Thanks, Phil.

Yes, I, of course, noticed those frames too during my work on this. My original assessment was that more work was needed (since it was not so clear cut as the three I was sure about) and I couldn't understand the shadows being shown without more modeling/analysis. Eric Jones and I went back and forth about this a lot. If someone in the audience wants to offer a model (i.e. 3D) for the shadow casting for these frames, then we would welcome it. It is baffling. You idea might work but I have not had the time to test it and other theories.

Spectacular oblique view of Tycho crater has been posted here. Must see!

Beautiful desolation!

New goodies keep turning up on the Moon. Another quasi-Ina structure in Mare Tranquillitatis.

Phil

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Aww, what a cutie

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a quick single image SFS HeightMap of that image

Today's LROC featured image is a spectacular oblique view of Tsiolkovsky's central peak.

Earthrise from LRO: http://lroc.sese.asu.edu/posts/895

Goodness! That is probably one of the top images of the year right there.
The DSCOVR view at the time seems almost tame by comparison....
http://epic.gsfc.nasa.gov/epic-archive/png...12120347_00.png

Wow! That Earthrise image is incredible. Thank you for posting the link to it.

I'm replying here to James Ficannon's post in the Apollo from LRO thread. He linked to an image of a very unusual object in images of the floor of Paracelsus C on the far side.

------------------
James:

By the way, any opinion of this blocky thing in Paracelsus C others have found? Simplified link to QuickMap.

http://bit.ly/2ljHDYT

Maybe it is just a blocky thing, but I would like it if there were a lot more blocky things in the area which there are not.
--------------------

Me:
That has to be one of the most puzzling things I have ever seen on the Moon. I looked at it with morning and afternoon illumination, and with the Sun nearly overhead. The shadows on the southern object hardly seem to make sense at all, and the northern one is not much better. No idea what it is. Some 3D modelling from stereo images would be useful... I see some of that has been done already, but I am not sure the shadows work with the suggested shape. I will keep thinking about it.

Phil
--------------------


Now I have had some time to think about it. I have a geometric interpretation of the southern object which makes sense to me:

Click to view attachment

(I'm still thinking about the northern object, but ultimately I expect it to be similar).

So, I interpret this thing as a steeply oriented thin rock slab. Just using the Quickmap scale bar, it seems to be about 50 m long, maybe 20 m high and maybe 4 m thick with an irregular top edge. There is a linear depression next to the object on it south side, probably a sign of a buried chunk of the same type of material. The shadows make sense to me now.

What can it be? It is on a small mound, one of several on the south floor of Paracelsus C at the foot of the southern wall. I would interpret it as a slab of impact melt (we see flows of melt around many other craters), originally on the rim of the crater and probably long buried under ejecta from other craters to protect it for a billion years or so. Then a wall slump brings it to the floor of Paracelsus C. The slump is the source of the mounds on the floor, and was probably caused by shaking associated with a big impact. By chance these long-buried but coherent, massive slabs of melt end up sticking out of the ground. This whiole area has a 'hilly and lineated' appearance resembling similar terrain on Mercury which has been interpreted as caused by seismic shaking from a giant antipodal impact (Imbrium).

A bit ad hoc, but not as ad hoc as an entrance to an alien base. I would also be happier if there were other similar objects nearby. But you can't have everything.

Phil

By "crater counting", these slabs seem to be as old as the surrounding surface, covered with small old craters. Old, since the small craters themselves look usharp due to microcratering.
A few hundred meters east of the slabs, some larger craters seem to be considerably(?) younger.
About one km west of the slabs there is an old large impact crater with ejecta (a hill) to the east, hence likely caused by an impactor coming from a western direction.
The slabs might be part of these ejecta.
Right of the slabs, there are traces of a sector of a disk with a radius of about 200m, and with the slabs near the center of the disk.
The slabs might have fallen back earlier than some of finer material and shadowed it causing the subtle structure.
Before the impact, the slabs might have been part of a basalt layer under the surface regolith, just shallow enough to be partially broken up by the impact.

...one of many conceivable scenarios...

Thanks for your suggestions!

I am no lunar scientist but I would have preferred an explanation of either:

1) a boulder that rolled to that spot (since it is at the base of the crater slope) and dust accumulated enough (!!) to cover the tracks or

2) low speed ejecta from elsewhere that landed the block (which broke upon impact) and somehow did not create a crater (like Gerald's suggestion except I cannot see the 1 km west impact that
he says might have caused it, I was expecting something much farther away).

Also, I would like to see examples of similar occurrences elsewhere on the Moon.

