The Stars Have Wings!

I’m posting this several places, because I’m baffled. I took my 9.25” Evolution out this evening to ensure it still works and I still know how to run it. Everything worked fine, but I had a problem that I could not solve.

The stars looked like they had wings. It was like diffraction spikes, but I could only see two spikes, not four. No matter what eyepiece, or how much I tried to focus, I could not get sharp dots for stars without the wings

Does anyone know what is causing that? Hardware? Atmosphere/wind? Eyesight?

Wings show an out-of-collimation scope.

Ahah! Thanks, Russ! I suspected that, but wasn’t sure. Now I just have to figure out how to collimate it…

Haha. :grinning: :rofl: The diagnosis was the easy part.

Could poor collimation also cause poor alignment? The targets were in the finderscope, but often not the eyepiece. (even at 40mm).

Here is a good “how-to” on SCT collimation:


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If the main scope is waaayyy out of collimation, misalignment with the finderscope might be possible.

But, in my experience, it doesn’t take much to knock a finderscope out of alignment with the main instrument. With my C8, for example, just taking the telegizmo cover on or off the rig knocks the finderscope out of alignment. Even though my rig is left set up in my backyard under a telegizmo cover, as part of my start-up ritual, I always realign the finderscope with the main tube.

Thanks, Brad!

Sorry, Russ, poor description on my part. The finderscope wasn’t misaligned, it was the scope that didn’t center the object after alignment. I would go to an object and it was in the finderscope, but not the eyepiece. I then had to adjust it to get it in the FOV of the scope. The alignment wasn’t far off, but it was off enough it wouldn’t appear in the FOV. Lining it up in the finderscope got it near the center in the eyepiece.

Oh well. I’ll collimate it soon and we’ll see if the alignment improves.

Thanks, guys!


Now you have piqued my curiosity. Unless the 9.25" scope has some sort of built-in fixed findescope, you need to center an object in the main scope and then adjust your finderscope until the object is centered in the finderscope. After that, whatever is centered in the finderscope will be centered in the main scope. The finderscope and main scope need to be in alignment with each other.

P.S. Disregard above. I missed your last line saying centering in finderscope got object into main scope field of view.

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I bet @DaveNH6SM could fix it for you. He has all kinds of collimation stuff, I think.


Having re-read your posts, it sounds like a go-to accuracy issue. Lots of possibilities for error there.

I’m not familiar with the specific alignment and go-to operation of your particular scope, but would suggest the following as a workaround in the meantime. It’s worked for me on several different types of mounts.

When trying find a particular object (usually faint), do a go-to to a nearby bright star first. Once there, center the bright star in the main scope field of view. Then, do a sync (or whatever your mount calls it). Then, do a go-to to the desired object. Synching on an object near your target will increase your pointing accuracy in that part of the sky (usually).

Oh, probaly best to do final centering before sync with eyepiece in 12-24 mm range.

Thanks Russ! If it’s still off after collimation, I’ll try all that.