33 research outputs found
A digital video system for observing and recording occultations
Stellar occultations by asteroids and outer solar system bodies can offer
ground based observers with modest telescopes and camera equipment the
opportunity to probe the shape, size, atmosphere and attendant moons or rings
of these distant objects. The essential requirements of the camera and
recording equipment are: good quantum efficiency and low noise, minimal dead
time between images, good horological faithfulness of the image time stamps,
robustness of the recording to unexpected failure, and low cost. We describe
the Astronomical Digital Video occultation observing and recording System
(ADVS) which attempts to fulfil these requirements and compare the system with
other reported camera and recorder systems. Five systems have been built,
deployed and tested over the past three years, and we report on three
representative occultation observations: one being a 9 +/-1.5 second
occultation of the trans-Neptunian object 28978 Ixion (mv=15.2) at 3 seconds
per frame, one being a 1.51 +/-0.017 second occultation of Deimos, the 12~km
diameter satellite of Mars, at 30 frames per second, and one being a 11.04
+/-0.4 second occultation, recorded at 7.5 frames per second, of the main belt
asteroid, 361 Havnia, representing a low magnitude drop (Dmv = 0.4)
occultation.Comment: 9 pages, 5 figures, 3 tables, accepted to Publications of the
Astronomical Society of Australia (PASA
Verifying timestamps of occultation observation systems
We describe an image timestamp verification system to determine the exposure
timing characteristics and continuity of images made by an imaging camera and
recorder, with reference to Coordinated Universal Time (UTC). The original use
was to verify the timestamps of stellar occultation recording systems, but the
system is applicable to lunar flashes, planetary transits, sprite recording, or
any area where reliable timestamps are required. The system offers good
temporal resolution (down to 2 msec, referred to UTC) and provides exposure
duration and interframe dead time information. The system uses inexpensive,
off-the- shelf components, requires minimal assembly and requires no
high-voltage components or connections. We also describe an application to load
FITS (and other format) image files, which can decode the verification image
timestamp. Source code, wiring diagrams and built applications are provided to
aid the construction and use of the device.Comment: 10 pages, 7 figures, accepted to Publications of the Astronomical
Society of Australia (PASA
Verifying timestamps of occultation observation systems
We describe an image timestamp verification system to determine the exposure timing characteristics and continuity of images made by an imaging camera and recorder, with reference to Coordinated Universal Time. The original use was to verify the timestamps of stellar occultation recording systems, but the system is applicable to lunar flashes, planetary transits, sprite recording, or any area where reliable timestamps are required. The system offers good temporal resolution (down to 2 ms, referred to Coordinated Universal Time) and provides exposure duration and interframe dead time information. The system uses inexpensive, off-the-shelf components, requires minimal assembly, and requires no high-voltage components or connections. We also describe an application to load fits (and other format) image files, which can decode the verification image timestamp. Source code, wiring diagrams, and built applications are provided to aid the construction and use of the device
OME-Zarr: a cloud-optimized bioimaging file format with international community support
A growing community is constructing a next-generation file format (NGFF) for bioimaging to overcome problems of scalability and heterogeneity. Organized by the Open Microscopy Environment (OME), individuals and institutes across diverse modalities facing these problems have designed a format specification process (OME-NGFF) to address these needs. This paper brings together a wide range of those community members to describe the cloud-optimized format itself-OME-Zarr-along with tools and data resources available today to increase FAIR access and remove barriers in the scientific process. The current momentum offers an opportunity to unify a key component of the bioimaging domain-the file format that underlies so many personal, institutional, and global data management and analysis tasks.ISSN:0948-6143ISSN:1432-119
Pluto Atmospheric Activity, Ephemeris Offset and Charon Orbital Radius Constrained by Stellar Occultations
International audienceWe have pursued in 2008 our observing program of stellar occultations by Pluto and its satellites. This program started in 2002, and revealed a two-fold increase of Pluto atmospheric pressure between 1988 and 2002. Various occultations observed in 2006 and 2007 did not reveal any further increase in pressure. Also, a measure of Charon's radius was made using an occultation observed on 11 July 2005
Pluto Atmospheric Activity, Ephemeris Offset and Charon Orbital Radius Constrained by Stellar Occultations
International audienceWe have pursued in 2008 our observing program of stellar occultations by Pluto and its satellites. This program started in 2002, and revealed a two-fold increase of Pluto atmospheric pressure between 1988 and 2002. Various occultations observed in 2006 and 2007 did not reveal any further increase in pressure. Also, a measure of Charon's radius was made using an occultation observed on 11 July 2005
OME-Zarr : A cloud-optimized bioimaging file format with international community support
A growing community is constructing a next-generation file format (NGFF) for bioimaging to overcome problems of scalability and heterogeneity. Organized by the Open Microscopy Environment (OME), individuals and institutes across diverse modalities facing these problems have designed a format specification process (OME-NGFF) to address these needs. This paper brings together a wide range of those community members to describe the cloud-optimized format itself-OME-Zarr-along with tools and data resources available today to increase FAIR access and remove barriers in the scientific process. The current momentum offers an opportunity to unify a key component of the bioimaging domain-the file format that underlies so many personal, institutional, and global data management and analysis tasks