At left are some images taken during the 2003 close
approach of Mars. I'm using this occasion to get
some experience using video to acquire planetary images.
Unless noted otherwise, all imaging was done with
a Celestron C11 mounted on a Losmandy G11 mount
from the Orange County Astronomers site in Anza, CA.
The July image was done very differently from the
August images. The camcorder was used only as a
recorder, recording monochrome video output
from an STV autoguider fitted (manually) with
B,V,R photometric filters to get R,G,B tri-color
components. Due to the long delay between acquiring
the R and B components (manually switching filters,
re-focusing, adjusting gain, and recording
5-minutes of video), there is probably blurring
due to planetary rotation, so this was abandoned
for later images. However, the July image is also
not as sharp as the August image because it has
not been processed
with the wavelet filters of Registax.
As you look down the sequence of images at left,
Mars is also varying in size, reaching a maximum
at the closest point to us (Aug. 27), though
it's not reflected in the image sequence at left.
Here's a graph over 2003.
Much had been made about viewing Mars exactly on the
night of closest approach, but as indicated on the
graph, for a few weeks the size difference is
not discernible to visual observers.
This graph is based on information
listed in the RASC Observer's Handbook
- The size of the polar cap is shrinking dramatically
as summer progresses in that hemisphere.
- The illuminated portion (phase) of Mars
changes as we overtake Mars in its orbit.
The fullest phase is at opposition (Aug. 28).
For August and later images, the camcorder was used to
directly image as well as record the signal.
Because the camcorder's
lens is not removable, a 16mm eyepiece was used
for afocal imaging as detailed at left.
For all images, the video sequence was brought
into my PC using a Firewire (iLink) digital video
interface. The resulting DV AVI file had to then
be re-encoded into an Indeo 5.10 AVI file for
compatibility with K3CCD and Registax which
are being used for post processing.