300 replies to this topic

[RyanSem]

Just picked up my first orange C90 after eyeing them for a couple of months. I'll share what I know about it for the registry.

 

Serial: 91271

Model: Spotter

Optics Number: 3051

 

Here are some pictures as well (I don't know how to embed them here): https://imgur.com/a/3pXnR3d

 

One weird thing to note: There are two numbers scratched off near my optics number. I can't make either of them out, but it's strange that this scope has (or had?) 3 numbers before two were scratched out. I included pictures of them, but it is a hard angle to get a good picture of. 

Edited by RyanSem, 12 January 2019 - 08:57 AM.

[houndsbourgh]

My orange tube has been gone for many years now. I really missed it camping. So when I saw this gold band in black I picked it up. Always thought this version was really cool but kind of an odd duck. Case and all the accessories included. Very little signs of use. Good cleaning and lubed the focuser was all she needed.
Model: Maksutov Telescope
Serial number: 918503
Lense number: 0517
1/4-20” tripod mount.
Marked “Made In U.S.A” on the gold band.
Finder is marked “Japan” with the V in the O.
If anyone has a good guess on production date please let me know. Focus ring, Celestron International plastic case and finder look like later models. Chassey and accessories seem to have more in common with the older orange tubes. Removable alloy dew shield.......unique to this model?
Update: Found the same scope in a 1982 catologe. Shown on a clock drive. Looks like this one has never been mounted that way. Surface is very minty.

Attached Thumbnails

• 

Edited by houndsbourgh, 16 February 2019 - 04:50 PM.

[Kasmos]

My orange tube has been gone for many years now. I really missed it camping. So when I saw this gold band in black I picked it up. Always thought this version was really cool but kind of an odd duck. Case and all the accessories included. Very little signs of use. Good cleaning and lubed the focuser was all she needed.
Model: Maksutov Telescope
Serial number: 918503
Lense number: 0517
1/4-20” tripod mount.
Marked “Made In U.S.A” on the gold band.
Finder is marked “Japan” with the V in the O.
If anyone has a good guess on production date please let me know. Focus ring, Celestron International plastic case and finder look like later models. Chassey and accessories seem to have more in common with the older orange tubes. Removable alloy dew shield.......unique to this model?
Update: Found the same scope in a 1982 catologe. Shown on a clock drive. Looks like this one has never been mounted that way. Surface is very minty.

Nice Kit.

I've only seen that dew shield on the glossy black ones.

Orange tube models seemed to have had a rubber dew shield as an accessory at some point.

 

Does your Porro say Celestron on it? The reason I ask, I have a un-branded one that came with a '74 C5.

[houndsbourgh]

Yes it does say Celestron. Actually every accessorie is branded the same. I know all of the pices are not included with the OTA. But I do think they may have been additional accessories at time of purchase. I have the LAR and Visual back as well. The picture just shows what came with the scope.

Attached Thumbnails

• 

Edited by houndsbourgh, 16 February 2019 - 06:30 PM.

[Senex Bibax]

I just picked this one up this afternoon. Bought it on Kijiji Ottawa for CAD $75.00. The seller had never used it, they received it as part payment for another sale. It looks to be in good shape, and the focusing is smooth. There is a diagonal with a single eyepiece, but no case or lens caps or tripod / mount. Apart from  those missing items, priorities include additional eyepieces and adapters to allow use wth a Nikon DSLR. Any suggestions are more than welcome. Primary use will be as a grab-and-go astronomical telescope, secondarily as a terrestrial spotting scope and telephoto lens.

 

 

 

[houndsbourgh]

Nice! The T-Ring adapter is still available for the C90. After that you will need the actual T-Ring for your camera. A quick internet search should bring up both. There is a recent thread A new (to me) C90 where eyepiece solutions for the C90 have been discussed.

Edited by houndsbourgh, 16 February 2019 - 06:48 PM.

[Uranotopia]

My orange tube has been gone for many years now. I really missed it camping. So when I saw this gold band in black I picked it up. Always thought this version was really cool but kind of an odd duck. Case and all the accessories included. Very little signs of use. Good cleaning and lubed the focuser was all she needed.
Model: Maksutov Telescope
Serial number: 918503
Lense number: 0517
1/4-20” tripod mount.
Marked “Made In U.S.A” on the gold band.
Finder is marked “Japan” with the V in the O.
If anyone has a good guess on production date please let me know. Focus ring, Celestron International plastic case and finder look like later models. Chassey and accessories seem to have more in common with the older orange tubes. Removable alloy dew shield.......unique to this model?
Update: Found the same scope in a 1982 catologe. Shown on a clock drive. Looks like this one has never been mounted that way. Surface is very minty.

