Good seeing, but really hot and humid in Sydney. But about the only clear skies in the last couple of months, so I shouldn't complain!
Red Spot Jr is rising, and there's a good bit of activity on the SEB.
Best 3000 frames of ~7500 for each image. 200mm f/5 Newtonian, Barlowed to f/30. ASI185MC, Firecapture, PIPP, Registax and a tad of PS2. The frame with Io and Callisto was at f/15
This is brilliant for an 8" scope Andy and that's a color camera I believe ? ?
Struuth, I cant create as good with the 12"SCT, oooh, what am I doing wrong, mate, what am I doing wrong,,, tell meeee
This is brilliant for an 8" scope Andy and that's a color camera I believe ? ?
Struuth, I cant create as good with the 12"SCT, oooh, what am I doing wrong, mate, what am I doing wrong,,, tell meeee
Thanks Bob! Just saw your very decent effort, I don't suppose you're too far away from mine, and you have 12" of aperture to play with
Advice from what I've picked up along the way... expose for no more than 3 minutes for Jupiter as rotation starts to blur it after that, but 3 minutes can give a good number of frames for your stack. I've not yet mastered the art of combining derotated images in Winjupos. Go for 40% on the histogram - the brightness is a tradeoff between shutter speed (for Jupiter I'm usually around 17ms, ~40ish fps), gain (I'm usually about 310, so higher than I'd like), image scale and aperture. I think it was Chris Go who recommended the 40% in one of his videos, though I'm not sure. With a larger aperture, you'll get a brighter image and survive a lower gain to get a similar size & brightness image. Lower gain is nice, because that's less noise and more levels. I use the 16 bit imaging option on Firecapture, seems to produce better images, it ought to give more levels in the captured image, but larger data files. The clip window in Firecapture is very handy to get smaller sized files. My settings allow me to get about 7,000 frames for a 180s Jupiter dataset, and stack the best 2-3000 depending on how good the conditions were. I use PIPP to select the best n frames, then go stack it. Collimation is important. And above all else - look for the good seeing (Skippy Sky or whatever), makes all the difference!
Quote:
Originally Posted by Camelopardalis
Nice one Andy I've never been brave enough to dial up the f-ratio that much
THanks Dunk It's probably a bit too much f/ratio, but I do quite often get better results than at f/15 (if I recall right, at f/30 I'm getting around 0.15"/pixel, probably oversampling a little on the 8", f/20-f/25 would be the sweet spot I think).
Yeah my Powermate gets me to about f/22, which gets the image size about where I'd like it to be. Of course, on most nights the atmosphere has other ideas, at least for the C11...the 8" is much more usable on 7/10 nights I reckon.
I don't recall how I summoned up the mental fortitude to sit and calculate it, but one night I scribbled away and figured I wouldn't want to capture for more than about 35 seconds with my 224 and its 3.75 micron pixels before risking rotation spoiling the stack. This would be focal length dependent of course, as with my C11 that puts me under 0.12"/pixel.
Anyhow, with an aggressively chopped region of interest, the 224 (and no doubt your 185) will ramp up to between 100 and 150fps, giving me about 3000 frames per capture. If the sky is kind, the stack will be decently detailed but with some residual noise. That's where I find the derotation kicks in, as 6-8 of those can give a nice reduction in noise again. Hope this helps someone
Thanks Bob! Just saw your very decent effort, I don't suppose you're too far away from mine, and you have 12" of aperture to play with
Advice from what I've picked up along the way... expose for no more than 3 minutes for Jupiter as rotation starts to blur it after that, but 3 minutes can give a good number of frames for your stack. I've not yet mastered the art of combining derotated images in Winjupos. Go for 40% on the histogram - the brightness is a tradeoff between shutter speed (for Jupiter I'm usually around 17ms, ~40ish fps), gain (I'm usually about 310, so higher than I'd like), image scale and aperture. I think it was Chris Go who recommended the 40% in one of his videos, though I'm not sure. With a larger aperture, you'll get a brighter image and survive a lower gain to get a similar size & brightness image. Lower gain is nice, because that's less noise and more levels. I use the 16 bit imaging option on Firecapture, seems to produce better images, it ought to give more levels in the captured image, but larger data files. The clip window in Firecapture is very handy to get smaller sized files. My settings allow me to get about 7,000 frames for a 180s Jupiter dataset, and stack the best 2-3000 depending on how good the conditions were. I use PIPP to select the best n frames, then go stack it. Collimation is important. And above all else - look for the good seeing (Skippy Sky or whatever), makes all the difference!
Very kind of you to put this together Andy,
It is very impressive 'your Jupiter' considering your only getting about 1/3 the light than I - so here is the Einstein - to you
I'm definitely taking all advice on board. also need to limit my video captures to just a few, one extreme to another, so-to-speak' so can get my head around the results, per setting etc - otherwise I end up with a dozen vids, twice as many stacks - 5% & 15% best frames, & that much again in binned stacks, not the best tactic in experimentation
Was looking forward to seeing the GRS tonight But too high a humidity tonight here, around 90% - and a wettish few days coming to look forward to, grrr !!
and that's a color camera I believe ? ? 
It's probably a bit too much f/ratio, but I do quite often get better results than at f/15 (if I recall right, at f/30 I'm getting around 0.15"/pixel, probably oversampling a little on the 8", f/20-f/25 would be the sweet spot I think).
