Planets 16 October 2022

[Averton]

Last night's clear skies were not predicted earlier in the day but were very welcome. While waiting for the GRS to rotate to centre, we cruised by Neptune for a look :) Then imaged Jupiter with Callisto followed by Saturn with six moons. Titan was in nice and close for once.

Images taken with 6" SCT, ASI178MC, ZWO ADC, x2 barlow for Jupiter & Saturn and x1.8 barlow for Neptune.

[Dave882]

Great shots! Good detail on Jupiter and I count 6 moons on your Saturn pic…really well resolved!! Can I ask what are your capture details for Neptune?

[Averton]

Thanks Dave. With only 6" aperture we are light starved for Neptune so the best we can manage is 2FPS, 500ms exp with gain of 390. This was 12 minutes of video with the best 10% stacked. With the gain so high we decided to take dark frames which we used with AS!3 when stacking. There is very little sharpening in Registax. This is the Registax info WSL1_0_WV10_10_10_10_10_73. We used GIMP to increase Triton's exposure level.

[Dave882]

Thanks for that! I had a go at Neptune on Friday with similar exposure length (lower gain of course) but I think the seeing was soo poor I couldn’t get a single frame with a “round” Neptune. It looked like a pice of play dough being pulled back and forth. Needless to say the stack was useless. I should have shot in IR now I think of it… but yours is quite clean which is why I asked :thumbsup:

[Averton]

No problems David. We had a bit of the play dough action happening but we could definitely see some good frames on occasion. The gut feeling was 10% which was confirmed by AS!3 quality graph. If we had more light we would definitely increase frame rate and reduce exposure before lowering the gain. These camera actually have lower read noise at high gain and if the exposure is quick enough thermal noise is also small. Our feeling is that frame rate rules if you can.