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The ring of Uranus from the Pic du Midi !

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#1 J-Luc Dauvergne

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Posted 17 August 2013 - 04:13 PM

Hi,


Last week, I've been to the Pic du Midi observatory for 3 nights, with Sylvain Bouley. The last night was very good. We have seen a very nice sunset with many green flashes : http://youtu.be/GwIphktocoQ, and after the sky was realy clear : http://youtu.be/HyLebsg_BVw
It was so a good night that we have tryed to see the ring of Uranus. At first it was quite a joke, but at the end we had it !
May be that the secret of this image is that we have used the news planetary camera of the telescope : an Andor NEO. It's a sCmos with a very low readout noise : 1 e-

Posted Image

An image of the night before :

Posted Image

And a view with colors. The red layer is done with a >680nm filter.
Posted Image

We have also seen a lot of Perseids :

http://www.astrosurf...mp/IMG_6373.jpg

http://www.astrosurf...mp/IMG_6312.jpg

http://www.astrosurf...mp/IMG_6570.jpg

Jean-Luc Dauvergne

http://astrophotography.fr/

#2 rolo

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Posted 17 August 2013 - 04:20 PM

I took this image with my C14 back in 2006..Many said it was processing artifacts...

Attached Thumbnails

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#3 Freddy WILLEMS

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Posted 17 August 2013 - 08:16 PM

Wow, stunning both of you guys..

#4 wenjha

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Posted 17 August 2013 - 08:50 PM

I can just say: amaznig!

#5 sfugardi

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Posted 17 August 2013 - 08:50 PM

J-Luc, absolutely mind blowing Uranus resolution! That new camera and 1m of glass combination is unbeatable. It is the new benchmark for groundbased scopes. True top shelf, amazing work.
Rolando, very impressive detail back 7years ago with the basic Toucam! You should repeat the effort again with the new high tech cameras.
Thanks for posting

Regards,
Steve

#6 wenjha

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Posted 17 August 2013 - 08:54 PM

Just wonder, what is the capture parameter?
Maybe high QE is more important than low read out noise for plantery imging

#7 PhilCo126

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Posted 18 August 2013 - 03:33 AM

Superbes image Jean-Luc... il faisait beau cette nuit là !
Well done !

#8 stanislas-jean

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Posted 18 August 2013 - 03:37 AM

Great documents Jean-Luc,
Uranus itself and its ring.
Congratulations.
Stanislas-Jean

#9 J-Luc Dauvergne

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Posted 18 August 2013 - 05:53 AM

Just wonder, what is the capture parameter?
Maybe high QE is more important than low read out noise for plantery imging

The exposure time is 200 ms. Each sequence is 10 min long.
For the ring I've also added sequences with 3 and 4 s of exposure with a 900 nm filter, but it's already visible on the sequence with 200 ms of exposure. With 3 or 4 second you loose resolution so it's not realy the ideal strategy.

The QE of this camera is not so good. It's around 57% at the best : http://www.andor.com...cifications.pdf

But on the final image you nearly keep all the dynamic because of the law readout noise. That's why their is still some signal in the very low values of the ring.

#10 PiotrM

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Posted 18 August 2013 - 06:12 AM

Just wonder, what is the capture parameter?
Maybe high QE is more important than low read out noise for plantery imging


If you would want to catch Uranus rings with for example methane band filter then even at 10 min exposures with a DS camera you won't saturate it. It's like very very faint nebula in narrowband imaging - and for that noise must be as low as possible.

Aside of dark current the read noise may vary a lot:
- good sCMOS has ~1e
- Atik 314L+ (DS camera) has ~4e
- ICX618 or alike machine vision camera: 6-8e
- average CMOS in a machine vision camera: up to 20e or more (or like ~3e if it's one of those super-latest designs).

It's easier to pass 1e of noise with the rings signals than 6-8 or more.

BTW. what about active cooled EV76C660 ZWO camera? You get the 3e, 80% QE... and rolling shutter which makes it very un-interesting for typical machine vision cameras (and for planetary if it's must be rolling then let it be really good :D)

#11 John Boudreau

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Posted 18 August 2013 - 06:54 AM

Bravo Jean-Luc! Excellent work! :bow:

That camera must be a dream to use with such a low noise level!

#12 John Boudreau

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Posted 18 August 2013 - 07:04 AM

BTW. what about active cooled EV76C660 ZWO camera? You get the 3e, 80% QE... and rolling shutter which makes it very un-interesting for typical machine vision cameras (and for planetary if it's must be rolling then let it be really good :D)


I agree, a cooled camera with that CMOS could well be the best all-around amateur camera currently possible. I would not be surprised to see something like that available in the next year or two.

