Hi Folks,
If you remember, I asked about a week ago about planetary images, ppl asked about the start test on my scope.
To refresh everyones memory, it's a 6 inch Discovery F5 EQ newt. Astro-sital primary. OK, last night we had some really steady skies and I got to do the star test. Also this morning I did a false star test on a small ball bearing I placed far away. Im not sure how to take the results, I've heard that long as intra and extra tests look the same, then the mirror must be good. I guess before I had really poor seeing conditons as I could not get decent rings on the star test. This time however, I could. Both sides of focus looked identical except one side was a bit "spikier". When the star was IN focus at high power I had the little round star with a couple faint rings around it also.
I downloaded the program "aberator" and when I type in the specifics of my scope it shows what the star test SHOULD look like. It shows more of just a brightening around the white dot as opposed to round rings. If I change the aberations to simulate spherical defects, then extra focal looks like BOTH sides of focus look for me, but it shows intra as looking differnt. I tried to photo the star test but couldn't get the camera to pick it up right. So I edited one of the samples in the Aberator to look like my test looks. Both sides of focus look just like (except add the spikey-ness thing and the follow info.} this attatched image, except for one issue...
The other issue that may explain why maybe my planetary veiws are sub-par is that when looking at the star test, I see lot's of what look like small water spots all super imposed in front of the image! It's not my eye or the eyepeices as I tried them on our little ETX90 and they are not there. If you move your eye around they move around too. Rotating the eyepeice has no effect. Could it be a rough secondary? The mirrors are clean, I tried that! Really weird!
Attached Image:
