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Mars - July 6 - Good seeing, poor transparency

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#1 Pete Gorczynski

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Posted 07 July 2020 - 01:06 PM

Transparency started out so poor that you barely see Mars with the naked eye. If figured if the conditions persisted, monochrome imaging would be very difficult. So I decided to try the one shot color cam. I had to go with a 40ms exposure with the gain nearly maxed out. With those settings the frame rate will no more than 25fps.

 

The sky decided to clear out a bit later so I was able to do a monochrome RGB sequence. R and G were captured at 200fps while the B was at 100fps. Seeing was good all along. Focus was always easy to achieve. This was not really a fair comparison of the two cameras, but it still amazes me how well the OSC performed in such poor transparency.

 

The RGB image came out much sharper. There does appear to be some dust activity south of Cimmerium. Other than the polar cap, the dust cloud was the brightest feature in the G channel. Also, Arsia and Olympus appear as dark spots near the terminator. Someone correct me if I'm wrong, but believe that indicates considerable atmospheric dust. It enhances the contrast of the mountains.

 

Pete G.

 

Mars-2020-07-06-Color.jpg

 

Mars-2020-07-06-0850-RGBrev1.jpg

 

 

 


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#2 AstroDan2015

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Posted 07 July 2020 - 01:53 PM

Well done Pete! waytogo.gif  That's a good update.



#3 KiwiRay

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Posted 07 July 2020 - 02:03 PM

Excellent work under difficult conditions, Pete.  You've confirmed my observation of dust activity at the same location on July 6.  According to Paul (Sunspot), the dust was already gone by this morning.


Edited by KiwiRay, 07 July 2020 - 02:23 PM.


#4 happylimpet

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Posted 07 July 2020 - 02:34 PM

Lovely stuff.

 

Yes, thats my interpretation of the visibility of the Tharsis volcanoes.

 

When I imaged them a few days ago it was Olympus Mons and Ascraeus Mons that were showing, so I guess its moving about.



#5 sfugardi

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Posted 07 July 2020 - 04:37 PM

Pete, excellent images! I am still waiting for my 290MM first light. Did you tune the ADC with the 120MC then just drop in the 290MM with those settings? Thanks for posting

 

Regards,

Steve



#6 Pete Gorczynski

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Posted 07 July 2020 - 06:40 PM

Pete, excellent images! I am still waiting for my 290MM first light. Did you tune the ADC with the 120MC then just drop in the 290MM with those settings? Thanks for posting

 

Regards,

Steve

Thanks Steve. I usually tune the ADC with the 290MM using a Wratten #47 filter.  I align the voilet blob to the IR spot that I see on the preview feed. I use a nearby star at roughly the same elevation. The #47 filter has a dedicated spot in my motorized 7 position filter wheel. For the images posted here today I just took a best wild guess for the ADC tune since the transparency was so poor.  I used a previous setting from another Mars session. I am pretty much a Mars only imager now.  I am thinking of totally ditching the ADC unless super seeing conditions occur and the B channel is super steady. I don't really think it matters that much with a filtered monochrome camera, especially when Mars is over a 45 degree evevation.

 

Pete G.


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#7 kevinbreen

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Posted 07 July 2020 - 06:42 PM

Great images 👌

#8 sunnyday

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Posted 07 July 2020 - 10:39 PM

nice details thx .



#9 Foc

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Posted 08 July 2020 - 02:11 AM

Very nicely processed dusty Mars



#10 Pete Gorczynski

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Posted 08 July 2020 - 07:37 AM

Here is my best and final image for this session. The color is better than in the previous posts. The dust cloud has rotated into view a little better. Also interesting are the spoke-like features in the polar cap.

 

Pete G.

 

Mars-2020-07-06-0911-RGBrev1.jpg

 


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#11 CPellier

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Posted 08 July 2020 - 07:55 AM

Also, Arsia and Olympus appear as dark spots near the terminator. Someone correct me if I'm wrong, but believe that indicates considerable atmospheric dust. It enhances the contrast of the mountains.

 

It can, but actually there it is simply because they are casting shadows close to the terminator with grazing sunlight.

Excellent images especially with the ASI290MM!


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#12 ch-viladrich

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Posted 08 July 2020 - 01:13 PM

Very nice !




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