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Skywatcher 200p dobisonian outside glass smudge

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Hi, I got a skywatcher skyliner 200p dobisonian a few days ago, my first observing session was out in the cold and the telescope dewed up when I bought it back in. I then noticed that the glass on the base of the telescope(not the primary mirror inside) was smudged and had a little ring shaped scratch on it. I tried cleaning with a lense cloth but it is still slightly dcratched and smudged. Does anyone know if this makes a difference to the inside primary mirror?

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If you mean the base of the mirror cell this will not affect the mirror side.

A photo would help to give you advice.


Just let the telescope dry out on its own after dewing up , this is usually better than trying to wipe it off.

The 200p is a very nice scope , I used to have one and you will get to see plenty interesting targets with it.



Once you have had it a while and got used to it, I would upgrade from the supplied eyepieces , BST starguiders and Celestron X-Cel eyepieces are very good upgrades and not as expensive as the elite brands , and can often be found used on the forum for sale in good condition.

They will give a nice boost to the quality of the image.

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Nothing to worry about there.

You don't need to clean the base of the cell , its there purely to hold the mirror surface on the other side.




The 2 sets of screws around the base ring are the collimation screws.

It is worth collimating your telescope, I suggest you take a look at uTube videos first.


I used a collimation laser on my 200p (and still use it on my CT10L) , I bought mine used on here or was it ABS the other reliable place for used astronomy bits.

You can get one on the usual auction site , but if you do that check the collimation of the laser before you use it on the telescope , again uTube explains how to to this.

Checking the laser , and collimating the telescope are both very easy.

I could collimate my 200p in about 5 minutes. I found it did need doing fairly often , but its not a big problem just to check it now and again.


There are other ways to check collimation without a laser , look on uTube .

Edited by fifeskies
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