These images, each of which shows a complete limb-to-limb pass, were constructed from frames taken by the HOMER on-board Video Camcorder Experiment. The videotape from the flight shows some tantalizing images, but those images are also rather fleeting due to the video camera's tight field of view (constrained to 10 degrees by the aperture size and camera placement) and the fast spin rate of the rocket (approximately 1/3Hz or 20RPM after despin).
These pictures were constructed by taking all the video frames in a single rocket rotation (approximately 90), trimming the black frames on each end (leaving the ones which show the earth, approximately 45), splitting those frames into fields (there are two 1/60 second fields for each 1/30 second frame; using fields instead of frames increases the time resolution and reduces blurriness; the down side is that each field has half the vertical resolution (240 lines) of a full frame (480 lines)), then assembling slices from each frame into a larger picture. The slices are sized to match the rotation rate of the rocket, and are also taken from the center of each picture to avoid the corners of the aperture that can be seen in individual frames.
The rocket was launched in an eastward direction, so north is to the left and south is to the right in each of these pictures. The bright area to the right is due to the fact that the south limb was imaged first in each pass because of the rocket's direction of rotation; when the video camera passes from black space to the bright limb, the auto-iris overexposes the earth until it can close itself down a half-second or so later.
These pictures have been compressed horizontally for practical reasons (they would be twice to three times as wide as they are now). The vertical axis has been left untouched; it still carries the full vertical resolution of the grabbed fields (240 pixels).
Click on any picture for a larger version (1280 x 240)
The first picture was taken from a pass shortly after despin, at
an altitude of approximately 60km. At this stage of the flight,
the rocket is closest to vertical, so the images sweep closest to
the eastern horizon. The "toothed" features to the
right are artifacts caused by sun glinting off the edge of the
aperture.
The second picture was from a pass close to apogee, at an
altitude of approximately 95km. The rocket has started to keel
over slightly, giving a more vertical view.
The final picture was taken from a pass just before re-entry, at
an altitude of approximately 40km, and 30km out to sea. The
rocket is almost completely flat at this point, giving a view
almost straight down at the center of the picture. Note how wide
the limb has become (this is more prominent on the right because
of over-exposure on that side), this is the atmosphere that the
rocket is about to re-enter.
Image processing by Mike Grusin.
The flight video was shot by an off-the-shelf Sony 8mm camcorder with minor modifications for ruggedness and remote control. The resulting tape was transferred to super-VHS and digitized in real time by a DPS Personal Animation Recorder / TBCIV combo running on an accelerated Amiga 2000 computer. An ARexx script, controlling the PAR and OpalPaint imaging software, did the tedious work (each picture took approximately an hour to render).
Page last updated on November 7, 1996.
mail or visit michael.grusin@colorado.edu
for HOMER web information
mail or visit shepperd@rodin.colorado.edu
for CSGC web information
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