Report of BY Cancri occultation by Saturn
(2006-01-25)
Telescope: 1200/254 Newton
Equipment: Baader IR-Pass Filter (685nm), B/W Videomodul SK1004X
KIWI-OSD + GPS, Videorecorder, Videograbber + Notebook
Location : Nonndorf-Austria, 48.787 N, 15.236 E, 549 NN
Observers: Gerhard Dangl
Report :
Setup
Due to my job, setup of my moveable station was accomplished not earlier
then 17:30 UT. At 18:22 UT the first video frames with GPS timestamps
from KIWI-OSD could be captured on a VHS videorecorder tape.
An USB2.0 videograbber + notebook was used for simultaneous video watching.
Weather conditions
17:30 - 21:30 UT high moving clouds always dimmed Saturn around 1-2 mag,
sometimes the planet disappeared completely, bad seeing all the time.
21:30 - 22:30 UT not clear but only thin high moving clouds, better
seeing, from now on Titan and star BY Cancri are clear visible on all live
video frames.
Some details
First I tried a blue filter (300-400 nm) for a better star-saturn contrast.
But characteristic of Sony EXview CCD-Sensor ICX255AL dimmed images
additionally more than 1.0 mag. Because of the dimmed and jumping saturn
system the goal now was to catch as many photons as possible and to stable
imaging. So I altered to long wavelengths and tried to stable images with
the use of an Baader IR-Pass (>685nm) filter. Here I had to accept a loss
of only around 0.5 mag. But again, different focal lengths of 1200, 3000
and 6500mm did not success to catch titan or the target star on video.
From around 21:30 UT on weather conditions become better so Titan and star
BY Cancri are clear visible on all live video frames. At this time star
was separated already 5.7 arcsec from planet.
My conclusion
Wether there would have been a chance that the star would have become
visible or not depends mainly on seeing and weather conditions. But with
a aperture of 10 inches nearly perfect conditions are required for
a +7.9mag star.
German textpage with event images of equipment and sky objects
Regards
Gerhard Dangl
Nonndorf - Austria
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