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Celestron C90 Registry

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256 replies to this topic

#251 oldmanastro

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Posted 01 August 2022 - 09:00 PM

Another one for the registry. Acquired just two months ago. Using it with a .965 to 1.25" adapter. Collimated after removing main mirror retaining clip and using nylon knurled screws. It was badly out of collimation and astigmatic. Now it provides nice round star test images.

Attached Thumbnails

  • C90Serial#.JPG
  • C90-Astroview-2022.JPG


#252 RSX11M+

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Posted 03 August 2022 - 07:02 PM

Another one for the registry. Acquired just two months ago. Using it with a .965 to 1.25" adapter. Collimated after removing main mirror retaining clip and using nylon knurled screws. It was badly out of collimation and astigmatic. Now it provides nice round star test images.

Thanks for registering. Congratulations - You are one of the few who has reported being able to collimate one of these. 

 

FYI - I would guess your scope to have been manufactured in 1979 or 1980. Our records aren't complete enough to be certain, and serial numbers in this range are not date-coded, as some other earlier Celestron scopes were.

 

The C90 f11s are excellent candidates for mounting on a friendly GEM or EQ. I enjoy their near 2.5˚ FOV with a 40mm eyepiece. My f5.6 model gets  4.75˚ which is hard to appreciate.

 

Enjoy, and thanks again. 


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#253 oldmanastro

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Posted 03 August 2022 - 10:31 PM

Thanks for registering. Congratulations - You are one of the few who has reported being able to collimate one of these. 

 

FYI - I would guess your scope to have been manufactured in 1979 or 1980. Our records aren't complete enough to be certain, and serial numbers in this range are not date-coded, as some other earlier Celestron scopes were.

 

The C90 f11s are excellent candidates for mounting on a friendly GEM or EQ. I enjoy their near 2.5˚ FOV with a 40mm eyepiece. My f5.6 model gets  4.75˚ which is hard to appreciate.

 

Enjoy, and thanks again. 

Many thanks for the information on the years of manufacture. I have been using this one on my Astroview equatorial mount. The adapter is homemade, simple but functional. It's an enjoyable telescope to use. The views with my wide field eyepieces are great. Collimation requires extra careful removal of the retaining ring that presses a plastic washer over the mirror to hold it against the spring to which the mirror is attached with epoxy. This leaves the mirror attached only to the spring and free to be adjusted with the three knurled screws without inducing stress on the mirror.  Mine was way out of collimation. I don't think it was ever collimated at all. The retaining ring can be substituted with a rubber O-ring after collimation. There's a 2006 article about the whole procedure. Google "Collimating the Vintage C90". 


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#254 Scheimpflug

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Posted 04 August 2022 - 10:40 AM

Even if such information does not appear to have a visible place in the Registry, I will make an effort to capture it. For example, several times I've seriously considered going back and collecting images submitted with entries. It has often been a research resource to me in resolving questions. Clearly, I cannot know everything and it occasionally happens that together we discover something no-one alive remembers or ever noticed.

 

I truly appreciate the tenacity of participants, and will be happy to undertake the additional work that may result from caring. (... it may kill me though lol.gif  - so please tolerate kindly any delay my death may cause)

I've recently acquired a C90, one of the black spotting scope variants with an 88xxxx serial number (889507 specifically) and the ridged rubber focusing ring.   I saw that there was only one other 88xxxx in the registry, but no known manufacture date bounds for anything beyond the orange tube versions, so following your advice I attempted to narrow it down with peripheral data.

 

One thing that seems "traceable" is the Celestron logo itself.  Each lens has a logo, as do many of the accessories, and the logos are prominent in dated publications (catalogs, owners manuals, etc).  This should help narrow down not just 88xxxx lenses, but others too.

 

 

So I went through every catalog I could find in a Google search, and here are the logos and dates observed:

 

June 1974 catalog:

Celestron Logo - 1974 - June.jpg

 

July 1978 catalog (two different logos used in the same catalog - possibly the transition period?):

Notes: First (italic) logo is different from 1974 version - particularly obvious being the "s".  Second logo is completely different.

Celestron Logo - 1978 - July - 1.png

Celestron Logo - 1978 - July - 2.png

 

1993 catalog:

Notes: Logo is now all uppercase

Celestron Logo - 1993.jpg

 

1998 accessories catalog:

Notes: Logo is very similar, but corners are sharper on all letters (most apparent on the "R"), and the "T" is more symmetrical.

Celestron Logo - 1998.png

 

 

...

Somewhere in here between 1998 and 2011 is an additional unique logo - I don't have a photo right now, or a date for it - but there is a version similar to 1998, but it has a three-stroke "N", not the up-sized lowercase "n" of the prior logo.

...

 

 

2011 catalog:

Notes:  Logo is completely different from prior.

Celestron Logo - 2011.png

 

 

 

I'm sure there are more variants, or more publications that could narrow down the date ranges...  this is just what I could find yesterday afternoon.


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#255 Scheimpflug

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Posted 04 August 2022 - 10:44 AM

Another tidbit of note, is that there seemed to be numerous variants of the molded plastic cases. 

Even if only looking at the later end of the "early" C90s, some of the cases had rounded edges, some squared... some had no branding, some had "Celestron" molded in, and others say "Celestron International".    And on top of that, some have two latches and others just one.   

 

The 1998 accessories catalog shows the C90 case as a rounded case with a single metal latch.  That's the only variant I have a date for.



#256 Kasmos

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Posted 04 August 2022 - 01:51 PM

I'd had done a similar post on the logos in another thread.

A few are repeats (with other years of dates) while the others are altogether different

 

Celestron-Cat-back.jpg

 

 

Celestron-Covers-cn.jpg

Note the two C90 manuals with different fonts

 

Celestron-ad-logos.jpg

Note how the typeface from 4/84 is squared off with slight serifs.

 

Celestron-83-Cat.jpg

Again the logo with slight serifs.

Technically there's no date on this catalog but the style of the telescopes correspond with what was offered in '83-'84

 

A few of these might have been just for printed material and not an officail logo.


Edited by Kasmos, 04 August 2022 - 01:52 PM.


#257 Scheimpflug

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Posted 04 August 2022 - 02:06 PM

Aha!  So I was wrong on my guess for the "capital N" variant... it came before the large lowercase "n", not after!  

Now that I had a reference for a targeted search, I see examples that that logo was used in the 1983-1985 range.

 

Thanks for the info!

 

I can see too, from archived versions of celestron.com (via archive.org), that Celestron changed their logo a number of times in the post-2000 era as well.

 

Also, the 6/82 version of the "Celestron 90" instruction manual has the logo which matches the second 6/78 logo and yours from 1/76 and 10/77. So they at least held on to that one for a little while.


Edited by Scheimpflug, 04 August 2022 - 02:10 PM.

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