From
Timothy J PARKER
@. . . . . . . . .
. Mars observers:
Attached are my first pretty successful attempts at imaging
Mars with a web cam I purchased last fall to try to take color images to combine
with grayscale images of Jupiter taken with a Starlight HX516 for LRGB
composites. My efforts to do so
then were frustrated by the fact that I had no way to quickly switch from one
camera to the other on the scope. After the
I recently downloaded a Mac driver for it that I like a lot
better than the software available for the PC.
This software gave me a nice, large window to see how I was
doing in setting the camera up for best color balance and exposures.
So I used this software to acquire uncompressed tiff video
at 1 frame/second for about 2 or 3 minutes at a time (longer and the files
would get too big). I then used
Canvas 7.0 to read the QuickTime movie and save individual frames from the
movie (can't understand why QuickTime Player doesn't allow that) so that Adobe
Photoshop could read them. All
subsequent processing was in Adobe Photoshop.
Of course, for monitoring Mars for flashes next month, I'll
need to compress the video some in order to take continuous images for 90
minutes! I'll experiment with my
options (there are many) and see which is the least lossy during compression.
The results with the web cam are as good as a series of
images I took with the Starlight HX516 between acquiring these two images, and
these are in color!
Hope all is well
where you're observing from!
planetarily,
(23June 2001
email)
@ . . . . . . . . .
Here is the result from the 30th (last
night). I used my 3Com Homeconnect
webcam again, with a larger projection distance from the Televue 2.5× barlow for
a bigger image scale. I continue to
be pretty happy with the results from the webcam, so I'm going to continue to
use it for the time being. On the 24th, I actually shot both with the webcam
and the Starlight Xpress HX516, but the results from the webcam were better and
a lot easier to acquire and process!
Don't anyone tell Terry Platt!
planetary
regards,
(
@ . . . . . . . . .
.Dear Masatsugu; I've been having good weather (but mediocre seeing) for Mars
observations this week in California, and have imaged the "Amazonis"
hemisphere as recently as this morning (I still have some processing to do of
those images, and will post them as soon as they're ready). The Valles
Marineris and western Acidalia region seem "normal" to me, though it
is certainly possible I'm missing something. I have been told by my Mars Global
Surveryor colleagues that the dust storm is "a big one", but I don't
think it's gone global as of this morning (early morning UT, July 01, 2001). I am hoping to have another
successful imaging session tonight, and will look for any westward expansion
into the Margaritifer and Acidalia longitudes.
planetarily,
(
@ . . . . . . . . .
.Masatsugu: By all means, call me Tim.
I'm just a regular guy, after all.
That certainly is a big regional storm,
judging from the pictures coming in. It may go global eventually, too. If it
does, it might be the first global storm since Viking in the late 70's. The
side I can see looks normal at the moment, but it might not stay that way.
Looks like prospects for seeing
I would go ahead and ask either Jim Bell or
Phil James about HST plans to image Mars. I would be surprised if there aren't
plans to do so already, but I could be wrong. regards,
(
@ . . . . . . . . .
.I've just uploaded my most recent Mars observations to the Marswatch website
(though it didn't completely transfer the first time, hopefully the page will
show the complete file, attached). Images were taken using my 3Com Homeconnect
camera on my "recently recollimated" 12.5" Springfield
Cassegrain at the prime focus (really coude' focus, as I shot without the star
diagonal, so have 3 reflections).
Sidebar: I shimmed the
focuser with an expired "proof of insurance" card. For those who might contemplate a
Again, I was using Vicam TV software to
image with my Mac Powerbook. Now that I know what camera settings work best, I
plan to try imaging with Dave Durant's webcam plugin for MaximDL, which I
prefer for it's excellent deconvolution filtering (much better than Photoshop's
unsharp mask, in my opinion). For those contemplating or using digital cameras
or webcams with color filters on-chip, you should split the color channels and
reregister them before recombining them for color composites. I've noticed
about a 10-pixel displacement due to atmospheric refraction between the blue
and red channels when Mars' disk subtends 192 pixels. I also realize now that
my relatively poor images with the HX516 last week were probably due to the
fact that I used no filters, so atmospheric refraction was a serious issue (especially
with around an arc-second displacement between red and blue, never mind IR!).
Hope it stays clear and steady where
you're looking up from!
(
Tim PARKER (CA,
tparker@mail1.jpl.nasa.gov