Hi,

very nice scope, looks nearly as new bought and unused!

Please tell me, what grease did you use to lubricate the focuser ring?

Edited by Uranotopia, 17 February 2019 - 07:14 AM.

[houndsbourgh]

Mobile 1 is the grease most often referenced for the original assembly. Petroleum based grease can out gas and attack plastics and adhesives. Some C90s suffer from breakdown of adhesives used on internal parts. I don't think Celestron really considered these scopes being in service over 25+ years. Second most popular choice seemed to be white lithium. No out gassing and a bit more stable with dissimilar materials. So that is what I went with. Honestly getting the grease where you need it and not all over the mirror and base is the real trick. First I very carefully removed all the old grease with qtips  and 99% alcohol. Then I painted the threads inside and out with a very light coat using an acid free brush. During assembly I pulled the focuser back out after every half turn. Every time I pulled the focuser out I removed the extra grease from the leading and trailing edges of the threads. As the threads bottomed out I had no pile up of lubricant to contaminate the mirror. Now the focuser is smooth and still holds adjustment nicely.

Edited by houndsbourgh, 17 February 2019 - 01:04 PM.

[wfj]

Disagree. Better luck with a very thin oil, makes the scope a one finger subtle focuser. You may need to lap the threads if they're cut too coarse to get this to work.

[houndsbourgh]

It may depend on the particular scope. After cleaning there was quite the knock or lateral play in the threads on mine. That's why I decided on the lithium grease and let the thread tolerances squeeze the excess away during the assembly. If I hold mine just right by the focus ring the weight of the finder can start the rotation. 

Edited by houndsbourgh, 18 February 2019 - 07:27 PM.

[Stevegeo]

I bought mine a few years ago, rarely used ... #9102

Currently as a spotter on my Celestron C8 black tube Cat.

 

Christmas I bought at a garage sale another older  c90 for my daughter .. I will text her and get the number.. she's in Okla.. and I'm in NY . That one has a finderscope attached .. while mine has none .. both came in cases .. both hardly used .

Great scopes ... just purchased a Meade 90 from a member and will soon make a comparison.. 

Unless someone else already has! 

Stevegeo

[Stevegeo]

# 9102

My C8 with c90 piggybacked.  Tried to get a close up of the number ... but it's too large 1.8 meg. To post. 

[wfj]

It may depend on the particular scope. After cleaning there was quite the knock or lateral play in the threads on mine. That's why I decided on the lithium grease and let the thread tolerances squeeze the excess away during the assembly. If I hold mine just right by the focus ring the weight of the finder can start the rotation. 

Most recent orange tube, the only one in 50+ I've ever kept for more than a month (this ones now going on years), had tight threads. When I removed the grease, I couldn't get it to "screw in" - it would seize up (needing PB Blaster). Thus the lapping. And then the ultralight oil.

 

Have been experimenting with the teflon spray - it may be an even better choice.

 

As to "loose" threads - in some cases, after extreme cleaning, I've used JB Weld as a "thread recovery" - but it's very, very risky, and you need to practice on another botched thread many times before trying it. Do not try it unless you want to "glue" your C90 irreparably. Really take the warning seriously.

 

Why dangerous? Because, even after applying thinly/selectively in damaged portions, scraping off excess, applying mold release to the other part, and waiting for the new material to "setup" almost completely ... the mold release can fail/wipe off, the material can have an uncured spot or become mounded - and then it adheres and you're screwed. So its very dangerous. And I've had to lap too tight threads from this afterwards as well. Possible to do, but definitely not recommended.

 

Guess its another reason I've been enhancing this "good DPAC" C90 - since it's a "single finger" focus, can get away with diagnostic insane mags (750x) as "accessible". I get a low contrast "waffle" pattern superimposed which appears to be a residual HSA effect - perhaps this can be cancelled to allow for realizable contrast/sharpness gain. Deciphering the puzzle.

 

(The pattern is possibly the "difference" between the SA under correction and the corrector over correction. The fact that the DPAC records very straight lines, and the star test shows subtle zones only in the extrafocal pattern suggests that the harmonic is an "averaging" function that is losing contrast/deteriorating the image, likely to the fact that there is now only HSA present, due to the angular deviation of the faster f/2 system. So now I need to figure out how to cancel the HSA w/o affecting the SA as a counter. It's like the surface of a drum with a standing wave pattern. Perhaps a null optical system with high dispersive asymmetry. )

Edited by wfj, 23 February 2019 - 08:00 PM.

[Dj4822]

Hi y'all. I just came into ownership of an orange Celestron C90, SN 923078. I'd give you that inner number... but unfortunately the dang thing is so covered in grime I can't hardly make it out myself, nevermind get a good pic of it. Here's an imgur album of current state of it. 

