Mars 8 Oct 2020 - good seeing

[geoflewis]

The seeing last night was a distinct improvement over what I had for closest approach on 6th Oct. I had completely clear skies, no wind to speak of and it was cold (brrr), but who cares when you get your best result yet.

This image comprises the best 20% of 7xRGB runs of 3 mins per filter, per run. It is actually an R-RGB image as the seeing was sufficiently good to reuse the red stack as luminance applied as 70% opacity in WinJupos rather than using the 7xIR data that I also captured. In total there aresome 87,000 frames stacked, which is more like 100,000 if I double count the R stack being used twice.

The image is presented south up with the much reduced south polar cap just seen at the top of the image. The long dark region of Mare Cimmerium runs along the equatorial region, with the spike of Sinus Gomer that extends from it clearly seen. Syrtis Minor is just rotating into view under blue clouds at the right limb. Blue clouds also lay over the north polar region. The bright red regions of Memonia and  Elysium dominate the northern (lower) half of the image. Elysium Mons is seen as a bright spot approacing the central meridian above the north polar clouds, with the dark spot Cerberus seen above it. The largest mountain in the solar system, Olympus Mons, is the bright spot just rotating out of view at the lower left limb. The dark region below the south polar cap, Mare Chronium and the lighter mottled region of Eridania just above Mare Cimmerium, show several detail structures.

Thanks for looking.

Geof

[geoflewis]

@7170 Thanks James

Geof

[Mick_H]

Hi Geof, thats a wow.

Lovely image, and glad you are here.

[geoflewis]

Thanks Mick, likewise good to see you here too... ? 

Cheers, Geof

[ChrisWright]

Awesome stuff Geof! You have been dedicated to the opposition cause and it really shows in your images mate ? 

[geoflewis]

@ChrisWright Thanks Chris, yes, but my body is paying for it today. My planetary imaging rig isn't automated, so I have to sit beside the scope under clear skies, changing the manual filter wheel every 3 minutes as I cycle through R,G,B & IR filters. It was properly cold last night and I didn't wear warm enough clothes, so got really chilled to the core. It was worthy it though ? . It's clear here again tonight, but such is Mars rate of rotation, that there isn't much change in features at the same time night to night, really it needs a few nights passing, or a much later session to capture something different, so I've decided to give it a pass tonight.

[MarkAR]

Another excellent Mars shot, well done.

[geoflewis]

@MarkAR Thanks Mark

Geof

[CraigT82]

Superb Geof! great write up of the visible features roo. Are you submitting to the BAA mars section? Cant remember if youre a member or not?

Craig 

[geoflewis]

Posted by: @CraigT82

Superb Geof! great write up of the visible features roo. Are you submitting to the BAA mars section? Cant remember if youre a member or not?

Craig 

Thanks Craig,

I'm pleased that you like it, I thought this one deserved a bit of a narrative, as a lot of detail is on show. Yes, I'm a BAA member, so I've already submitted it and the previous ones to Richard McKim and had a reply from him.

Cheers, Geof

[geoflewis]

Hi all,

After some discussion and helpful feedback over the last couple of days, from my planetary imaging mentor, Dave Tyler, I decided to completely reprocess my Mars data from 8 October. I've dialled back the sharpening a good deal and resisted the temptation to mess with the colours to make Mars look red. Also with 90 mins of video data captured, I decided to process that as 3 separate images rather than throwing everything into the same bucket.

The attached composite image presents the resulting 3 slightly different aspects of Mars, annotated with respective time stamps, CM and changing altitude. Perhaps the most noticely feature that changes with the rotation is that Olumpus Mons, the bright spot near the lower left limb in image 1, has completely rotated out of view in image 3.

I am reliably informed that the sandy hue seen in these images, is a more accurate representation of the correct colour of Mars.

Thanks for looking.

 

[CraigT82]

Hi Geof, I just copied your two versions together for easier comparison. Personally I like the sandy colour of the new one but I prefer the detail/sharpening of the original as I think there are more subtle details seen in the plains of the northern hemisphere. 

Amount of sharpening is such a personal thing... I think if you like it then you like it! 

[geoflewis]

Thanks Craig,

I really appreciate the feedback and your critical eye. It's certainly tricky isn't it ?.

I agree with your comments about the detial extracted in the northern hemisphere plains, however, what convinced me that the earlier redder version was oversharpened is that some of the smaller features in the southern hemisphere regions of Mare Chronium, Eridania and Mare Cimmerium, just visible as separate features in the later version, had been joined togther into blocks in the earlier one. Initially that gives the impression of more detail, as our eyes are 'impressed' by the greater contrast, but actually detail has been lost.

I must have reprocessed the data 10, 12, maybe 15 times, or more over the past few days, not only varying the amount of sharpening, but trying different degrees of luminance, with either the red stack, or IR stack, or none. I ended up with the R stack again, but at 50% opacity rather than the 70% that I used in the earlier version.

Thanks for taking the time to look and to discuss this difficult 'art', I really do appreciate it.

[Gina]

Brilliant Geof - fantastic images!  ? ? 

[geoflewis]

Posted by: @Gina

Brilliant Geof - fantastic images!  ? ? 

Thanks Gina, I'm glad that you like them.

[gufo20]

Nice image, as ever Geoff! Mars has certainly put on a show for us this time around.

Chris

[geoflewis]

Posted by: @gufo20

Nice image, as ever Geoff! Mars has certainly put on a show for us this time around.

Chris

Thanks Chris, yes, it looks great when the clouds get out of the way; I had some lovely visual views with the binoviewers too. I would like to get some full frontal images of Olympus Mons, which is available at a sensible time currently, but I can't even see Mars the last few nights ☹️. Unfortunately I will be at Kelling next week, so no access to my C14, even if the skies deign to clear....

[CraigT82]

Geof you inspired me to have a go at reprocessing my last Mars image from the 9th Oct!

Previously I just stacked one sequence (the best one) and  then derotated/combined the colour channels together in winjupos (left image) but this time I've derotated all 4 sequences that I collected together, and then derotated/combined the colour channels together. I also went easier on the wavelets for the new version (right image)

I don't think there is any extra detail to be seen but it's certainly a more aesthetically pleasing image to my eye.

I haven't fiddled with the colour at all for the new version, that is how it came out of winjupos. When stacking in AS3 I unticked the 'normalised' box so each stacked channel was at the same brightness as it was collected, and I collected with the same gain/exposure for each channel, so I think this new version is about as accurate as I can get the colour.

 

 

[GazAstro]

That's really lovely ?? I prefer the original version.

[geoflewis]

@CraigT82 Hi Craig, I agree that just stacking more images won't by itself yield more detail, but it will allow a bit more sharpening of whatever detail is there, whilst retaining a smoother image, that as you say is more aesthetically pleasing. It's interesting to note the overall darker look and less contrast of the right hand image, but it certainly has a more globe like look about it.

[GazAstro]

Very nice , lovely amount of detail and well presented.