First scope, fuzzy/blurry stars and disapointed

[Hatan]

I just got my first scope. Ok this is not the best top notch scope. I bought it to a specialized store for 200$. This is a refractor 80mm with focal of 910 mm.

On top of that I'm in a very light polluated city. With my eye I could maybe see magnitude 2-3 at max tonight. So Ok, I'm not in the best case.. but still.

So I wanna try this new toy. I start looking at stars with a 25 mm (36 power). Ok I see light point in the sky, but actually what I see is just a fuzzy blurry spot of light. Kinda far away of a perfect circle of light. Kinda hard to explain the actual image but I thought that I could see a point of light or a star-like light. What I actually see is triangle of light or something like that. Like if I was far away than being focuses but actually I am. I also tried with 10mm and barlow blabla but this is even worst.

So I decided to look the far building to check if it works. From power 36 to 72 I see no problem, images are crisp. with my 10mm it is still good but it starts to blur a little bit (power 90). With barlow up to 180x the image is starting to be blurry.

Any idea why I cannot see stars correctly, is it because of the light pollution, or the small aperture scope, or bad quality or that is just normal?

Thanks

[cjl]

Well, it definitely isn't normal. With our scope (admittedly a 10" reflector), we have no problems resolving stars to a point, regardless of the light pollution. It should not be dependent on scope size though. With my old 3" newtonian, I could also resolve them to points (and I live between Boulder and Denver, arguably one of the worst possible areas for light pollution). I know this may sound stupid, but you did try to focus it, right? It sounds like a focus problem to me.

[njnightsky]

You may try and upgrade your eyepieces. You can pick up a couple Plossls pretty cheap.

[Dave Mitsky]

If there is a black hole in the center, the image is not completely focused. The triangular shape may indicate astigmatism.

A blurred image could be due to bad "seeing" (atmospheric turbulence), insufficient athermalization (cool down) time (which can even occur even with refractors), or the telescope being out of collimation.

Dave Mitsky

[aurora]

In addition to what Dave said, it might be pinched optics. In a refractor, it is possible for the lens to be held too tightly in the scope which could slightly deform the glass.

If you cool it down, and you never can get it to focus on a star, then I would suggest returning it for repair or refund.

[Dave Mitsky]

Yes, one common result of pinched optics is, in fact, astigmatism.

http://www.scopecity.com/OpticalAberrations.cfm

http://www.skywatchertelescope.net/EducationST.html

Dave Mitsky

[Crum]

If you observed the distant buildings critically and they seemed sharp and undistorted to you, I would guess it's a thermal equilibrium problem, as already mentioned. Taking even a refractor from warm indoors to the cold night air is going to result in thermal currents running inside the refractor tube. If you have not already done so, try leaving the scope outside for an hour before you begin observing and see if the results are any better.

Yes, an hour is much longer than small refractor is likely to need, but it won't hurt to go overboard just to be sure.

[Hatan]

actually, I forgot to mention that I was indoor when I did my first look (it's cold here did not want to get out ;). So I called my vendor and he said that was 90% sure that this was the problem. I'll check again tonight outside (looks to be a good night) and I'll check if it does the same thing.

Thanks for your answer

[aurora]

actually, I forgot to mention that I was indoor when I did my first look (it's cold here did not want to get out ;). So I called my vendor and he said that was 90% sure that this was the problem. I'll check again tonight outside (looks to be a good night) and I'll check if it does the same thing.

Thanks for your answer

Umm, yes.

Do not observe through a window, whether the window is open or closed. If closed, the glass makes the seeing worse. If open, air currents will make the seeing worse.

[redshifter]

Also, the atmosphere on a given night may not show very crisp stars at higher magnifications regardless of the quality of the scope. If the seeing (a measure of the stability of the air) is bad and/or the transparancy (a measure of how clear the air is) is bad, objects will get blurry/fuzzy/distorted at higher powers. And as others have said, looking through a warm house and glass window will most definitly make a mess of things.

A good way to determine how good the seeing is on a given night is to look at brighter stars with your naked eye, the more they twinkle, the worse the seeing.

[cjl]

Also, the seeing will always be worse on stars that are close to the horizon than stars that are close to the zenith. Try starting with stars that are close to the zenith to test your scope, as they will always be slightly sharper and clearer.

[aurora]

Also, the seeing will always be worse on stars that are close to the horizon than stars that are close to the zenith. Try starting with stars that are close to the zenith to test your scope, as they will always be slightly sharper and clearer.

If you are in a reasonably high northern latitude, try polaris since it will pretty much stay in one place and won't drift out of the field of view.

Try focusing back and forth and see if the star will "snap" into focus, or if it kind of "mushes" through focus (which could be poor optics or bad seeing), or if it never comes to focus at all (which is what was originally described, and is a problem).