TheSkySearchers

I noticed my STC had some strange marks on the inside of the tube and the corrector plate and mirror had dust. I had just fitted the mounting bar for the guide scope and wondered if the screws had created dust but there appeared to be far too much for that. I emailed Celestron and they replied that I could remove the secondary mirror and hoover it out!

With more contemplation I remembered one particularly dew laden night the tube was so wet I didn't want to put it away so I brought it into the house to dry out. Now I'm wondering if the droplets of condensation have damaged the inside black paint coating. So tonight I took the thing apart and discovered that the marks were indeed caused by the black paint coating breaking up.

My mirrors and corrector plate are now spotless but I'm concerned the thing will spew more dust as soon as it gets wet again.

Anyone else seen/heard of this problem?

Regards

Graeme

Yes! Despite using desiccant I had a long cross country trip in very wet weather. The dew shield ONLY of one of my scopes (the VMC110L) suffered from this. I have cleaned it with alcohol (90%) and replaced the desiccant. So far so good.

I'm surprised, and somewhat concerned, that Celestron chose to use a paint that could suffer that kind of problem.

notFritzArgelander wrote: ↑Wed Feb 05, 2020 11:58 pm Yes! Despite using desiccant I had a long cross country trip in very wet weather. The dew shield ONLY of one of my scopes (the VMC110L) suffered from this. I have cleaned it with alcohol (90%) and replaced the desiccant. So far so good.

Tonight I only hovered the inside of the tube with a brush attachment. I could take it apart again and clean with alcohol, I have some alcohol lens cleaning cloths. But I am reticent to do anything else to it and make the problem worse.

Did the problem return on your dew shield? Did the alcohol make the paint flake more? Or is the surface more stable now.

I'm also concerned that loosing the matt black even surface will introduce reflections into the optical train. Do you think this is likely?

AntennaGuy wrote: ↑Wed Feb 05, 2020 11:59 pm I'm surprised, and somewhat concerned, that Celestron chose to use a paint that could suffer that kind of problem.

I've replied to the email response I had from Celestron to ask if it's a problem that they're familiar with and what my options are. I'll post up their response. Their R&D must include robustness tests for the materials used in the manufacture. I'm surprised too.

Graeme1858 wrote: ↑Thu Feb 06, 2020 12:13 am

notFritzArgelander wrote: ↑Wed Feb 05, 2020 11:58 pm Yes! Despite using desiccant I had a long cross country trip in very wet weather. The dew shield ONLY of one of my scopes (the VMC110L) suffered from this. I have cleaned it with alcohol (90%) and replaced the desiccant. So far so good.

Tonight I only hovered the inside of the tube with a brush attachment. I could take it apart again and clean with alcohol, I have some alcohol lens cleaning cloths. But I am reticent to do anything else to it and make the problem worse.

I think that you are being conservative which is wise. Since we have different OTAs it would probably be best to get advice from Celestron.

Did the problem return on your dew shield? Did the alcohol make the paint flake more? Or is the surface more stable now.

No the problem was resolved and has not returned. Our situations are likely different. In my case the dew shield appears to be a black powder anodized surface, not paint. So I think contacting Celestron for support is the best way to go. If you are the original owner then they should at least talk to you. If you bought it used they might not.

I'm also concerned that loosing the matt black even surface will introduce reflections into the optical train. Do you think this is likely?

Yes, I do. The problem is "how much" not "whether". Please contact Celestron since they know their materials and have probably run into this problem before. I would not translate my experience to yours without further research.

One last thought, though. If Celestron does or cannot address your concerns and your own measures cause interior damage, you can always repaint or flock the interior. It's a big job but if the scope is one you like, well worth it.

Please let us know how things turn out. I'm keenly interested since I have inklings of considering and Edge....

notFritzArgelander wrote: ↑Wed Feb 05, 2020 11:58 pm
Did the problem return on your dew shield? Did the alcohol make the paint flake more? Or is the surface more stable now.

No the problem was resolved and has not returned. Our situations are likely different. In my case the dew shield appears to be a black powder anodized surface, not paint. So I think contacting Celestron for support is the best way to go. If you are the original owner then they should at least talk to you. If you bought it used they might not.

I bought it new from Rother Valley Optics.

I'm also concerned that loosing the matt black even surface will introduce reflections into the optical train. Do you think this is likely?

Yes, I do. The problem is "how much" not "whether". Please contact Celestron since they know their materials and have probably run into this problem before. I would not translate my experience to yours without further research.

Email sent. I have found their Customer Support keen to help previously.

One last thought, though. If Celestron does or cannot address your concerns and your own measures cause interior damage, you can always repaint or flock the interior. It's a big job but if the scope is one you like, well worth it.

Yes, I had considered that an option to flock the interior.

It is a scope I like, it's the only one I have!

Please let us know how things turn out. I'm keenly interested since I have inklings of considering and Edge....

Will do.

How old is your SCT Graeme?

Bigzmey wrote: ↑Thu Feb 06, 2020 12:56 am How old is your SCT Graeme?

I bought it in November 2018 when my company pension plan matured!

I sold the 10" dob at the same time. Should have kept it for visual!

Graeme1858 wrote: ↑Thu Feb 06, 2020 1:09 am

Bigzmey wrote: ↑Thu Feb 06, 2020 12:56 am How old is your SCT Graeme?

I bought it in November 2018 when my company pension plan matured!

I sold the 10" dob at the same time. Should have kept it for visual!

This is strange. I got mine 8" SCT in 2016. I have been using it a lot and on a several occasions it got condensation inside, but there is no issues with the tube paint.

Depending on what Celestron response is I would look at flocking it after doing some more cleanup inside.
Is the telescope still under warranty?

Sorry to here that. I have a C8 from 1976. A C14 from two years ago. C8 never had any issues. Back then they made them in the US. My C14EdgeHD is mounted in my dome. Has been since end of 2018. I will have to look at the inside to see if the same thing is happening. Would be very upsetting. What ever happened to quality control. They know their scopes will be outside in the heat, bitter cold and humidity.

Lady Fraktor wrote: ↑Thu Feb 06, 2020 4:37 am Depending on what Celestron response is I would look at flocking it after doing some more cleanup inside.
Is the telescope still under warranty?

It's probably not under warranty now but I'll ask the supplier. It would be good to know what their opinion is about it too.

They'll probably all tell me it's my tough luck and to jog on! If so, then I'll be flocking it death!

Regards

Graeme

Graeme1858 wrote: ↑Thu Feb 06, 2020 8:37 am

Lady Fraktor wrote: ↑Thu Feb 06, 2020 4:37 am Depending on what Celestron response is I would look at flocking it after doing some more cleanup inside.
Is the telescope still under warranty?

It's probably not under warranty now but I'll ask the supplier. It would be good to know what their opinion is about it too.

They'll probably all tell me it's my tough luck and to jog on! If so, then I'll be flocking it death!

Regards

Graeme

flocking it to death!

I believe Celestron warranty is still two years so hopefully still under warranty.

The supplier got back to me with this response:

"I have heard back from the technical chap at Celestron and he agrees with me that we've never seen anything like this before. If it has been caused by dew, then it must be very heavy dew and even then, it shouldn't affect the coating. Our advise is to leave it well alone and keep an eye out on it to see if it worsens. Can you get the OTA to me so I can assess it as images can be very misleading."

I best go buy some bubble wrap!

Regards

Graeme

Hopefully they will arrange a return or exchange, do not be shy in asking about it since you paid for the warranty.

Lady Fraktor wrote: ↑Thu Feb 06, 2020 4:37 am Depending on what Celestron response is I would look at flocking it after doing some more cleanup inside.
Is the telescope still under warranty?

Yep that's what I would do!

BTW could that be from pollen?

It would be hard to say but to me it seems improperly cleaned aluminium before painting.
It will be interesting to hear what they tell Graeme.

UlteriorModem wrote: ↑Thu Feb 06, 2020 5:52 pm BTW could that be from pollen?

Interesting thought! Are there precedents?