# Apollo 11: what's the shadow in this pic? **URL:** \ **Category:** Factual Questions\ **Created:** [March 19, 2019, 2:02pm UTC](https://boards.straightdope.com/t/apollo-11-whats-the-shadow-in-this-pic/831366 "2019-03-19T14:02:20Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [March 19, 2019, 2:02pm UTC](https://boards.straightdope.com/t/apollo-11-whats-the-shadow-in-this-pic/831366/1 "2019-03-19T14:02:20Z")
See this pic on Wikipedia: [![](https://en.wikipedia.org/wiki/Mare_Tranquillitatis#/media/File:Apollo-11_nasa_536.jpg) ](https://en.wikipedia.org/wiki/Mare_Tranquillitatis#/media/File:Apollo-11_nasa_536.jpg) Based on the shadows in/around the craters, the sun appears to be behind the camera. The shadow in the lower left quadrant of the photo appears to be from part of the lander, but what part? The shape looks sort of like a rocket nozzle, but to cast a shadow like this, it would have to be on top of the lander, pointed upward. From [this illustration of the lander,](https://upload.wikimedia.org/wikipedia/commons/4/4a/LM_illustration_02.jpg) it looks like it could be the upward-pointed thruster on one of the RCS pods…but based on the size of the shadow in that photo, that would mean the camera must be zoomed in pretty tightly. Also, the shadow below the nozzle-shaped shadow doesn’t match what I would expect to see based on the illustration, which shows a pretty substantial base for each array of RCS nozzles. So what am I looking at? 😕 ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [March 19, 2019, 2:20pm UTC](https://boards.straightdope.com/t/apollo-11-whats-the-shadow-in-this-pic/831366/2 "2019-03-19T14:20:12Z")
It’s one of the RCS quads- the picture is likely taken out of the window of the LEM, so it’s in very close. The Apollo cameras were all fixed focal length medium format Hassleblads- 80mm f2.8 for within the LEM, and another camera with a 60mm f2.8 lens for outside. The outside one had what’s called a “reseau plate” that gives it those little crosses in the grid pattern. They had manual settings for aperture, distance and shutter speed. All you’re seeing here is that their depth of field is proper for what they’re taking photos of (the ground outside the LEM), and that the RCS quad isn’t within the range of the depth of field- it’s too close-in, so it’s blurry. This is due to the particular combination of aperture and distance set on the camera (we don’t know the actual settings AFAIK, so we can’t calculate the DOF). ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [March 19, 2019, 2:33pm UTC](https://boards.straightdope.com/t/apollo-11-whats-the-shadow-in-this-pic/831366/3 "2019-03-19T14:33:52Z")
> [@bump](#): > > It’s one of the RCS quads- the picture is likely taken out of the window of the LEM, so it’s in very close. So I’m not seeing a shadow cast on the lunar surface by an RCS quad - I’m seeing the _actual_ RCS quad, just very close to the camera? ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [March 19, 2019, 2:34pm UTC](https://boards.straightdope.com/t/apollo-11-whats-the-shadow-in-this-pic/831366/4 "2019-03-19T14:34:26Z")
It’s not a shadow but it IS the RSC engine, but the photo was taken from orbit, not on the surface. From this site :[Apollo 11 Mission image - View of Moon,TO 115 : NASA : Free Download, Borrow, and Streaming : Internet Archive](https://archive.org/details/AS11-37-5437) > [@](#): > > Image taken from inside the Lunar Module LM from orbital altitude over the moon during the Apollo 11 Mission. It also explains the edge of the sunlit section as I don’t believe any Apollo mission was landed near the end of lunar day. ---
**Author:** ![BrotherCadfael](https://avatars.discourse-cdn.com/v4/letter/b/977dab/32.png) [@BrotherCadfael](https://boards.straightdope.com/u/BrotherCadfael)\ **Post date:** [March 19, 2019, 2:51pm UTC](https://boards.straightdope.com/t/apollo-11-whats-the-shadow-in-this-pic/831366/5 "2019-03-19T14:51:04Z")
It’s probably a stagehand… ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [March 19, 2019, 2:57pm UTC](https://boards.straightdope.com/t/apollo-11-whats-the-shadow-in-this-pic/831366/6 "2019-03-19T14:57:02Z")
