Video recordings of asteroidal occultations, 2003 - 2007
Updated: 2007 June 15, 23:50 UT
In October - December 2005, I video recorded 8 asteroidal
occultation chords, mostly at unattended (remote) telescopes.
The better ones are below. These are very large files, you
will need a high-speed connection to get them, although they include
only several seconds around the time of the occultation. In all of
the videos, north is up. Most of them were recorded with either
Kiwi OSD or McAfee GPS video time inserters to provide accurate UTC.
Except for the Regulus occultation, all used Supercircuits PC164C
video cameras. I have now added several other videos that are given
after the ones of October - December 2005.
Occultation of Regulus by (166) Rhodope, 50-mm telephoto
lens and image intensifier, near the southern limit south of
Monesterio, Spain, 2005 October 19. Brightness across the star's
disk might be determined from the gradual event light curves.
18 megabytes. For more information about this occultation,
click here.
For the 2005 Dec. 1st occultation by (99) Dike, the occulted star is
the lower (southern) one of three, the second-brightest star in the
field of view (mag. 8.9). For more information about this occultation,
click here.
Greenbelt, MD, 8" SCT, 48 megabytes, near northern limit;
Note that both the disappearance and reappearance occur in quick
steps, showing that the star may have a fainter companion one or
two milliarcseconds to the north.
La Plata, MD, 8" SCT, 83 megabytes, near path center
The companion is not evident in this view, or the next one, because
its events must have occurred while the primary was visible.
Dahlgren, VA, 5" SCT, 38 megabytes, near southern limit
Michael Richmond has analyzed these videos here.
Occultation of 9.5-mag. PPM 90693 by (955) Alstede, 2005
November 26, Oraville, MD, 8" SCT, 37 megabytes. For more information,
click here.
Occultation of 8.9-mag. SAO 145911 by (345) Tercidina, 2005
November 15, Weeks, NV, 4" SCT, 54 megabytes. The bright star to
the left was not occulted; SAO 145911, the considerably fainter
occulted star, is near the middle in the upper part of the video
frame when it is occulted during the later part of the clip.
This was my first asteroidal occultation video recorded with
Kiwi OSD GPS time insertion. For more information, click here.
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Other asteroidal occultation videos, 2003 - 2007
Three of the events have been analyzed with help from others noted
below.
2003 Mar. 23, (704) Interamnia, 140 megabytes.
I located the target star, 6.7-mag. SAO 96908 (HIP 36189), with Becky
Sydney's C8 and my PC164C camera, and she kept the star in the field
and recorded the occultation with a camcorder turned on a few minutes
before. This includes a WWVH minute tone and shows the
disappearance; I hope that a Limovie analysis of this file will
enable a time to be determined for the disappearance of the star's
secondary star, about 2 mags. fainter; it should have disappeared
about 5 seconds before the primary star. The location was Honolua
Bay on the north side of Maui; after locating the target star, I
drove to the south side of Maui to obtain another recording at
Makena. Good event times were obtained from that recording, but it
will probably not show the companion since it was made with a 50mm
lens. Becky Sydney's reappearance is here (76 meg.) but it might not
show the companion since she turned off the camcorder only about a
second after the primary star R. More about this outstanding event
is here, but more information has become available since that update.
Tony George has made a preliminary analysis that may show the
disappearance of the secondary star, but the result is not
conclusive; more about this will be posted later.
2004 Dec. 3, (268) Adorea, 137 megabytes.
This occultation was recorded with a C8 and PC164C camera as a
remote station set up in my backyard in Greenbelt, MD. The star,
UCAC2 38382705, is only mag. 12.0 so it is not visible, but might be
seen by stacking images with Registax. But even that might not help
since conditions were not good, with 9th-mag. stars very faint in
the video. I'm pretty sure that the pointing was right since about
a minute earlier a 6th-mag. star passed through the field that you
can see here (63 megabytes). I tried to record another chord
from southern Laurel, MD, but thicker clouds moving in foiled that
attempt.
