Mars Image 2020/09/27(UT)
三品利郎,井上 修,柚木健吉,荒川 毅,畑中明利,黒田瑞穂,熊森照明,遠藤宏次,佐々木一男,尾崎公一
Pericles Enache,Anthony Wesley,Mark Lonsdale,Robert Heffner,Du Jin Kim,Christofer Mauricio Baez Jim,Silvia Kowollik,Chris Nuttall,Kev Wildgoose,Willian Souza,Manos Kardasis,Vlamir da Silva Junior,Niall MacNeill
T.Mishina,P.Enache,O.Inoue,Anthony.W,K.Yunoki,T.Arakawa,M.Lonsdale,A.Hatanaka,M.Kuroda,R.Heffner,T.Kumamori,D_J.Kim,K.Endo,K.Sasaki,C.Baez,K.Silvia,K.Ozaki,C.Nuttall,K.Wildgoose,W.Souza,Kardasis,V.da Silva Jr.,N.MacNeill
≪神奈川県 横浜市 三品利郎≫[Toshirou.Mishina:Kanagawa Japan]
[Pericles Enache,Sao Paulo,Brazil]
≪大阪府 枚方市 井上 修≫[Osamu Inoue. Hirakata-shi,Osaka,Japan]
[Anthony Wesley,Murrumbateman Australia]
≪アンソニ オーストラリア≫
[Kenkichi Yunoki (Sakai City,Japan)]
≪大阪府 堺市 柚木健吉≫
≪奈良県奈良市 荒川 毅≫[Tsuyoshi Arakawa:Nara Japan]
[Mark Lonsdale : [Canberra,Australia]
≪三重県熊野市 畑中明利≫[Akitoshi Hatanaka:Kumano Mie Japan]
≪黒田瑞穂 : 兵庫県 太子町≫[Mizuho Kuroda : Taishi Hyogo Japan]
[Robert Heffner:Osaka,Japan]
≪大阪府堺市 熊森照明≫[Teruaki Kumamori:Ohsaka Japan]
≪埼玉県越谷市 遠藤宏次≫[Koji Endo : Saitama Japan]
[K.Sasaki:Ohsaki-City Miyagi-Prefecture Japan]
≪宮城県大崎市 佐々木一男≫
[Christofer Mauricio Baez Jimenez :Santo Domingo,Dominican Republic.]
[Silvia Kowollik Ludwigsburg,Germany]
[Ki.Ozaki,Sobue Inazawa Aichi JAPAN]
≪愛知県稲沢市祖父江町 尾崎公一≫
[Chris Nuttall : York,UK]
[Kev Wildgoose:Oswestry,UK]
[Willian Souza : Sao Paulo,Brazil]
[Manos Kardasis,Glyfada-Athens;Greece]
《カーダシス マノス:ギリシャ アテネ》
[Vlamir da Silva Junior : Sao Paulo,Brazil]
Update at 2021/12/09
I don’t know whether Andy Casely is more persistent in trying to dodge the clouds than I am,
but hats off to him for capturing images given the overall inclemency of the weather here on the eastern Seaboard of Australia at the moment.
I returned again to my Mars data from 2020, knowing there were some data that I didn't process.
In fact on the 27th of September I did a long series of runs, but only ended up processing the data from later in the session,
as it looked the best. However, on review, there were also some nice conditions early on that evening.
This also gave me an opportunity to see whether I could use the rotation feature in WinJUPOS to mitigate the Mars Edge Rind Effect.〓
The〓first image is the one I did process from that run, with a timestamp of 17:00UT.〓 It has already been uploaded to PVOL and Alpo Japan.
In that image, Elysium Mons, the extinct volcano, is at the Central Meridian to the north (up).
It is the slightly ruddy protuberance, surrounded by a lighter coloured plain.
Sinus Gomer is to the south, below it in the image, like two fingers of dark paint dripping upwards.
The second image is one I just processed from an earlier run that night at 14:43UT.
Notice the beautiful white cloud around the Tharsis Shield Volcanoes at the terminator, with Olympus Mons bulging prominently to their north.
On the other limb at about the same latitude is Elysium Mons, which was rotating into view,
to be central as seen in the first image 2+ hours later.
The Mars Edge Rind Effect can be readily seen at the lower left limb as the dark ring inside it.
This is a diffraction effect, where there is a sudden change from light to dark.
It is real and optical in nature, and therefore hard to get rid of. It does spoil many if not most images of Mars.
I did some work to mitigate the Mars Edge Rind Effect using WinJUPOS and Photoshop as described below.
In the〓3rd image, the artefact has been substantially removed. Please upload this one to PVOL and Alpo Japan.〓
I had wondered if, using the derotation function in WinJUPOS,
I could rotate the later image (17:00 UT) to the same timestamp of the earlier image(14:43 UT) and this was indeed possible.
The result is shown as the 4th image.
Since the edge here was rotated from the later image, where there was no such edge effect, the limb is clean and the detail goes right to the edge.
I brought this into a layer in Photoshop, under the 14:43UT image with the Edge Rind Effect (2nd image) and was able to replace the edge rind affected area with the clean limb.
The only problem was that near the limb there are blue-white clouds,
which show up when edge on, but not so much when we are looking perpendicularly through them at the more central longitudes of the planet.
I had to do some work to match colours and brightness, to retain the blue-white hue clearly present at the limb, due to these clouds.
This did complicate things, and is the reason some of the effect remains since I had to feather in the new area quite a bit so it blended seamlessly.
So yes there is still a touch of the diffraction effect but pleasingly it is vastly reduced. I hope you’ll agree.
Of course, it will not always〓be possible to get a good second image sufficiently displaced in time,
but where possible this technique can be used to reduce the impact of Mars Edge Rind Effect.
If the images are being acquired before opposition, as was the case here,
the image to be rotated will need to be captured after the main image. Conversely,
after opposition, the image to be rotated will need to be before the main image.
This is obviously〓because the hard limb edge moves from one side of the planet to the other over the opposition.
[Niall MacNeill : Wattle Flat,NSW,Australia]
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