> [@Machine\_Elf](#): > > So I’m not seeing a shadow cast on the lunar surface by an RCS quad - I’m seeing the _actual_ RCS quad, just very close to the camera? The shape is not black (compare to the crater shadows). ---
**Author:** ![gnoitall](https://avatars.discourse-cdn.com/v4/letter/g/bb73d2/32.png) [@gnoitall](https://boards.straightdope.com/u/gnoitall)\ **Post date:** [March 19, 2019, 4:20pm UTC](https://boards.straightdope.com/t/apollo-11-whats-the-shadow-in-this-pic/831366/7 "2019-03-19T16:20:18Z")
> [@CookingWithGas](#): > > The shape is not black (compare to the crater shadows). With what’s been described so far, and looking at how the LEM was designed, that’s the back of the RCS quad, out of focus because it’s so close, and dark because it’s in the shadow of the hull of the LEM. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [March 19, 2019, 4:45pm UTC](https://boards.straightdope.com/t/apollo-11-whats-the-shadow-in-this-pic/831366/8 "2019-03-19T16:45:48Z")
> [@gnoitall](#): > > With what’s been described so far, and looking at how the LEM was designed, that’s the back of the RCS quad, out of focus because it’s so close, and dark because it’s in the shadow of the hull of the LEM. Concur. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [March 19, 2019, 5:10pm UTC](https://boards.straightdope.com/t/apollo-11-whats-the-shadow-in-this-pic/831366/9 "2019-03-19T17:10:37Z")
> [@kanicbird](#): > > …but the photo was taken from orbit, not on the surface. That explains why the surface looks so creamy smooth. I suppose if I had followed the link under the photo, I would have found that [Maskelyne Crater](https://en.wikipedia.org/wiki/Maskelyne_(crater)) is 22 km across, realized that photo was taken from orbit, and that the thing I thought was a shadow from the lander couldn’t possibly be a shadow from the lander. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [March 19, 2019, 7:09pm UTC](https://boards.straightdope.com/t/apollo-11-whats-the-shadow-in-this-pic/831366/10 "2019-03-19T19:09:10Z")
> [@Machine\_Elf](#): > > That explains why the surface looks so creamy smooth. I suppose if I had followed the link under the photo, I would have found that [Maskelyne Crater](https://en.wikipedia.org/wiki/Maskelyne_(crater)) is 22 km across, realized that photo was taken from orbit, and that the thing I thought was a shadow from the lander couldn’t possibly be a shadow from the lander. Also, the object is very fuzzy (out of focus) whereas the surface of the moon is in focus, so it can’t be a shadow on the surface (and also the moon can’t be a miniature model just outside the window ;)) ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [March 19, 2019, 8:24pm UTC](https://boards.straightdope.com/t/apollo-11-whats-the-shadow-in-this-pic/831366/11 "2019-03-19T20:24:21Z")
> [@Colophon](#): > > Also, the object is very fuzzy (out of focus) whereas the surface of the moon is in focus, so it can’t be a shadow on the surface (and also the moon can’t be a miniature model just outside the window ;)) Shadows do get fuzzy the farther you get from the surface they’re projected on. ---
**Author:** ![Reindeer\_Flotilla](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reindeer_flotilla/32/3024_2.png) [@Reindeer\_Flotilla](https://boards.straightdope.com/u/Reindeer_Flotilla)\ **Post date:** [March 19, 2019, 8:36pm UTC](https://boards.straightdope.com/t/apollo-11-whats-the-shadow-in-this-pic/831366/12 "2019-03-19T20:36:10Z")
Also notice the RCS “shadow” (which is what initially I thought it was too) itself has reflections off of it. Those reflections mostly are on the right half, and due to the location of the light source which appears to be behind and to the right of the camera. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [March 19, 2019, 9:28pm UTC](https://boards.straightdope.com/t/apollo-11-whats-the-shadow-in-this-pic/831366/13 "2019-03-19T21:28:05Z")
> [@pulykamell](#): > > Shadows do get fuzzy the farther you get from the surface they’re projected on. I should clarify, this is certainly _not_ what is happening here, as the distances involved I would expect the shadow to be much, much more diffuse (if at all really visible from that distance.)