Unfortunate that I have to post after Bird's fantastic shot, but oh well
Had a great morning imaging Jupiter, GRS transitting, and at 3:30am when I got up, Europa and it's shadow were on the disc too. I got a few avi's with the shadow visible, however my image scale just isn't large enough to see Europa itself. It's probably just 1 of the lighter coloured pixels
I had about 70 separate avi's, grouped into bunches of 3 or avi's with slightly different capture settings in each, trying to find the optimal for my setup. Each 'group' of avi's lasts about 60 seconds or so (around 8-13 seconds per avi).
I've just used Virtual Dub to join them together and save them as bmp's, and used Bird's ppmcentre program to centre them all within the frame.
I didn't delete the bad frames from Virtual Dub, the seeing was quite good and it was difficult to find the bad frames, plus I didn't have the patience.
The first few avi's were taken at 15fps, but then I remembered that when seeing was good, use a lower FPS, so I used 5fps. What I noticed immediately, is that at 15fps I could use 1/25s shutter and the image wasn't overexposed, but at 5fps I couldn't use any less than 1/50s shutter otherwise it was too washed out. I guess that goes to show how much compression it does at 15fps.
I tried imaging at 1/50s and 1/100s mainly, to try and freeze the image before the earths rotation blurred it as it zipped across my preview screen. I tried various gamma settings, and found the best result during my very last capture, and that was with no gamma. The colours were much more natural. Wish I'd tried zero gamma earlier, as it was clear right away that it looked better
The last few avi's were taken with the 2x barlow pulled out of the barrel a way, and the ToUcam pulled out of the barlow a little way. This gave me a slightly longer focal length and therefore a slightly larger image. Not much, but i'll take all the scale I can get
These images were also taken with my new ES IR filter, my first images taken with the filter. I'm yet to do with/without IR filter comparison, i'll do that next time out.
Details:
- 10" dob no tracking @ 2500mm FL (f/10 with 2x barlow)
- ToUcam, taken at 5fps
- Approx 90 frames out of ~200 stacked
- The images on the left are raw out of registax, the images on the right are processed in AstraImage (split/LR deconvolution/recombine RGB)
Comments, suggestions are welcome.
These are my best Jupiter to date, got some detail in and around the GRS, the top shot shows Europa's shadow. Europa is on the disc somewhere in all 4 images below, good luck finding it
Those shots are great ice man.
Great detail and the grs is looking sweet. Cool shadow of Europa, where about is the moon on the disc. The grs looks much bigger when it is pointing straight at earth. It looks smaller on my shots. Awesome
Simon
Going by the "Jupiter 2" program (and comparing to Bird's image), Europa should be almost above the GRS, in the same band as the shadow.
If anyone wants to process my avi, please feel free. It's a zip file containing the centered bmp's. I just drag/drop these into registax to process them.
Really good stuff Mike! Getting these sorts of results with a non-tracking scope is fantastic.
A gamma of zero actually means "maxium gamma correction" on the ToUCam. I know, it's upside down, but that's the way that everyone does it. To have no gamma correction you'd have to have the gamma slider left on 1.
It's normal for people to set the gamma to zero, cause that gives the greatest contrast.
ps I reckon I can see europa in the right hand bottom image. It's just about to leave the disk and makes a bump in the northern white band (north temperate zone?) on the left-most edge of the planets disk.
Ice,
I have said it before, and I say it again, how you persevere with a dob is beyond me. I am very impressed with this latest batch though. They are stunning. Now all you need is a bit more image scale (upping the difficulty factor of course),
Well done.
Gary
All,
forgot to ask, and perhaps it needs a separate thread of it's own, but what is the consensus with fps.
I was always "taught" 10fps, and have almost exclusively used that.
Is there a better way? Does 5fps, or 15fps give a better or different result?
Ideas/guesses?
Gary
Nice Mike, did not see this hiding here until today. Very good more detail present and a nice shadow also and the GRS. Very good. Just looks a tad over processed, but great work mate.
nice work Mike, will be interesting to see how the IR/non IR tests turn out. \
RR, I feel the fps setting isn't a as hard and fast rule as some of the other settings are (eg as Mike's just found low gamma gives more natural looking colour) - if your camera + system can handle the higher workload from dealing with more fps before needing to compress the data then why not grap a few more frames each sec.?, birds last Jupiter shot he put up was at 25fps....
Andrew, there's a difference in our cameras that makes it hard to compare my 25fps to his 15fps or 10fps. His camera (ToUCam) will compress data because its using a usb1 cable, and the higher fps makes for more compression and loss of detail in the image.
I used to use a ToUCam, bought one on 2003 for the mars opposition and used it for a year or so, but I'm currently using a firewire camera that can do up to 30fps without any compression on the image (firewire bus is 400Mbit vs usb bus as 12Mbit).
This means I can pick a fps that suits without having to worry about loss of detail in the image, but Mike (and others using the ToUCam) have to be a bit more careful. 10fps or 5fps gives the most detail, but there's the problem of blurring the image with long exposures, so it's a tradeoff.
FWIW, I tend to favour 15fps @ 1/25 or 10fps @1/33 Usually though its a case of taking 4 or 5 short (around 20 - 30 sec) shots, quick rough process and see what works best on the night.
Had a bit of a chop at your bmps Mike. Couldn't get them to open in Reg 3 for some reason so did the stack and initial histo in K3ccdtools (no image deletions, just used what you had) and then did some final touching up in Reg 3. A little despecling and sharpening in PS. couldn't seem to push the wavelets in Reg as far as I would have liked. Might play with it a bit more and see what I can get
Last edited by [1ponders]; 24-02-2005 at 03:05 PM.
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