I do see a number of spots with very entertaining slabs at the bottom of the crater. For instance, here are a lot of slabs in Giordano Bruno.
http://bit.ly/2mgWnWH

Re 2) Do you see the fuzzy shadow of almost 500m diameter 1km to the left from the slabs? I'd interprete this as an old impact crater. Over time, the craters erode due to subsequent impacts.

I used Quickmap to measure the distance from the slabs to the leftwise crater and it is only 500 m to the center of it. It is about 500 m diameter.

Being a neophyte I would have thought that the erosion of that crater would be matched by the erosion of the presumed slabs ejected from it. That looks like a lot of crater erosion to me!
But the slabs appear sharply defined.

I'm assuming the slabs composed of (bulk) basalt, and the surface layers consisting of (finer grained) regolith. The regolith should erode much faster than basalt.
Therefore, I've assumed the slabs being ejected fragments of a basalt layer beneath the surface regolith.
The slabs cannot be very young, since they are partially covered with cratered regolith, and there is no obvious sign of the slabs having impacted recently. Therefore they should be considerably harder (resistant to erosion) than the other material around.

Just one scenario.

I can see the Apollo 15 flag's shadow clearly.

Click to view attachment

Basically, if you see a small shadow that, with the changing of the sun angle, seems to travel being detached from the ground, that's a flag's shadow, due to the flag being elevated above ground on a pole. The "Flip Book" is very helpful for noticing such things: http://lroc.sese.asu.edu/featured_sites/view_site/4

Shadows from objects lying directly on the ground stay attached to them.

Taking note of this, and my similar post about Apollo 14, perhaps it's time to update the ALSJ article?

I've come across a thread about these objects at another forum, so I'm currently "investigating" them and trying to see how the various NAC images can help us.

M1207284757LC and M1207277724LC provide a nice stereo view of these object.

Flick-gif:
Click to view attachment

Red-cyan anaglyph:
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A few NACs comprise this "Flip Book" animation arranged by the sun angle:
https://media.giphy.com/media/3og0IJ9m19EJf7rJKM/giphy.gif

https://twitter.com/LRO_NASA/status/859473553443495936

ETA: just noticed there is a blog post with zoomable image

http://lroc.sese.asu.edu/posts/902

http://lroc.sese.asu.edu/posts/973

Re: http://lroc.sese.asu.edu/posts/973

Very subtle in the full NAC image.

Below image: in left, white lines midway down represent approximate location of the jittered part in the original NAC; in right, context - the camera was looking at the eastern sector of Lowell W crater at the time of occurrence.

John Moore

Here are some renders made with LRO data...













Elevation data had to be compressed to half res to be read by the displacement modifier.

Same data rendered at 625 Megapixels...[ 25k x 25k ]



Now hosted over at Gigapan

I had some fun locating the Apollo 15 landing site at Hadley Rille on Sean's Gigapan. I really enjoy the LROC images. Ty Sean.

Great renderings, Sean.

Over at my Facebook group Colour of the Moon, Alain Paillou has been sharing his renders that used his telescopic images with increased saturation and LRO's DEM data. The results are quite cool:

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His telescopic images themselves are quite stunning:

Click to view attachment

Video: http://www.youtube.com/watch?v=I8O5g06Ak2M

In case people had not seen it, the LRO Camera team have produced an atlas of permanently shadowed regions (PSRs). It's online here:

http://www.lroc.asu.edu/psr

You can also download a PDF of the whole thing.

It takes a bit of getting used to, but it has some very interesting things in it. The LRO Narrow Angle Camera can see into PSRs using light scattered off nearby illuminated terrain. But the signal is very low, so they boost it by binning pixels, thereby reducing resolution. The binning also reduces smear produced by the longer exposures used in the shaded areas.

For each PSR there are several mosaics made of different sets of images. Sometimes complete or nearly complete coverage can be obtained by adding the mosaics, and where they are very streaky or otherwise compromised they can be improved by averaging mosaics. Here is an example, Shoemaker crater near the south pole, the site of Lunar Prospector's impact at the end of its mission, and the resting place of some of Gene Shoemaker's ashes. The resolution is nowhere near enough to look for the impact site.

The LCROSS site does not seem to be well represented in the Atlas. The deep double shadow at its location did not give good results.

Incidentally, the modified LROC-NAC instrument called Shadowcam, to be flown on the Korean Lunar Orbiter in 2020, will be able to obtain much better images inside PSRs.

Phil

Click to view attachment

Lunar Orbit made with LROC data



4k 60 fps version over on Youtube

Copernicus made with LROC data



4k60 version over on Youtube

Bay of Rainbows made with LROC data...



4k60 version over on Youtube

Thanks, Seán...lunar animations are well overdue...it's all Mars at the moment (no offence intended to your Mars's animations that are superb).

John Moore

Yes, Sean, your animations are great!

