Re: Possible outgassing - questions
Thomas
I would like to add one more comment to our discussion about “Outgassing”
on your mirror.
I Iooked at the picture of your mirror again and noticed something
peculiar. It looks like this haze on your minor, if deposited by something
that is released into the air space inside the OTA, is it not deposited
evenly on the whole surface of the mirror. If the picture is correct you
have area, a ring or band if you will where there is no deposit, just the
central region is hazy. This is very peculiar. If something was floating
around in the OTA like dust or particulate matter of any type it would not
be selective in its deposition. It would coat the entire surface evenly, so
this leads me to wonder if maybe you store your scope pointing down.
This is just a theory but if the mirror is looking down like a bowl upside
down and grease is melting and getting past the hole in the mirror around
the baffle tube it could flow out evenly from the center of the mirror. This
could account for it not reaching the outer edge of the mirror, YET.
Do you store your scope facing down? Has it been stored facing down setting
on the ground, shelf, or other such surface in a relatively warm or hot area
like a garage for any extended period of time at elevated temperatures?
One last thing..
Are you sure this is not a reflection?
Gary
Carpe Noctem
Sent from the Astro Cave via my MS Surface Tablet
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?° 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
.
<mailbox://Users/thomasashcraft/Library/Thunderbird/Profiles/y0km5ois.defaul
t/Mail/pop.netfirms.com/Drafts?number=139337303&s=97359714/grpId=3367692/grp
spId=1705082856/msgId=15042/stime=1454643287>
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t/Mail/pop.netfirms.com/Drafts?number=139337303&ywarid=515FB27823A7407E&a=10
001310322279&js=no&resp=img>
_._,___
|
Re: Possible outgassing - questions
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° -
90° 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° 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?° 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
.
<mailbox://Users/thomasashcraft/Library/Thunderbird/Profiles/y0km5ois.defaul
t/Mail/pop.netfirms.com/Drafts?number=139337303&s=97359714/grpId=3367692/grp
spId=1705082856/msgId=15042/stime=1454643287>
<mailbox://Users/thomasashcraft/Library/Thunderbird/Profiles/y0km5ois.defaul
t/Mail/pop.netfirms.com/Drafts?number=139337303&ywarid=515FB27823A7407E&a=10
001310322279&js=no&resp=img>
_._,___
[Non-text portions of this message have been removed]
|
Re: 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@...
[C14_EdgeHD] wrote:
toggle quoted message
Show quoted text
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?° 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
.
_._,___
|
Re: Possible outgassing - questions
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° 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 ? Carpe Noctem ? Sent from the Astro Cave via my MS Surface Tablet ? ? ?
toggle quoted message
Show quoted text
From: C14_EdgeHD@... [mailto:C14_EdgeHD@...]
Sent: Thursday, February 4, 2016 4:06 PM
To: C14_EdgeHD@...
Subject: [C14_EdgeHD] Possible outgassing - questions? ? I am just assembling information at this point on possible outgassing in
my one and a half year old C14 Edge.
I have some "haze" on the primary mirror. I am not sure if it is water
residue or petroleum outgassing haze. I am still investigating.
I am thinking about getting into the scope and cleaning it myself. If
this might be outgassing residue, then what cleaning agent would be
recommended?
Also, if this is outgassing, then will it continue to outgas throughout
the life of the telescope? I am aware that people change the greases
inside but I am not sure if I want to attempt this.
Thanks in advance for any replies.
Thomas
|
Possible outgassing - questions
I am just assembling information at this point on possible outgassing in my one and a half year old C14 Edge.
I have some "haze" on the primary mirror. I am not sure if it is water residue or petroleum outgassing haze. I am still investigating.
I am thinking about getting into the scope and cleaning it myself. If this might be outgassing residue, then what cleaning agent would be recommended?
Also, if this is outgassing, then will it continue to outgas throughout the life of the telescope? I am aware that people change the greases inside but I am not sure if I want to attempt this.
Thanks in advance for any replies.
Thomas
|
Re: Alignment of corrector plate to secondary mirror for EdgeHD1400
Hi Don, I see the surface of the original gasket has a little friction to the glass and must have the problem again soon or later. I bought the scope 4+ years ago and removed the corrector plate several times for cleaning, so replacing with Starizona one will be better choice for me. Thank you very much for the information. It really helps me with the next action. Best Regards, Yasushi
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Re: Alignment of corrector plate to secondary mirror for EdgeHD1400
Hi Yasushi,
We had the same problem on the C14 Edge at the Mauna Kea VIS here in Hawaii. ?I talked to Dean at Starizona and he said the secondary notch may not be at the three o'clock position as some of the earlier models were, but the Fastar logo should be level with the scope horizontal. ?The secondary cover should be rotated to hide the collimation screws. ?When we did that, the notch was at the three o'clock position. ?You can tighten the secondary tube without removing the corrector plate, but it's tricky and works best with two people. ?You should get it as tight as you can by hand, but it will probably loosen again. ?Dean has an improved gasket that will solve the problem, but you must removed the corrector plate to install it.
Hope this helps.
Don
|
Alignment of corrector plate to secondary mirror for EdgeHD1400
Hi, Seems like the alignment of?corrector plate to secondary mirror is critical to the optical performance of the tube, and how can I tell the correct alignment for EdgeHD1400?
Two weeks ago when I was trying to unthread the retaining ring from the secondary mirror of my EdgeHD1400 to use HyperSar in the field, I found the whole secondary mirror assembly unit was rotating against the corrector plate because it was loose. I did not remember how many revolutions they were as I kept rotating it in the dark till I found the problem, but ?the orientation must be already different from what it used be.
