- uploaded: Dec 23, 2010
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This brief presentation shows the 16mm Data Acquisition Camera (DAC) footage that was shot during the Apollo 17 ascent from the valley at Taurus Littrow. In this ascent footage, the DAC motion picture camera was mounted in the right side forward-facing (LMP) window of the Apollo 17 Lunar Module "Challenger", providing us a view looking down at the Moon's surface as the LM ascent stage fires and sends the spacecraft on its way back up to lunar orbit for rendezvous and docking with the CSM "America".
Rather than just showing the raw footage here as it is cataloged in the NASA film archives, I instead show two examples of the same clip, presented in a side-by-side style format to allow for a direct comparison between the two versions. On the right side, you see the raw ascent footage just as it is archived by NASA, showing the full scene from the standard, unmoving camera angle. On the left, I show the same scene, however in that example, the footage has been rotation-corrected in order to always keep the scene in it's proper "horizon up" viewing orientation throughout the duration of the clip.
This proper "horizon up" perspective can be established based on some simple criteria, with the goal being to ensure we are viewing the footage with the lunar surface being shown so that the Moon's horizon that is closest to the camera's current principle point always remains aligned and level towards the top of the field-of-view (even if the horizon itself is not actually visible at the time). This ensures that the surface scene you are viewing can be accurately interpreted.
As you can see in this footage, the rotation correction to align the scene to the "horizon up" viewing perspective is an absolutely vital adjustment that must be applied first in order to be able to even begin attempting to analyze and interpret scenes such as this one accurately. Because the DAC camera was hard-mounted in the window of the LM during liftoff from the lunar surface, this meant that the standard locked display perspective that NASA provides in their archive clips showing the Apollo ascent footage is ALWAYS displaying the lunar surface scene below in an inaccurate perspective. For 40 years, the public has actually been watching ascent footage like this from the various Apollo missions where the lunar surface after liftoff is being shown essentially upside down (between 140 to 180 degrees off of the "horizon up" viewing perspective).
The point to this simple presentation is to merely serve as a reminder to everyone who is interested in doing their own analysis of ANY of the Apollo DAC footage or still frames of the lunar surface to always consider the question of "what is the proper viewing perspective for each scene?" The ugly fact is that the vast majority of the Apollo DAC footage and still frames, as they are archived by NASA, are not presenting their lunar surface scenes to you in the proper "horizon up" viewing orientation that our eyes expect to see. Obviously, unless this improper viewing perspective is corrected for first, you have very little chance of being able to analyze the scenes you are looking at with any degree of accuracy at all.
When attempting to analyze any NASA footage or imagery, always keep in mind that perspective really is everything. You better believe that NASA is very well aware of how difficult it is for anyone to properly analyze footage or imagery of the lunar surface if it is being presented in the incorrect viewing perspective, and that is precisely why the vast majority of their footage and imagery is archived that way. This is a simple, deliberate, and highly effective obfuscation technique they employ that must be appreciated in order for us to accurately interpret what NASA is showing us in their archives.