 

It was delivered to me in a plastic bag, parts just bumping into each other with a shirt hopefully separating them. Included was an old magazine from 1985 about stargazing and a moldy cookbook.... Never mind that though.

 

I'm not much into any thing like this, we received it from a family member who was clearing out their home. The paint is chipped and the lenses are very dirty. I also notice that I'm missing an adjustment screw on the finder scope, as well as the thumbscrew adjustment for the star diagonal. Does anyone have any suggestions for where I can replace these? Going to try my hardware store soon, but I'm not sure about that thumbscrew. 

 

So anyway, I'm not sure this is salvageable, but I'd love to give it a try!

 

Guess first I'll need to figure a safe way to clean this thing up without damaging anything! Does anyone have any suggestions? 

 

Thanks! 

[houndsbourgh]

Great thread to start with on the classic forum "Cleaning solutions, old and new". Nylon bolts at the hardware store provide a nice budget replacement for the missing finder adjusters. Best thing to remember when cleaning a scope, no shortcuts. Lots of info about cleaning all over the forums. Good luck.

Edited by houndsbourgh, 25 February 2019 - 12:10 AM.

[davidmcgo]

Here is serial number 95298 which I bought from Augustus and received Saturday.  My first sharp telescope was a C90 spotter back in 1983 or so when a Roger Tuthill wanted a Star Trap 4.25” RFT back which I had bought from one of his sons who was renting a room in a house nearby.  I couldn’t convince him to swing me an Astro and always wanted one.

 

Here it is alongside my 1976 C5.

 

Dave

 

 

 

 

Attached Thumbnails

• 

[artemis.sleeps]

Hi everyone, I forced my father to hand over his C 90 that he bought for my mother to birdwatch with in Illinois in the early 1980s, I am guessing. I only remember them using it once on a rather flimsy photographic tripod and I used it last year at their place to show them some of the planets. I have since brought it home to Sydney, Australia to use as a grab and go for outreach events held by my Astronomy club. It was a great success mounted on my Sky-Watcher AZ-GTi GoTo mount, in manual and auto mode, so I decided to find out more about the OTA and landed here. 

 

My scope and finder are orange with black focus ring and gold band. The scope SN is 909714 ‘Made in USA’ and the optics etching is 2950. It has the original moulded plastic case which was great for carry-on back to Australia with a belt around it for safety in case the clasps popped open. The accessories are in a small white (cardboard and styrofoam) box with the label “Celestron C90 Standard Visual Package” and packed inside are 2 Kellner .96 eyepieces 18mm and 30mm as well as a Celestron Star Diagonal .96” Japan. It also has Nikon camera adapter tube.

 

Regards, Ann

[Uranotopia]

Hi y'all. I just came into ownership of an orange Celestron C90, SN 923078. I'd give you that inner number... but unfortunately the dang thing is so covered in grime I can't hardly make it out myself, nevermind get a good pic of it. Here's an imgur album of current state of it. 

 

It was delivered to me in a plastic bag, parts just bumping into each other with a shirt hopefully separating them. Included was an old magazine from 1985 about stargazing and a moldy cookbook.... Never mind that though.

 

I'm not much into any thing like this, we received it from a family member who was clearing out their home. The paint is chipped and the lenses are very dirty. I also notice that I'm missing an adjustment screw on the finder scope, as well as the thumbscrew adjustment for the star diagonal. Does anyone have any suggestions for where I can replace these? Going to try my hardware store soon, but I'm not sure about that thumbscrew. 

 

So anyway, I'm not sure this is salvageable, but I'd love to give it a try!

 

Guess first I'll need to figure a safe way to clean this thing up without damaging anything! Does anyone have any suggestions? 

 

Thanks! 

Hooo, the front plate (Meniscus lense) looks terrible dirty...

try to clean it very carefuly, as the dust can scratch on the glass of front plate.

I would recommend you to use first air (using a lense bellows), then perhaps carefully with water (hoping, that the tube is tight enough not to let the water inside) - therefore you can use a syringe. This should remove the harder components of dust that may scratch the lense...

And then you can use a optical cleaner fluid or some destilled water with one or two drops of washing-up liquid, take soft paper tissues (without oil or perfume) and let them mve over the glass without pressure.

 

(I hope, I've translated good enough into English, as this is not my native language...  but perhaps one can help and give more detailed recommends here).

