After successfully capturing a brilliant Leonid meteor shower fireball last November, I decided to mount a greater photographic attack on the 1999 Leonids. I mounted all of my functioning 35mm cameras on a common equatorial mount in order to cover as much sky area as possible while eliminating star trails during the exposures. To do this, I used a 17- by 20-inch piece of 3/4-inch plywood and brackets fabricated from 2-inch wide 1/4-inch steel strap. To maximize sky coverage while using 50 mm lenses, I also mounted my wife's three cameras in addition my own five. (In the illustrations below, a semi-inopperative Yashica J-5 has been substituted for a Nikon so the later could be used to shoot these pictures.) For the sake of clarity, all cable releases have been removed from the cameras. All photos by Robert Reeves
|Pre-aimed brackets tilt the center four cameras upward at a 75 |
degree angle while the outer cameras are tilted 45 degrees. The
12V 33 amp/hr battery to the right powers the Velcro-mounted
dew heater on each lens.
|The motorized equatorial
platform under the camera mount was
built by Kurt Maurer from Houston, Texas. The platform measures
17.5 by 17.5 inches, is powered by two C-cell batteries, can
easily carry 50 pounds, and tracks exceptionally well.
|In order to supply 12V to each of the eight lens dew heaters, two |
heavy aluminum wire "buss bars" run the length of the mount board.
The two AAA cells power two all-electronic Minolta cameras.
|Power to the dew heaters is routed
through a self-illuminated toggle
switch. The heaters usually only need to be on every other exposure.
|Dew heaters were fabricated by soldering three resistors is series |
with an aligator clip wire pigtail. The assembly was then sandwiched
between the "hook" and "fuzz" sides of 2-inch wide Velcro. Staples
were used to reinforce the pigtail extending from the Velcro.
|The exposed tabs of "hook" and "fuzz" Velcro are wide enough to
allow each heater to wrap around any of my camera lenses. The pigtails
clip onto the central 12V buss bars.
|Long time exposures with an all-electronic camera rapidly drains |
its small internal battery. Such a camera can be powered by a higher
capacity external battery of the same voltage. The positive lead goes
into the battery compartment while the negative lead clips onto the
mount bolt securing the camera to its bracket.
|The positive external lead powering an all-electronic camera
be fabricated from a piece of wooden dowel and a brass thumbtack.
The dowel should be just long enough to be held gently in place by the
camera mounting bracket while the thumbtack rests on the camera's
positive battery terminal.
A Bright Perseid Meteor
13 August, 1999
The above Perseid image was taken using the meteor photography camera cluster described above. This particular exposure was the second shot of the session, taken at 3:30 A.M. on the night of August 13, 1999. In a case of beginner's luck, this was the only meteor captured durring the photography session. The other seven cameras captured no meteors at all. This exposure was on Fuji Superia 400 film, exposed five minutes through a 50 mm f/1.7 Minolta lens.
Note: For better dramatic effect, this image is displayed upsidedown. In reality, it was "rising" higher in the sky as seen visually.
The camera cluster's "shakedown cruise" during the 1999 Perseid meteor shower revealed a number of items that should be changed or added to the platform to make it easier to opperate. Some planned future improvements include: 1. Longer cable releases so all shutters can be tripped from the same side of the platform.
My wife, Mary, is shown attaching the last of the dew heaters to the latest version of the meteor camera platform and mount.
All of the platform upgrades described above have now been incorporated into the design except item 3. Finding a stable 12V to 3V DC converter proved to be a challenge. Therefore I solved the problem by simply adding two more 1.5V D-cells to the equatorial platform drive motor power supply and runing a coiled power lead from the battery holder to the 3V camera shutter leads on the camera mount. The power connection is made through a cigarette lighter accesory plug and socket to allow quick disconnect when the camera mount is removed from the equatorial platform. The two volt meters in the center of the platform monitor the 3V needed to run the drive motor and operate the electronic camera shutters, and the 12V from the gel cel battery used to power all eight dew heaters.
The three-legged stand under the equatorial platform has proved to be quite stable. It folds flat for transport and is locked in the open position with two steel strap braces which bolt onto the "south" side of the stand. The stand has an adjustable jack screw under each corner of the platform to allow leveling before polar alignment. The individual camera brackets have also been staggered differently to allow easier film advance on the north and south rows of cameras.
The apparatus now works quite well and was used to shoot 200 images during the 1999 Geminid meteor shower. This year's Geminid shower was quite active as seen from south Texas where visual meteor counts often exceding 200/hr. Unfortunately, while the meteors were numerous, they were faint. Only three recorded on film and none were spectacular enough to display here.
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