Europa occulting Ganymede, 8th May

[bird]

Here's an animation of Europa occulting Ganymede on the morning of May 9 (May 8 18:02 UTC or thereabouts).

The seeing was not very good, and so I was only able to use 250/1200 raw frames for each final frame in the animation. You can see that the seeing improves a lot toward the end of the sequence.

Capture details:
Astrodon I-Series filter (Red)
PGR Dragonfly2 camera @ 38 fps
TV 5x powermate @ 7.7x on LEXX
Images resampled to 300% before processing

Each animation frame is approx 31 seconds of raw data (1200 raw frames) and the best 250 as chosen by ninox were stacked and processed in registax.

cheers, Bird

[matt]

That's a great capture, Anthony, despite the negative effects of the seeing.

I can't recall seeing an occultation of this type before captured by an amateur....although I'm sure someone has captured one.

Thanks for sharing it with us:)

[Miaplacidus]

A triumph, Anthony, nothing less. I can only imagine what you might achieve with a fraction of NASA's budget. And LEXX will belong in a science museum one day. Congratulations.

(But you really ought to get that OCD treated.)

Cheers,

Brian.

[Rob_K]

Amazing Bird, what a capture, congratulations!! :thumbsup:

Cheers -

[Quark]

Hi Bird,

What an achievement, stunning incredible gob-smacked.

Sorry about this but I just cannot think of the right superlative to describe my reaction to viewing this.

Extremely well done
You are a Legend

Regards
Trevor

[AstroJunk]

Jaw dropping.

We (the occultation timing lot) have been doing light curves of mutual events of saturns and jupiters moons, but NOTHING like this!

Fantastic :thumbsup::thumbsup::thumbsup:

(here is IIS member DaveGee's light curve: http://users.tpg.com.au/users/daveg/stuff/090508_JIIOccIII.PNG - I'll let Dave tell to the rest.)

[bird]

Thanks for the comments, it's very exciting to see these sort of results, especially in the not-so-stellar conditions at that time.

Checking on sizes... Europa is 0.8" and Ganymede is 1.4".

cheers, Bird

[AstroJunk]

Here is the prediction form Occult watcher (worth a download if you don't already have one: http://www.hristopavlov.net/OccultWatcher/OccultWatcher.html)

Great match.

[bird]

Thanks, I've printed out the predictions from here:

http://asa.usno.navy.mil/SecF/Jupiter.html

cheers, Bird

[astroron]

Great animation Anthony:) very impressive:thumbsup:

[DaveGee]

Thanks Jonathan, I'm kind of embarrassed that my pathetic light curve is mentioned on this thread.:sadeyes:

Anthony, that animation is most impressive. WOW :thumbsup:

I have taken the liberty of posting the link to the animation on the IOTA (mainly American) and PLANOCCULT (mainly European) occultation egroups.

If you have not done so already, may I suggest you create a light curve and report and post it to IMCCE (part of Paris Observatory).

[bird]

Dave, I'm working on the light curve bit now, not having done this before I'm not entirely sure what the right thing is to do here... I was thinking of simply accumulating all the light in each frame and using that as the "value" for each frame. Plotting that will clearly show the dropoff during the event, and the relative values between frames should be ok. I have no idea what sort of "absolute" values I could produce as nothing is calibrated.

cheers, Bird

[bird]

Dave, here's my first go at a light curve, not sure what it means or if it's useful.. this is just the total flux in each of the animation frames, you can see how much the seeing variations cause havok...

cheers, Bird

[Paul Haese]

Excellent work Anthony, was wanting to capture this myself, but cloud once again.

Having said that, I can think of no other person whom I would like to see capture this event. Terrific stuff. :thumbsup:

[bird]

Thanks Paul.

Dave, ignore the graph above, I've found a much better solution and will post a new version later. I've added simple flux accumulation to ninox, now it can spit out a csv from all the raw frames - all 21000 of them :-)

cheers, Bird

[jjjnettie]

Jaw dropping stuff Anthony.
Amazing.

[DaveGee]

Hi Anthony, The more samples, the smoother the curve, Can give a reference time? To the nearest second is OK for these events. Can you synchronise your PC clock to a time server. Dimension4 works well.

Regards
Dave

[Lester]

Top capture Anthony.

[h0ughy]

fantastic results Anthony.

[allan gould]

Absolutely brilliant, Anthony

[AstroJunk]

Don't listen to him, Dave is one of the finest observers in his field of astronomy (sorry for further embarrasment:P).

