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Ganymede emerges from Jove's shadow + camera comps

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#1 Kokatha man

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Posted 30 October 2012 - 05:09 AM

Hi all - I should start this thread by declaring that these comparisons between the Flea3 ccd & ASI120mm cmos cameras aren't really a genuine comparison at all! - taken 1&1/4 hours apart in "slow" seeing I cannot make a clear difference between the seeing for each except to say it was fairly similar, but "average" at very best.....the faster frame rates of the Flea3 coupled with the fact that I had much more control over the image scale with it would have given it the edge regardless - I have quoted the FireCapture logs for f/l but am always suspicious of the figures therein.....suffice to say that the ASI image was significantly larger in 640x480 resolution onscreen.....

I have mentioned this before and really should have had an adaptor flange made up to drop the TeleVue 2X barlow back to about 1.4X for the ASI, but I have to work with what I've got up here and really, the seeing has just not supported the minimum scale I can attain atm with the cmos camera. :(

The Flea3 image clearly comes out on top but I think I can go much better with both if I get one decent session, even at 49 degrees - Zuo Zhao's images from Shenzhen with this cam and a 10" newt show what good seeing (and good elevation!!!) can achieve.....and at less than 1/3 the cost of the Flea3 or around 1/2 that of the DMK618 (whose frame rate it outperforms) there is no doubt in my mind that it will be a serious competitor in the planetary imaging stakes... :)

Apart from that we're still waiting on that one good night (a "reasonable night" would do very well thank you!! :bow: :lol:) but we shot some iR742nM's with the Flea3 the night before - and it was great to not only watch Io emerge from behind Jupiter's disk but also Ganymede come out of Jove's shadow where it was eclipsed.....the enlarging crescent in the processed images was great to capture (no processing "fancies" here - just straight general treatment grabbed Ganymede's eclipsed appearances.)

Here's the Flea3 & ASI120MM side-by-side.....

#2 Kokatha man

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Posted 30 October 2012 - 05:19 AM

.....and Ganymede coming out of Jupiter's shadow, the first whilst still totally eclipsed.....2nd with a thin sliver of Ganymede revealed and 3rd where G exhibits a clear crescent-shape.....4th which was taken a deal after the other (about 1/2 hour) - we faffed around with a few rgb sequences between the 3rd & 4th iR742nM's, but G's full disk does reveal some small albedo detail in this last image.

That's Io on the other side which "popped" out from behind Jupiter sometime before Ganymede became visible... :)

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#3 Kokatha man

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Posted 30 October 2012 - 05:54 AM

.....and a more-detailed close-up of Ganymede emerging from its' eclipse by Jove. :)

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#4 ZuoZhao

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Posted 30 October 2012 - 06:18 AM

Very nice. I got IO eclipse from G , it just became dimmer and dimmer and cant find detail.

#5 Space Cowboy

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Posted 30 October 2012 - 07:00 AM

Very nice images Darryl! Lots of detail and nicely processed.

#6 Kokatha man

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Posted 30 October 2012 - 07:32 AM

Thanks Guys - it must be the combination of a long journey in extreme heat and getting up every night bar one to image since then.....along with "The Curse of The Electronics-Eating Ants" :shocked: :lol: that has faffed my brain here.....I know this is what happenned from the sequence of avi's including the red channels of the rgb's between the 3rd & 4th images above - but I can't for the life of me "see" the shadow cone coming from Jupiter to envisage how Ganymede comes out of eclipse as it approaches Jove..... :question: :confused: :foreheadslap:

I'm sure the penny will drop - or someone wil explain it before then.....and talking of imaging every night bar one, the seing so far has been quite bizarre.....aside from clouds preventing imaging that night it allways seems to border on "maybe" but transparency is a big issue imo: possibly dust-generated and high up also because it isn't seen as such on the ground..... :question:

But we live in hope..! :bow: :bow: :)

#7 wenjha

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Posted 30 October 2012 - 08:50 AM

Very nice!
to play with 2 cameras at the same is not a easy job!
Hope good seeing will come soon!

#8 lcd1080

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Posted 30 October 2012 - 10:42 AM

I agree with Sam, juggling the idiosyncrasies of two very different cameras is major undertaking especially when one is starved for sleep. You did a good job though Darryl, I think I like imaging the Galilean moons at least as much as Jupiter itself.

Pete

#9 BKBrown

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Posted 30 October 2012 - 02:51 PM

Terrific images Darryl :grin: I like the phase captures in particular. Got to say my hats off to you for the comparo work with the different cams, I find it challenging enough to switch back and forth between my DMK and DBKs...

Clear Skies,
Brian :waytogo:

#10 AztecastroMcJ

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Posted 30 October 2012 - 04:11 PM

Nice collection, work there Darryl, interesting details aswell :)

James

#11 DesertRat

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Posted 30 October 2012 - 05:17 PM

Good work Darryl. Interesting to compare different cameras, but difficult.

That Ganymede eclipse is wonderful!

Glenn

#12 Kokatha man

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Posted 30 October 2012 - 11:47 PM

Thanks for the generous comments fellas! :)

I had to tell Sam that I "whimped out" using the ASI120MM this morning in probably the best seeing so far.....but this has been a pretty exhausting trip in all ways! :shocked:

I allways recollimate if I change optical components - commonsense indicates that it is well-nigh impossible to swap gear and have the collimation identical.....so that is an inevitable factor in changeoevers - at least I have the camera orientations marked on each setup! :grin:

I mentioned above that I was becoming more and more suspicious of transparency as a significant issue in the seeing up here at Tennant Creek - particualrly since we've had reasonably good Diffraction Rings almost every night.....today I think I know why! :(

We went for a test-drive of the old Ford up to Threeways where the roads to Darwin, Mount Isa (Queensland) and Adelaide meet (hence the name!) and just out of Tennant Creek the other side of the small Honeymoon Ranges ridge there is a lot of recently burnt-out scrub...

A small tornado (we call them "willy-willies") was sucking huge volumes of the fine white ash high up into the sky.....it would build up to quite an impressive size and then peter back down, but they form and reform in this country in the heat regularly during the day, so I'm not surprised transparency can be down with a lot of fine white ash suspended in the sky, which could hang up there for a long time..! :(






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