From Edward A GRAFTON
@. . . . . . This image was taken 5/10 at
http://www.kwasan.kyoto-u.ac.jp/~cmo/cmons/EGf10May01.jpg
MARS IMAGE :
Ed Grafton,
Eyepiece Projection @ f/60
Integration Times:
1 BLUE + IR rejection,
.5 seconds, Edmunds filters
1 GREEN + IR
rejection, .5 seconds, Edmunds filters
1 RED + IR
rejection, .5 seconds, Edmunds filters
10 CLEAR+ IR rejection, .5 seconds, Edmunds filters
Seeing variable,
fair-good 4-7/10,
transparency hazy 4/10, wind calm, moderate dew.
Elysium orographic
clouds appear to be broken into two nearly equal parts.
(10 May 2001 email)
@. . . . . . . . . . This image was taken 5/14 at
http://www.kwasan.kyoto-u.ac.jp/~cmo/cmons/EGf14May01.jpg
MARS IMAGE :
Ed Grafton,
Eyepiece Projection @ f/60
Integration Times:
4 BLUE + IR rejection, .5 seconds, Edmunds
filters
1 GREEN + IR rejection, .5 seconds, Edmunds filters
1 RED +
IR rejection, .5 seconds, Edmunds filters
14 Magenta + No
IR, .1 seconds, Edmunds filter
(luminance channel)
Seeing variable, fair-good, slow undulating
waves 4-7/10, transparency very hazy 3/10, wind calm, moderate dew.
Hazy conditions with thin cirrus passing through.
(15 May 2001 email)
@. . . . . . . . . . Please note that my Mars observations from 5/10
and 5/14 were incorrectly labeled for UT. The
PS: The surgeon general has determined that working all day and imaging all night is hazardous to you brain! Sorry for the confusion
(16 May 2001 email)
@. . . . . . . . . . I am very pleased that you find my images worthy
of your publication "Communications in Mars Observations".
Please feel free to use them as you wish. It is also fine to make a
hyper-linkage to my web from your site. Please note that the UT on the original
images was incorrect. I have corrected this and the UT is now correct on both
image files. Each was off by one hour due to the shift to day light saving time
which I did not take into account. The
http://www.kwasan.kyoto-u.ac.jp/~cmo/cmons/EGf14May01.jpg
http://www.kwasan.kyoto-u.ac.jp/~cmo/cmons/EGf10May01.jpg
If you need anything from me let me know. Regards
(17 May 2001 email)
@. . . . . . . . . . This image was taken
http://www.kwasan.kyoto-u.ac.jp/~cmo/cmons/EGf19May01.jpg
MARS IMAGE :
Ed Grafton,
Eyepiece Projection @ f/60
Integration Times:
4 BLUE + IR rejection,
.5 seconds, Edmunds filters
1 GREEN + IR
rejection, .5 seconds, Edmunds filters
1 RED + IR rejection, .5 seconds, Edmunds
filters
10 Magenta, No
IR .1 seconds, Edmunds filters
(luminance)
Seeing variable, fair-good 4-7/10,
transparency hazy 6/10, wind calm, heavy dew.
Occasional low clouds blowing through. A Dusky
"Collar" is noted along the entire length of northern borders of Mare
Sirenum and Mare Cimmerium.
(20 May 2001 email)
@. . . . . . . . . . The seeing here is good in the summer but not
really any better than most favorable locations. It is a real struggle to get
the sky to cooperate with Mars being only 35 degrees altitude here in
http://virga.sfsu.edu/crws/jetstream.html
The C14 is collimated well. I
use the standard method of looking at the diffraction pattern of a star at high
magnification to keep the optics aligned.
The images are produced using a
method called LRGB (as opposed to RGB). The Luminance channel for the images is
created separately from the color channels. This allows one to take shorter
exposures since the L channel does not require any filters (although I have
used a magenta filter to gather the L channel information on the last couple of
images). The color data is derived in the standard way with RGB filters and an
IR blocking filter. The color data in this method tends to be weak but the L
channel is stronger. The image processing is done mainly on the L channel
images as the RGB data has low S/N since I have gathered little data for the
color channels. I usually capture one red, one green and four blue and 40 L
images in a few minutes time. I can get four data sets of the RGBs and L images during about 90 minutes (with focusing
and adjusting the scope etc). I only have 90 minutes of visibility of Mars per
night as it passes between two trees located in my neighbors
yard. I examine to see which of the four data sets have the best images and
choose that set for processing. If I am lucky I can use 10 and so of the L
images out of the 40 that were taken for the best data set. Processing is done
on the L images first using CCDOPS (SBIG CCD software). The images are
sharpened using the bipolar filter (hard) and then smoothed (soft) and then
sharpened again (hard) in CCDOPS. I save the images and then use Megafix software to average the 10 or so L channel images.
This results in a high S/N L image that are made up of 10 or so low S/N images
but they only have required 0.1 seconds exposure each so the atmosphere and the
tracking problems are at a minimum. The averaged image is then sharpened again
in the megafix software. The L is then aligned with
the RGBs and a color image is produced. The image is
saved and opened in Photoshop where a mild unsharp
mask is applied.・・
(22 May 2001 email)
@. . . . . . . . . . Yes..please
feel free to use the information however you wish. If one can improve their
technique from my experience then I am pleased.
You have understood
exactly. The RGBs are only to give a reasonable color
balance and most of the detail is in the non-filtered (or magenta filtered
images). These are my first attempts to image Mars although I have imaged
Jupiter and Saturn before. Unlike Jupiter, I noticed that Mars had high
contrast in the infrared so I altered my technique to include IR in the L
channel. This had the effect of gathering more light per time unit and allowed
me to shorten the exposure times and cope better with the atmosphere. The
exposure times had already been shortened by the application of the LRGB
technique since the whole image did not have to be constructed from just the
filtered and IR blocked RGBs. The RGBs
were shot with the IR in place to give proper color balance.
I used the
Magenta and no IR filter for the L channel with the idea that all the albedo feature contrast was in the red and IR. I wanted to
try and capture the cloud features also so using the magenta picked up the blue
also. There may be better combinations of filters that can be applied but since
this is my first attempt to image Mars I have not experimented much. I do not
know if my magenta filter is open to the UV but have wanted to include data
down to 300nm and see if that helped to enhance the cloud features. The QE of
the CCD chip is getting very low at that wavelength though. Here in
http://www.egrafton.com/juphr.jpg
I will send the following unless you let me know differently. The
uncompressed but processed files are in .tif format
I will send the images tomorrow
as now I have house guest and do not want to appear rude with self interest.
(23 May 2001 email)
@. . . . . . . . . . Attached are the images that I said I would send
in yesterdays email.
I hope that you can make use of
them.
(23 May 2001 email)
@. . . . . . . . . . I would be very pleased to receive the printed
version of the CMO. I will send you all observations that I get.
(25 May 2001 email)
Ed GRAFTON (
