Saturn September 23

cometcatcher (Kevin) · #1 23-09-2018, 10:39 PM

Not my first Saturn but first RGB Saturn with the ASI 183mm Pro. Seeing was meh, could have been better so there's room for improvement yet. Doesn't have that silky smooth sharpness to it.

Telescope was a Meade LX90 ACF 8" F10 SCT, Camera ZWO ASI183mm Pro, RGB 700/700/700, captured in Sharpcap, aligned in PIPP, stacked In registax and processed in Photoshop. Probably need more frames but I couldn't go faster than 12fps, and even that was with the gain up.

Mickoid (Michael) · #2 24-09-2018, 12:55 AM

Good job Kevin. Those planets are shrinking and fading now so you've done well to capture Saturn so nicely. With the days getting longer and nights shorter, it doesn't give you much time to shoot the planets at reasonable altitude. Mars is still quite high but is also small which means more magnification which equals larger f ratios so longer exposures or more gain/iso to achieve a useable image. Never mind, it's still giving you the opportunity to practice with your RGB filters and it looks like you're getting the hang of it very quickly.

cometcatcher (Kevin) · #3 24-09-2018, 01:58 AM

Thanks Michael. Mars is in the too hard basket at the moment. Saturn is directly overhead here but seeing is not steady. Still, I need the practice to squeeze out as much as I can from what I've got.

doppler (Rick) · #4 24-09-2018, 08:03 AM

That's a very respectable Saturn. Keeping the frame rate up is hard when imaging smaller objects even when they look bright in the eyepiece. It's a pity with mars moving away and shrinking in apparent size, the dust storm is clearing nicely.

Forge · #5 24-09-2018, 09:49 AM

Wow, I've never been able to capture the reddish tinge on Saturn that you have there.

What kind of processing did you do in Photoshop for this image?

sil (Steve) · #6 24-09-2018, 11:30 AM

Beautiful saturn there.

Why limited to 12fps? I'd thought the 183 was much faster. are you shooting at its full resolution (which will limit you to slow fps) or a cropped smaller resolution (where it'll run considerably faster). btw recording to a HDD will also limit recording speed, a SSD will open the throttle for you as a recording destination. I suspect you can get much more fps with your setup and thus more detail with your planets. I use a 178 and get about 20fps i think at full resolution, but when i limit to a small res ROI I get over 150fps and get over 20,000 frames to process regularly for a 2-3min capture.

cometcatcher (Kevin) · #7 24-09-2018, 12:17 PM

Quote:

Originally Posted by doppler

That's a very respectable Saturn. Keeping the frame rate up is hard when imaging smaller objects even when they look bright in the eyepiece. It's a pity with mars moving away and shrinking in apparent size, the dust storm is clearing nicely.

Yes Mars is smaller but brighter. I am starting to see surface features where it was covered in dust before.

Quote:

Originally Posted by Forge

Wow, I've never been able to capture the reddish tinge on Saturn that you have there.

What kind of processing did you do in Photoshop for this image?

Most of the photoshop processing was with unsharp masks. I didn't use wavelets in Registax as I've found Photoshop to be very similar in outcome. The colour seemed to come more or less naturally.

Quote:

Originally Posted by sil

Beautiful saturn there.

Why limited to 12fps? I'd thought the 183 was much faster. are you shooting at its full resolution (which will limit you to slow fps) or a cropped smaller resolution (where it'll run considerably faster). btw recording to a HDD will also limit recording speed, a SSD will open the throttle for you as a recording destination. I suspect you can get much more fps with your setup and thus more detail with your planets. I use a 178 and get about 20fps i think at full resolution, but when i limit to a small res ROI I get over 150fps and get over 20,000 frames to process regularly for a 2-3min capture.

I managed to get 70fps with Mars, but could only manage 12 with Saturn. I thought this was a bit low too. I'm using ROI at the lowest resolution 320x240 so it can't be data lag. I'm also using USB2 and a SATA drive, not SSD, but again at 320x240 it shouldn't need it. Maybe the 183 is just slower than the 224, 178 or 290? Sharpcap settings maybe?