SkyCam
One of the SkyCam Andor cameras
"SkyCam" is a project to provide simultaneous wide field
observations with normal LT data taking. All data taken
with SkyCamA and SkyCamT is immediately public to all and may be used for any
non-commercial scientific or educational purpose. Data taken with SkyCamZ
remains proprietary. Please contact the LT group if you require access to that
data.
At present the system consists of three cameras:
- SkyCamA - an "all sky" camera on a fixed mount inside the
LT enclosure. This uses a 4.5mm fisheye lens to provide near
all-sky coverage down to about 6th magnitude. It is capable
of detecting reasonably thin cirrus cloud and is most
likely useful for checking for the presence of
clouds affecting data etc.
- SkyCamT - a "medium field" camera mounted on the LT mount
which parallel points with the telescope. This uses a 35mm
focal length lens to provide a 21° field of view and
can detect sources down to about 12th magnitude. The pixel
scale is 73.4 arcsec/pixel.
- SkyCamZ - a "zoomed field" camera mounted on the LT mount
which parallel points with the telescope. This uses an Orion Optics
AG8 telescope to provide a 1° field of view with a pixel
scale of 3 arcsec/pixel and
can detect sources down to about 18th magnitude.
Small section of SkyCamT image with all objects brighter than V=12 identified
(click for bigger)
All cameras use Andor ikon-M DU934N-BV cameras equipped with a 1024x1024 pixel, back illuminated and anti-reflection coated CCD running at -40°C. There are no filters in the system. A quantum efficiency curve is presented below:
When the enclosure is open, data is taken automatically once per minute with a 10 second exposure time. All data is automatically dark subtracted and flat-fielded and a world coordinate system fitted. SkyCamA and SkyCamZ data is then immediately publicly
released both as JPEG and FITS files here. In addition both browsable and searchable image archives are available.
Testing of SkyCamT has shown it is capable of repeatable photometry to a few hundredths of a magnitude for objects of around 8th magnitude. No testing has yet been done at fainter magnitudes. The lightcurve below of RR Lyrae (period about 1.1 days) was constructed from two images per night obtained over a six week period and shows the quality of data that can be expected. The scatter in the lightcurve is dominated by variability in the object from phase to phase rather than the skycam data itself.
Small section of SkyCamT image with all objects brighter than V=12 identified