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Uranus - August 16 (my best so far)

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#1 Alexander Obukhov

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Posted 17 August 2014 - 12:15 PM

Good day everyone!
It is, i believe, my best picture of Uranus so far.
4 stacks were stacked and deconvolved.

 

No any trace of spots (as on the some of my previous pictures with similar CM).
It seems that if spots are there (and can be detected), they could be only on some almost constant location somewhere between CM=70 and 150

 

Interval: 2014/08/16 | 22:10 - 2014/08/17 | 0:20

 

2014/08/16 23:15(UT)  CM=249.8 (130 mins: CM=227...269)

 

280mm S-C (Celestron C11), QHY5L-2, 1.8x Barlow, Baader >610 nm
Seeing 8-9/10, Trans 9/10

35000 frames X 100ms

Attached Files


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#2 John Boudreau

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Posted 17 August 2014 - 01:28 PM

Superb result Alexander! Fine work!

 

:waytogo:



#3 cyberplocos

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Posted 17 August 2014 - 10:19 PM

Great image Alexander, as always!  :bow:  :bow:  :bow:

 

Which is your processing routine? Did you use Registax for stack or AS!2? 

 

Keep up up the great work!  :waytogo:

 

best regards,

Fabio and Gabriela - OTUS Observatory



#4 CPellier

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Posted 18 August 2014 - 02:36 AM

Superb, belts are well defined :)



#5 stanislas-jean

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Posted 18 August 2014 - 03:52 AM

Good day everyone!
It is, i believe, my best picture of Uranus so far.
4 stacks were stacked and deconvolved.

 

No any trace of spots (as on the some of my previous pictures with similar CM).
It seems that if spots are there (and can be detected), they could be only on some almost constant location somewhere between CM=70 and 150

 

Interval: 2014/08/16 | 22:10 - 2014/08/17 | 0:20

 

2014/08/16 23:15(UT)  CM=249.8 (130 mins: CM=227...269)

 

280mm S-C (Celestron C11), QHY5L-2, 1.8x Barlow, Baader >610 nm
Seeing 8-9/10, Trans 9/10

35000 frames X 100ms

Hi Alexander,

I observed on the same night at 23H30UT, so not far your picture time.

I presume the spots are still present but diming it seems.

Anyway, again a good picture.

Good luck.

Stanislas-Jean



#6 Alexander Obukhov

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Posted 18 August 2014 - 06:56 AM

Thanks, guys.
----
I use registax 5 for Uranus (In my opinion, it is more reliable for single-point stacking of small planets).
After wavelets i make correction of diffraction artifacts on the limb (in the Photoshop mainly). It is necessary. You simply cannot make raw artifact-free image of Uranus with 300 mm telescope. First diffraction ring is very bright (especially on the instrument with large central obstruction, i think).

Before stacking i make dark/flat calibration, 2x resampling and cropping of SER file in one self-made utility.
---
Stanislas, it is unclear by now, how spots are moving and whether they even visible in R/NIR. I think, we need some undoubtful images from large instrument (or may be more good images from small). To be honestly, i don't see how it may be possible to catch spots visually if they are not visible on the R/NIR picture which is  taken in excellent conditions.



#7 Alexander Obukhov

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Posted 18 August 2014 - 07:09 AM

About diffraction artifacts:
Wavelet preview for one of the stacks is shown below. Here you can see potential brightening of the limb after wavelet sharpening. It always be with amateur-size telescope and it must be corrected manually. I'm sure many of you know it already. Ring artifact on Mars has the same origin

Attached Files


Edited by Alexander Obukhov, 18 August 2014 - 07:11 AM.


#8 stanislas-jean

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Posted 18 August 2014 - 09:20 AM

Thanks, guys.
----
I use registax 5 for Uranus (In my opinion, it is more reliable for single-point stacking of small planets).
After wavelets i make correction of diffraction artifacts on the limb (in the Photoshop mainly). It is necessary. You simply cannot make raw artifact-free image of Uranus with 300 mm telescope. First diffraction ring is very bright (especially on the instrument with large central obstruction, i think).

Before stacking i make dark/flat calibration, 2x resampling and cropping of SER file in one self-made utility.
---
Stanislas, it is unclear by now, how spots are moving and whether they even visible in R/NIR. I think, we need some undoubtful images from large instrument (or may be more good images from small). To be honestly, i don't see how it may be possible to catch spots visually if they are not visible on the R/NIR picture which is  taken in excellent conditions.

Franly I cannot answer about your question precisely.

What I can answer is on last 14th with the 254mm the spots were obvious.

On the 16th I started with the refractor, the planet being around at 26° elevation and then change the bigger scope if this will be still observable but with a better contour and brightness. The exercise was not possible because after the moisture deposition the sky conditions became worst by the seeing.

You know with such apertures, moderate, there is a world between "seen" and resolved. The answer could be here, this mean the contrast as you know faint but accessible still.

Now the move of the spots can be predicted as we know the atmospheric circulation speed versus the planet lattitude. Few (°) of drift may be necountered per day.

This is a challenge for determining the speed rotation with such very dim features, on short periods (1 or 2 weeks) hard to do with an acuracy.

When we catch these brightness discontinuities visually we are in a certain way satisfied of the results.

Persevere in your works on, this shall be over a greater period you will conclude something.