#13 J-Luc Dauvergne

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Posted 18 August 2013 - 07:32 AM

If you would want to catch Uranus rings with for example methane band filter then even at 10 min exposures with a DS camera you won't saturate it. It's like very very faint nebula in narrowband imaging - and for that noise must be as low as possible.

Yes, but the problem is the resolution.
I think that the best strategy is to use a CH4 filter with a wide band.
On Uranus and Neptune we are lucky because CH4 band is realy wilder than the CH4 band of Jupiter :

Posted Image

So with a very sensitive camera I think that a 890 nm filter with 50 to 60 nm of fwwm would be ideal.
An emccd camera would be perfect for that, and it's not as expensive as the Andor NEO.

With this kind of CH4 filter you can even detect Uranus ring with a deep sky imager, but the result is a very poor in resolution. Let see for instance this observation by a German group at the botom of this page : http://www.astrode.de/uring2012.htm

#14 CPellier

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Posted 18 August 2013 - 09:46 AM

Superb observation of the rings ! The IR image of the globe is very nice as well.

#15 corpusse

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Posted 18 August 2013 - 11:01 AM

These are amazing. I am in awe.

#16 PiotrM

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Posted 18 August 2013 - 11:14 AM


BTW. what about active cooled EV76C660 ZWO camera? You get the 3e, 80% QE... and rolling shutter which makes it very un-interesting for typical machine vision cameras (and for planetary if it's must be rolling then let it be really good :D)


I agree, a cooled camera with that CMOS could well be the best all-around amateur camera currently possible. I would not be surprised to see something like that available in the next year or two.


There is a lot OEM stuff with EV76C661 so it shouldn't be a long time before someone can release the EV76C660 camera. Even e2v may help as it would be the first thing to really use the *60 sensor.

I have IDS camera with EV76C661 - it works, but I only use rolling mode. In global shutter the noise is a disaster. On Saturn the broad red+IR luminance looks very nice on a black background while blue... shows a lot of hot pixels and noise. Cooling is a must if it would be usable for Uranus and alike imaging.

#17 John Boudreau

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Posted 18 August 2013 - 12:26 PM


BTW. what about active cooled EV76C660 ZWO camera? You get the 3e, 80% QE... and rolling shutter which makes it very un-interesting for typical machine vision cameras (and for planetary if it's must be rolling then let it be really good :D)


I agree, a cooled camera with that CMOS could well be the best all-around amateur camera currently possible. I would not be surprised to see something like that available in the next year or two.


There is a lot OEM stuff with EV76C661 so it shouldn't be a long time before someone can release the EV76C660 camera. Even e2v may help as it would be the first thing to really use the *60 sensor.

I have IDS camera with EV76C661 - it works, but I only use rolling mode. In global shutter the noise is a disaster. On Saturn the broad red+IR luminance looks very nice on a black background while blue... shows a lot of hot pixels and noise. Cooling is a must if it would be usable for Uranus and alike imaging.


A local club member has one of the IDS cameras with the EV76C661, but apparently hasn't used it yet. A few months back he asked me about the latest cameras and I mentioned the IDS series with that sensor along with a couple of other cameras. Although he has some fantastic deep sky imaging scopes, at this time I don't think he's got anything larger than a TMB 203 APO refractor but knowing him, I'm sure that will change very soon and probably in a big way. :grin:

#18 Kecktastic

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Posted 18 August 2013 - 08:34 PM

Congratulations Jean-Luc on this superb work, top stuff.

Cheers
Trevor

#19 wenjha

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Posted 18 August 2013 - 10:34 PM


BTW. what about active cooled EV76C660 ZWO camera? You get the 3e, 80% QE... and rolling shutter which makes it very un-interesting for typical machine vision cameras (and for planetary if it's must be rolling then let it be really good :D)


yes,we have interesting. it just a little hard to get the sensor in market now.
rolling shutter which makes it very un-interesting for typical machine vision cameras.
it also means it won't produce much. so would be very expensive

#20 PiotrM

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Posted 19 August 2013 - 12:38 AM

E2V did a lot of marketing work on this sensor (most sensitive, low noise). Aren't they willing to push it at least to one camera? :)

#21 J-Luc Dauvergne

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Posted 19 August 2013 - 02:14 AM

Thank you for your comments !

#22 mikewirths

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Posted 19 August 2013 - 10:29 AM

Just astounding results Jean-Luc!!!! I am afraid to look at the price of that Andor camera :) Besides the pixel size is too big for my application.....

congratulations!!!

Mike

#23 J-Luc Dauvergne

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Posted 27 August 2013 - 11:48 AM

Thank you mikewirths :)

#24 swalker

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Posted 28 August 2013 - 09:56 AM

Amazing result, Jean-Luc.


#25 Ptarmigan

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Posted 28 August 2013 - 12:14 PM

Nice photos of Uranus! :cool: :bow: The pictures have details visible, which I have never seen through my telescope.


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