[freespace]

Originally Posted by rmcpb

When I first started reading this I immediately thought "collimation" then found its a refractor and the "diffraction spikes" change with eye position. If these spikes move when you rotate an eyepiece then suspect the eyepiece, if they move as you rotate your head around the optical axis then suspect your eyes. It may be that you have a mild form of astigmatism in your eyes?? Wouldn't hurt to have it checked out with an optometrist.

I might. When I got radiotherapy as conditioning for my transplant they did warn me something about my eyes... I will get it checked, thanks.

Originally Posted by Dennis

I see you have a UO 5mm and I would have expected this to perform quite well on Jupiter? Did you view Jupiter when the planet was above, say 60 degrees altitude (above the horizon)? When low down in the skies, the Moon and planets tend to produce views such as you described due to atmospheric distortion.

Thats what I thought as well. However Jupiter was fairly flow in the sky, and sydney is apparently suffering from a jetstream at the moment.

Traditionally, a refractor "should" produce point like images with concentric diffraction rings when the star is slightly inside or outside of focus. The description of seeing little tails > may indicate some problems, as does the vertical line?

Perhaps, It might be just something on the diagonal too, I will test it tonight. The bintel plossl just in and just out of focus gives these "spikes" too, but they are more symmetric and they also change as I move my eyes.

It could just be I have doggy eyes I am extremely short sighted, and have fairly thick glasses. I normally take my glasses off when I look through the EP, as I can get closer, but it might also be having certain optical effects I am no familar with. This does not seem to be a problem with the 5mm UO when I focused on the Jewel Box nebula, however stars had sort of a fuzzy halo around them.

Thank you very much for your help Dennis, it was very informative :-)

Cheers,
Steve