The Dutch Observatory

Another day beginning with clear skies (1/31), but I got interrupted in the middle of imaging by a cloud streak which did not want to leave. AR2268 is decaying again, but AR2277 is making up for it.  Total flare activity is a lot less than the day before.

This morning (1/30) temps were decent and seeing was OK.  AR2268 has not made its mind up what to do.  It now is increasing in size again to a little over 500 millionth and produced 7 Flares over the 24 hour period of which 3 were M-Class flares.  AR2277 is a new one to watch with 260 millionth and a respectable 7 flares.  Today a full disk image and a close up of AR2268 and 2277. Newton rings are getting bad.  Need a leveler.

Some stable and clear skies today for a change.  The Sun is showing some increased activity with AR2268 having rebound again to 480 millionth and three other areas also having grown.  AR2268 even managed to produce a C9.8 as well as an M1.4 flare.  The rest is still relative quiet.  Today a full disk image of the Sun and two close ups of AR2268 and AR2273.

Friday evening’s clouds are gone but the seeing is still unstable.  Today a full disk image.  The largest and most active regions is AR2268 with a size of 460 millionth.  The largest flare in the last 24 hours however was only a C2.0 flare.

Well, as expected the triple shadow transit was clouded over.  I followed the transits and events on-line.  Was hoping that the Griffith Observatory in LA would bring some nice images, but the feed was terrible.  Very unstable skies.  Every once in a while you could see some banding.  Bate-Papo from Brazil had the best feed for most of the event, but they stopped showing before the third shadow showed up and went into a discussion reviewing what had happened, so Heart of Texas was the final straw!!    Below screenshot of the three shadows just before Io’s shadow runs off the disk.

It really is getting quiet.  Today AR2266 has become smaller again, and of  the four identified regions, three of them have one tiny sunspot only.

The Sun is getting quieter by the day now.    AR2266 is the largest active region at only 130 millionth, and produced only 1 C-class flare in the last 24 hours.

In my previous solar post I asked where all the Sunspots had gone….. but today a little improvement.  Stability had improved a lot since the Jupiter session last night, so this morning I was able to also capture a few white light close ups of AR2266 including some nice granulation.  Four active regions today, all very small, 10, 20, 30 and 90 millionth respective.  Only two flares from AR2259.  The Close ups are from AR2266, which contains 13 spots.

The Tale of the Triple Shadow Transit
……… and a whole lot more……

Some of us are hoping for clear skies to see the  Triple Shadow Transit on Jupiter in the early hours of 1/24/2015.
However, that is only part of the story, and here is the rest.

The fun starts around midnight when the shadows of Io and Calisto are visible on Jupiter and the moon Io is already in front of the Jovian disk near the Eastern limb.  As time goes on you will notice that the distance between the shadows declines as they transit across.  This is because the shadow from Calisto, which is much farther away from Jupiter than Io, moves relative slower on the planetary disk than the shadow from Io. Around 0:40 AM, Io’s shadow will have caught up to the shadow of Calisto and they will merge to one shadow.  However at the same time, Calisto’s shadow ”beam” will also partially eclipse the moon Io, so Io will become partially dark, which shows up from our vantage point as a small shadow against Jupiter behind it.  This shadow will pop up out of nowhere, and is only visible for a few minutes.  In the meantime around 1:15 am, Io has moved ahead and has caught up with Calisto’s shadow, and now it will start to cover, and block our visibility of the shadow of Calisto on Jupiter.  Io will not totally cover the shadow, but the change of the ”dark” shadow should be very well noticeable.  Finally, at 1:30 I would expect Europa’s shadow as well as the moon Calisto have moved onto the planetary disk as seen from Earth and you have arrived at your “Triple Shadow Transit”.

So you thought you’d see three shadows only?  Now you know what to look for in the 90 minutes leading up to the Triple Shadow Transit.  And once you have seen this, think again what you just witnessed.  This is why I am so excited this year about the chance to see what those many “Mutual Events” of the Jovian Moons create for us to observe from Earth.
Complicated?  I’ve added some screen shots of what will happen to make it better understandable.
Clear Skies,
Theo Ramakers
Images generated with WinJUPOS.

In 2009 I was pretty active in Planetary imaging, including imaging the Mutual Events between the Jovian Moons.  This year Earth and Jupiter are lined up again for these events, but so far the weather has been terrible here.  Tonight however, we had clear skies and as so many times in 2009 the conditions were awful.  Although no clouds, the Jetstream and wind gusts caused seeing conditions of 1 to 2 out of 6, which translates to a very wavy planetary disk.  However, I wanted this so bad so took a chance.  Captured 48 total images in R, G, B and IR and ended up using 3 IR images. The animation shows Jupiter and its moons in IR at 02:22.0 UT, 02:35.6 UT, and 02:473.7 UT.  The shadow is from Ganymede.  Ganymede is moving from the right to the left towards the Jovian disk, while Europa which just appeared coming from behind the disk, moves to the right.  At 02:35 Ganymede which was in front occulted Europa.  (The middle image).  Apologies for the bad quality.  This was not caused by a lack of processing, and yes, the moons have been pushed a bit in levels to make them brighter in the images. Click the thumbnail to see the animation.