17 replies to this topic

[MvZ]

This evening I again imaged Venus, and started a couple of hours earlier. Seeing was much better, so I just kept on imaging and imaging.

The animation consists of 23 processed stacks of about 4.000 frames each, stacked using AutoStakkert (.. it would take days to do this in Registax), and further processed in Photoshop. Each stack was processed in exactly the same way, so that didn't take too much time either.

Sorry for the 'very cool' tag in the title, I normally don't like that stuff, but I was just really happy with these results:

http://www.astrokraa...R_Animation.gif

I'll try to upload a youtube version tomorrow, because animated gifs don't always do the images justice.

Now I quickly go to process a Saturn image of this evening, results will follow within the hour (I hope).

[OMAR]

Emil this is very cool indeed!!
Looking forward to see Saturn.
Bests,

Omar

[Yuri_18]

Superb!

[Kokatha man]

No apologies nor justification needed there Emil - very cool indeed!!!

Which filter/s are used here....?

[Freddy WILLEMS]

Fantastic Emil, Very Cool indeed.
Love to see that Venus gets skinned...

[MvZ]

Thanks all!
Kokatha man, I used an Ir-pass filter (>807nm) for these recordings; it is most robust against seeing, and the cloud contrast are slightly higher than in red light.

Attached is also what Venus looks like through Astronomik RGB filters, and an Astronomik >742nm IR pass filter. Also from last evening.

Interestingly, the contrast in green and red is not all that different from the IR recordings. Again I'd like to stress out the importance of capturing with noise when using an 8-bit camera. You NEED the noise to end up with a stack that has more than 8-bit in data. The sweet spot for my modified DMK21 seems to be at a gain of about 700. If I had recorded at a low gain, all these details would be lost...

Attached Thumbnails

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[astrodoctor]

Amazing!

[ZielkeNightsky]

I love these images, very good work.

[Mert]

Superb Emil, great work!

[Kecktastic]

Very impressive work Emil and most interesting analysis of the performance of your camera.

Regards
Trevor

[Kokatha man]

< Kokatha man, I used an Ir-pass filter (>807nm) for these recordings; it is most robust against seeing, and the cloud contrast are slightly higher than in red light. .>

Thanks Emil - are you saying simply that without the values of gain that inherently create noise with 8 bit data accumulation you aren't able to capture these cloud details (which seems to be so demonstrable in your "low" and "high" gain examples) - or something more than this....?

[MvZ]

Yes, that it what I'm saying, although it might not be as 'big a deal' as I first thought it was (I just hadn't tested it before, I only tested two conditions: lowest gain, and gain at 700). The image does look really flat and contrasts are lower when I record Venus at the lowest gain setting. But when I increase the gain to about 500, that flatness (and lack of contrast) is gone, anything above that gain value just adds more noise, and doesn't do anything to the contrast.

[Kokatha man]

Thanks for clarifying that Emil.....for a moment I thought perhaps you were suggesting some bizarre characteristic of ccd's and 8 bit data accumulation when noise was present at high levels....!

I guess what we're seeing here is that for a particular system (yours!) you need those types of gain/exposure to bring out these details.....sure, not "as big a deal" but an interesting observation nonetheless that'd be interesting to compare in other apertures, imaging systems and other than 8 bit to see if these "fuller" exposures are required to discern Venus's cloud details?

I think it's making these sorts of observations and getting others to test them that is a big and important aspect of learning for us all....!

[lukasik]

Hi Emil,

these, and all your Venus work lately is just outstanding. Keep it coming!

Regards,

Bob

[MvZ]

I think you are right Kokatha, but for testing to be of any use, it has to be done under pretty good seeing conditions, and you have to have a bright object to play around with (but we might just simulate a bright 'venus like' planet by imaging Jupiter with really low magnification. Good testing takes time, and who wants to test when you can also just make normal recordings as usual.

But I for one will be doing some more testing on these issues with the lower gain values on the DMK21 (< 500). Then at least I know which settings to avoid for the different planetary targets.

I just performed a quick calculation, and came to a speed of about 220 km/hour for some clouds at the center of the planet. I'll do a better calculation later on to improve the accuracy, I might be off by about 50km or so now, but not much more than that I think.

[sfugardi]

Emil, Stunning animation & images! Cloud detail is very impressive. Thanks for posting

Regards,
Steve

[Kokatha man]

I think you are right Kokatha, but for testing to be of any use, it has to be done under pretty good seeing conditions, and you have to have a bright object to play around with (but we might just simulate a bright 'venus like' planet by imaging Jupiter with really low magnification. Good testing takes time, and who wants to test when you can also just make normal recordings as usual.

But I for one will be doing some more testing on these issues with the lower gain values on the DMK21 (< 500). Then at least I know which settings to avoid for the different planetary targets.

I just performed a quick calculation, and came to a speed of about 220 km/hour for some clouds at the center of the planet. I'll do a better calculation later on to improve the accuracy, I might be off by about 50km or so now, but not much more than that I think.

I agree entirely with your comments here Emil - I guess what i was really referring to is that within the objectivity of our own setups on any one imaging session (assuming the seeing isn't going up and down!!! ) it's being prepared to do a little experimenting that assists us each to know what the parameters are for optimum imaging of Venus, or Jupiter etc, etc.....and with the info you've given here it'll be something I'll run several avi's at different settings so I can determine if it's relevant to my own equipment (specifically for Venus!)

But of course when you're aware of what works and you get that good seeing there's this very strong compulsion to stick with what you know and not waste the possibility of a swag of good avi's/end images rather than "fiddle"....!

And as for those cloud velocities, that's really rockin' & rollin' at 220km/hour.....and I guess taking these "guestimations" at the meridian is where we'd get the nearest to linear/flat distance measurements vis angular displacement.....

Perhaps it's all incidental to the main game, but I myself DO find your "experimenting" with filters, gain etc something most interesting and provocative especially re what I might attempt to emulate myself - when i get this "super-tuning" of my C11 finished!!!

[blackhaz]

Superb work, Emil! Never seen Venus animation before.