Jump to content


Photo

Defective Mirror Coating on New C9.25

  • Please log in to reply
25 replies to this topic

#1 james7ca

james7ca

    Viking 1

  • -----
  • Posts: 566
  • Joined: 21 May 2011
  • Loc: San Diego, CA

Posted 23 August 2014 - 04:02 AM

Just picked up a new Celestron 9.25" EdgeHD and shortly after I unpacked the scope I took a flashlight and looked down the tube to inspect the optics. My first reaction was one of satisfaction as the front corrector lens was clean to the point of near invisibility (i.e. no dust, no streaks, completely transparent). Then I looked down at the primary mirror and was shocked to see that nearly the entire surface was covered by a hazy, milky mottling -- almost like the mirror was covered with condensations or dew. However, the mottling appears to be permanent, it hasn't changed or cleared after several hours of waiting.

 

Attached is a photo of the mirror that was taken through the front corrector lens. This photo makes it look a little worse than it really is but it should give you an idea of the extent of the problem (IMO, the mirror surface should look very dark, almost black when it is reflecting a similarly dark or black background). Using the same test I looked at the mirror on a ten-year-old NexStar 5 and its mirror still looks bright and clean (except for a few flecks of dust). Something obviously went wrong during the manufacturing or shipping of the EdgeHD. Interestingly, there was no desiccant packed with the scope, which on retrospect seems a little odd.

 

Has anyone ever seen something like this before? I can't believe that it left the factory this way, so it may have been something that happened during shipping or storage at the vendor. Only problem is, why is the corrector plate so clean while the mirror looks like it might have been left sitting uncovered in a chicken coop for several weeks (it's not dusty, just stained with a hazy mottling)?

Attached Files



#2 tonyt

tonyt

    Viking 1

  • -----
  • Posts: 764
  • Joined: 01 Sep 2009
  • Loc: Australia

Posted 23 August 2014 - 05:11 AM

Outgassing is not an uncommon problem for celestron in recent years, leaving a film on the corrector or mirror. You can have it exchanged for another scope since it's obviously not in acceptable condition for a new scope.



#3 james7ca

james7ca

    Viking 1

  • -----
  • Posts: 566
  • Joined: 21 May 2011
  • Loc: San Diego, CA

Posted 23 August 2014 - 08:19 AM

Tony, thanks. However, what will this "outgassing" look like? What I see on this mirror is only obvious when you shine an oblique light source on the mirror while it is reflecting a dark background. Then, what should look like a nice, dark reflection appears as a cloudy, milky surface. You can see in the above photo a section of the mirror that isn't too bad, a concentric, circular band that is about 1/3 to 1/2 of the way from the center to the edge of the mirror (if appears darker and with less mottling).


Edited by james7ca, 23 August 2014 - 08:20 AM.


#4 tonyt

tonyt

    Viking 1

  • -----
  • Posts: 764
  • Joined: 01 Sep 2009
  • Loc: Australia

Posted 23 August 2014 - 09:33 AM

The film from outgassing that I've seen on the correctors of a couple of scopes has a cloudy, mottled appearance and gets worse over time. I pulled the corrector on one scope and the film cleaned off easily. The film was easily visible on the corrector in daylight. 

 

There was a recent thread on CN where an owner had the film on his celestron mirror and the scope was sent to the shop and cleaned under warranty - the shop owner thought it was outgassing.

 

I can remember several instances of these films being reported on forums over the last few years.

 

If you have two scopes side by side and can see cloudiness on the mirror of one and not the other I think there's little doubt that you have a deposit of some sort that shouldn't be there.

 

Celestron has never explained the origin of the film so we are left to guess the cause.



#5 TG

TG

    Apollo

  • -----
  • Moderators
  • Posts: 1286
  • Joined: 02 Nov 2006
  • Loc: Latitude 47

Posted 23 August 2014 - 12:37 PM

If you bought from a dealer, just return the scope. Don't wait for it to get serviced under warranty. Here's where a great dealer (such as our host, Astronomics) comes in handy. I once received a defective hand controller with my mount and Astronomics had Celestron desperately trying to contact me within a day.

Tanveer

#6 elwaine

elwaine

    Apollo

  • -----
  • Posts: 1143
  • Joined: 18 Jun 2006
  • Loc: Jupiter

Posted 23 August 2014 - 01:31 PM

Jim, I'm really sorry to read about your problem. I agree with the above advice to contact your dealer and have them exchange the scope for another new one. That said, I have to laugh to myself because of all the negative responses I received that condemned the use of a flashlight to examine the primary mirror.  Your unfortunate experience is exactly what I was trying to illustrate... but to little avail.

 

I'm dismayed about all of the reports here on CN that have reported this so-called outgassing problem. I do not recall outgassing being a problem prior to the Edge series SCTs. - Please let us know what happens.



#7 Ed Whitney

Ed Whitney

    Messenger

  • -----
  • Posts: 482
  • Joined: 08 Jul 2010
  • Loc: Palm Coast, Florida

Posted 23 August 2014 - 03:24 PM

This same anomolly of cloudy looking mirror happenned to a C9.25 EdgeHD I got a few years back. The mirror looked great until I used the flashlight test. It looked like the mirror was cleaned with a dirty dish rag and left to dry, all streeky and smeery white stuff on it. Ugh!

 

This is a QC problem for sure.

 

I just returned the scope. :bawling:



#8 james7ca

james7ca

    Viking 1

  • -----
  • Posts: 566
  • Joined: 21 May 2011
  • Loc: San Diego, CA

Posted 23 August 2014 - 06:03 PM

Okay, my vendor gave me a credit and asked no questions (I returned the scope). Unfortunately, they don't have any more 9.25 EdgeHDs in stock so I'll have to wait until something comes in so that I can redeem my credit. If I'm lucky I may only have to wait another week or two.

 

Here is another picture that I think makes the problem a little easier to see (almost the entire mirror looks this way, the picture shows less than one quarter of the entire surface). The few areas that appear dark are "clean." As I said earlier, this is NOT dust, some to a little dust is expected but this appears to be a stain, or discoloration, or variation in the coating.

 

 

 

 

 

 

Attached Files



#9 tonyt

tonyt

    Viking 1

  • -----
  • Posts: 764
  • Joined: 01 Sep 2009
  • Loc: Australia

Posted 23 August 2014 - 09:17 PM

The more scopes that get sent back the more likely Celestron is to actually attend to the cause. Manufacturers deserve credit and criticism where appropriate. I still prefer Celestron to Meade because the tubes are lighter and they have vents to make cooling easier, but Meade has never had this particular outgassing problem with new scopes.

 

When you do get a replacement scope James I'd recommend avoiding exposure to higher temperatures (eg. hot car or observatory) as the film is more likely to appear under warm conditions in my experience.



#10 PowellAstro

PowellAstro

    Apollo

  • *****
  • Posts: 1094
  • Joined: 14 Oct 2009
  • Loc: Tennessee

Posted 24 August 2014 - 01:03 AM

My new C5 was the same way. I pulled it apart and it did clean off easy. I think it is where they cover the mirrors after coating with a film material to protect the coatings. When they peel it off they do not clean the mirror because in normal light the surface looks clean. The protective film is leaving this pattern and residue.



#11 dweller25

dweller25

    Apollo

  • -----
  • Posts: 1449
  • Joined: 30 Aug 2007
  • Loc: Lancashire, UK

Posted 24 August 2014 - 01:07 AM

Jim, I'm really sorry to read about your problem. I agree with the above advice to contact your dealer and have them exchange the scope for another new one. That said, I have to laugh to myself because of all the negative responses I received that condemned the use of a flashlight to examine the primary mirror.  Your unfortunate experience is exactly what I was trying to illustrate... but to little avail.

 

I'm dismayed about all of the reports here on CN that have reported this so-called outgassing problem. I do not recall outgassing being a problem prior to the Edge series SCTs. - Please let us know what happens.

 

 I had a C9.25 Starbright with an outgassing problem



#12 EverlastingSky

EverlastingSky

    Viking 1

  • *****
  • Posts: 585
  • Joined: 12 Sep 2006
  • Loc: Vancouver Canada

Posted 25 August 2014 - 12:27 AM

First of all, James, that is a real nuisance to find a new instrument so afflicted. Be patient and wait for a new C9.25 to arrive.

 

And now a little comment aimed at the makers of this defective instrument:

 

This outgassing issue appears to be a chronic and persistent problem that has spanned many years.

 

Cloudynights forums are littered with the threads of distressed owners anxious to find a cure for this hazy outgassing deposit / film on corrector and mirror alike. A new instrument can be "just" returned. Had the scope' a while and it can't be returned? Then you learn of the horrific necessity of performing disassembly of the instrument for cleaning of the optical surfaces. But even this may be only a temporary fix. Actual removal of the offending inferior incorrect grease is required for a full solution!

 

Why our favorite venerable corner cutting mass producer can't simply use Dow Corning high vacuum grease or DuPont Krytox 240AC or at least Novagard G661 in the first place is rather disappointing... to say the least.

 

While Big C are applying one of the superior & appropriate lubricants mentioned above... they could look into the really off-the-wall idea of actually... painting the inside of the tubes truly black. ( The use of a ProtoStar-like flocking material would be too much to expect since that is level 5 thinking :grin: )


Edited by EverlastingSky, 25 August 2014 - 12:28 AM.


#13 amicus sidera

amicus sidera

    Skylab

  • *****
  • Posts: 4071
  • Joined: 14 Oct 2011
  • Loc: East of the Sun, West of the Moon...

Posted 25 August 2014 - 05:13 PM

Okay, my vendor gave me a credit and asked no questions (I returned the scope). Unfortunately, they don't have any more 9.25 EdgeHDs in stock so I'll have to wait until something comes in so that I can redeem my credit. If I'm lucky I may only have to wait another week or two.

 

 

Not only were you inconvenienced by getting a defective product, now your money is tied up while waiting for the dealer to restock; seems to me a full refund would have been in order.



#14 tonyt

tonyt

    Viking 1

  • -----
  • Posts: 764
  • Joined: 01 Sep 2009
  • Loc: Australia

Posted 25 August 2014 - 05:37 PM

... painting the inside of the tubes truly black. ( The use of a ProtoStar-like flocking material would be too much to expect since that is level 5 thinking :grin: )

 

....... another area where Meade does a better job. If Meade put vents (and fans) in their tubes they'd once more be a true competitor for Celestron. Without a competitor the top dog can become lazy. 



#15 james7ca

james7ca

    Viking 1

  • -----
  • Posts: 566
  • Joined: 21 May 2011
  • Loc: San Diego, CA

Posted 25 August 2014 - 09:06 PM

 

Okay, my vendor gave me a credit and asked no questions (I returned the scope). Unfortunately, they don't have any more 9.25 EdgeHDs in stock so I'll have to wait until something comes in so that I can redeem my credit. If I'm lucky I may only have to wait another week or two.

 

 

Not only were you inconvenienced by getting a defective product, now your money is tied up while waiting for the dealer to restock; seems to me a full refund would have been in order.

 

It's really not a problem (yet). The vendor is local (i.e. no shipping) and I still want the C9.25 since I've already started to build a system around that configuration (0.62x reducer, camera adapter, dew shield and heater). Also, since it was on a credit card I won't actually have to pay the bill until next month and I get cash rewards for using the card. Besides, it is not the vendor's fault, it's really Celestron's problem.

 

Lastly, they think the replacement scope will be here this week but if it takes significantly longer than that then it could become a bit of a disappointment (but really, I should just be thankful that I can afford such equipment in the first place).



#16 Erik Bakker

Erik Bakker

    Gemini

  • *****
  • Posts: 3152
  • Joined: 10 Aug 2006
  • Loc: The Netherlands, Europe

Posted 26 August 2014 - 01:32 AM

James,

 

Patience is a requirement in our hobby :) 

 

With a little time, this issue will be resolved and you will have a fantastic scope to enjoy.



#17 james7ca

james7ca

    Viking 1

  • -----
  • Posts: 566
  • Joined: 21 May 2011
  • Loc: San Diego, CA

Posted 28 August 2014 - 11:46 PM

Okay, I got my replacement 9.25" Edge HD and the mirror and optics look really clean. And miracle of miracles it's also clear tonight so I'm using the scope right now (for some quick astrophotography at prime focus). The focus is really touchy and the turbulence in the atmosphere is a real killer at a 2350mm focal length (that and the fact that the tube/optics may not have yet reached temperature equilibrium -- there has been maybe a 5 degree shift in the last hour and one half since I moved the telescope outside). I also have a 0.62X reducer so I suspect that will be the typical configuration when I do any DSO photography (which probably won't be that often until I can upgrade from my CGEM mount).

 

Right now I'm going to have to wait a few days until the moon is higher in the sky to try some high-resolution work (that's the main reason I purchased the scope -- lunar and planetary photography). Eventually I'll try to work up to handling the long focal length for DSO photography, but that's probably not going to happen soon.

 

In any case after only about a week of waiting I now have a clean looking (replacement) Edge HD. Thanks to OPT and Chris and Dave for getting the replacement scope -- they didn't even ask any questions or even look at the original scope -- but then I've been dealing with OPT for several years now and they know I'm a pretty good customer (or, at least I hope they think so).