Going back home, I carefully removed the corrector plate from the tube and then unthreaded the secondary mirror assembly unit from the plate. I saw a magic mark at the side of the secondary mirror (one line), and also two marks adjacent to each other at the inner side of the center hole of the corrector plate. Does it mean the mark of secondary mirror should be positioned between the two marks drawn in the corrector plate?
I found the guideline for the normal tube and that EdgeHD version may depend on the year of manufacture. http://www.celestron.com/c3/support3/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=1655.&group=iframe
Thank you for your advice,
Yasushi
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very nice! You are in the same league as?Christopher Go.
Stan
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I had a period of quite good seeing this morning. Io can be seen transiting.
Brian
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This is my first image of Jupiter this year. Seeing was slightly above average:
Brian
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Re: Focus Shift on HD after the Meridian Flip
That should have been shocked, shocked?to find mirror flop with stock? pole dancing C14.
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Re: Focus Shift on HD after the Meridian Flip
I have a C14 and the mirror flop is almost imperceptible. Certainly no loss of collimation or quality of the stars. I can do a closed loop slew across the Meridian, my rotator rotates, and I find the object or star with no degradation in the quality of the picture. ? Gary ? Carpe Noctem ?
toggle quoted message
Show quoted text
From: C14_EdgeHD@... [mailto:C14_EdgeHD@...]
Sent: Monday, November 23, 2015 10:08 AM
To: C14_EdgeHD@...
Subject: [C14_EdgeHD] Re: Focus Shift on HD after the Meridian Flip? ? I am shocked, shocked to find mirror flop on the C14.
|
Re: Focus Shift on HD after the Meridian Flip
I am shocked, shocked to find mirror flop on the C14.
|
Re: Focus Shift on HD after the Meridian Flip
Actually, I am not sure about the human error part of it now. I don't think I check the direction of the final mirror focusing. It's entirely possible it was counterclockwise and the mirror does have a play. Remains to be checked. I admit with the mirror locks I'm a bit complacent about this, perhaps wrongly.? Thanks for pointing it out. I will post the results.
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Re: Focus Shift on HD after the Meridian Flip
I feel your frustration. I too am experiencing a problem that I cannot seem to get my head around. After shutting my Observatory down for better then six months and then start imaging again I just cannot seem to guide quite as good as I did last year. When I started up my pointing was still dead on with The Sky x. Guiding with Maxim always yielded under .300 RMS, usually around
.200 or? better RMS. Now I have trouble getting under .400 RMS with Maxim. I have tried every conceivable setting combination, new T-Point model, new PEC curve etc. So I know what frustration is. I hope someone comes up with a suggestion for you. I tried direct guide still not better.
Good luck.
Gary
Carpe Noctem
Sent from my space ship via my LG V10 Phone
?
To clarify: I'm using Celestron x0.7 reducer - very sturdy, no play. Moonlite is a Crayford-style (extremely well-built) and used from mid-point after mirror-focus. I never touch mirror focusing after locking up the mirror. So, I guess, you two possibilities remain, though I checked all of the "operator-induced" errors as much I could. Short of sending it back to C, or disassembling it myself, I guess I have to live with the refocusing after the flip as I did before... Sigh...
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Re: Focus Shift on HD after the Meridian Flip
To clarify: I'm using Celestron x0.7 reducer - very sturdy, no play. Moonlite is a Crayford-style (extremely well-built) and used from mid-point after mirror-focus. I never touch mirror focusing after locking up the mirror. So, I guess, you two possibilities remain, though I checked all of the "operator-induced" errors as much I could. Short of sending it back to C, or disassembling it myself, I guess I have to live with the refocusing after the flip as I did before... Sigh...
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Re: Focus Shift on HD after the Meridian Flip
Are you saying you have a Moonlight focuser on the rear, a crayford style focuser? Something does not sound right here. Once the mirror is locked down you cannot focuse it (tweak) it. Locked is locked.. If you crank on that screw focuse after you lock it down you will slant the primary.
If you are using a rear focuser after your focal reducer like a Starlight instruments or Moonlight it should be set to its mid point. All other spacers etc. should now have you mechanicay at the back focus distance. You would then use your built in screw focuser to attain the best focus you can. When this is done you lock the mirror down and forget about it. Now all subsequent focusing will be done with the crayford style on the back. I might add with regards to collimation. You must take care when collimating that your mirror focuser moves the mirror up towards the sky against gravity when you come to focus prior to your collimation efforts. When you are done collimating do a focus with the mirror always ending up pulling the mirror up. This is the same way you did it prior to collimation. Now lock the mirror and start using the crayford. Do not mess with the mirror again..
The way you stated it in your querry you implied that you tweaked the mirror after locking it down which can be disastrous.
If it just came back from the factory it is highly unlikely that something is loose in the telescope so this leaves only two possibilites.
1. You are doing something wrong.
2. Somethig is loose at the rear of the scope.
If you are using the Celestron focal reducer it is a monster. I have one and it is solid as a rock so as stated above it is you or something is loose beyound the focal reducer.
Garu
Carpe Noctem
Sent from my space ship via my LG V10 Phone
On Nov 22, 2015 12:23 PM, "cosmoimager@... [C14_EdgeHD]" <C14_EdgeHD@...> wrote:
>
> ?
>
> I have my 14" EdgeHD for over 2 years now. It originally had a problem with not holding it's collimation and had to be sent back to "C" where they "span" it - much better after that. I use it mostly for DS imaging with 0.7X focal reducer and Moonlite focuser. Everything seems to be very tight and sturdy. I focus it first crudely, lock the mirror then use Moonlite to tweak it. It all works fine even for long slews, until I do the Meridian Flip. After that focus is gone, collimation too is worse (though still usable). It usually is off by 100 steps or so.
>
> Any idea what can cause such a shift?
>
> Thank you for any thoughts.
>
> Ian
>
>
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