Mars - animation of high-altitude ice cloud
Posted 21 March 2012 - 01:10 PM
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 21 March 2012 - 01:38 PM
Posted 21 March 2012 - 02:35 PM
Posted 21 March 2012 - 05:08 PM
Posted 21 March 2012 - 05:09 PM
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.
Posted 21 March 2012 - 05:12 PM
Posted 21 March 2012 - 05:14 PM
TMB 8" F/9
Posted 21 March 2012 - 05:16 PM
Posted 21 March 2012 - 05:22 PM
"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
Posted 21 March 2012 - 05:22 PM
Well done Wayne! Thank you for spotting this and bringing it to everyone's attention!
Posted 21 March 2012 - 05:25 PM
Posted 21 March 2012 - 05:45 PM
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!
Posted 21 March 2012 - 06:01 PM
Posted 21 March 2012 - 06:31 PM
Posted 21 March 2012 - 07:49 PM
WayneJ, that is very awesome!!!
Posted 21 March 2012 - 08:28 PM
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 21 March 2012 - 09:42 PM
Posted 21 March 2012 - 10:44 PM
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.
Posted 22 March 2012 - 07:09 AM
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.