Stanislas-Jean



#9 stanislas-jean

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Posted 18 August 2014 - 09:43 AM

 

Thanks, guys.
----
I use registax 5 for Uranus (In my opinion, it is more reliable for single-point stacking of small planets).
After wavelets i make correction of diffraction artifacts on the limb (in the Photoshop mainly). It is necessary. You simply cannot make raw artifact-free image of Uranus with 300 mm telescope. First diffraction ring is very bright (especially on the instrument with large central obstruction, i think).

Before stacking i make dark/flat calibration, 2x resampling and cropping of SER file in one self-made utility.
---
Stanislas, it is unclear by now, how spots are moving and whether they even visible in R/NIR. I think, we need some undoubtful images from large instrument (or may be more good images from small). To be honestly, i don't see how it may be possible to catch spots visually if they are not visible on the R/NIR picture which is  taken in excellent conditions.

Franly I cannot answer about your question precisely.

What I can answer is on last 14th with the 254mm the spots were obvious.

On the 16th I started with the refractor, the planet being around at 26° elevation and then change the bigger scope if this will be still observable but with a better contour and brightness. The exercise was not possible because after the moisture deposition the sky conditions became worst by the seeing.

You know with such apertures, moderate, there is a world between "seen" and resolved. The answer could be here, this mean the contrast as you know faint but accessible still.

Now the move of the spots can be predicted as we know the atmospheric circulation speed versus the planet lattitude. Few (°) of drift may be necountered per day.

This is a challenge for determining the speed rotation with such very dim features, on short periods (1 or 2 weeks) hard to do with an acuracy.

When we catch these brightness discontinuities visually we are in a certain way satisfied of the results.

Persevere in your works on, this shall be over a greater period you will conclude something.

Stanislas-Jean

 

Documents are issued on the Alpo japanese site.

The picture given at the top is the more interresting as when pushing the parameters at my sony screen, spots are (2), faint, but are.

This image appears less resolving but has data into.

So what the difference between the 2 images? The site of publication seems has not the same capacities (CN and alpo).

Stanislas-Jean



#10 Alexander Obukhov

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Posted 18 August 2014 - 10:13 AM

I already wrote about this picture with "spot" here:

http://www.cloudynig...g/#entry6165322


Edited by Alexander Obukhov, 18 August 2014 - 10:15 AM.


#11 phileefan

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Posted 18 August 2014 - 10:58 AM

Alexander,

 

Very nice capture! You have some really good viewing conditions there in Russia. Thanks for sharing. Clear skies.  :goodjob:



#12 Sunspot

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Posted 18 August 2014 - 11:08 AM

Awesome image! I'm interested by the process to eliminate the diffraction artifacts. The process is probably simple, just wish I knew what to do. :waytogo:

 

Paul M.



#13 Alexander Obukhov

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Posted 18 August 2014 - 11:29 AM

It strongly depends on the shape of the artifact.

The easiest way is to use levels with the mask created from the sharpened image itself, because in this case levels automatically will affect more on bright parts of the image. You just must ensure  that central part is not being brightened. The inverted image as the "mask for mask" can help for that.


Edited by Alexander Obukhov, 18 August 2014 - 12:04 PM.


#14 Alexander Obukhov

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Posted 18 August 2014 - 11:38 AM

Mick, Actually a good seeing is not very often here.  :(

But if you shoot very often (and with some patience ;)), you can always catch the good conditions.


Edited by Alexander Obukhov, 18 August 2014 - 11:39 AM.


#15 sfugardi

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Posted 18 August 2014 - 11:46 AM

Alexander, Superb results! Best resolved Uranus from any C11 I've ever seen. Getting 10fps capture at 1.8x is very impressive. I picked up an RG610 filter late last year but have not tried it on Uranus or Neptune yet. Congradulations and thanks for posting

 

Regards,

Steve



#16 Alexander Obukhov

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Posted 18 August 2014 - 12:03 PM

Thanks, Steve. 10 fps is not problem with QHY5L-2 if transparency is good.



#17 stanislas-jean

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Posted 18 August 2014 - 01:39 PM

I already wrote about this picture with "spot" here:

http://www.cloudynig...g/#entry6165322

Data are published as well on the Alpo jpn site.

Make your market with. There is no contradiction in fact.

The below image you issued is less interresting than the upper one, indeed less pretty.

Stanislas-Jean



#18 Marc Delcroix

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Posted 19 August 2014 - 04:17 AM

Hi Alexander,

 

This is an excellent image, showing nicely the belts - and "only" with a 280mm, congratulations !

 

But no spot unfortunately :(



#19 Sunspot

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Posted 19 August 2014 - 09:38 AM

It strongly depends on the shape of the artifact.

The easiest way is to use levels with the mask created from the sharpened image itself, because in this case levels automatically will affect more on bright parts of the image. You just must ensure  that central part is not being brightened. The inverted image as the "mask for mask" can help for that.

I'm sure that's the theory. Now to find a way to translate it to a procedure.



#20 Alexander Obukhov

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Posted 19 August 2014 - 02:10 PM

Thanks, Marc. Today i catched again some good data and there is no spots too (as it seems to me now). May be the spot is visible only in relatively far IR (>1mkm) ?

 

 

It strongly depends on the shape of the artifact.

The easiest way is to use levels with the mask created from the sharpened image itself, because in this case levels automatically will affect more on bright parts of the image. You just must ensure  that central part is not being brightened. The inverted image as the "mask for mask" can help for that.

I'm sure that's the theory. Now to find a way to translate it to a procedure.

 

I believe it is impossible. Shape of the artifact depends on the wind, thermal effects in the tube and other random factors.








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