[bird]

Dave, I have about 21000 frames covering the event, each one has the UT embedded accurate to a small fraction of a second :-)

cheers, Bird

[Dennis]

Hi Anthony

Wow – you have done something quite special here, quite extraordinary. The occultation is one of the most beautiful animations I have ever seen, not only in what it reveals but in the planning and execution behind it all.

This is truly one of those rare, breakthrough moments in amateur planetary imaging to be savoured to the full. Well done Bird, well done indeed.

Cheers

Dennis

[iceman]

Brilliant animation, very well captured.

How did you decide on 30s per run? If it was Io would you go even shorter?

There's a few more like this coming up this season - can't wait to see more of them.

[Dennis]

In recognition of Anthony’s outstanding animation of Europa and Ganymede, can I suggest that we present him with the inaugural RAPMO trophy; aka the “2009 Römer Award for Planetary Moon Occultations".:whistle:

In 1676, Ole Römer (http://en.wikipedia.org/wiki/Ole_R%C3%B8mer), a Danish astronomer working at the Paris Observatory, made the first real measurement of the speed of light. He made a systematic study of Io, one of the moons of Jupiter, which was eclipsed by Jupiter at regular intervals, as Io went around Jupiter in a circular orbit at a steady rate.

Römer found that for several months the Io eclipses lagged more and more behind the expected time, but then they began to pick up again. In September 1676, he correctly predicted that an Io eclipse on November 9 would be 10 minutes behind schedule. He explained that as the Earth and Jupiter moved in their orbits, the distance between them varied. The light from Io took time to reach the earth, and took the longest time when the earth was furthest away. When the Earth was furthest from Jupiter, there was an extra distance for light to travel equal to the diameter of the Earth’s orbit compared with the point of closest approach.

Cheers

Dennis

[Glenn Dawes]

I too would like to offer my congratulations Anthony.
You made Space Weather:

http://spaceweather.com/

It is very rare, especially when you realize the earth only passes through the Jupiter satellite plane ever 6 years.

There are lots of Jovian mutuals coming up this year. They are detailed on p 115 of Astronomy 2009. I think the eclipses would be the most appealing for visual observers. There is one on the morning of May 17 when Callisto eclipses Io.

Regards

Glenn

[StephenM]

That's brilliant Anthony!!! Very well done!

Cheers,
Stephen

[bird]

Yep, that one is on my list :-) It lasts almost 11 minutes too!

Guys, there are many more Jovian occultations and eclipses coming up - in decent seeing anyone with a well collimated and cooled scope can create these animations... we only get a chance once every 6 years, and the next time Jupiter will be low in the north for us, so effectively it will be 12 years until this chance comes around again!

ie you should all have a go at this, it's lots of fun and you can get a result that shows no surface details at all and still feel happy :-) a rarity in the planetary imaging world.

cheers, Bird

[jjjnettie]

I second that Dennis.

[Liz]

Amazing animation, and congrats for Spaceweather!!!!!

[bird]

Thanks Mike. The 30s for each frame roughly came out of wanting 1200 raw frames, actually its about 31.5 seconds or something @ 38fps.

I figured that 1200 raw frames should yield at least 250 decent ones to process so that's what I did for each frame of the animation. Some of the later groups of 1200 had more than 250 good frames but I limited them all to 250 so the frames would all look roughly the same with identical processing.

If the seeing was better then I could shorten the groups to 600 frames, still looking for 250 to process and that would be about 15 seconds per frame.

cheers, Bird

[spacezebra]

Congrats Anthony on an excellent capture, animation and the top news story on SpaceWeather!

What a great achievement.

Cheers Petra d.

[pelu]

Incredible, Anthony. I have made visual and photometric Phemus a lot of years ago, but this is a higher level...

[tonybarry]

This is splendid stuff. Congratulations!

Regards,
Tony Barry

[prova]

Well done Bird, I think we're all waiting to see what you can do with the 16"!

Cheers
Prova

[Terry B]

This is very clever.
Well done.

[g__day]

Very, very well done and thanks for sharing!

[DavidU]

Awesome job Bird !
Excellent, can't say enough.:thumbsup:

[dcalleja]

This is just remarkable. I've never actually seen this imaged before

[Ric]

Amazing imaging Bird.

What a fantastic prize to capture.

Top stuff indeed.