Thomas
I left myself some wiggle room when expressing my ¡°opinion¡± which is always
prudent on the groups for many reasons. Now that being said I will say this.
I own two Crestron Scopes. One is 8 years old, the 11¡± SCT GoTo with GPS,
and the 14¡± Edge HD which I have had for 5 years. I live in Arizona and
although my two scopes are in an observatory and the 14¡± is cooled in the
summer by a protective foam box they still see elevated temps above 80¡ã -
90¡ã on occasion.
I have a friend that lives 10 miles away. For several years he kept his 11¡±
Celestron SCT Edge outside under one of those aluminized telescope covers,
his is at least 5 years old. To this day he has no haze on his mirror. I am
absolutely positive his scope has seen temps above 120¡ã for days on end and
has never mentioned this problem. I convinced him to build a permanent
structure which I designed for him and together we built and erected it in
his back yard. Parijat¡¯s Observatory
But again I want to emphasize I had a situation where grease that was
applied by Celestron in copious amounts dripped off the back of the Mirror.
It was disassembled by Dean Konig of Starizona, and I have the photos of
the handfuls of red grease that was packed behind the Mirror. I can post
them if anyone wants to see them. I was fortunate as the scope was still
under warranty and I eventually sent it back to Celestron at a cost of $200
to me for shipping for a more thorough cleaning. Is this the norm? I don¡¯t
think so but we all know of horror stories where a disgruntled employee may
have had a bald day and was just getting even with the boss or the company
So Gary has to pay!
So what am I trying to say??
From (my limited sampling of scopes I personally have not heard of this. Is
it ¡°Possible¡±, absolutely yes, but I have not heard of it period. Can cheap
grease from other countries be used on occasion for a myriad of reasons,
yes. And we all know what Country I am talking about!! This country would
would sell you cow crap with perfume in it and tell you it was body lotion.
Sorry am not a politically correct person. I call them as I see them!
Let us examine another possibility. Remove your Corrector, reach in with a
soft natural cotton ball with some alcohol on it and on the edge of the
mirror see if the haze comes off. If it comes off then remove the mirror and
do the cleaning in the prescribed manor and replace the grease with the
proper type of grease. If it does not come off then perhaps the haze is
indicative of a problem with the mirror itself or the coating.
If I were you I would start with a call to Dean at Starizona, he has sold
thousands of Celestron scopes. He is a wonderful human being and his
experience and advice is Gold.
It is totally within the realm of possibilities that the grease is breaking
down and you asked if this is possible? And I would say, with reservation
based on the lack of historical and empirical evidence that it is unlikely
but it would not be the first time one grease was substituted for another
for expediency. Call Dean and start there and tell him Gary suggested that
you seek his advice.
From: C14_EdgeHD@... [mailto:C14_EdgeHD@...]
Sent: Friday, February 5, 2016 8:17 AM
To: C14_EdgeHD@...
Subject: Re: [C14_EdgeHD] Possible outgassing - questions
Gary,
Thanks for your reply.
I am not sure about the term "outgassing." Maybe there is a more precise
term.
On the Cloudy Nights Cats and Casses forum there are numerous threads and
posts about recently produced Celestron SCTs developing a haze or film on
the inner glass elements of their SCTs. Some folks suspect it is from some
petroleum product that Celestron uses or did use.
I have some sort of haze on my primary mirror but I don't know if it is
residue from dew or if it is chemical. Here is a photo and if you look
close at the arrows you can see the "haze."
So now I am pondering my options, one of which is to learn how to clean it
myself so I am trying to get as many facts as I can before proceeding.
Thomas
On 2/4/16 8:34 52000, 'Gary Jarrette' garyjarrette@...
<mailto:garyjarrette@...> [C14_EdgeHD] wrote:
Thomas
I (Personally) have never heard anyone mention or use the term ?
€?Outgassing?€? with regards to the grease used on SCTs. In my (Personal)
experience, and I have had a considerable amount of machining, building, and
TIG welding high vacuum systems together for Arizona State University not to
mention working on dozens of Electron Microscopes daily for 20 years, this
is the only place where the vacuum is remotely high enough to cause things
to outgas. We had to be painfully aware of what was put into the systems
even to the point of what metals were used in the construction of these
instruments.
We of course wore gloves and triple washed everything with TCE then Freon,
lab grade purity of course. We then housed the entire microscope then baked
it out for 24 hours at about 4000?¡ã f. Even a fingerprint would ?€?outgas?€?
and would be visible on the Mass Spectrometer we used to monitor this
situation when we pumped the system down to 10 to the negative 12 torr.
But this is the first time I have heard of ?€?outgassing?€? with reference
to a SCT mirror so (In my personal opinion) outgassing is not a concern.
What can be of concern is having grease with an low ?€?Dropping point?€?
melt and drip all over the inside of your OTA. I have had that happen and
had the grease drop onto my corrector lens. If your scope is left outside in
the Arizona Sun this can be a concern but I think outgassing is not even
remotely possible under normal operating conditions, emphasis on ?€?Normal?
€?. Now if you are are operating your scope in space or a vacuum chamber you
might run into problems.
The above is based on my experience but is not the last word.
Gary
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