Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

New Old Stock C11 - dirty or oxidized coatings?

  • Please log in to reply
13 replies to this topic

#1 Trudge

Trudge

    Lift Off

  • *****
  • topic starter
  • Posts: 9
  • Joined: 22 Jul 2015
  • Loc: Cape Town, South Africa

Posted 13 August 2019 - 10:10 AM

Greetings from South Africa!  I just picked up what I thought was a deal from the Celestron dealer, a NOS CGEM DX1100. It's been sitting around for 5-7 years, had the old Nexstar hand controller.  

Now, here's my concern - are the coatings intact after such a long sit in the sealed box.  I know, the flashlight test is unfair, but have a look at the primary. I've had plenty of other Celestron SCTs (C11, C8, C14) - and have not seen this before.  

I've spoken to the dealer and they're speaking to Celestron.  BUT - eager to get your expert opinions.  Have a look!  

Attached Thumbnails

  • smP9650021.jpg
  • smP9650024.jpg
  • smP9650025.jpg


#2 ngc7319_20

ngc7319_20

    Viking 1

  • *****
  • Posts: 935
  • Joined: 25 Oct 2015
  • Loc: MD

Posted 13 August 2019 - 10:21 AM

In my experience the blue stuff is usually oil that will clean off OK.  It is tempting to assert that it is all oil and grease.  Oil gets on the primary when it evaporates from the focusing mechanism in hot weather, and then re-deposits and condenses on everything.  The streaks suggest to me this is the result of a poor or incomplete cleaning job.

 

I guess an interesting test would be to get the mirror out, and then try shining a light through the back.


Edited by ngc7319_20, 13 August 2019 - 10:23 AM.


#3 LarsMalmgren

LarsMalmgren

    Mariner 2

  • *****
  • Posts: 254
  • Joined: 22 Jan 2010
  • Loc: Denmark

Posted 13 August 2019 - 10:22 AM

Looks a bit like cleaning marks to me.

Like a cloth with some cleaning fluid has been swiped lightly over the mirror.

The fluid has then left a residue that we now see.  confused1.gif


  • clusterbuster likes this

#4 dark sky newbie

dark sky newbie

    Lift Off

  • -----
  • Posts: 22
  • Joined: 11 Nov 2011
  • Loc: Lost in your skies.

Posted 13 August 2019 - 11:41 AM

I'm going to vote dirty. It looks like wipe marks to me.


  • Trudge likes this

#5 aa6ww

aa6ww

    Surveyor 1

  • *****
  • Posts: 1968
  • Joined: 23 Oct 2011
  • Loc: Sacramento, Calif.

Posted 13 August 2019 - 11:45 AM

I bet you just need to get to the Mirror and clean it with some distilled water. I had a friend I knew from 20 year back who bought is son a Celestron C8 back then. He left the scope in its trunk for 20 years in his gargage, then noticed me on the news one day talking about astronomy and contacted me and asked me if I wanted his scope. He thought the mirror was ruined and oxidized and needed recoating.
I took the scope home and cleaned it, and the mirror was immaculate.

Id say take off the corrector and clean up the mirror and enjoy it.

...Ralph
  • Trudge likes this

#6 Trudge

Trudge

    Lift Off

  • *****
  • topic starter
  • Posts: 9
  • Joined: 22 Jul 2015
  • Loc: Cape Town, South Africa

Posted 13 August 2019 - 11:46 AM

Looks a bit like cleaning marks to me.

Like a cloth with some cleaning fluid has been swiped lightly over the mirror.

The fluid has then left a residue that we now see.  confused1.gif

My thought as well EXCEPT - new in sealed box from Celestron!

I like the theory of residue from the focuser lube. 

What I thought was going to be simply another OTA in the collection has become s science experiment...

Will be interesting to see what Celestron service has to say.  I'm sure they've seen other interesting issues crop up with NOS.  



#7 ngc7319_20

ngc7319_20

    Viking 1

  • *****
  • Posts: 935
  • Joined: 25 Oct 2015
  • Loc: MD

Posted 13 August 2019 - 12:27 PM

My thought as well EXCEPT - new in sealed box from Celestron!
 

Interesting...  I guess the box was from Celestron, and someone had newly sealed it....scratchhead2.gif   I suppose someone might have cleaned it at Celestron and left some invisible marks on it, which over the years through some molecular physics have attracted vaporized oils or whatever....



#8 Erik Bakker

Erik Bakker

    Cosmos

  • *****
  • Moderators
  • Posts: 7856
  • Joined: 10 Aug 2006
  • Loc: Netherlands, Europe

Posted 13 August 2019 - 12:42 PM

Doen't look like normal oxidation to me. Likely some cleaning marks and/or evaporated grease.

 

I have a 36 yo C5 with all coatings stil looking like brand new. They are very durable under normal use, so most certainly in an unopened bow with NOS.

 

Just have a look at some stars and Jupiter, once properly collimated. That will tell you if the figure and polish of the optics are OK.

Flashlight scrutiny isn't kind to cosmetics on optics wink.gif

 

If it is just dirt, a person in the know would disassemble the corrector and clean the primary in 15 minutes. But that is perhaps bit of a daunting task to perform on a new scope.


  • Trudge likes this

#9 jgraham

jgraham

    ISS

  • *****
  • Posts: 20125
  • Joined: 02 Dec 2004
  • Loc: Miami Valley Astronomical Society

Posted 13 August 2019 - 01:38 PM

If it is oil you will need a mild solvent to remove it. We use isopropyl alcohol in my lab to remove oil followed by distilled water. If it's not covered under a warranty I'd try cleaning it. I have SCTs that are over 40 years old with coatings that are still in good shape. I have also refurbished several old SCTs and have cleaned quite a few mirrors and corrector plates. Just use a light touch and don't agonize over the last little smudges.
  • barbarosa and Trudge like this

#10 carolinaskies

carolinaskies

    Surveyor 1

  • *****
  • Posts: 1574
  • Joined: 12 Dec 2014
  • Loc: Greenville SC

Posted 13 August 2019 - 05:42 PM

Looks like a resealed unit that is used NOT NEW.  This has been through an incompetent cleaning process, not a result of oxidation.  Your vendor is either unaware of the true history of the OTA, or is aware and being less than honest.   Celestron would never let optics out of the factory looking like this... those of us who have bought new know what new looks like, and this 'ain't' it. 


  • junomike and B 26354 like this

#11 Traveler

Traveler

    Gemini

  • *****
  • Posts: 3055
  • Joined: 19 Aug 2007
  • Loc: The Netherlands

Posted 14 August 2019 - 04:36 AM

Isnt there any on the backside of the correctorplate? If not then it is likely not grease vapor but just a bad example of a cleaningjob...

 

Clean the mirror and you will have a nice C11!. Have fun. When cleaning by yourself, do read how to disassembly and assembly the correctorplate first.



#12 Trudge

Trudge

    Lift Off

  • *****
  • topic starter
  • Posts: 9
  • Joined: 22 Jul 2015
  • Loc: Cape Town, South Africa

Posted 14 August 2019 - 06:11 AM

Looks like a resealed unit that is used NOT NEW.  This has been through an incompetent cleaning process, not a result of oxidation.  Your vendor is either unaware of the true history of the OTA, or is aware and being less than honest.   Celestron would never let optics out of the factory looking like this... those of us who have bought new know what new looks like, and this 'ain't' it. 

One way or another, there's a happy ending here.  Celestron customer service is shipping me a brandy-new in-the-box swap...in Cape Town!  

 

I'm totally impressed - and pleased.  I bought new, and I'm getting new - not refurbed or refreshed or whatever.  

So - kudos to Celestron in going out of their way (nine time zones away) to make this 100%!


  • Paul Hyndman, Erik Bakker, Traveler and 6 others like this

#13 luxo II

luxo II

    Viking 1

  • -----
  • Posts: 957
  • Joined: 13 Jan 2017
  • Loc: Sydney, Australia

Posted 14 August 2019 - 06:05 PM

Good to hear they’re doing the right thing.

FWIW I’ve seen similar on a mirror that was stored for years with the surface in contact with plastic wrapping courtesy of someone who didn’t know how first surface mirrors are normally boxed.

#14 Trudge

Trudge

    Lift Off

  • *****
  • topic starter
  • Posts: 9
  • Joined: 22 Jul 2015
  • Loc: Cape Town, South Africa

Posted 15 August 2019 - 11:23 AM

Good to hear they’re doing the right thing.

FWIW I’ve seen similar on a mirror that was stored for years with the surface in contact with plastic wrapping courtesy of someone who didn’t know how first surface mirrors are normally boxed.

Will report back when this becomes a done deal.  The dealer/distributor now tells me I will be dealing directly with Celestron service.  I look forward to hearing from them!




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics