Posts Made By: Oliver Pettenpaul

Hi Ed,

really impressive what you squeeze out of the 8" @ f/60 even at below average seeing conditions. Nice clean processing & colors. Thanks for sharing

Cheers & clear skies,
Oliver

Hi Kim,

there have been alerts of orographic clouds over Arsia Mons. The clouds are visible on various images (e.g. Damian Peach, Christophe Pellier amongst others). Ed's excellent image shows these clouds very well I guess.

Clear skies!
Oliver

Hi Jan,

oh, a new scope - now I know where all the cloud come from
Welcome to the C.925 club and congratulations to the very fine fistlight - great job!

Clear skies & best regards,
Oliver

Hi Robert,

one of the best images I have seen so far in the very young Saturn-season. I observed the lord of the rings visually yesterday morning through some trees - nice to see the low angle of the rings and the polar cap so well in your image.

Clear skies!
Oliver

Hi Richard,

what an excellent capture Your processing is beautifull. Looks like you had some nice seeing over there - I didn't had much luck with seeing lately

Best regards & clear skies,
Oliver

Hi Alan,

excellent capture & excellent processing. What a fine level of detail 8)

Cheers, Oliver - ’scuse me while I kiss the sky...

Hi Anthony,

great to see your new DF-express performing so well. Considering the conditions the image came out crisp and clear. Hope you have some good seeing soon so that the camera can stretch it's muscles.
How many frames did you stack for each color channel ?

Best regards,
Oliver

Hi Richard,

again an outstanding image from your roof-observatory 8O
Can you throw some of that good seeing over the border ?

The ATK-HS2 you use has a Sony ICX424AL CCD, did you had a chance to compare it to
an ICX098BL equiped camera (ATK-HS1 II), Philips ToUcam or similar ?

Groetjes,
Oliver

Hi Ed,

a very good image considering the seeing, good processing. Multiple alignments work wonder for captures taken under suboptimal seeing

Cheers & clear skies!
Oliver

Hi Anthony,

well, I fight this effect on all my mars image this opposition. I guess it's caused by the "triple edge effect" at the hard sunlit rim showing the edge inside and outside the real edge again. I can even observe this 'overshooting' visually so it's not a pure photographic phenomena. The best explanation I heared so far are turbulences in the lower atmosphere. It's been observed at all planets with a distinctive phase - mars, mercury, venus. Of course all sharpening processings enhance the edge.
According to my experience the effect can be more dramatic in better seeing when the overshooting at the edge is smaller and the contrast of the ghost edge is harder defined, in bad seeing with a wide overshooting the contrast is lower.
I took a look at your images again and the hard inside edge and the ghost edge outside are visible but not really that dramatic compared to other images.
Alan Friedman proposed a processing variant some time ago to minimize the enhancement during processing/sharpening - I guess it can't be avoided at all if it's already present in the raw frames. IIRC he uses a layer mask or selective processing to sharpen only the inside of the planet's disk and to avoid sharpening the edge. I tried this on one of my hard edge images, selected the planet and applied some "feather" to the selection to have it fade out towards the edge and applied the sharpening only to the selection. It helped a bit but wasn't that sucecssfull - I guess the effect was too strong in my source image. I also tried to select a reference frame in Registax without the effect visible and use a harsh difference-cutoff to use only similar frames but that's not been too succcessfull either.
I've seen some people removing the hard edge in the final image (inside and outside) but I don't like this kind "repainting" the original image. The phenomena can be seen on many excellent images e.g. Damian Peach's stunning captures so I think it's not a shame to have it in an image.

Best edgeless regards,
Oliver