Got out again last night and I got some pretty good seeing – perhaps slightly better than the night belonging to my first entry in this comp. The equipment was virtually the same as before (accept for an experiment with my 3x Barlow), however on this occasion I used
Registax to do the mods on wavelets and gamma, rather than play with brightness and contrast in Irfanview.
Refresher on equipment:
12.5’ f6 dob, 8mm Radian eyepiece, 2x Shorty Plus Barlow, 3x Televue Barlow, Canon A40 – auto mode accept for selection of macro and no flash and some optical zoom, patience, small step ladder as the planet reached the zenith.
Last night saw a shadow transit and actual transit of Io. The transit of the GRS followed this.
I managed to capture the ingress of Io’s transit across Jove, with its shadow already on the planet. The first three images cover this. The view through the eyepiece was steady for perhaps 60% of the time. The first image shows the raw capture after being cropped and resized a little for input into Registax. I used Irfanview to resample (using Mitchell) the image to a smaller size. If I didn’t do this I found the image was too big to put into Registax and have the ‘processing area’ cover the whole planet. Is there a way to resize the processing area? After “stacking” the single shot, I was at the wavelet tab. Here I selected the wavelet filter to be Gaussian (seemed to give a smoother result (using default value of 0.10?)). I then modified the wavelets to be 1,1,1,9,20,34. I am not sure if this is the best approach, but it seemed to work for me and the little detail in my single shots. I also dragged the gamma line below the curve and that seemed to improve the colours somewhat – not really sure what is the correct colour, but the details seemed to be easier to see. I then saved this image and that appears as the second image. Thirdly I resized the image down to 50% as this seems to hide some of the pixilation created from the wavelet adjustments. I found the B-spline option gave the smoothest and most pleasing result.
I took several other (read couple of hundred) shots as the night wore on. I used the same processing for the other images attached here as described above.
Later while experimenting with my 3x TV Barlow (giving ~708x!!) I could hold a reasonable view so I decided to give this a go with the camera. What I noticed straight away was the “goobies” on my eyepiece and possibly the Barlow were very pronounced. Maybe it was because of the high power, or maybe it was harder for the camera to auto-focus on the blurrier planet than the image created by the goobies. I did manage a shot at this power that showed Io’s shadow leaving Jupiter’s disk while the GRS was rounding the opposite limb. The idea behind this was to get as many pixels into the details. The view through the eyepiece indicated it was possible, unfortunately most of the raw images showed otherwise. I have attached the pick of the bunch here (resized raw and reprocessed resized final and it did come out OK – in that you can see Io’s shadow and the GRS (remember to squint!
)
After going back to the 2x Barlow I got a few shots of the GRS coming around and I have attached the raw and processed-resized images of one of the better ones (sometimes it is hard to pick which is the better one as they often show slightly different detail).
Finally I have attached the processed image of perhaps my best (read clearest and steadiest) shot. Unfortunately the slight delay in clicking and capture meant it was leaving the field of view of the camera at the time - wish I had of got that a second or two earlier
The quality of the images don’t necessarily indicate changes in seeing as the largest component of variability is my ability to hold the camera steady enough to capture the shot – of course the seeing has to be OK otherwise my steady shots would look the same as the unsteady ones
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Of course being the visual observer that I am, and having the conditions that I had, it was a constant battle to remove my eyeball from the eyepiece and hold the camera up to it. One final comment is that this sort of imaging gets more difficult when your on a step ladder moving the dob near the ‘dob-hole’
Thanks for looking. If anyone wants the originals to play with, just PM me, otherwise feel free to grab the ones attached here and have a play. Any advise on Registax settings would be greatly appreciated.
