Apollo 17: The Blue Marble - Overview

By Eric Hartwell - Last updated January 11, 2006

Here's a summary of events from the the Apollo 17 Lunar Surface Journal with selected photo thumbnails from the Apollo Image Atlas:

"As usual, once the crew reached orbit, they and NASA took time to thoroughly check the health of the spacecraft before committing to the lunar journey. Twice the crew orbited Earth and, then, just before their third sunrise over the Atlantic, they reignited the S-IVB, the Saturn's third stage, for the 351-second burn that accelerated them to nearly escape speed. A half hour later, Evans separated the CSM from the spent S-IVB and turned around so that they could examine the LM and then dock with it. Schmitt reported that he could even see the Rover and that it seemed to be in good shape, still snugly stowed against the Descent Stage.

80mm lens
AS17-148-22661	AS17-148-22668	AS17-148-22669	AS17-148-22679	AS17-148-22687

"The docking went smoothly, even though the crew was bothered by occasional soundings of the Master Alarm system. They suffered intermittent alarms throughout the first two days of the mission; but, because there were no accompanying warning lights, they concluded that the problem was probably due to an intermittent short in one of the instrument panels. It was a nuisance that could be ignored.

80mm lens
AS17-148-22690	AS17-148-22694	AS17-148-22698	AS17-148-22700	AS17-148-22701

"While they waited for the S-IVB burn, Cernan reported that, while he knew "we're not the first to discover this, but we'd like to confirm, from the crew of Apollo 17, that the world is round." In the two hours since the TLI burn, they had moved out far enough - about 16,600 miles - that they could see the whole Earth. Because of the Moon's position in its orbit, they were south of the terrestrial equator, over the southern tip of Africa, and had no trouble seeing Antarctica. The Earth was nearly full and, at 30,000 miles, they took a stunning portrait of the planet.

80mm lens	250mm telephoto lens		80mm lens
AS17-148-22704	AS17-148-22714	AS17-148-22719	AS17-148-22724	AS17-148-22727

"Throughout the outbound journey, they had a good view back toward Earth. Schmitt, in particular, provided lengthy and detailed weather reports, complete with predictions. His first report, given while Cernan and Evans were getting out of their suits, went on for a full half hour and, as the Earth turned beneath them, he could update his predictions for various parts of the world. Later in the mission, CapCom Gordo Fullerton told him, "You're a regular human weather satellite."

Why?

This all started with a Geek Trivia article on TechRepublic.com, titled "Worth a thousand worlds", which claimed that "most people are looking at the Blue Marble photo upside down," since the photo was taken with Antarctica at the top of the frame.

I immediately jumped in with the obvious comment:

"Given a weightless astronaut, floating around in the cramped cabin, peering through a tiny window (at a 45 slope), through the view screen (perpendicular to the lens) on a Hasselblad, I don't see how anyone can claim to know what's up, down, or sideways."

After doing a little research, I added more explanation:

"If you look at the original transposition, docking, and extraction photos, you'll see that ALL of the pictures are "upside down" relative to the camera. So it's more likely to say that the CAMERA was upside down. The Apollo Hasselblads didn't have a viewfinder (except for an external ring sight used with the 500mm lens). So the photographer would have held the camera in whatever orientation was most convenient given the location in the cabin and the orientation of the window."

Photo Analysis

"Check the lens now. I took an F-22 stop"

The famous "blue marble" photos were taken before, during and/or immediately after the burn, while Cernan complimented mission control on the boosters' performance. [Apollo 17 Digital Picture Library says "at about 5:06", which is definitely after the burn.] There were actually four "blue marble" photos. The "official" one according to NASA is AS17-148-22727; many sources use AS17-148-22726 which was taken a few seconds earlier. 

80mm lens
AS17-148-22724	AS17-148-22725	AS17-148-22726	AS17-148-22727	AS17-148-22728

The first Earth photo looks brighter and less colorful than the next three. These images were produced by the Lunar and Planetary Institute for the Apollo (Handheld/Still) Imagery Catalog. The Apollo film from the NASA Johnson Space Center was scanned using a video camera with a resolution of over 700 lines. Each frame was digitized as a 24 bit color image at 756 x 486 pixels, producing a file of approximately 1.1 megabytes in Targa format. The images then received some "color" processing because the aging of the film had altered the original colors captured when the film was exposed. For the images on color film, a generic color processing formula, arrived at by tweaking representative images by hand, was applied in an attempt to shift them back closer to their original colors.

The histograms show the luminosity of the 6 MB print resolution images (Eric Hartwell, using Adobe Photoshop Elements).

The first image, AS17-148-22725, is definitely lighter.

The Lunar and Planetary Institute says, "Because of all this processing, these catalog images should not be used for research purposes." However, it's unlikely that they would have applied a different color "tweak" to the first image only, to make it look different from the next three. It's much more likely that they applied the same correction to all four photos, and the difference was in the original photo.

It's reasonable to conclude that the last three photos were taken with a different exposure setting.

Frame Counter: "It's frame 105" ... "On about 123"

80mm lens	250mm lens		80mm lens
#104 AS17-148-22711	#105 AS17-148-22712		#121 AS17-148-22728

There are two references to the Hasseblad's frame counter in the transcript. The first is 105 for the start of the 250mm pictures of the S-IVB. The second is 123 when the astronauts started cleaning up after the S-IVB's evasive burn.

(around 05:00 GET)
SC [Cernan] Let's just get a picture or 2 here yet, and then we'll give you a GO.
CAPCOM And Gene, it'll be about 7 minutes until the evasive burn, 5 plus 03.
SC [Cernan] Okay, you have a GO. And for your reference, it's frame 105, I started a few 250 millimeter pictures of the S-IVB.

(around 5:07 GET)
SC [Evans?] Houston, Magazine, November, November is on about 123 right now.
CAPCOM Okay, Ron, magazine November November is on 123.

The actual frame count could be off by one either way in either reading, since the camera's film magazine had a very small analog frame counter. I've arbitrarily assigned frame #106 to the first 250mm photo and #122 to the last Blue Marble photo. Since the camera was motorized, it would have automatically advanced to the next frame after the last picture was taken.

Earth Photography on Translunar Coast

From the Apollo 17 Technical Debrief:

EVANS Photography - Jack, I guess you've taken most of the pictures on the translunar coast.
SCHMITT Most of the photography came to GET within a few minutes. It was almost a continuous effort at the beginning of the day and maybe in the middle and at the end with some irregularities - getting a continuous record of a very nice view of the Earth and the weather patterns. We had about three-quarters to two-thirds Earth through most of the translunar coast period. And that should be in the photographic logs on the ground. ...
EVANS Orbital science photos - We really didn't have any on translunar coast.
SCHMITT Nothing was called out. We used about a half a mag on the Earth, maybe more.
EVANS More than that. We used a full mag before we got to the Moon.