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The mirror on my telescope has been taken off and put back on will it need te be re-set

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The mirror will need to be collimated. Do google search for 'reflector telescope collimation', you'll get a bunch of links.

Posted on Jul 22, 2009

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My son completely disassembeled all the parts and lenses of his microscope. how can i find out how to correctly put it all back together?

The image is of a telescope. This type of scope has only one optical part in the tube, a mirror on the end opposite the focuser end. The smaller tube just goes in to the focuser and it uses a small screw to hold it in place. If the lenses are truly taken apart then there may still be hope as most critical optics are glued together with crystal clear glue.Clean them and reassemble.

Dec 23, 2014 | Optics

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How to use the 40-114675 telescope,ive got it set up but carnt see anything. It came with a black circular card in the lens which i have taken out.How do i see anything? is card ment to be in or out thanks...

Light enters the front of the tube -- TAKE the lens cap off-- goes down to the bottom of the scope and its the primary mirror--- then bounces back up and hits the tiled secondary mirror which sends it OUT to the side into the focuser and the eyepiece. The largest the number on the eyepiece the LOWER the magnification. Start with your lowest magnification until you learn how you focus. Try this during the day time on a distant building or telephone pole.

Aug 25, 2011 | Tasco Luminova 40114675 (675 x 114mm)...

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My boy put coins in the eyepiece receptable and damaged or dislodged the mirror. Can this be fixed?

Yes there are two mirrors-- the small secondary underneath the focuser and the large primary-- on the bottom.

You can remove the entire secondary "spider" and then glue the secondary back on using epoxy or silicon.

Then put it back in an collimate the scope. If the primary mirror is damaged then it is not worth repairing.

Jul 14, 2011 | Celestron AstroMaster 114EQ (100 x 114mm)...

1 Answer

Hi i have aseben900mmreflector scpe that is 2yrs old had a dent put in tube that was pushed out then the person put back together and i bought it 1st time into this so how do i align the lower mirrior...

This is called "collimation" and is a complex process. You will find many guides to doing this on the internet if you search for "telescope collimation". There is not much point in me repeating the information here- find several of these how-to articles on the net and read them all to get a good idea of what is required.

Unfortunately, Seben telescopes (at least the ones I am familiar with) don't have a simple secondary mirror, but a more elaborate arrangement with a cell containing a diverging lens (similar to a Barlow lens) as well as the diagonal mirror. This allows them to use a much shorter tube for the telescope while retaining a longer effective focal length, but it makes it more fiddly to collimate.

It may be that the secondary cell does not require adjustment, and you can just adjust the primary mirror.

Jan 18, 2011 | Optics

1 Answer

I have an older ETX Astro Telescope or ETX spotting scope. A small rectangular mirror has come loose in the main body of the telescope. It appears undamaged. Is there a manual that shows me how to place...

This is a known issue with the older ETX scopes. You can use silicon sealant or a small amount of hot glue -- and just put the mirror back on it's small platform.

However you might need to disassemble the rear of the scope to do this. See this web site for instructions on disassembly.

Sep 08, 2010 | Meade Optics

1 Answer

Is it possible to remove mirror for cleaning if yes what is best thing to use

Yes you can remove the mirror and clean it-

Here are cleaning instructions:

and you will need to collimate the scope, after you put the mirror back in:

Watch the above web sites for instructions-

Apr 10, 2010 | Tasco Galaxsee® 46-114500 (500 x 114mm)...

1 Answer

On the back of the optical tube where the mirror is, there is a peice of what seems to be a felt material. It has dislodged itself from the center and I was wondering if I can put it back in place without...

The felt is used as a cushion to prevent marring of the mirror and to give protection during temperature changes (the mirror cell and glass expand at differing rates) You may need to re-collimate the mirror after that.

Aug 19, 2009 | Meade DS-2114 ATS (325 x 114mm) Telescope

1 Answer

Rear mirror

I may be telling you something you already know, but just in case.

If your telescope is a newtonian/dobsonian (i.e., long, large tube) then the mirror in the bottom can be adjusted to collimate or align properly.

On the other hand, if the top of the telescope has glass over it (refractor telescope) then putting it back into place will be more labor intensive and I wouldnt even try it. Try going to the manufacturers website and asking them. You might post the same question on a telescope forum called If you live in a large city, try searching for local astronomy clubs as every astronomy club has some guy there who takes these things apart for no reason just to put them back together.

Dec 30, 2008 | Tasco 578x60mm Reflector Luminova...

1 Answer

We have focused the telescope on an object - but it appears that the mirror is in the center of the view

If your telescope is like the one in the picture it is a refractor telescope. It does not have mirrors-- the diagonal in the rear of the telescope has a mirror. Put the lowest magnification eyepiece in the telescope-- the one with the LARGEST number-- and try again. This may be easier to learn in the day time on a distant object.

Dec 26, 2008 | Edu-Science (10166) Telescope

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