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Mouldy lenses We have an old telescopic gunsight with maker's mark Watson and Son, London near the eyepiece end, presumably from WW2. No other markings that we can find. We can see that the large lenses are mouldy inside, but cannot work out how to get the telescope apart to clean them. It seems to be made of brass, but has been painted over with black paint. Can anyone help, please? Our grandchildren would love to be able to use it. The Richardsons

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On many telescopes the front lens screws out and is removable for cleaning--- this may have been covered with paint--

Posted on Jan 11, 2009


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What does F=900mm and D=4.5 actually mean? Also the lens you look through is an H=15mm? Where can I find replacements or new lenses etc?

F900 is the focal length of your telescope. (achieves focus in 900mm) D=4.5 means you have a 4.5 inch mirror An H15mm is a Huygens 15mm eyepiece. Very old and, by now, poor design. magnification is fl of scope/ fl of eyepiece
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To get replacement eyepieces first you must measure the diameter of your focal tube. Eyepieces come in 3 sizes .965in (on cheaper scopes) 1.25in (most popular) and 2in.( mostly higher end scopes) If you have a .965in focal tube, you are limited in your choices. Antares makes some .965 plossl eyepieces also surplus shed has some inexpensive eyepieces. Or, if you want to spend the money , get a .965 to 1.25 adapter. This way you can buy 1.25in eyepieces and they will serve you well when you upgrade to a better telescope.
1.25 eyepieces are available all over the internet.

Nov 22, 2011 | Tasco Optics

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Where can I find replacement lenses for the Jupiter telescope model 60AZ-m?

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and here is another

Jul 14, 2011 | Meade 60AZ-M Jupiter Telescope 60mm...

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NEVER EVER disassemble an eyepiece --- no one can tell you how the lenses go together there are dozens of combinations and some eyepieces have as many as 6-8 glass lenses inside!

Sorry buy another eyepiece and only clean the outside surfaces.

Jan 07, 2011 | Celestron AstroMaster 114EQ (100 x 114mm)...

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How do i get the lenses attached to the telescope. neither one of them is fitting in the opening

I think you mean the eyepieces. There is more than one fitting size of eyepiece, but if you bought the telescope new, the ones supplied with it should certainly fit. There may be a little plastic plug in the opening that the eyepiece goes into, to keep out dust, and there may be a protective cap on one or both ends of the eyepieces as well. You need to remove these before fitting the eyepiece. The commonest sort of eyepiece measures 1.25 inches in outside diameter, and fits in a tube of the same inside diameter, with a little screw that you tighten by hand to hold it.

Jan 04, 2011 | Edu-Science (10166) Telescope

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I need replacement lenses for my Bushnell 78-9003. what should i get and where is the best place to purchase them from Mark

You mean an eyepiece. There are many on-line retailers. Here are two:

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My 9t eye piece was rattling and mislined. I took it apart cleaned lenses and wondered is there a lense location or direction?

Never disassemble an eyepiece unless you know exactly how to put it back together. Only the outer glass lens ever needs cleaning.

Without knowing exactly what link of eyepiece you have (they are all different designs) it's impossible to tell you which way the internal lenses go.

Your best bet may be to simply purchase another eyepiece.

Nov 07, 2009 | Tasco Astronomical 302675 Telescope

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Things are upside down looking thru the eyepiece on main telescop

If things are upside down in your telescope, you probably have a reflector has curved mirror in the sealed end.take off the cover near the finder and point in the general direction of what you want to see.Make adjustments with the stuff on the mount.If you are viewing terrestrial objects, you will need an inverting lens to correct the image.It is called a Barlow lens and is much longer than the other lenses that come with the telescope.Good Luck

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1 Answer

Misplaced lenses

You don't need to get Vivitar brand eyepieces to get replacement ones for your telescope. I'm not sure of the specifications for this particular telescope but in general they come in two barrel sizes for the eyepieces. The diameter of your eyepiece is probably 0.965" but could come in the more standard 1.25". You can measure the diameter and determine this quickly.

Once you know the diameter to shop for you can look for the focal length of the eyepiece you wish to purchase. They are rated such as 4mm, 10mm, 25mm, etc. The smaller numbers give you higher magnification. You can calculate the magnification by dividing the telescopes focal length by the eyepiece focal length. For example, let's say your telescope is has a focal length of 360mm and you have an eyepiece rated 10mm. Divide 360 by 10 and that gives you a magnification power of 36.

You can find eyepieces at many telescope dealers on the internet. Your selection will be far less if you use 0.965" eyepieces. You can purchase 0.965" to 1.25" adapters so that you can use the larger eyepieces with your telescope. However, on some telescopes the adapters will cause the new eyepiece to not come into focus.

You'll also find that eyepiece prices go all over the place. A good general purpose eyepiece is a type called the Plossl. The better eyepieces have more coatings too that allow more light to get through to your eye. You'll find these listed with terms like "fully multi-coated".

I hope this helps.

Good luck and clear skies!


Feb 11, 2009 | Vivitar (1607225) Telescope

1 Answer

40mm tasco refractor telescope.

Can you remove the eyepiece from the telescope--- if you can -- GOOD, throw it away and buy a new one on-line at these web sites--

Eyepieces come in 3 different barrel sizes-- .965, 1.25, 2 inch

Yours is probably either a .965 or 1.25 inch.

Jan 01, 2009 | Optics

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