Polarization observations require three or more images with the polarizing filter spanning a large range of position angles on the sky. For WFPC2, this may be achieved by using different quads of the polarizing filter (each quad being oriented 45њ to the others), by rotating the spacecraft though different angles, or by a combination of these methods. Rotating the spacecraft through use of ORIENTs provides the simplest calibration, as a single polaroid can be used for all images. ...

GRANAT is the Russian x-ray sattelite launched to the high apogee orbit (200,000 km) and operated almost for 10 years (1989 -1999) , carrying out four major instruments: French SIGMA coded-mask hard x-ray telescope (30-1000 keV), Soviet ART-P coded-mask telescope (2??-60?? keV), all-sky monitor WATCH (6-150 keV), and a gamma-burst detector PHEBUS . ... Since September 1994, GRANAT is in the survey mode. ... Explore pages devoted to individual GRANAT instruments (including main scientific results): . ...

Magnetic field measurements onboard the Interball Tail spacecraft are carried out by the FM-3I instrument which consists of two flux-gate magnetometers covering two different ranges: [-200, +200] nT and [-1000, +1000] nT. Besides scientific goals, the FM-3I experiment data is used to perform the attitude control of the Interball Tail spacecraft. ... August 22, 1995 . ... October 18, 1995 . Top of the page . ... Back to the Interball Home Page . ...

... The spacecraft of Magion type have been selected as the subsatellites of the Interball project: Magion-4 (C2-X) for the Tail Probe and Magion-5 (C2-A) for the Auroral Probe. ... Magion-4 was produced in the Czech Republic in collaboratrion with Russia, Ukraine, Hungary, Austria and has onboard scientific instruments and sensors designed and built in Czech Republic, Russia, Poland, Hungary, Romania, Bulgaria and Slovak Republic. ... Plasma flow detector VDP-S (Czech Republic, Russia) . ...

Next: Some theory Up: userhtml Previous: Calibration . By many measures, the ATCA 3-mm observing band is a completely different domain to the other ATCA bands. ... Not surprisingly many aspects of the data reduction are also different. This chapter reviews the theory behind some of the differences, and then considers a practical approach to calibration. ... Antenna gain considerations and flux calibration . Instrumental phase . Atmospheric phase and phase calibration considerations . ...

... Let us first find out which way -- rise in spectral resolution with some loss in the S/N ratio or increase in the S/N ratio with a fixed spectral resolution -- is better for the purpose of reduction of equivalent width determination errors. ... N -- number of counts for 1 ? ... line equivalent width, . ... Thus if the spectral resolution is managed to be increased (i.e. to decrease )without loss in the number of counts falling at 1 ?, the equivalent width measurement error is then proportional to . ...

... There are 6 different analysis options: . 0:all : all the exposures corresponding to the chosen observation are reduced to calibrated event lists, unless disabled via the corresponding parameter ( PN , MOS , RGS , OM , all set to "yes" by default). ... The EPIC data is then searched for source detections, via edetect_chain . By default, for the EPIC data, if more than one exposure is present, these actions are taken over the event list corresponding to the longest observation. ...

Estimations of the change of the Sun s mass and the gravitation constant based on high-accuracy observations of planets and spacecraft . ... More than 635 000 positional observations of planets and spacecraft of different types have been used for estimating possible changes of the gravitation constant, the solar mass, and semi-major axes of planets. ... gravitation constant, positional observation, Sun's mass. ...

... In order to compare the number of different evolutionary stages obtained and X-ray luminosity of the chosen X-ray sources with the observed galactic values we use the sum of C/O+O/C , where C and O are the calculated and observed values of a given binary type, respectively. If we make comparison for a number of different binary species (for example, we compare the number of CV, number of X-ray pulsars,   total X-ray luminosity of LMXB, etc.), we write this criterion in the form: . ...

... the time of observation . ... Observing the Changing Position of the Sun To Establish Cardinal Directions . ... Observations of the Sun's apparent movement across the sky and its pattern of rising and setting in the east and west horizon helped to establish the cardinal directions. ... The final stage of the Sun's return was marked by the observation that the Sun had reached its highest altitude when the full width of your mitted hand could fill the gap between the Sun and the horizon. ...

... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . ... The interface between the lower solar atmosphere where energy is generated by subsurface convection and the corona comprises the chromosphere, which is dominated by jet-like, dynamic structures, called mottles when found in quiet regions, fibrils when found in active regions and spicules when observed at the solar limb. ... In addition, how they affect the coronal heating and solar wind need to be further explored. ...

Crater Gassendi . ... I made this drawing was made on the 26th of november 2001. If you compare this one with the previous drawing of Gassendi (below) the differences are clear. ... This drawing was made on the 28th of september 2001. After nearly a full month without observations I had a one hour gap between the thicker clouds. ... This drawing was made on the 29th of august 2001. ... This drawing was made on the 27th of august 2001. ... This drawing was made on the 25th of august 2001. ...

... The Batch Reduction window allows catalogs of observations to be processed and a data reduction scheme to be defined dynamically. The different steps like Bias, Dark, Flat-Field correction, etc. are optional and must be set by clicking on the option buttons located on the left side of the window. ... Image numbers: by indicating the prefix of the images in the field Prefix/Catalog and providing the image numbers in the field Numbers , using dashes and/or commas. as in: . ... Numbers: 3-5,8 . ...

... 2003 March 19 . Jupiter's Great Dark Spot . Credit: Cassini Imaging Team , Cassini Project , NASA . Explanation: Seventeenth century astronomer Giovanni Domenico Cassini was an astute observer of Jupiter's Great Red Spot. So it seems only fitting that his namesake, the Cassini spacecraft, has enabled detailed observations of another planet-sized blemish -- Jupiter's Great Dark Spot . ... About APOD | ... NASA Technical Rep.: ... A service of: LHEA at NASA / GSFC . NASA SEU Edu. ...

Next: Calibration with the ISOPHOT Interactive Analysis (PIA) . ... ISO P HOT I nteractive A nalysis, PIA , is a scientific and calibration data analysis tool for ISOPHOT data reduction. The PIA software was designed both as a tool for use by the instrument team for calibration of the PHT instrument during and after the ISO mission, and as an interactive tool for ISOPHOT data analysis by general observers. ... PIA is entirely based on the Interactive Data Language IDL (IDL92). ...

... They are concerned with Attitude Control System of the spacecraft, satellite visibility from tracking stations, limits on the satellite autonomous operations during the orbit, and needs for auxiliary operations with the spacecraft. ... Among the operational constraints the most important one is the number of programmed slews per orbit, which determines the maximum number of radio sources to be observed during one orbit. ... System temperature (K) . ... Progress of the RadioAstron Project in Pictures...

These observations are aimed at fully charactering FORS1 photometric system (UBVRI zero-points, color-terms and extinction coefficients) for the Tektronix 2048x2048 pixel CCD (24µm px) . To this aim, the two Landolt/Stetson photometric fields SA95 and SA101 will be observed on a number of epochs and at different airmasses during February and March 2007. ... SA101 . ... OBs for SA101 have to be observed during evenigh twilight (exceptions are expected for the second half of March) . ...

Databases (NSDC) of the Natural Planetary Satellites. ... NSDC: Database of astrometric observations of Natural Planetary Satellites . ... They are thoroughly looking for observations in different sources, creating their owndatabases which are then mostly inaccessible to other researchers. ... In the file "content" with explications, the reference is given to the data source as well as the bibliographic reference. ... Data sources. ... Why a specific bibliographic database for Natural satellites? ...

Astronotes Armagh Planetarium's Stellar Blog! ... Space Flight . ... Concept Spacecraft . ... By admin September 24, 2010 Posted in: Concept Spacecraft . One of the most grandiose of the vehicles suggested by Cole was the Aldebaran concept, a gigantic nuclear-powered launch vehicle he proposed in 1959. ... Scott Lowther has recently added fascinating scale drawings of this and other nuclear space propulsion concepts at his blog (the Unwanted Blog). ... The Amazing Aldebaran Spacecraft | ...

... Contact A Problem of an estimation of accuracy of the asteroid CCD observations . The Minor Planet Center supported by the Interntional Astronomical Union is the main office for keeping observational data of the small Solar System bodies and their investigations. ... At Pulkovo Observatory we are estimating an accuracy of the CCD asteroid observations obtained by amateurs and professional astronomers all over the World using the MPC database. ...