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Started by imgary, 06/27/2005 12:51PM
Posted 06/27/2005 12:51PM | Edited 06/27/2005 12:53PM Opening Post
I wonder if what I see through my 102 Orion StarMax Mak is normal. I bought this awhile back and I like it because it's portable. It seems to have good views except for one thing, ring around the planet. It's a ring of fuzz and its on everything. The star test reveals a very nice airy disk with one faint ring during times of good seeing. There is a ring of fuzzy light around all objects including the planets. Looking at the scopes mirrors, I see no dust nor anything else that might cause this. The sky background is very black. It's not the EP's cause I've tried several. The edges "can't think of the proper word for this" of planets are fuzzy while the center of the disc reveals good detail. With my 4.5 inch Orion XT along side, the 102 looks very sick. Any Ideas would be helpful. BTW, the collimation appears to be as dead on as would be attainable and like I mentioned, it has a very nice airy disk. No other problems have been noted, just seems the images are "soft" and not as I would expect. Thanks for reading this and for your input....
Posted 06/27/2005 01:16PM #1
Posted 06/27/2005 02:02PM #2
If the ring of fuzz seems to disappear or lessen on one side of focus and get worse on the other side of focus, then you have a classic case of turned edge on the mirror. Quite common on a machine polished optic.

Roland Christen
Posted 07/05/2005 12:29PM #3
One thing you might check is the polish of the secondary. If the secondary mirror is not fully polished out, and there are lots of pits left over, this would indeed cause a glow or fuzz to be seen around bright objects. This assumes you don't have a turned edge. You would need to remove the corrector to examine the secondary suface.

Turned edge can be easily tested for by masking 1/4" to 1/2" all the way around the outer diameter of the aperture. If the fuzz is still the same, then the edge is not at fault. If it goes away, then you have a turned edge.

RC
Posted 07/07/2005 08:22PM | Edited 07/07/2005 08:24PM #4
Sad to say but Roland is right. It has a turned down edge. It must be pretty bad too. I made a mask and attached it to the very front of the scope. All gone now ! And I'm left with about 80mm of aperture. Thats not all, in the star test it was observed that the first defraction ring was far placed from the airy disk but with the mask in place its no longer there "at least as far as I can tell." Ok, so now what ? Fixable or lost cause ? My luck, and one would think I would learn to stop buying problems from others huh ? K+ to you Roland.....And all who had good ideas, thanks..
Posted 07/15/2005 01:51PM #5
My experience with Orion is that they bend over backwards to satisfy their customers (as does every astro dealer I've done business with on this site). If I were you I'd give them a call and see if they will exchange the scope, even if you have had it a long time.

BTW, I've owned two 127 Maks and both had great optics. The first one was stolen and I just got the replacement. The new one is just as good as the first one. No mirror shift, perfect collimation, and a very good optics. One of the members of our club who knows 1000 times more about optics than I do told me that star images can't get better than the little Mak's.

Anyway, I bet your mirror isn't typical and they will work with you on fixing the problem.

Tom B.