I bought an amateur(and rather cheap) refracting telescope and while I can see moon quite clear and crispy I am having difficulties in observing some larger stars.

All stars appear as lines rather than dots. It is always one longer line. I read something about those lines but this stands only for reflecting telescopes that have some kind of structure inside that holds a mirror and this structure interfers thus producing these lines. But I don't have a reflecting telescope, mine is refracting.

I cannot seem to find anything on google regarding this. Maybe it is because I lack the vocabulary.

EDIT #1:

This is the telescope I have.

Edit #2:

This is my depiction of what I see. Forgive my MS pain skills. As I focus out(or in, not quite familliar with the naming) it goes more clearer and clearer but I never get to see a simple shiny dot. The closes to dot is the first image but this is so blurry that I barely see it. The red line is the one I perceive as the clearest. The orange lines is what I perceive as "outline" and the yellow inside is that shiny effect one usually gets when looking at objects that emmit light.

enter image description here

  • $\begingroup$ When you look at objects on land, do they appear the right way up, and not inverted left to right? $\endgroup$
    – Dr Chuck
    Mar 20, 2019 at 8:40
  • $\begingroup$ I haven't noticed if they are inverted. If I look on on land than the image is upside down. $\endgroup$
    – Robert
    Mar 20, 2019 at 8:53
  • $\begingroup$ Ok, my potential explanation isn’t valid. $\endgroup$
    – Dr Chuck
    Mar 20, 2019 at 14:06
  • $\begingroup$ If line changes direction when you adjust the focus, it might be astigmatism. $\endgroup$
    – Mike G
    Mar 20, 2019 at 14:37
  • 3
    $\begingroup$ All eyepieces or just one? If all, then main objective may be slightly tilted. Take it out and put it back in carefully. Only 1 eyepiece?, then take it apart, if possible, and reassemble. Eyepieces can be tricky. I've seen some glued together so taking apart without wrecking it is impossible. $\endgroup$ Mar 20, 2019 at 15:55

1 Answer 1


First off I want to say I am a complete amateur when it comes to stars and even bigger when it comes to optics.

I was looking at sky from indoors and my windows have double glass. It turns out that this was the problem or maybe the glass on the window is not some good quality.

In any case, all works well now and I am thrilled at what I'm seeing in the night sky.

  • $\begingroup$ Congratulations and have fun! $\endgroup$
    – uhoh
    Mar 23, 2019 at 23:59
  • $\begingroup$ Thanks for the update, glad you solved it. $\endgroup$
    – Mike G
    Mar 24, 2019 at 5:31

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