2005 July 24, (780) Armenia, 75 megabytes.
This occultation of 8.7-mag. SAO 146999 (HIP 118132) was recorded at
Belle Meade, TN, a suburb west of Nashville. I prepointed my C5 and
provided the video equipment that John Graves turned on a few
minutes before the event to successfully record it. Similarly,
James Thompson video recorded the occultation with my prepointed C8
from Fairview, TN, about 20 miles farther west, while I travelled
about 12 miles east of Nashville, where I recorded a miss.
2006 Sep. 9, (25) Phocaea, 107 megabytes.
The star is 10.9-mag. TYC 2254-01227 that I recorded with an image
intensifier and C8 near Myersville, MD with bright moonlight and
haze. The predicted mag. drop was 0.46, but I don't see a drop, so
probably no occultation occurred. But a Limovie analysis would be
useful to be sure. Dan Caton recorded an occultation with a CCD
drift scan from Dark Sky Observatory near Boone, NC.
2006 Nov. 15, (356) Liguria, 98 megabytes.
The target star is 11.7-mag. UCAC2 41657910 but although the
reappearance is clear in this image-intensified video with a C8 at
Skippers, Virginia, near the predicted northern limit, the
disappearance is not as distinct; the predicted mag. drop was only
0.37. I'm hoping that a good time for the D can be obtaiend with a
Limovie analysis. Pedro Valdez Sada video recorded the occultation
from a location near Monterrey, Mexico near the southern limit.
2007 April 10, (7) Iris, 187 megabytes.
The target star, UCAC2 39104329, at mag. 11.8 was much fainter than
Iris, so the predicted dmag. was only 0.21; I'm hoping that a Limovie
analysis will reveal an occultation. The recording was made with a
C8 and image-intensified PC-164C from a location about 10 miles north
of Petersburg, Virginia. The star and asteroid can be seen
separately in this video taken about 15 min. after the expected time
of the occultation. Although well within the predicted path, I'm not
sure that I had an occultation since Bob Cadmus also obtained a
recording with a 24-in. telescope at Grinnell College, Iowa, and
could find no event in his recording, although he was closer to the
central line (and also north of it) than I was. Kazuhisa Miyashita
in Japan has analyzed this event and claims to have determined event
times; he writes:
To: IOTAoccultations@yahoogroups.com
From: "kazuhisa_miyashita"
Date: Mon, 11 Jun 2007 15:17:27 -0000
Subject: [IOTAoccultations] Re: Several more asteroidal occultation videos posted
Hello Dr.Dunham,
Thanks for release of the valuable videos.
I have analyzed the (7) Iris - UCAC2 39104329 event.
The result is here.
I will analyze some of other events in several weeks.
Best regards, Kazuhisa Miyashita
- Next, we need to see if there's any evidence of an occultation at
the corresponding times in Bob Cadmus' recording at Grinnell, Iowa;
Dave Herald feels that Miyashita's evidence for an event is not
strong.
2007 May 24, (471) Papagena east sta., 75 megabytes.
I recorded this occultation of 11.0-mag. TYC 1965-00020-1 with an
image-intensified C5 near Nottingham, PA. The star is not visible
well enough with single-frames to determine the times, so I just
obtained times with a stopwatch. More about this triple success is here.
2007 May 24, (471) Papagena central sta., 70 megabytes.
This was recorded with a prepointed remote C8 near Poplar Grove, MD;
see above for more information about this event. Like the above, the
star can't be reliably seen in single frames, so event times were
determined with a stopwatch.
2007 May 24, (471) Papagena west sta., 71 megabytes.
This was recorded with a prepointed remote C8 near Bagley, MD; see
above for more information about this event. Like the above, the star
can't be reliably seen in single frames, so event times were
determined with a stopwatch.
- Tony George has done an excellent analysis of all 3 tapes, using
Registax and Limovie to determine event times more accurate than my
stopwatch times, as he's described in his account that I've included
here.
David Dunham
e-mail home dunham@starpower.net; office david.dunham@jhuapl.edu