Bob

#10 Michael Rapp

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Posted 11 September 2013 - 07:50 AM

Thanks all.....I did some googling about cleaning a corrector and it looks like a fairly straightforward process: unscrew some screws, remove the retaining ring, and pull out the corrector, taking great care to mark the corrector's orientation to the tube, and clean like one would any piece of astronomical glass.

The only thing that gives me pause (other than I just got the scope collimated better than I ever have before) are reports on some scopes that the corrector is stuck and requires some use of solvents to get out.

#11 hottr6

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Posted 11 September 2013 - 09:35 AM

I'm guessing this is the same kind of haze that builds up on the inside of older-car windscreens, from outgassing of the plastic materials in the dash.

If the C8 baffles are made of plastic, I'd say the baffles are the source of the outgas.

#12 RobertED

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Posted 11 September 2013 - 08:10 PM

I had an "old" Meade LX-2 back in the mid 1980's that developed a strange hazing on the corrector....both sides. Cleaned it with the Arkansas Sky Observatory cleaning formula/method. Cleaned it right up! (This was before learning about Uncle Rod's Windex procedure!). The problem was that I stored the Meade sct in its case in the garage....and we do get a lot of damp weather here in Rhode Island. :foreheadslap:

#13 frobi6852

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Posted 11 September 2013 - 08:37 PM

I don't think that it is an out gassing from in the OTA, judging from image #2 there is a pattern to it, you would think Out gassing would create a fog on the glass much like your hot breath on a cold window, not to mention it appears to be on one side and there appears to be considerable amount of lint and a few cat or dog hairs in that same area stuck to the corrector. I would say that someone placed a wet towel on the corrector plate

#14 stevew

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Posted 11 September 2013 - 08:41 PM

Ive' owned about 6 Celestrons, and only ever had a problem with one. A Celestar Deluxe model from the 90s.
Similar to your problem, a haze on the inside of the corrector. Pulled it, and cleaned it with Windex, and it was perfect after that.
I'm sure it was out gassing from something. The grease, the black paint? Who knows :question:
At the time I stored the scope in my closet with a plastic bag over it to keep the dust off.
These days I use an old pillow case, as it will keep the dust away but wont seal in any moisture or gasses.

Steve

#15 bcuddihee

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Posted 11 September 2013 - 08:50 PM

It!s out gassing from the paint and or the solvents contained in the grease on the baffle tube. It is not difficult to clean. You may also find upon close observation that you have this same build up on the mirror. With visual inspection it is harder to notice since you are looking at a surface and not through a glass plate. It to can be cleaned. I have a 7 year old C8, and have cleaned both with great results.

#16 Michael Rapp

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Posted 12 September 2013 - 08:17 AM

Heh, and to think one of the reasons I was pleased at getting an SCT was, "I'll never have to clean the mirror."

So now I need to figure out just when I want to take apart a scope that isn't meant to be taken apart. There is always that nagging feeling of risk that even if I mark the corrector plate and whatnot, I won't get the scope back exactly the way it was and I'll be worse off than I am now.

I probably won't touch the the mirror, unless a build-up is obvious. Even a cursory look at the SCT's mirror shows that it is far more reflective (granted it is 2 years old) than my 22 year old 8" mirror.

#17 HowardK

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Posted 12 September 2013 - 10:22 AM

Only in the astro marketplace are high priced, delicate products produced that need pulling apart and cleaning because of poor part placement in the first place.

You would have thought that SCT manufacturers would have sourced internal components be they paint, grease or plastic that does not outgas and ruin the whole point that the product was designed for.

You have to laugh...pathetic really.

#18 brianb11213

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Posted 12 September 2013 - 10:49 AM

Only in the astro marketplace are high priced, delicate products produced that need pulling apart and cleaning because of poor part placement in the first place.

You would have thought that SCT manufacturers would have sourced internal components be they paint, grease or plastic that does not outgas and ruin the whole point that the product was designed for.

You have to laugh...pathetic really.

You get what you pay for.

Celestron SCT tubes aren't cheap but neither are they premium priced. It's somewhat hard to find direct comparisons but comparing the price of a Celestron SCT with e.g. Officina Stellare astrographs in the same aperture range gives you a reasonable frame of reference.

Same thing as you don't expect the same quality from a $10,000 Ford as you do from a $250,000 Bentley.

#19 HowardK

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Posted 12 September 2013 - 02:42 PM

You really feel that the price vindicates internal parts screwing up the corrector and/or mirror?

You are easily pleased mate
Me am not....it's rubbish quality...after all these years of making SCT's they should have eliminated this ridiculous problm years ago.

Officina Stellare do not have correctors that have to be removed to remove outgassed haze *BLEEP*.

#20 Wmacky

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Posted 12 September 2013 - 09:46 PM

You really feel that the price vindicates internal parts screwing up the corrector and/or mirror?

You are easily pleased mate
Me am not....it's rubbish quality...after all these years of making SCT's they should have eliminated this ridiculous problm years ago.

Officina Stellare do not have correctors that have to be removed to remove outgassed haze *BLEEP*.


I agree, this is a defect. They haven't rectified the issue because they feel they can get away with not doing it. That way of thinking doesn't work well in the internet age.

#21 HowardK

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Posted 13 September 2013 - 08:02 AM

Thanku.

Astronomers take a lot of nonsense from manufacturers...I have never seen anything like it.

Mounts that fail out of the box, scopes that outgas, firmware that needs updating immediately you purchase...only for the new firmware to screw up, handcontrollers that never work properly, etc.

Of course lots of products are fine...but quality control really is a problem.

#22 Raginar

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Posted 13 September 2013 - 09:08 AM

Mike,

It's probably just outgassing from the paint. Not a huge deal, and cleaning an SCT is easy once you get over the trepidation of taking it apart. I've done the corrector on my 12" twice now... and the second time around was definitely 'meh, whatever'. The first time? Man, I was VERY nervous.

OPT sells a cleaning kit based on Dr. Clay's cleaning supplies. It works very well and it's super easy to do. The instructions are very helpful and it should fix any problems you have.

Hope that helps, good luck!

#23 mayidunk

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Posted 13 September 2013 - 09:28 AM

I have yet to clean the C8 OTA on my non-Fastar, Celestron Ultima-2000, and it is still sparkling clean! And, yes, I do use it. :)

#24 WesC

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Posted 13 September 2013 - 07:14 PM

Hey don't forget how NASA had to send several repair missions to Hubble! Telescopes are demanding instruments.

#25 Retsub

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Posted 13 September 2013 - 11:30 PM

>>reports on some scopes that the corrector is stuck and requires some use of solvents to get out. [/quote]<< Pay close attention to the tightness, or lack of, of the screws holding the retainer ring. Retighten 'em the same way. With the ring off make note of the gap all around the plate and put it back in with the same gap as before. Piece of tape at the edge of the plate to the cell then slit in the middle it to relocate again. IF the plate seems stuck give it a Bear Hug being careful and you might be able to deform the cell slightly for a nano second to get it loose. Don't laugh ! Most of all be ready for it to come loose at any time. *BW*






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