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Ganymede Observation + sketch

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#1 HellsKitchen

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Posted 19 November 2010 - 10:14 PM

Seeing was good enough to view the Galilean moons as disks, each with obvious difference in size. At 534x, in moments of good seeing, I caught some surface markings on Ganymede. In the northern hemisphere a dark wedge shaped feature could be seen, while the northern polar regions appeared lighter and whitish compared to the orange-yellow hue of the rest of the moon. Seeing was still blurring the image, but it also settled enough to get a crisp view of the disk momentarily. I also noted Ganymede's orange-yellow colour contrasting with nearby Callisto's Ice-blue, which was a neat sight.

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#2 frank5817

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Posted 19 November 2010 - 11:00 PM

Very impressive capture.

Frank :)

#3 hbanich

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Posted 20 November 2010 - 02:47 AM

Fantastic! The seeing and your scope must be equally good for an observation of this caliber. Do you often get such good conditions?

#4 Roel

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Posted 20 November 2010 - 03:06 AM

Wow! I have a 12" f/4 Dobson myself but with the seeing conditions (and the low altitude of Jupiter, 30 degrees) from the Netherlands this must be an impossible observation to me. Just incredible to see surface details and even color differences on Ganymede!

#5 lunar

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Posted 20 November 2010 - 01:01 PM

Very nice sketch! I like your description too.

#6 Tommy5

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Posted 20 November 2010 - 05:54 PM

Nice sketch of a very difficult subject.

#7 HellsKitchen

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Posted 20 November 2010 - 07:47 PM

thanks all for your kind words :)


Fantastic! The seeing and your scope must be equally good for an observation of this caliber. Do you often get such good conditions?



These conditions are painfully rare. Even though, Ganymede was still blurring and jumping around so patience was required to capture each fleeting moment to confirm surface detail. So as good as seeing was, there's still room for improvement. I only had 1 other night this year of similar seeing where I was able to observe plantery nebulae at in excess of 700x. Scope has excellent optics, focusing on 47 Tuc and NGC 362 on the same night I was blown away by how crisp and clear they were at 334x. Even at 762x there was that "snap" focus rather than it just mushing thru it, (which promptly dissappeared later in the night)! Went out last night again, but seeing was back to the usual with Jupiter observation difficult even at 200x :(

#8 Jef De Wit

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Posted 22 November 2010 - 09:50 AM

It must be impressive to see detail on a Jupiter moon. :waytogo:

#9 hbanich

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Posted 22 November 2010 - 08:32 PM

These conditions are painfully rare. Even though, Ganymede was still blurring and jumping around so patience was required to capture each fleeting moment to confirm surface detail. So as good as seeing was, there's still room for improvement. I only had 1 other night this year of similar seeing where I was able to observe plantery nebulae at in excess of 700x. Scope has excellent optics, focusing on 47 Tuc and NGC 362 on the same night I was blown away by how crisp and clear they were at 334x. Even at 762x there was that "snap" focus rather than it just mushing thru it, (which promptly dissappeared later in the night)! Went out last night again, but seeing was back to the usual with Jupiter observation difficult even at 200x :(


That's about the same for me, but it's nice to know that your scope can handle steady seeing when it comes along.

#10 Heidescoper

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Posted 24 November 2010 - 03:21 PM

great observation :bow:
Fine sketch!

#11 dweller25

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Posted 24 November 2010 - 04:28 PM

That's fantastic, I can only dream of seeing that level of detail in the UK.

#12 CarlosEH

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Posted 24 November 2010 - 10:40 PM

An outstanding observation of Ganymede showing albedo features over the surface. The largest satellite in the solar system does present some interesting detail if sufficient aperture and seeing conditions allow.

If you would allow me to post a revised version with the colors that you note above I will do so.

Carlos

#13 HellsKitchen

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Posted 25 November 2010 - 02:09 AM

thanks all. Dweller, Melbourne is no better than the UK that's for darn sure! It's very rare to get such good seeing, only had one other night this year with similar conditions!

Carl, you're more than welcome to modify the sketch. I look forward to seeing it.

cheers

#14 CarlosEH

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Posted 25 November 2010 - 11:02 AM

The image below is based upon your fine observation and report of Ganymede. I hope that you like it. I look forward to your future observations.

Carlos

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#15 HellsKitchen

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Posted 27 November 2010 - 03:58 AM

Yep that's good Carlos, you've done well capturing the subtle differences in colour as I saw it in the eyepiece. Cheers.

#16 ericj

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Posted 27 November 2010 - 08:20 PM

Very impressive observation and fine sketch.

Best,

Eric

#17 Special Ed

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Posted 27 November 2010 - 10:05 PM

HK,

That's a terrific observation and sketch of Ganymede (I like Carlos's augmented version, too). You mentioned patience and waiting for those brief moments of steady seeing--that's what it takes for an observation like this. :cool:

#18 astroducky

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Posted 30 November 2010 - 11:07 AM

2 weeks ago, I also managed to glimpse hints of detail on Ganymede. I could see that it was generally yellowish in colour and a portion of it brown. There was also a dark black spot on it. I was observing at 320x and 400x with my 12.5" Obsession. The seeing was very good to excellent; typically noted with high humidity (slight condensation) and little wind and cool temperature. At 320x, Jupiter was razor sharp and at 400x it was sharp. This was the second time I managed to catch details on Ganymede. :)

I also noticed a brown kind of like a storm at the North Temperate belt and it was beside a barge. The storm looked something like the GRS but probably it was smaller in size and circle in shape. I could see swirling details within it too. Another interesting feature I saw that night was a 'Z' shape blue coloured festoon at the SEB area and there was a white oval in the Z shape.

Unfortunately, I did not sketch Jupiter that night as I had to work the next day and did not want to sleep too late.






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