Jupiter in excellent seeing - what is visible visually?

[mikeDnight]

On 09/04/2016 at 09:52, Size9Hex said:

What a outstanding post. Nice one Stu! 

I wish I had more time to do it justice. I'll paste a quick screenshot below, and if you put your eyeball a close few inches from the screen, I think it's a reasonable approximation of the view in the Skywatcher 250px on a good night with patience. 180x is my main mag, but 250x when seeing allows. A few things that spring to mind compared to the photo.

• The Great Red Spot is seen to be darker in the south than the north.
• White spots in the southern temperate belt in the photo have never been seen.
• North polar region does indeed look bit marbled (seen 1 or 2 nights in 10 maybe), but I'd struggle to say anything specific about it. It's just a subtle texture.
• The moons intrigue me too. When they are close together, I feel that Ganymede and Callsito can be identified as being larger than Io/Europa. Io looks a muddy ochre yellow compared to Ganymede which seems more of a grey-brown colour, but the colour is extremely dependent on where you catch them (transit or open sky). When Europa emerged from eclipse (only seen once and I'm keen to check this again one day), it looked briefly "wrong" for 30 seconds or so - tall and thin basically, but not with any specific shape exactly.

 

Edit: I definitely did paste a screenshot here! Let me see if I can figure it out... 

Hi Paul,

I'm curious about your second bullet point regarding white spots never having been seen in the STB. It got me wondering if I'd ever recorded such spots in my many sketches over the years, as I felt certain I had, and sure enough I found several recent drawings that implied such features. Some may have simply been contrast effects but others appeared as definite spots. 

Mike

[John]

I've definitely seen white spots / ovals, from time to time, in the STB / SSTB. They are challenging targets and often you need to wait for the seeing to steady for a moment for them to "pop" into view but they can be seen.

[Size9Hex]

Thanks Mike and John. Interesting to read your comments about the white spots. I'd not given up on seeing one, and from what you've said I'm encouraged to keep trying. I've only had one season with Jupiter and probably not more than a dozen sessions. I've looked for them a few times, although I believe my efforts are aimed most often at more attention grabbing features elsewhere. Perhaps easily overlooked when I wasn't specifically focusing on them.

[Stu]

On 06/04/2016 at 12:50, John said:

Very interesting post Stu and a great way to correlate the visual with the image.

It sounds like your 4" Tak can discern similar levels of detail on Jupiter to my 12" dob. Maybe I'm going to have to re-think my scope strategy

 

John, just thought that now you have your 100DL you perhaps now know that I wasn't making it up?