Saturn - 17/02/2006

[iceman]

Hi guys and gals.

Here's a Saturn I took on Friday night at about 10:30pm. The seeing was good, 7/10, but transparency was poor (5/10). I had to have the gain and gamma up quite high to get an acceptable white level, and as usual the blue channel was almost glowing, resulting in a slightly soft looking image.

The one on the left is the result of the first round of processing, and the crepe ring is very visible although the overall look is softer than I would've liked. The image on the right is processed a little more (reducing gamma and a little more sharpening, plus a decreased image size) to make the image look sharper, however the crepe ring is not as visible now.

I'm happy with the width of the Cassini Division, it goes pretty much all the way around if you squint hard enough, and i'm happy with the width of the "A ring", which shows a much more natural width - captured thanks to the higher gain and gamma. I'm quite happy with the shape of the globe now too - much more round and less cut off at the intersection of the rings. Got 2 moons as well.

So unfortunately it's a trade off and I just can't seem to win with Saturn.. when the seeing has been good the transparency has been bad so I just can't capture a sharp delicate image with good banding on the globe lately.

No storm captured either, by the looks of it.

Anyway comments welcome.

[Robert_T]

Hey Mike, these are very good.:) Great colour and natural feel, yet with plenty of detail. I prefer the one on the right - it's sharper, but doesn't look over-processed in any way. I can still see the crepe ring readily enough on my screen and the full CD doesn't need squinting.

I know what you mean though, it always seems to be a juggling act with this imaging, hoping for that one moment when ALL the balls are in the air at the same time; seeing, transparency, gain versus gamma settings, with some favouring certain features and some others.

Looks to me like your winning though;)

cheers,

[h0ughy]

nice Mike very nice!

[davidpretorius]

This is one tough planet to do right (keep quiet down the back young dennis).

as you say softer than you would like, but 100% cd, great colours.

at least this planet will hang around and not shrink into nothingness like mars, so there is hope that the seeing and trans will be 8/10 or better on the same night!

[Dennis]

Hi Mike

I always like the colours on your Saturn shots. The rings and planetary bands are always well processed, along with the greenish tinged "hat" yet you manage to retain a very natural and pleasing appearance. Well done!

Cheers

Dennis

[robin]

Why 5 fps Mike?Are you able to get more detail? Nice Cassini div.Top shot

[davidpretorius]

to get that video down the usb1.1 cable to the computer, the data needs to be compressed. at 5fps, you are not pushing it as hard as say 10fps or 15fps, therefore less compression.

so if seeing is great and you think you can get 90% of 450 odd frames to be rippas, then 5fps. if the seeing is average and the image goes in and out of focus, then sacrifice compression for more frames to hopefully get a larger pool of ok images

[robin]

Thanks a lot David.That makes sense. Just another question...when i split my channels in AstraImage or even photoshop, the blue channel always looks rather shabby.Red & green good but the blue is always rough.Any clues or fixits?

[ving]

Ooo!!! rings!!! :)

nice shot mike :)

[davidpretorius]

just consulting my memories of pestering bird......... blue is a longer wavelegth from memory, so it will always be shabbier than the middle of the road green and opposite end of the scale red. nothing can be done with this colour property, bird finds it harder to focus when the blue filters are in his filter wheel.

i have found red and green to respond very well to lr devconvolution with jupiter, bird mentions even vc deconvolution for the blue channel which seems a very harsh treatment, but maybe blue needs it sometimes.

also if you have split your videos prior to registax, then when aligning and limiting, you will find the red and green will have more passing the grade.

this is the beauty of splitting prior to any processing or even better, capturing each colour separately, as each colour has its own personality.

given the same conditions, same focal length, then bird will always edge us out due to focussing, adjusting camera settings and then finally capturing on each colour. we can get halfway by splitting prior to registax or a 1/4 of the way there by splitting after registax stacking in astra image.

how much do you want to pay to have control over all the factors and then build a system that automates this???

I spose you know what it is like with your professional photography. $$ need to be spent to get that last 1-2% improvement towards that perfect shot.

[iceman]

Thanks for the comments everyone. With Saturn so low I just can't get the transparency as it's around 30° in the muck.. It's probably no accident that the best Saturn's this year have come from Brisbane with the extra 6° of altitude.