Returning to the Permanently Shadowed Region atlas I mentioned a few posts earlier, here's an example of how the data can be used. This image has 4 sections. At top left is the Shoemaker PSR, enlarged and cleaned of artifacts, especially the stripiness in the original LRO mosaics. At top right is a mosaic of LRO Mini-RF radar images registered to the LROC image. At lower left is a composite of the two (not made by merging them, though that would be possible as well). Rather, the brighter pixels in the Mini-RF image were selected, and that selection (that pattern of pixels) was applied to the LROC image and brightened. It's not necessary to do it, I was just experimenting. Finally, at lower right the Lunar Prospector impact site is indicated - not guaranteed to be exact, but this is probably the best image we have of that location. A LOLA shaded relief image could be made as well, but that will have to wait.

North is at the top.

Phil

Click to view attachment

Ah thank you.

I wonder Phil if you know where I can get my mitts on an LROC global mosaic with no shadows? It exists as a layer in the wonderful Quickmap LRO model online and can't seem to find it in the usual places.

Lunar Orbit 2, made with LROC data



4k60 version over on Youtube

Maria, made with LROC data...



4k 60fps version over on Youtube

Pretty nice to see these Sean - this reminds me of the Kaguya videos and such. I wonder if you are using (or have considered) a BRDF (bidirectional reflectance distribution function) with the lunar surface. For example this would show things like the opposition effect and other differences in brightness with the geometry, over and above the shaded relief. I've been using a BRDF in my Earth view simulations and finding or formulating one for the moon might be of interest.

Ah thanks but I wouldn't know where to begin with BRDF! I'm really just trying to present the data in an easily digestible format to the highest quality I can muster, along with some subtle image processing.

Is there a primer you can recommend? How would I utilize it with this dataset?

It's possible others on the forum have considered this in lunar rendering. To start I can suggest this as one reference on Hapke parameters. Another more recent reference is here.

In brief, I assume your images use terrain slope and solar illumination geometry to get the brightness at any location. The BRDF (or ARF for anisotropic reflectance factor) is simply a correction factor to multiply the brightness by that depends on some additional aspects of the geometry. One key quantity would be the phase angle, among some others. There would be a tradeoff with these functions in terms of simplicity and accuracy.

Hills, made with LROC data



4k60 version over on Youtube

I made the videos with data already assembled into global mosaics, each set well over 100k pixels across. I optimized these to get them to fit into my 32gb PC as well as polygon culling at rendertime which dramatically increased efficiency. Each frame takes about 12 seconds on average at 4k resolution. Each video has around 1600 rendered frames which I then interpolate to reach a more comfortable orbit speed.

Sean - sounds like you have a well oiled processing pipeline, so I want to avoid throwing too much of a monkey wrench in it At least at an academic level, here's some further insight into what could be possible in this Celestia Matters forum thread. I'm still learning about the Hapke parameters, though I am familiar with the subset of them that use the Henyey-Greenstein functions (that key off of the phase angle) so I should know how to code that part.

Isn't this image data draped over the DTM? If it wasn't, there wouldn't be any albedo features. Since it is, the BRDF is baked into the image at least for the original imaging geometry.

No worries Steve, I understood some of the words you used!

As MC said, this is imagery draped over DTM, as straightforward as it gets from a rendering standpoint.

Steve, if you were referring to my request earlier regarding the no shadow mosaic found on the LROC quickmap?...if there is a way to achieve that with your recommended method that isn't too taxing for my blue collar brain then I'll check out your suggestions. Appreciate the assist.

Thanks for the reminder about your "no shadows" post. I notice online these datasets for Hapke Normalized and Empirically Normalized mosaics: http://ode.rsl.wustl.edu/mars/pagehelp/qui...lroc_mdremp.htm

Hopefully these have the corrected albedo in them (with no shadows), so then in theory one could apply the BRDF for various viewing geometries.

'Moon' is a montage of previous videos set to 'Lux Aeterna' by György Ligeti



Full 6 minute 4k60 version over on Youtube

Here are a couple of videos... I eyeballed the sun angle so I wonder how wrong the shadow direction is!

Sunset on Clavius


Sunset on Tycho

Moon High... 60 Megapixel portrait rendered from LROC data


Detail 001



Detail 002

Here is a video made from LRO data...



4k60 Youtube version

I'll add this to this thread because if its confirmed it might make the case for polar exploration even more interesting.

Skylights in the polar regions have been lacking up til now I think.

https://seti.org/seti-institute/press-relea...north-pole-moon

P

Some new flyby clips on Flickr... full length versions at the Youtube link...


Full 3 minute 4k60 Youtube version


Full 3 minute 4k60 Youtube version


Full 3 minute 4k60 Youtube version


Full 1 minute 4k60 Youtube version