#18 Traveler

Traveler

    Apollo

  • -----
  • Posts: 1261
  • Joined: 19 Aug 2007
  • Loc: The Netherlands

Posted 29 August 2014 - 08:21 AM

James, good for you OPT fixed your problem!

 

 

I wonder, is there a way one can prevent this outgassing problem?



#19 Gil V

Gil V

    Viking 1

  • -----
  • Posts: 640
  • Joined: 09 Sep 2012

Posted 30 August 2014 - 10:24 AM

How did the scope's optics look to you?

#20 james7ca

james7ca

    Viking 1

  • -----
  • Posts: 566
  • Joined: 21 May 2011
  • Loc: San Diego, CA

Posted 30 August 2014 - 05:02 PM

How did the scope's optics look to you?

The old (problem unit) or the new? On the old unit I didn't really try to determine how much it affected the view through the telescope. What would I compare it to? How could I judge maybe a 5% to 10% (or any) decrease in contrast or brightness? The new unit looks clean (other than some dust, as could/should be expected) and it seems to produce some fairly well focused stars in my photos, but I haven't had good enough sky conditions to even check the collimation let alone do any quantitative tests on resolution.



#21 james7ca

james7ca

    Viking 1

  • -----
  • Posts: 566
  • Joined: 21 May 2011
  • Loc: San Diego, CA

Posted 30 August 2014 - 11:37 PM

James, good for you OPT fixed your problem!

 

 

I wonder, is there a way one can prevent this outgassing problem?

Some have suggested to keep the scope as dry and cool as possible. So, I've loaded up on desiccant and will be very careful about storage temperature. However, I have a NexStar 5 that is about ten years old and its mirror still looks as good as new and it even endured several winters and humid summers in North Carolina (sure, it has a bit more dust but there is no film or discoloration on the mirror). If it is outgassing (plain and simple) I don't know why it would affect some scopes and not others.


Edited by james7ca, 30 August 2014 - 11:55 PM.


#22 james7ca

james7ca

    Viking 1

  • -----
  • Posts: 566
  • Joined: 21 May 2011
  • Loc: San Diego, CA

Posted 31 August 2014 - 04:22 AM

Okay, here is a "first light" image from my replacement 9.25" Edge HD. The Ring Nebula (M57) in just under fourteen minutes of total integrated exposure time (83 subs at 10 seconds each with a Sony NEX-5N at ISO 800). No darks, no bias, no flats. This also used the Optec Lepus 0.62X focal reducer (probably closer to 0.7X, although I haven't actually checked the reduction factor yet). This reducer only seems to cover about a 15mm diameter image circle (Optec claims something like 22mm, but not nearly that on my sample, so yet another example of a manufacturer not delivering what they promise). In any case, the edges and corners of my APS-C camera aren't usable with this reducer (which admittedly would even be the case at 22mm, let alone the 15mm I'm seeing). However, the 1X prime focus on the Edge HD does appear to cover the full APS-C frame. I used 10 second exposures because I wasn't guiding and besides the Celestron CGEM mount really isn't up to either guiding or tracking at focal lengths greater than 1000mm (IMO). Even at 10 seconds I lose quite a few frames.

Attached Files


Edited by james7ca, 31 August 2014 - 08:12 AM.

  • herrointment likes this

#23 Erik Bakker

Erik Bakker

    Gemini

  • *****
  • Posts: 3152
  • Joined: 10 Aug 2006
  • Loc: The Netherlands, Europe

Posted 31 August 2014 - 06:46 AM

Great M57 image James! 



#24 WesC

WesC

    Vanguard

  • *****
  • Posts: 2056
  • Joined: 06 Feb 2013
  • Loc: La Crescenta, CA

Posted 03 September 2014 - 06:15 PM

Still, your stars look round, so nice!



#25 james7ca

james7ca

    Viking 1

  • -----
  • Posts: 566
  • Joined: 21 May 2011
  • Loc: San Diego, CA

Posted 04 September 2014 - 07:28 PM

Eric and Wes, thanks for the notice.

 

As for the stars being round, they are actually slightly distorted but not too bad given the image scale and the fact that I wasn't guiding (although I don't think guiding would have help that much with a 10 second base exposure). Also, I used PixInsight's subframe selector script to reject the worst of the images, thus this was made from the best shots from the sequence.

 

I photographed over two nights and probably ended up with about 700 subframes (all with a base exposure time of 10 seconds). I haven't combined all of them as yet, but out of those 700 I MIGHT be able to cobble together about 200 good frames. I lost almost one half of the frames from user error, the rest of the rejects were the result of bad tracking by the CGEM. 








Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics