Double shadow transit on Jupiter this evening (4 October 2021: 19:00 to 21:15 UT)

[Pixies]

Callisto's shadow transit starts at around 6pm BST (17:00 UT)

Ganymede's shadow transit starts at around 8pm (19:00 UT)

Callisto's shadow transit ends at around 10:15pm (21:15 UT)

Ganymede's shadow transit ends at around 11:15pm (22:15 UT)

 

Rough times. It will vary on your location. See link below

 

Looking possible to catch the latter half here:

the Met Office has been the most reliable cloud forecast for me in recent months. 

 

Looking forward to seeing the difference in shadow sizes.

https://www.skyatnightmagazine.com/advice/skills/jupiter-moons-how-see/

 

[Pixies]

Oh - the times in the subject line for the duration that both shadows are visible.

[Alan White]

Typical in that Iook like it will be clouded out....
I had been looking forward to this, obviously attracted the clouds 
But 🤞that Met Office are wrong.

[Stu]

Thanks for the heads up @Pixies. Not looking good here but you never know….

[John]

Thanks for the reminder.

I was going to go to my society observatory to observe this but that has been scrubbed due to the poor forecast. I'll have a scope on standby in case there is a clear patch but more out of hope than expectation

[Knighty2112]

Forecast not looking great, but maybe a break around 8/9pm. If clouds allow then depending on seeing conditions might be hard to view the smaller shadow of Callisto. View at 8:30pm below from Skysafari. Fingers crossed!  

 

[IB20]

Jammy or what! Clear after an afternoon of rain showers. Seeing not perfect but better than the previous few nights. Can see a nice black dot just under the SEB. Let’s hope the conditions hold out til Ganymede transits. 

[IB20]

Ganymede has just egressed from the planetary face. There’s a real celestial ballet going on. 😃

[Peter Drew]

Only double transit here is a double thickness of cloud!       ☹️

[Stu]

Yep, windy and cloudy here unfortunately. Enjoy the views @IB20

[John]

Raining now here

Glad somebody's getting some views though

 

[IB20]

Clouds have finally come over although I still have some hope as it’s not blanketed. Managed to view Ganymede’s shadow just after ingress, looked the same size as Callisto’s shadow to start with, as this was more centrally positioned on the disc. After some transit time the relative sizes of the shadows could be discerned, Ganymede far bigger and inky black, which started to make Callisto’s appear more grey. 

Short and sweet with some glorious views but that’s what a small refractor does so well. 

 

 

[JeremyS]

Was enjoying the Callisto shadow transit. Superb view through the Tak FOA 60Q at x130. I was keeping an eye of the cloud bank very slowly approaching from the south. Was just approaching ingress of Ganymede shadow when cloud obliterated the view.

Before this it was very clear. Had enjoyed views of M71, 27, 56, 57, 13and 92, plus eps Lyr, in between views of the transit. 

[Pixies]

Had the 8" dob out cooling, waiting for Jupiter to come round past the chimney pots from a house 2 doors down.

Eventually got a clear view around 21:15. Ganymede's shadow was central, just North of the SEB. Callisto's shadow was further to Jupiter's East and South of the SEB, clearly within the South Tropical Zone. Of course Ganymede's shadow was much larger, but the smaller moon's shadow was still clear. Seeing was average, but the shadows were still obvious, the boiling view gave the impression that the shadows were slightly above the planet's surface.

I could take the magnification down to x60 and still make out the smaller shadow. x150 was the best view for my scope and the conditions.

I watched until Callisto's shadow got close to the limb and vanished in the turbulence. Some high clouds are coming over, so I'll let them pass hopefully, and see if things remain clear. 

 

[Knighty2112]

Managed an hour from just gone 8pm until low cloud and haze rolled in at 9:15pm. Got great views of both shadows with my AA 102 ED  f11 ‘frac using a 6mm Starbase EP to give magnification of x187. Was surprised how easy it was to see the smaller shadow as easy as I could see it. The larger shadow was easy seen even at much lower magnifications. The addition of my semi apo filter made the views much better too. Pity that clouds then spoiled play. 

[John]

Still here.

Good to hear some reports from those who have clear skies though

[Nik271]

Agains all odds I managed to get a good view of both shadows at around 9pm. The seeing was ok-ish half of the time, I could only push the magnification to x120 but still very happy with the opportunity.

The sky in the south was all looking good at 7pm but then, just as I went out, clouds arrived and started raining. I had packed up and given up, but at 9pm I looked outside and it had cleared again! Thankfully I  have a fast 'grab and go' set up (SW Mak 127 on EQ5) and was up and running in 5 minutes. Ganymede's shadow was right in the centre and looking obvious. Callisto's was creeping towards the edge and harder to see in the turbulent air, still 50% of the time was detectable. Then at 9:30 more cloud arrived and eventually it started pouring again. Very glad to see part of the double transit at all!

Edited October 5, 2021 by Nik271