A bit of Saturn - 09.04

[riklaunim]

Saturn f/20 RGB, LRGB, RedLum-RGB; ~22:15 UT 09.04.2012:

And comparison LRGB (bright) vs RedLumRGB (dark green): http://www.rkastrofoto.appspot.com/site_media/astro/orig/saturn-09-04-2012/anim.gif

Channels at f/20: L filter, Orange Baader longpass, Red Baader longpass, Baader IR Pass (30 ms exposure, 30 FPS; variable gain):

Baader IR pass was the darkest usable filter. ProPlanet 742 didn't gave high histogram fill at that exposure and full gain. As you can see IR pass is noisy (should be gausian blurred), while brighter channels are not - thanks to lower gain. As the wavelengths get shorted with L and Orange filters seeing also may kick in blurring some details. Also those two filters would be rather useless without a atmospheric dispersion corrector I used (for such planet altitude). 610 nm red longpass won that night giving best quality.

What's funny - L filter (IR/UV cut) will be darker than yellow and orange longpass filters (they kick out blue and add IR - which is brighter than blue).

Red Longpass 1,5x drizzled:

Is that "fog" a diffraction/airy ring of Saturn?

[neil phillips]

Saturn f/20 RGB, LRGB, RedLum-RGB; ~22:15 UT 09.04.2012:

And comparison LRGB (bright) vs RedLumRGB (dark green): http://www.rkastrofoto.appspot.com/site_media/astro/orig/saturn-09-04-2012/anim.gif

Channels at f/20: L filter, Orange Baader longpass, Red Baader longpass, Baader IR Pass (30 ms exposure, 30 FPS; variable gain):

Baader IR pass was the darkest usable filter. ProPlanet 742 didn't gave high histogram fill at that exposure and full gain. As you can see IR pass is noisy (should be gausian blurred), while brighter channels are not - thanks to lower gain. As the wavelengths get shorted with L and Orange filters seeing also may kick in blurring some details. Also those two filters would be rather useless without a atmospheric dispersion corrector I used (for such planet altitude). 610 nm red longpass won that night giving best quality.

What's funny - L filter (IR/UV cut) will be darker than yellow and orange longpass filters (they kick out blue and add IR - which is brighter than blue).

Red Longpass 1,5x drizzled:

Is that "fog" a diffraction/airy ring of Saturn?

That doesnt look right at all, even under poor seeing i havent had seperation like that, i have on mars occassionally at really high powers, that almost looks like mis collimation. But i assume thats not the case. you sure you nailed focus, or scope was cooled enough ?

[riklaunim]

It was collimated before imaging, and if it was uncooled the image would be very poor.

[neil phillips]

What ever way you look at it, its a optical or seeing problem, that is not a real ring of saturn, as such it shouldnt be there. its also on the back of the rings and on the the top of the planet, i suspect its a seeing problem. like the edge you have on venus, im not sure ? looks to me like its on the other images but is being hidden by the darker background seeing doesnt look great as can be seen by the straight RGB, its likely that

[AztecastroMcJ]

Nice results and write up Piotr

could the ADC corrector have caused that effect ?

also where did u buy corrector from ?

James

[riklaunim]

I got it from ASH Untitled Document - it's not a new addition to the imaging setup.

[AztecastroMcJ]

ah ok thx for link,

[AztecastroMcJ]

heres site i found with regards to dispersion

http://www.astrosurf.com/prostjp/Dispersion_en.html

def going on my evergrowing accessory list