A Photo of the Moon | Hacker News Reader

A Photo of the Moon

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95 pointssurprisetalk34 comments

Is the coloration augmented in some way here as is common in astronomy photographs? Like they do with the reds and blues of Pluto, or translating different spectra to visible colors for nebula and such. Or are those "bruises" on the moon "what it actually looks like" with better-quality imaging?

I don’t think it’s false coloured, it sounds like he used a consumer interchangeable lens camera, like a dslr or a mirrorless camera attached to a telescope.

I’m more a photographer than an astronomer but as far as I understand it those false coloured images are produced by monochrome sensors that are sensitive to a broad range of frequencies which have filters placed in front of the sensor to seperate out a specific frequency and then to create a single image they will photograph with different filters to get various “colours” then that data is mapped to the colour your monitor can display.

Whether the colour is true to life is a really complicated question for basically any photo you see lol. like, there is no simple objective answer for any photo imho unless it’s obviously a no

Thanks for the context. I'm not too experienced in this area, but I am aware of the very relative nature of color in imaging, that's why I quoted "what it actually looks like".

I guess what I'm asking is if it looks so colorful when you look at it with your eyes from low orbit. Generally if those different regions are clearly visible, however lifelike the coloring is. Or is it actually just mostly flat grey like the traditional depictions.

They often augment the contrast/saturation so geological features are more distinguishable or for aesthetic reasons. There's a trend of "Look! Astronomical object X is not as boring and homogeneous as you thought!".

>I guess what I'm asking is if it looks so colorful when you look at it with your eyes from low orbit.

To be honest, I don’t know

A lot of the colour in these images just blurs together at the scale we see the moon at from earth, at least with my eyes, and that would still be true in low earth orbit.

It's not false colors (that btw have a scientific goal), but the saturation is processed to be increased. Those are the "real" colors provided by a normal camera added to a very clear and highly resolution picture

I always wondered - is there some physical limit on how close we can zoom in on the moon? Or is it "just" that building a large enough lens isn't technically feasible?

From Earth, yes. It's called the diffraction limit [1]. With an ideal 1m diameter lens or mirror you cannot resolve features smaller than about 250m on the Moon. To capture a sharp 100 Mpx image, you would need a telescope of at least that size. When the aperture grows above 1m, atmospheric disturbances get progressively worse too, which is why all the really sharp imagery comes from satellites around the Moon.

[1] https://en.wikipedia.org/wiki/Diffraction-limited_system

You are totally ignoring AO, Adaptive Optics[0], that allow for compensating for that atmospheric distortion. If you've ever seen picture of an observatory with a bright laser beaming out from it, that's what it is. It is the capabilities of AO, the cost of building on terra firma vs space platform, and the ability for humans to service the observing platform that leads many astronomers to not be so gung-ho on space based observation platforms in the visible spectrum

[0]https://en.wikipedia.org/wiki/Adaptive_optics

I know, but adaptive optics for large apertures also pose a progressively serious engineering challenge. I don't think we could build a 100m diffraction-limited telescope today (on the ground). It would still be useful for it's light-gathering capability, but resolution would not scale proportionally.

Making the extremely large primary out of smaller units working together to make an adaptable cohesive unit might be a challenge, but it is doable. This was how SDI was working, it's how DLP tech work[s|ed], it's the same concept that allowed JWST to work.

Apollo missions zoomed all the way the surface, so no physical limits in that regard

Is anyone else tripping out that the moon isn't completely white / grey? I had absolutely no idea it has these dark spots on it, and I've looked at it many times through a Telescope, what am I missing here?

Shattered my sense of reality a little bit actually...first time I've seen this.

I had the same reaction. It's strange, as I assume I have seen photos in larger detail before, but perhaps they have all been black and white.

What's the highest resolution image of the moon taken from Earth? Presumably some stitched together image from one of the large telescopes?

Not presumably. The highest resolution image is a stitched together image. Depending on the magnification of a given telescope, you'd have to stitch multiple shots to see the entire surface from multiple shots depending on the particular telescope used. My personal telescope was purchased specifically to see deep sky objects without needing to do stitching; a wide angle telescope if you will. In my scope on a full frame DSLR, the full moon is less than 25% of the frame.

