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Mars - animation of high-altitude ice cloud

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#1 WayneJ

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Posted 21 March 2012 - 01:10 PM

Hi all,

Here's a 5-frame animation in green-light of something I imaged on the evening of March 20 (2:15-2:51ut, March 20) -- that's two nights ago. I had no idea what this was and after receiving information from a number of sources, it's most likely a high-altitude water-ice cloud over the Acidalia region. These are not particularly uncommon and have been imaged on occasion before.

Also, I know of at least one other imager in the eastern U.S. that captured the phenomena last night, so if you captured this CM in your images, you should check careful to see if you got it too. Note that it shows up best in green and blue light and becomes nearly invisible in IR (at least from my images.)

Click here for the Animation (750k)

Also, here's an RGB image (around 2:51ut) showing the feature on the upper right side. I haven't processed all the data from the 20th or from last night (when I captured it again), but I think I have some better images showing the cloud over the limb with a slight separation from the planet. The seeing was running in the 8-9/10 range on the evening of the 19th and 7-8/10 last night.

Posted Image

Regards,

Wayne

#2 john rozakis

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Posted 21 March 2012 - 01:30 PM

Wow Wayne ! Great capture ! :waytogo:

#3 James W.

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Posted 21 March 2012 - 01:38 PM

Here is my blue channel image from last night (21st) taken at 0258UT that shows your cloud at about the 12 O'clock posistion. I stretched it with levels some to bring it out better.

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#4 swalker

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Posted 21 March 2012 - 01:45 PM

Excellent Wayne- very odd phenomena.

#5 James W.

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Posted 21 March 2012 - 02:03 PM

Here is another blue channel taken at 0307UT on the 21st and a link to an animation of both the 0258 and 0307 images.

http://howardastro.i...ageViewsIndex=1

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#6 CPellier

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Posted 21 March 2012 - 02:35 PM

Wayne and James : very good work ! Especially, good B images :)

#7 Space Cowboy

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Posted 21 March 2012 - 03:10 PM

Incredible resolution! Wow!

#8 Rutilus

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Posted 21 March 2012 - 04:24 PM

Very good captuere, interesting feature.

#9 Yuri_18

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Posted 21 March 2012 - 04:34 PM

Incredible!!

#10 lcd1080

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Posted 21 March 2012 - 05:08 PM

I measured the height of the cloud based on the known diameter of the planet and the number of pixels that the cloud extends above the surface. The height is approximately 100 kilometers which is interesting because that's the maximum height to which particulate matter rises during planet wide dust storms. From what I've read gaseous clouds don't rise to anywhere near that altitude which is the very top of the Martian atmosphere.

Pete Nerbun

#11 Kecktastic

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Posted 21 March 2012 - 05:09 PM

Very impressive Wayne & I see James has also captured the same feature, well done James.

Most excellent "G" channel data Wayne and nice animation, thinking back, I recall Asi also captured a similar feature a few weeks ago, though not as prominent as in your "G" channel.

Top Stuff.
Regards
Trevor

#12 JimP

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Posted 21 March 2012 - 05:12 PM

Here is one of my images from last night plus the blue channel just to confirm.

best,

Jim Phillips

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#13 JimP

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Posted 21 March 2012 - 05:14 PM

Here's the color image.
TMB 8" F/9
Good seeing.

Jim

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#14 JimP

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Posted 21 March 2012 - 05:16 PM

Not sure what it is. Ice cloud? Perhaps but if it is it certainly is not usual nor is it common. This would be Highly unusual for an ice cloud.

best,

Jim Phillips

#15 JimP

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Posted 21 March 2012 - 05:22 PM

Here is what Richard McKim of the BAA e-mailed me after I sent him my images:

"If it's real then it's staggering! I am looking for other images at the same time but thanks in advance. A dust storm at that location at this season would be unheard of. Have you eliminated the possibility of some filter defect by rotation during the session, perhaps, or was it only noticed at processing?
All the best
Richard"

#16 Lsummers

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Posted 21 March 2012 - 05:22 PM

We've seen high-altitude water-ice clouds on Mars in the past. Never to my knowledge has one so clearly been captured in ground-based amateur imagery. Certainly a rare and exciting event.

Well done Wayne! Thank you for spotting this and bringing it to everyone's attention!

