With the weather forecast for the next week looking damp here in Sydney, I seized the clear evening, albeit with iffy seeing, although it deteriorated noticeably over the following hour and this was the best I could get
Mars is also appreciably smaller than my earlier attempts, being about 2/3 the size of a month ago. So long Mars, it's been fun...see you in a couple of years
Best 500 frames of 10000 stacked with Registax
C11 Edge HD at f/25 with TV Powermate
QHY5L-ii 320x240 ~50fps (resized by 50% here)
I've been reading that 5-10 fps is probably the optimal FR to capture at, given the balance between peering through the bad seeing vs avoiding data-stream compression. Any reason you're going at 50 fps?
IMHO, 1000 frames at 10 fps is typically more valuable than 10000 at 50 fps.
Yep...to capture those fleeting moments of better seeing. Last night was definitely proving a case for an even faster camera
You may be right in perfect seeing, but I've not experienced that here. I would suspect it would depend on individual camera specifications, notably sensitivity...with a more sensitive camera, you could capture better quality frames with usable gain and push the frame rates higher still.
My camera uploads raw data to the computer at ~50fps at that resolution, so the data isn't subject to compression.
My camera uploads raw data to the computer at ~50fps at that resolution, so the data isn't subject to compression
I thought mine did too, but I've read elsewhere that this may not be the case. It may be worth doing a qualitative check of the quality of the stream at 50 vs 10 (or 5) fps. You could also confirm this via a file-size calculation for a fixed number of frames. If data compression is not an issue, then I agree that 50 fps is preferable.
I thought mine did too, but I've read elsewhere that this may not be the case. It may be worth doing a qualitative check of the quality of the stream at 50 vs 10 (or 5) fps. You could also confirm this via a file-size calculation for a fixed number of frames. If data compression is not an issue, then I agree that 50 fps is preferable.
Yeah mine consistently gives identically sized output files for the same number of frames. I'm pretty certain they're the raw data.
The old old Neximage I had was limited to USB 1.0 speeds, so good for about 10fps max but the QHY is much more sensitive, and faster. Still not enough that I'm completely happy with my Saturn captures though, always has to be room for upgrades
There's also a difference between lossy and lossless compression...and it's possible the capture software could be doing either, or neither.
I use the software that came with the camera (EZPlanetary) and it does the job, but if it's hard to decipher from what you're using it might be worth trying something like Sharpcap or Firecapture. In EZPlanetary I can set the exposure time (which determines the frame rate), resolution, gain and colour balance. There may be more but I haven't played with them
Obviously, for this sort of experiment it doesn't need to be plugged in to the scope, as a raw capture from the sensor should work out the same size (for a given resolution and number of frames) regardless of what it captures.
Also, do you have the option to select a Region of Interest? Or do you use the lower (and faster) resolutions? What you mentioned before about 10 or 5fps sounds suspiciously like the original Neximage and I'd be really surprised if that held true for the Neximage 5 which is a whole kettle of fish different from the former.
I use iCap, it allows me to change exposure, gain, rez, CB etc. yes. I usually capture at 640 x 480 but it allows up to 2000+ pixels. It's a good software capture program. The NexImage 5 is great - set on 2x2 binning for instance, it makes a pretty decent autoguider too. I'm not particularly suspicious about it -- just want to convince myself that I'm not selling my images short at high frame rates.
but the QHY is much more sensitive, and faster. Still not enough that I'm completely happy with my Saturn captures though, always has to be room for upgrades 