This particular photographer stitched more than just enough shots to cover the full disc, but also from multiple phases which allows parts that would be in shadow during one night of imaging to be in full light during other nights of imaging. A "simple" mosaic of the full moon can be captured in a single night, but this guy said "hold my beer" and went nuts. Dedication doesn't even begin to describe

If we were to talk about hypotheticals, let's look at this picture of Io[1] taken from Earth's surface. Io's angular size is 1.2 arcsec. Feature of that apparent size would be ~2.2km in diameter on the surface of our Moon. With that kind of resolution it seems that you could map out features of 50-100m in diameter. Obviously though, no one will tie up one of the most expensive telescopes with a project of covering half of Moon's surface with that kind of pictures. A satellite would be a better tool for this job.

[1] https://news.berkeley.edu/2024/05/30/with-new-sharper-optics...

Thx!

I would like to know how much these images overlap or at least see a few of the single shots. I’m curious what the inputs look like.

I found this article[0] that shows the gear he used for the images discussed within, but that was from 2022. He used a Celestron NexStar 8SE with a Canon EOS 1200D. If you really want to know, you can look up the magnification of that particular scope with the sensor size of that camera, and you can see how much of the moon would be imaged in a single snap. That would at least get you a closer guess. However, how much he overlaps is still a question. For this particular final image, it sounds like he's completely overlapped each image multiple times since there's 81,000 images used.

[0] https://www.ndtv.com/world-news/stunning-detailed-image-of-m...

You would be doing "lucky imaging" to get around atmospheric disturbances. Basically, you take 100 images with <100msec exposure times. You check which ones were good, and discard 95 of them. Then you overlay the good ones. That would explain the high number of images taken.

Yes, except those numbers will be a lot higher.

81,000, so 810x higher which definitely qualifies as a lot in my book

There's informed ways to increase your luck like choosing a location at the highest altitude you can, pick a night with cool crisp air vs hot summer air, be fortunate to have a storm system roll through and clear our just before you shoot to clear out the air.

TFA says he is Kurdish which would suggest to me that finding a spot in the mountains with some altitude was probably not out of the realm of possibilities.

Why do some areas have relatively few craters? I'm assuming it can't be due to erosion.

if you have 2000 small craters in an area from 100000 years ago, and then one big crater obliterates all that 1000 years ago - do you have relatively few craters?

Your explanation makes sense to me for some of the relatively smooth areas, especially the ones that are generally circular.

I don't think it adequately explains those smooth areas that are not so circular, especially if you claim that these smooth areas are due to craters formed quite recently.

ok I went and investigated https://www.iop.org/explore-physics/moon/surface-features-mo... evidently the areas that appear to be smooth to us from far away were covered by lava relatively late in moon's evolution and also have lots of craters as well, we just don't see them as well as we see the other areas that were not covered and took maybe more damage.

Oh man, thanks for this! (Something I should've done myself!)

Really interesting. Yeah, the crater patterns that I saw seemed a little too complex to be explained simply.

Also, my naive self would've assumed that the spatial distribution of meteor impacts would be uniform, but apparently this doesn't appear to be the case.

in statistics true random distribution is a smell anyway.

Actually, the cartoon infographic from that article offers a short and to the point explanation: "Giant impacts created oceans of molten rock that formed the dark maria" ("Maria" being the plural of sea in Latin) - so the craters that were there before were actually molten, and any craters that can be seen were formed later and are therefore fewer than in older regions.

Why are most of the craters relatively the same depth? Wouldn't we expect at least some to have done massive damage?

Perhaps because the same part of the moon always faces the earth which 'shields' the moon somewhat?

Just a guess

there's no way for such images to happen in more densely populated area. The night city glow we as civilization have created is like a light-blanket..

A 1.3 gigapixel image of the moon that has a nice zoom interface is at https://www.easyzoom.com/imageaccess/40d920f226e9451cba72a74...

Not quite as high resolution however.

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