[Uranotopia]

Hi everyone, I forced my father to hand over his C 90 that he bought for my mother to birdwatch with in Illinois in the early 1980s, I am guessing. I only remember them using it once on a rather flimsy photographic tripod and I used it last year at their place to show them some of the planets. I have since brought it home to Sydney, Australia to use as a grab and go for outreach events held by my Astronomy club. It was a great success mounted on my Sky-Watcher AZ-GTi GoTo mount, in manual and auto mode, so I decided to find out more about the OTA and landed here. 

 

My scope and finder are orange with black focus ring and gold band. The scope SN is 909714 ‘Made in USA’ and the optics etching is 2950. It has the original moulded plastic case which was great for carry-on back to Australia with a belt around it for safety in case the clasps popped open. The accessories are in a small white (cardboard and styrofoam) box with the label “Celestron C90 Standard Visual Package” and packed inside are 2 Kellner .96 eyepieces 18mm and 30mm as well as a Celestron Star Diagonal .96” Japan. It also has Nikon camera adapter tube.

 

Regards, Ann

Hi Ann!

Seems to be a really older C90, great!!!

Please can you write sth more about your observations with the C90, how you estimate the quality of optics?!

I'd like to recommend you to get some eyepieces for higher magnification (for example with focal lengths of about 9mm and 6mm). With my not-so-old C90 I had some really good observations of the planets and the moon using an original Celestron eyepiece with 6mm (probably made by Vixen, Japan).

 

Regards, Carsten

[Dave Trott]

I would like to register this C90. Serial number 906047 came complete with all original accessories and a camera adapter. I bought it on Ebay a few years ago so don't have any history for the scope.

[wfj]

Have been experimenting with the teflon spray - it may be an even better choice.

Didn't work out. The solid (dust) lubricants gum up after a while, and they're difficult to remove afterwards. Argan hair oil works still better. Disreccomend.

[daltons]

Here's mine, just arrived from eBay  

 

 

 

 

[Masvingo]

Thanks to RyanSem, houndsbourgh, Senex Bibax, Stevegeo, Dj4822, Dave (davidmcgo), Ann (artemis.sleeps), Dave Trott and daltons for your contributions which, as ever, are gratefully received. I've entered all the details into the C90 Registry which is now at edition 3.

 

I'm intriged by the extra numbers on RyanSem's corrector - that's the second instance reported of a C90 having more than one number as Jim (ftwskies) has two numbers on his C90.

 

houndsbourgh - yours is the earliest serial number for the new gloss black style on the C90 Registry - best I can do for a date is to say it must be some time after late 1984.  In the S&T Sept 1984 issue on page 249 there was an advert headed "Celestron Close Up News Notes" which stated:

"New Colors.  Celestron’s complete line up of Refractor, Newtonian and catadioptric telescopes is sporting a striking high-tech black tube trimmed in Celestron orange accents.  See your local dealer for an introduction to the new Celestron colors!"

I'm guessing that this is when the C90 changed to the gloss black style with the ribbed rubber focusing ring and the screw-on metal dew shield. The Celestron double page ad in S&T in November 1984 (page 438-439) includes a gloss black C90 with ribbed rubber focus ring and screw-on dew shield.

 

Ann - thanks for the details about the accessories that came with your scope, mine (Spotter s/n 903937 so slightly earlier than yours) came with the accessories in a small blue cardboard box with styrofoam insert with no label and with a single 18mm 0.96" Kellner marked (KD) for Dai-ichi Kogaku Co Ltd (and which still has its Japanese Telescope Institute Inspection sticker), Celestron Star Diagonal 0.96" Japan and a 2.5x Celestron Barlow Lens 0.96" Japan.

 

houndsbough & wfj - when I got my Astro the focusing was very rough and scratchy - after cleaning the old grease off I also had quite a bit of lateral play in the threads - using Super Lube (synthetic grease with PTFE) helped a lot - any thoughts about outgassing or any other issues with Super Lube? Whilst it has made the focusing much smoother it is rather stiff so I may have a think about using something else.

 

Stevegeo, have you had any luck with getting the details for your daughter's C90?

 

Dj4822, looks like quite a clean-up job there, how did it go? 

 

Please keep the details and pictures coming along for the C90 Registry, many thanks.

 

Edited to add manufacturer for the (KD) mark - see Galakuma's post here.

Edited by Masvingo, 23 June 2019 - 03:39 PM.

[jstrandberg]

I just picked up a C90 500mm f/5.6 black tube in camera lens configuration (no holes to mount finder scope) SN 500467. Came with a Celestron branded traditional style lens carrying case. Optics number 679.

Edited by jstrandberg, 29 June 2019 - 02:09 PM.

[Masvingo]

Thanks to jstrandberg for the details of your C90 f/5.6 Telephoto - that's the second f/5.6 for the C90 Registry which is now at version 3.1.

 

Please post some pictures of the lens and case if you have them.