Orion ShortTube80 owners, star test at high magnification

[ebeygin]

Hello,

A lot of people use the ST80 as their guide scope, or a wide field grab-and-go. 

I recently purchased one, and after doing star tests at extremely high magnifications, trying to determine, if I'm super picky, or my scope has a flaw in it.

With 20mm/9mm (20 - 44x), the bright stars look pretty good, although I wouldn't say they are 100% pinpoint (maybe that's just chromatic abbr).

With 2.3mm (176x), bright stars initially had a comet diffraction pattern like this:

 

I corrected that by unscrewing the lens cap, and tapping on the sides of the tube while slowly tightening the cap back. This fixed the comet issue, but now, the stars look like this:

If I tighten the cap a bit, I get the comet pattern back.

 

How does this compare with your scopes? I can't get a pin point star at high mag. Am I really picky, since this is a chromatic $100 scope (although people praise it for its high quality)

Should this type of scope display perfect pin point stars when using high mag eyepieces? I really don't want to waste time sending this back, if it ends up me being picky, and I get back the same or worse optics.

Thanks!