Larry

#17 Bird

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Posted 21 March 2012 - 05:25 PM

Well done to Wayne and the others that captured this phenomenon! Shows that there is still a lot to be discovered on nearby planets...

cheers, Bird

#18 JimP

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Posted 21 March 2012 - 05:45 PM

Whoops, here is a second e-mail from Richard McKim:

"Dear Jim:

Thank you. In fact I misunderstood your ......-18LTL image, as I was looking more at the large light area you had artificially highlighted rather than the terminator projection. Before your blue image arrived on its own I had assumed, from quickly reading, that the artificial area was the new feature! It is all perfectly reasonable-looking now that I have your blue image and, although we don't see much phase visually yet there will be a slight and growing phase defect on the following side.

Although quite evident the projection is no doubt standing out even more because the processing of any image has caused the terminator to darker somewhat (and in the case of Venus to recede) to leave the projection more visible. There is a history of high latitude martian projections. I am thinking of certain HST images from the 1990s, and visual observers have certainly detected many, and I can recall quite a few examples even in my own Mars reports. I don't think our amateur images were good enough to catch them before 2003. I have examples in the 2003 BAA Mars report which is posted as a pdf at www.britastro.org\mars...............

This particular one you have caught so nicely is certainly on the large side, and I hope you will get the chance to repeat the observation at the same CM over several nights. And that brings me to ask if you can compute the CM and put it on each image because it does save looking it up. From the position of Propontis with regard to the morning terminator I would say that the attached image by Efrain Morales is really pretty similar to yours in CM but is dated two days earlier (March 19d 02h 31m UT). I notice that he shows the same effect but it is less visible. It is easily missed unless one enlarges the image.

I will of course search for others. I receive a lot of material which is not uploaded to any of the image archiving websites.

Let me know what you think.I am off to bed as it is getting late here and I must teach first thing in the morning!

With regards

Richard"

#19 Jim Chung

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Posted 21 March 2012 - 06:01 PM

Just wanted to confirm that I also captured this strange feature last night which I thought was a processing artefact.


Jim

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#20 rumples riot

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Posted 21 March 2012 - 06:31 PM

Yet another land mark breached in planetary imaging. Well done guys impressive work.

#21 Mike Phillips

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Posted 21 March 2012 - 07:49 PM

Hey JimP, how'd you get clear, t-storm free skies? We've had some rain or thunder nearly every 6 hours for 4 days straight now!

WayneJ, that is very awesome!!!

Mike

#22 WayneJ

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Posted 21 March 2012 - 08:28 PM

Thanks all for your comments and contributions. This is certainly an interesting event and the more data that's contributed will certainly be helpful to the experts in sorting-out what we might be looking at. The prevailing theories are an orographic cloud at an unprecedented altitude and a dust plume (although that would be quite an plume!)

Here's another image from the day prior to noticing the cloud (for lack of a better term at present) with the phenomena appearing as a "nipple" while transiting the disc.

Posted Image

Wayne

#23 Az Frank

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Posted 21 March 2012 - 09:42 PM

Great catch of an amazing event Wayne! Congrats to you and Jim and others! Great stuff!

#24 Flying_Fox

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Posted 21 March 2012 - 10:44 PM

Excellent results everybody! Since I was imaging Mars at the same time between 2:34 and 3:11 UTC, I just quickly processed the green channel from one of the brighter AVIs and can also confirm that it is there. Since this is from NexStar 8i SE the cloud is very small, but noticeable.

Here is my green channel from March 20, 2012 03:11 UTC, overprocessed in Registax to highlight the feature. I might try to do the animation too when I have time.

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#25 swalker

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Posted 22 March 2012 - 07:09 AM

I suspect this is a rare trick of lighting, not a cloud. I measured the position of the feature in WinJUPOS, and (if I did the measurements correctly) it appears to correspond to the highlands that surround the large Martian craters Newton and Copernicus. Thus the area in question gets sunlight before the surrounding region at only this time of year. Additionally, its appearance is exaggerated due to sharpening; the area of our planetary images most distorted by sharpening is the limb.
The trick of lighting also explains its appearance in all wavelengths from near-IR to Blue.
I could be wrong, so feel free to poke holes in my hypothesis.






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