Seeing was unusually good early in the night & I made some AVIs of Jupiter which are not yet processed. I did however process this sequence, which has Jupiter badly overexposed but shows three of the Galilean satellites excellently, showing the size differences clearly.
2009 Sep 09, 2149 UT. Ganymede & Europa to the left (east), Io to the right. Callisto out of frame much further to the east.
I'll replace the overexposed planet image with the LRGB composite I took at the same time when I get a chance to process it. Should be reasonable despite the low altitude (Jupiter is still heading south as retrograde motion continues, it's noticeably lower in the sky than it was even a few weeks ago.)
Incidentally the close double moons formed an excellent focusing aid! I often focus on Jupiter's satellites rather than Jupiter itself as the details on the disc are poor in contrast, but the gap between the moons really helped get the focus spot on this time.
Unfortunately, though the sky remained more or less clear, the good seeing deteriorated to very poor later in the night, with heavy jet stream smearing as well as severe boiling - it was hard to focus on a star at x140 by 5am.
Hello Brian, Quite an interesting pic. The satellite disks are quite noticeable. I had another go at Jupiter last night, but the planet dips below the rooftops at 10.30, so an early start is esential. The seeing was variable, but at no time was Jupiter steady. The limb continually "boiled" to a more or less degree. pic taken at 21.50
Hello Brian, Marvellous detail there along with decent colour. I cant seem to get any colour im my webcam images despite the ir filter and contrast booster. I tried a large size avi file around 1.1gb but that made no difference. Looking at Jupiter through the eyepiece shows a washed out image with low contrast disk detail, so perhaps the low altitude of the planet is the problem. This image was taken last night at 8.35
perhaps the low altitude of the planet is the problem.
Yes it is ... The contrast booster won't help much unless you're using a scope with significant false colour.
Last night (Sep 17) was odd, it was supposed to be overcast according to the forecast, fortunately they were wrong (not unusual), there was a very thin veil of high cloud but the transparency was reasonable. There was a southerly breeze which was vibrating the scope a bit but the seeing was unusually good for the low altitude (18 degrees at culmination). Nohing special going on in this image ....this is a quick & dirty process, I may be able to tidy it up a bit.
2009 Sep 17, 2145 UT. CM(I)=175 CM(II)=084 CPC1100 prime focus, Astronomik type 2c RGB + Planet Pro 742, Imaging Source DMK41.
Hello Brian, The sky here at Glengormley was marred by thin cloud which reduced the transparency so much that only 1st mag stars were visible. This is due apparently by an area of high pressure which eventually fills with cloud.Probably a cold front woud be better. I will try imaging Jupiter without the contrast booster, but will leave the IR filter in place. The scope, which is a 130mm F9 APO built by Beacon Hill is almost free from CA. Interestingly the false colour in my webcam images seems to be due to refraction caused by the low altitude of the planet. As regards disk detail I think that the relativly small aperture of the scope will inevitably limit that. As they say, there is no subsitute for aperture. Regards, Virgo
Hmmm, I had intermittent cloud ... and very poor seeing of the "jet stream smearing" type. Hard to focus on a star at the zenith even at x140. Didn't bother trying to image Jupiter, it would have been a complete waste of time.
The jet stream has now brought a band of thick high cloud in from the west, I reckon that's it. So much for the forecast "clear all night"....
Hello Brian, The sky was still clear at 4.00 AM, and by that time Mars was well up, situated in NE Gemini so I zeroed in on it at X340, and the gibbous disk was well defined, but disk detail was limited to a few vague streaks. No webcamming due to a lack of hard disk space. High level cloud arrived soon after and ended the observing session. Regards, Virgo