Found a old Celestron 21066-wos-a

[Revilo]

Hi all,

was just going through the garage to find something and had come across my dads old Celestron telescope  the ,model of the scope says it’s a 21066 wos a. The focal length is 900mm and aperture is 2.3”. Was wondering if any of you knows something about this telescope? I’m guessing it’s not that great. here’s a few pictures of it.

 

 

Olly.

Edited January 25, 2018 by Revilo

[Stu]

Depending on the optics, some of these old scopes were quite nice. At f15 it will be well corrected and may give nice sharp views of planets and the moon.

Can you post some pics of the actual scope and any labels or info on it, might make it easier to tell.

The mounts can be quite wobbly!

[Revilo]

10 minutes ago, Stu said:

Depending on the optics, some of these old scopes were quite nice. At f15 it will be well corrected and may give nice sharp views of planets and the moon.

Can you post some pics of the actual scope and any labels or info on it, might make it easier to tell.

The mounts can be quite wobbly!

Have just edited the op for the pictures. We have a box of eye pieces somewhere not sure how good they are.

Edited January 25, 2018 by Revilo

[Stu]

It's a Chinese made one unfortunately, most of the more highly prized ones are Japanese manufactured. Only thing to do is give it a go, try on moon and see how you go.

[Revilo]

Thanks, needs a good clean up before I use it. The mount does seem a bit wobbly. Will give it a go be a waste to throw it out,

[tuckstar]

Show us the eyepieces as well please. If you can.

[happy-kat]

Let's see the front lens first, it may not need a clean and cleaning badly may damage it.

[JOC]

10 hours ago, tuckstar said:

Show us the eyepieces as well please. If you can.

The eyepieces might be that good it will be worth buying a new scope!! LOL

[tuckstar]

You never know, they might be good enough to pay for a new scope

[ijpom]

Dragging up this old post because I have this scope. Mine appears to be complete except it needs an eyepiece (or a bunch of them?)

Trying to get advise on what will fit, but I'm going to use the wrong astronomical and telescope terms.  Scope will be used for my 9 yo's to see moon features, and maybe a planet if they gain an interest.

I'm thinking it's as easy as getting a couple of these:

https://www.ebay.com/itm/184725910913?hash=item2b0285b581:g:iysAAOSwObNf6Tpu

 

But not sure if my scope interface is this standard (1.25 inch), or if the scope is missing bits that would allow a standard eyepiece to work.

I'd maybe two eyepieces, at maybe 32mm and 6, because I believe that will give me a wider angle and greater magnification.

Any input welcome, but may only be understood with follow up questions.

Thanks

Edited December 22, 2021 by ijpom

[Starwatcher2001]

Hiya and welcome to SGL.

Your telescope has a focal length of 900mm and a diameter of 60. If you divide one by the other, it gives you a focal ratio of 15. (Written as f/15). That's "slow" for a telescope meaning that it doesn't provide a massive field of view, but can work well with less expensive eyepieces.

A 32mm eyepiece will give you a magnification of 900/32 = 28x  which should work well with that telescope. Assuming the 32mm has an apparent field of view (AFOV) of 55 degrees, which is typical for inexpensive Plossl style eyepieces, that will provide around 2 degrees of visible sky. If you hold a finger up at arm's length, the width is about what you'll be able to see through the telescope. You'll typically be able to see the moon taking up about a quarter of the view.

Running the same sums on a 6mm eyepiece will give you 150x.  A reasonable maximum magnification for a telescope is 50x for each inch of diameter. For your 60mm (2.4 inches) telescope, this works out at around 120x. So your 6mm e/p seems a bit too powerful. I think you'd be better with a 12mm or 9mm (giving 75x or 100x). The 50x thing is a rule of thumb. You can go higher but the image won't contain much more detail if any. You'll just get a bigger and dimmer view - so called "empty magnification".

As far as missing bits goes, I'm not quite sure what the shiny metal cylinder is on the smaller end of the scope. Does that come out if you undo the knurled screw on the top? If so, that might be an adapter of some kind (noticed it has a thread). Alternatively it might be part of an old eyepiece. I'd remove it and measure the inside diameter of the telescope tube itself. Hopefully it's 1.25 inch. If that's the case you could probably get away with inserting an eyepiece directly into the black part of the tube and securing it with that knurled screw. You'd need to point the telescope at the moon or somesuch and see if you can get focus. Having said that, you'd be better buying a 90 degree "diagonal" which goes into the tube, and into which the eyepiece fits. That way you get a much more comfortable viewing position. Otherwise it's a pain in the neck, especially looking upwards towards the zenith. 

A typical diagonal looks like this: https://www.firstlightoptics.com/diagonals/astro-essentials-90-erecting-prism-diagonal.html

If the tube measurement turns out to be 0.96 inches you'll need a converter, but let's tackle that once you know.

I spent a year or two with a similar telescope when I first started, and saw a whole bunch of good stuff.

Edited December 22, 2021 by Starwatcher2001
clarification

[ijpom]

Hi Mark,

Thanks for your full explanations in Noob-speak. That was helpful on all the topics I was questioning.

Here are the pics of eyepiece as it exists with with pertinent ID and OD measurements:

 

Once the silver (chromed plastic) piece was removed, it appears to be around this 0.96 inch measurement you mentioned. No threads, smooth bore, 2 x ribbed thumb screws. 

This means a converter (0.96 to 1.25), diagonal (1.25 to 1.25)  and then 1.25 eyepieces? Is this the best combination to standardize?

I saw an AFOV of 48 deg on some of the eyepieces. I assume that is close enough to the 55 deg mentioned. I also saw some at 68 deg - better or un-suited?

 

Looks like some sets of eyepieces could be had that would cover the ranged mentioned and provide extra pieces. Some have Barlows, some have filters.  

https://www.ebay.com/itm/192060073416

 

Here's an example of mirrored diagonal. I also see prism type. But I note they go into expensive range ($100's) very easily.

https://www.ebay.com/itm/115134764897?hash=item1ace911761:g:eKIAAOSw2zpftU2H

https://www.ebay.com/itm/115143104382?hash=item1acf10577e:g:tLEAAOSwUm5fsyV0

Maybe these two pieces would allow me to see if the rest of the telescope is functional, before buying a $100 eyepiece set?

I trust that the Plossl are sufficiently lowend enough to do the job for the quality of scope they are going in. I understand it to be a starter setup.

Anything to avoid? Can I under spend on these pieces and get a terrible image as a consequence?

 

Happy to hear that this is enough of a scope that it encouraged rather than discouraged your use.

Thanks again.

Erin