Hi Isis One

if your scope is 16" you either own the DS-2114S or DS-2130S. It's a so called "Short Tube".
Mirror 114mm or 130mm, focal length 1000mm.

Actually the focal lenght of the mirror is about 500mm and is doubled by a barlow element in the focusser.
These kind of scopes have some flaws: Because of the barlow-lens some chromatic aberation (colored borders around bright objects) and (because of the spherical mirror they use) at the margins in the eyepiece image some spherical aberation (distorted stars). For the diameter/focal length ratio the manufacturer should use parabolic mirrors, but spherical mirrors are cheaper.

The two eyepieces (25mm and 9mm) give you a magnification of 40x and 111x. At least the 25mm should produce a quite good image. If not make this test:

Point the scope to a bright star, center it in the eyepiece and keep it centered.
De-focus until the now blurred star fills 1/3 of the eyepiece image.
Is the shadow of the secondary mirror (the black dot within the blurred star) exact in the middle of the blurred star?
If not, you have to collimate the mirrors of your scope. The instructions should be in the manual or the CD. If it isn't, PM me - I'll try to find the instructions for you.

I assume you also have the Autostar.
It works best, when you exact level the tripod (bubble level), level the tube and point it to north.
The better you do it, the better the Autostar works.
Use the "Two star alignment" with stars you know (If it gives you a star you don't know, you can skip it)

If you have more questions, please PM me ( won't derail the thread).


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