First attempts with ASI MC120 sensor

[Sebbie]

Hi everyone,

Here's some of my first tries at planetary imaging with ZWO ASI colour camera and FireCapture software. I have finally set aside some time to go through Saturn clips from early late April (taken at F30) and February (at F16).

North polar region shows characteristic hexagonal storm and hints of central polar vortex in the high power image. Number of smaller gaps are also visible in A and B rings. I think my exposure settings were touch too low resulting in high overall noise levels / stacking artefacts.. Taken with TeleVue 3x Barlow the image shows Saturn one hour before meridian transit, 12:36am LT. Non drizzle stack of approximately 1000 frames over 3 minutes (60 FPS).

February image was taken in rapidly brightening dawn sky and is a drizzle stack of 840 best frames over 90 second window (54 FPS capture rate). Icy moon Tethys is visible at 2 o'clock (magnitude 10.6).

FC settings for F30 image: ROI=640x480, FPS (avg.)=60, Shutter=16.61ms, Gain=100, Gamma=50, WRed=52, WBlue=95, Brightness=0, AutoExposure=off, USBTraffic=80, Histogramm(min)=0, Histogramm(max)=60, Histogramm=23%, Noise(avg.deviation)=10.74, Sensor temperature=7.2 °C / 45.0 °F

..and for F16 pic: ROI=352x288, FPS (avg.)=54, Shutter=18.36ms, Gain=57, Gamma=100, WRed=52, WBlue=95, Brightness=0, AutoExposure=off, USBTraffic=80, Histogramm(min)=35, Histogramm(max)=187, Histogramm=73%, Noise(avg.deviation)=28.29, Sensor temperature=18.5 °C / 65.3 °F

Comments / suggestions very welcome (particularly on how to reduce noise levels at capture time).

Thanks for looking,
Sebastian

[Star Catcher]

Great results Sebastian. I not much into planetary imaging, but I suspect you are up against the light sensitivity limits for your camera using a 12 inch scope and the 3X barlow at 54fps. You can drop the frame rate or stack more frames to improve s/n. Other more experienced planet imagers should be able to confirm this and your choice of parameters that you used for the camera,

If you don't want to compromise frame rates or use extra stacking that may cause you rotational grief, you might find it acceptable to deal with the noise in post processing without destroying too much detail. I have attached a quick noise reduction example on your image just to give you an idea.

Ted

[Sebbie]

Thanks Ted, I wish I was taking more / longer clips that April night, unfortunately this is the only avi I have (so not enough quality frames captured). Yes, ASI is much less light sensitive at F30 than my colour DFK but I am very impressed with the detail it brings.

Your DNR example produced a very good result, thanks for sharing. Being a bit of purist myself I will have a go at stacking more frames as I have about 11,000 to play with.

Rgds,
Sebastian

[Camelopardalis]

Nice one Sebastian!

I have the QHY5L-ii which I believe uses the same sensor and I've found it to be similarly lacking in sensitivity at f/25 with my C11. I was pretty happy with the results from capturing Mars and look forward to Jupiter, but Saturn was similarly noisy, looked a lot better at f/10 but small :sadeyes:

[Rac]

You have the some really good detail there!

I use my ASI120mm at f20 on my 10" f4 newtonian with a 5 X powermate and find it good. For Saturn i use a gain of 92 and the exposure is about 30-40ms for a histogram of around 70%.
You can go longer than you think with Saturn. I do about 150sec/colour.

[xelasnave]

Sebastian
Great image
It will be hard work to do it better
You should be very very happy