Deep Lens Survey : Real-time Transient Detection |
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CTIO, Apr 2002
This page contains REAL-TIME information on detections of
transient astronomical happenings from the Deep Lens Survey, currently being
undertaken on the KPNO and CTIO 4-m telescopes using the wide-field
MOSAIC imagers.
A by-product of this wide-field survey is the detection of
transient astronomical phenomena, including Near Earth Objects (NEO),
Kupier Belt Objects (KBO), Supernova (SN), and even previously unknown
events which happen with such rarity that only a deep, wide field
survey, such as this one, is even reasonably sensitive to them.
The table below contains recently updated information on objects
detected during the course of this survey. These are extracted from
the images in real-time using a combination of SExtractor
for object detection and image subtraction to provide differenced
images, from which we are able to identify transient, or "new",
objects, after filtering out spurious objects like cosmic rays. These
objects have also been inspected by eye and categorized as probably
real.
We include the date, DATE-ARCH, when the object was added to this
archive or updated, the date the object was most recently observed
DATE-OBS (MJD), and the FILTER of this observation. Additionally, we
include the RA and DEC (J2000, to ~0.5'' accuracy) of the object, a
preliminary categorization of the nature of the transient, and a
preliminary estimate of the magnitude of the variability (+/- 0.1 mag in
R and B, +/- 0.5 in V and z). Two types of images are available for
download: .jpg mosaics and .fits finding charts.
The mosaic page includes a time-series of JPEGs showing 200-pixel (50")
postage stamps, with time increasing from top to bottom. The
discovery mosic includes a template observation on the left, discovery
image in the middle, and difference image on the right. Subsequent
mosaics show a similar collection of images, or the new observation
image only, in the case where a subtraction image was not available.
The files are generally a few hundred kilobytes. In CTIO mosaics, East
is up and North is to the right. For KPNO, East is down and North is to
the left.
The finding charts are 3'x3' FITS images centered on the discovery
position. The time in the header is the start of the exposure and the
world coordinate system in the header is accurate to 0.5". The files
are 3 MB. The images are zero-padded to maintain the object in the
center even if it was near the edge of the discovery image. Your
browser may not bring up saoimage/ximtool automatically on the FITS
file. Right-click on the link to save to local disk.
Moving objects are submitted to the Minor Planet Center at the end of each night. For those objects
which receive a designation, we provide a link to query the MPC database - new
objects are indicated with bold font.
For those objects which do not receive a designation, we provide our own ASCII
list of positions and times.
To make things considerably more exciting, we will color code interesting transients
using the following notation
| Supernova |
| Unknown (stationary) |
| Variable Star |
| Rapidly Moving Transient |
| Slowly Moving Transient (< 2" / hr) |
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