a quickie on SATURN - Mar 11th NO ONIONS

[Robert_T]

Clouds parted this evening after afternoon rain. Seeing again a bit ordinary but could be worse, say 5/10, lots of detail coming in and out of focus but basic planet shape fairly stable.

Got a couple of AVi's off. The first I'm pretty happy with, reasonably sharp and all that. Taken with the 2.5x powermate. The second is with the 4x powermate, but the conditions just weren't quite good enough to support it hence the relatively grainy apearance.

One thing I did this time was drop brightness down below 50% and really cranked up the gain to 60-70% and Gamma 50-60%. NO Onion rings. The lessen I've taken out of this is it's not under-exposure (as the light meter is still reading the same ~180), rather the gain and or gamma's contribution to the exposure is more important than brightness.

cheers,

[asimov]

Did I hear some one yell 'NO ONIONS!' ???????

Ah yes...I thought it must have been you Robert!?

Mate, great shots!:eyepop: Even the 4X looks good to me.

Ok, so heaps of gain & gamma does the trick for the onions...& less than 50% brightness kills the centre burnout!? How much lower than 50% brightness did U go exactly Rob?

[davidpretorius]

who's being a little experimenter now??? top findings!!

that 2.5x is very very good, and thanks for posting the 4x. Did you increase the brightness / gamma / gain with the 4x to compensate for the extra mag???

how did the cassini division look thru the ep??

last question, do you have a feel for the collimation.

and a final request, with the 4x, what is the result of the best 100 frames look like with say a histo stretch at stacking time??

these are great!

[Dennis]

Hi Robert

Those are very nice images; you managed to get some good captures in spite of the mediocre seeing. Thanks also for the details on your experiments - very useful stuff to be tried next time I am out.

Got the gear out last night but clouds kept rolling in and then the heavens opened up on me so the covers went on. Managed to grab one Saturn avi but doesn't look too promising.

Harrumph….imaging in Qld’s wet season – oh well, I'm sure she’ll be right later.

Cheers

Dennis

[Robert_T]

Thanks Guys,

Dennis us northsiders must have copped out lumps earlier - last shower here around 5pm then not again till after midnight... I'm learning to be agile with these conditions;)



Asi - i had it around 30% for the 2.5x shot and 50% for the 4x.



Yeh Dave with the 4x I had to have gain up to 80%, brightness at 50% and gamma around 60-70% to get sufficient exposure... you can imagine the grain!

Cassini division was clear and most of the way round but coming in an out with the seeing.

Collimation I checked just prior to imaging. It's pretty close. It may not be absolutely perfect, but it was as close as could be achieved with the quality of the seeing.

I can give the 100 frames a try, but the killer is grain. Even with 1200 frames it's still there. With 100 it would be very noticable.

cheers,

[davidpretorius]

thanks.

it was more the cassinni division, i stacked 77 frames the other day and the cd was 100% or as close as i have been

[[1ponders]]

Onya Robert. I like the colour balancing you've gotten in that first shot. :thumbsup:


Glad to seem someone is getting out around here. :(

Still the absolute pits here. Nothing but 15 minute sucker holes between 15 min "half a dozen spits, hardly enough to wet a tally ho" showers.

[asimov]

Permission to play with your images Robert. ?

[janoskiss]

Nice Saturn, Rob! :) But Jupiter is the onion-ring planet. ;)

[Robert_T]

go for your life Asi!

[asimov]

Cheers :thumbsup:

Ok, your originals..my mucked with versions side by side.

Again, you've done great on the processing! All I could do to make them any better (to my eye) was to bump the gamma a tad on a couple of channels & a bit of grain killing & sharpening in neatimage.

I love playing with your images, there so easy to work with! :)

Well done again on some nice captures! :D

[iceman]

Nice job Asi and Rob!
Great C ring capture.

[Robert_T]

Thanks Asi, you're images look much better just in the thumbnails alone. Did you bump the gamma Up or Down, they look brighter. I'm beginning to think I need a new post processsing program like Neatimage or Photoshop. The ones I'm working with are a little limited ("cheap";) ).

cheers,

[asimov]

Up on blue & red channels Rob. Yeah, Neatimage does ok for taking a bit of grain out. I'd love to try photoshop one of these days, my proggy (pic. publisher) is a bit limited also...(free with an el-cheapo scanner I bought)

[ving]

nice ones rabert and asi :)

[Robert_T]

I should have done an Astra Image deconvolution on these straight away, but was pressed for time. When I did do this today to my originals they come up much like Asi's reprocessed - see below.

On the left is another 2.5x powermate view, but this time with 4 iterations of LR deconvolution at 1.5 curve radius in Astra Image 2. The one on the right is the 4x powermate one with an ME deconvolution run on it and an unsharp mask and a median 3 x 3.

cheers,