120 replies to this topic

[Masvingo]

Hi all!

I read somewhere that the C90 telephoto lenses are black and either 500mm or 1000mm focal length. Anyone know if this is correct?

I think that generally the telephoto versions were black although there are a couple of early ones on the registry that are orange. 

 

The first telephoto was essentially the same OTA as the spotter and astro and had the same specs being f/11 with a focal length of 1,000mm.  A finderscope was added to make the spotter version and a single arm fork mount was added to the spotter to make the astro version.

 

Later on in production, there was also a f/5.6 version with a 500mm focal length.  There are 4 f/5.6 versions on the Registry, all have a black OTA.

[houndsbourgh]

Thanks houndsbourgh, I've updated the entry for #919048.  I note your other C90 serial number is quite close, did you specifically look for one with a similar number or was it just chance?
 

I just like that particular incarnation of the C90. Seems the ribbed focuser on a gold band in black was short lived.

Edited by houndsbourgh, 29 March 2020 - 03:44 PM.

[ANM]

hI all,

I recently acquired an orange C90 telescope OTA s/n 902563 and I'd like to get it added to the registry if possible. There is a number etched into the edge of the corrector but all I can see is two digits, either 18 or 81 depending on whether I stand on my head or not. I've attached a photo of it here:

 

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[Masvingo]

Thanks for your details, ANM, I've updated the C90 Registry to edition 5.4 to include your C90.

 

That's an interesting corrector number having only two digits.  Is yours a telephoto, spotter, or astro model?  If the latter two, does the finder have a chrome or black eyepiece barrel and is the finder marked with a circle dash, oval M or something else?

 

As ever, all contributions gratefully received!

[ANM]

Thanks for your details, ANM, I've updated the C90 Registry to edition 5.4 to include your C90.
 
That's an interesting corrector number having only two digits.  Is yours a telephoto, spotter, or astro model?  If the latter two, does the finder have a chrome or black eyepiece barrel and is the finder marked with a circle dash, oval M or something else?
 
As ever, all contributions gratefully received!

Thanks for adding me to the registry. I have just the OTA and the band
around the primary cell says it's a Maksutov Telescope and 1000mm f11.

P.S.: the finder is orange with black lens cells (no chrome eyepiece barrel) and is marked circle T.

Edited by ANM, 13 April 2020 - 12:05 PM.

[Terra Nova]

Hi all!

I read somewhere that the C90 telephoto lenses are black and either 500mm or 1000mm focal length. Anyone know if this is correct?

I had a very early one. It was SN/9429, production no. 429. It was 1000mm f.l. and was Orange, (pebble finish IIRC).

[Senex Bibax]

I had a very early one. It was SN/9429, production no. 429. It was 1000mm f.l. and was Orange, (pebble finish IIRC).

Mine is serial # 95346, 1000 mm FL, and it is black with the gold band. I assume it's the telephoto version because the band says "Mirror Lens", not "Makutsov Telescope".

[Masvingo]

Thanks for the additional info on your C90, ANM, which I've added in to the C90 Registry.

[ANM]

I just acquired a black C90, astro version, but I can't find a serial number. It's nowhere on the OTA like my orange one, does anyone know where it is?

[houndsbourgh]

If it is a US made black gold band the serial number should be right where the mount attaches to the OTA. I had to remove mine from the mount to see the complete number. If it is a later thin orange band you could peek under the tripod mounting block as well.

[ANM]

If it is a US made black gold band the serial number should be right where the mount attaches to the OTA. I had to remove mine from the mount to see the complete number. If it is a later thin orange band you could peek under the tripod mounting block as well.

It is gloss black with the thin orange band, and it's attached to the one armed fork. I can see between the OTA and the fork mount, but there doesn't appear to be a S/N. Would it be inside the base? Or maybe under the Declination axis cover?
 

[ANM]

I have always lusted after the C90 Astro and I saw this on eBay. I decided that there were few opportunities to acquire a C90 Astro and if I didn't get this one I may never have one.

 

So, this is the C90 I bought off eBay a few days ago:

 

 

 

image is swapped left to right

 

It appears to be in very good condition but it came with no:

case, caps, eyepieces, diagonal, barlow, or power cord.

It came with:

threaded metal dew shield, 5x24 finder, and Celestron T2 adapter.

The finder is marked CELESTRON ® 5X24 FINDER SCOPE   JAPAN (V) in white paint.

The OTA is marked CELESTRON C90 1000MM F/11.

 

So far I can find no serial number, just the corrector number: 5993.

 

James, I would like to add it to the registry if you could with no S/N for now.

 

 

Edited by ANM, 07 May 2020 - 06:47 PM.

[houndsbourgh]

Cool scope. Unfortunately I got no other suggestions on the serial number. All the other pieces of your kit do show up in the classifieds. Just need to be patient.

[ANM]

If it is a US made black gold band the serial number should be right where the mount attaches to the OTA. I had to remove mine from the mount to see the complete number. If it is a later thin orange band you could peek under the tripod mounting block as well.

If the S/N was on the tripod mounting block it is long gone, and most of the C90 Astros I've seen do have the tripod mounting block even though they are Astros.

I would like to do an exhaustive search for the S/N, do you have any idea how to get the OTA off the mount? Does the plastic cover over the Alt/Dec axis pry off?
 

[houndsbourgh]

The cover is a friction fit. On mine it is a tin cover held in place by an o-ring. After the cover is off you will see an allen screw. Lock the clutch and remove the screw. A set of washers will be under the nylon washer. Keep them in order and set aside. Grasp the OTA and release the clutch. You should be able to slide it all out of the mount arm. Two tapered head allen hold the OTA on the assembly.

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[ANM]

Mine is exactly the same, I managed to get a finger nail under the edge and pull the cover off. I'll go a bit further and see if I can find the S/N.

 

P.S.: I pulled the OTA off the single mount arm and there is no S/N hidden there. Since the S/N "has" to go with the OTA I'm at a loss, the only other possibility is that it was on the tripod (the photo tripod) block which is missing. I have seen some C90s with what appear to be numbers on the photo tripod block.

Edited by ANM, 08 May 2020 - 05:27 PM.

[ANM]

Here's a picture of a C90 that looks the same as mine and you can see what looks like the S/N on the tripod block:

 

or here:

 

On mine the tripod block is missing.

Edited by ANM, 09 May 2020 - 09:28 AM.

[ACG]

<p>Hello, I would like to include my C90 in the registry. &nbsp;S/N 915647 and optic number 5400. I suppose it will be from the mid 80's. It comes with a 5x24 search engine with a V circle and a rubber parasol</p>
<p>(I have been lucky in this regard).&nbsp; His optics is really good.&nbsp;<br />
Thank you</p>
<p>Regards</p>
<p>ACG (Spain)</p>

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[CoolPanoramas]

I would like to include my C90 in the registry please.

I have acquired an orange C90 telescope OTA. The S/N is 9818  Made in the U.S.A.
It is an orange tube with the black knurled focusing ring and the gold metal band. It says Makutsov Telescope, so I do not think it is a Telephoto model.

It came with the metal holder for the small spotter scope, but no scope. It also came with a Celestron T-Adaptor, but something appears to be missing (possible the adapter to the specific camera(?), as it distal end rattles & moves.

It also is missing the mounting block and the mount itself, and no eyepieces were included. Initially, the black focusing ring was stuck, but we gradually worked it loose. The threads are a bit gritty and it needs to be cleaned and lubricated. 

[CoolPanoramas]

 

[houndsbourgh]

T-Adaptor requires a T-Ring for your specific camera. Hard to see in your photo but it looks like something is already mounted on the T-Ring end of your adaptor.