... While much high spatial frequency information in the image is permanently destroyed by smearing with the response of the "fat" pixels, the quality of the image can nevertheless be greatly improved by combining sub-pixel dithered images. ... Another standard simple linear technique for combining shifted images, descriptively named "shift-and-add", has been used for many years to combine dithered infrared data on a finer grid. ... Drizzle runs under the NOAO image processing software IRAF. ...

... In combining the data, it is assumed that the low resolution image better represents the short spacing data, whereas the high resolution best represents the fine structure. ... Key: out The output image. ... Key: factor The flux calibration factor. ... In practise, the calibration may not be perfect, and an extra calibration factor will be required to align the flux scales. "factor" gives the factor to scale the low resolution image to put it on the same flux scale as the high resolution image. ...

... It lists the coefficients defining the colour transformations, the zero points for the different filters and the aperture radii used in the photometric calibration analysis. ... The AB system zero point of the filter FilterID is stored in the keyword ABM0 FilterID , e.g. the AB zero point of the the U-filter is stored in ABM0U. The flux conversion factor derived from White Dwarfs of the filter FilterID is stored in the keyword FCF FilterID . ... description . ... AB Flux conversion factor of U . ...

... Data may be optionally rescaled. copyheader copy header keywords from one FITS file to another ( see also FTOOL cphead ). copywcs copy just the World Coordinate System keywords from the header of one FITS image to others. fcolappend append a constant column to a FITS table fitsparsename Prints components of the extended FITS file name. fitspha convert ASCII files to FITS PHA ( See also listhead supplied with FITSIO. modifyheader modifies FITS header. ...

... The COMBINE/CCD command offers the possibility to combine a number of input images using different combining methods. COMBINE/CCD takes three input parameters at maximum: the exposure type of the images to be combined, the input frames themselves and and output frame. ... In the case of DO input (association) table, from the name of the output calibration frame in the table the command extracts the names of all requested single calibration frames and combines these frames in the output frame. ...

... AstroCC is a coordinate conversion utility for astronomy. It accepts an object designation or the coordinates of an object and calculates coordinates in alternative systems, and at different dates, times, and locations. It also provides lunar and bright planet coordinates to aid in planning observations. ... BJD values may also be retrieved from http://astroutils.astronomy.ohio-state.edu/time/utc2bjd.html which is based on Eastman et al. ... Coordinate data are obtained from SIMBAD. ...

... LO frequencies were 1/2, 1/3 and 1/8 of signal frequency 75 GHz. ... But single junction SIS mixer has 30 dB input signal power range only [ll and it may decrease at high frequencies more than 200 GHz due to Josephson and 1 "switching" noise rise [2 e Our experiments show that subhurmonically pumped SIS mixer may have improved saturation power and reduced noise at high frequencies in some operation modes. ... 269 Fig.2 Quantum for LO and signal frequencies SIS operating mode. ...

TUI supports the following offsets: . Object Arc offset by a given amount on the sky (i.e. along the arc of a great circle). ... Arc offsets are useful for moving a different portion of your object or a different nearby object onto the boresight . ... Object Arc XY this is identical to an Object offset except that it has been rotated to align along the instrument x-y axes. ... This is just like the Calibration XY offset, except that it is typically cleared when you slew to a new object. ...

Quasar VLBI network observatories as co-location sites A. Ipatov, I. Gayazov, S. Smolentsev Institute of Applied Astronomy, Saint Petersburg, Russia ... supposes: 1. installation of different observational techniques at sites (co-location) 2. combined processing of different types of observations (collocation) IAA activity in space geodesy · Quasar VLBI network : ­ VLBI observations ­ GPS /GLONASS observations ­ DORIS ( ...

... Avg: the average value of the spectra (maybe throwing out some channels at the edges). <>:average over the spectra (throwing out points at the edges if you want). gCal(f) :- frequency dependence of the tabulated cal values. ... calInK(Avg): Scaler cal value averaged over the band. calOffSpc(Avg): cal off value averaged over the band (in spectrometer counts) . ... cntsToK(avg) = calInK(Avg) / (calDif_cnts(Avg)) . To convert a spectrum b_cnts in spectrometer counts to b_K in Kelvins using cntsToK: . ...

For the calibration of RATAN-600 data you will need to Download Nobeyama Fluxes (1, 2, 3.75, 9.4, 17 GHz): year 1999 2000 2001 2002 2003 . Brief description of Work Scan . Main functions of processing, realized in the program are: . ... Correction of various (not fatal) defects of data; . ... Calculating of the lower enveloping curve or an average scan from observations data for a few days; . ... COMMENT This table contains the set (TFIELDS) of 1-dimensional (TFORM# . ... AZIMUTH = 'float' / . ...

Next: Quadrant DC Offset Removal in NICMOS Images Using an Eye-pleasing Criterion . ... This paper describes a simple imaging model which allows the limits of dithered imaging to be readily appreciated and briefly reviews available software. ... Dithered imaging can improve this sampling. ... ACOADD was originally developed for combining images with different PSFs but can also be used, with shifted PSFs and sub-sampled output images, for combining dithered under-sampled images. ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2004 March 25 . An Orion of a Different Color . ... But the striking picture combines images taken through three separate filters, each designed to record different emission lines - light from Sulfur, Oxygen, and Hydrogen atoms glowing in the tenuous nebular gas. ... About APOD | ... NASA Web Site Statements, Warnings, and Disclaimers . ...

... An Orion of a Different Color . ... It is a familiar object though, the grand stellar nursery known as the Orion Nebula . But the striking picture combines images taken through three separate filters, each designed to record different emission lines - light from Sulfur, Oxygen, and Hydrogen atoms glowing in the tenuous nebular gas. At such low densities , Sulfur and Hydrogen atoms emit red colors while Oxygen glows green. ... Publications with keywords: Orion Nebula . ... The Heart Of Orion . ...

... ESO is building what will be the World's largest optical telescope array, The Very Large Telescope (VLT). The VLT Project organisation is responsible for the design and construction of the Unit Telescopes, including enclosures, optics, adapter-rotators and coating unit. ... Unit Telescopes Overview - This page is outdated, an update is in process. ... Secondary mirror (M2 Unit) - This page is outdated, an update is in process. ... Coating Unit - This page is outdated, an update is in process. ...

... The value of tile-size, NW , may be thought of as a sixth coordinate axis in the chirplet transform parameter space - TF-area. Including this sixth coordinate axis provides us with a hierarchical (multi-resolution) CCT. ... Various 2- D slices through the multiresolution CCT may correspond to useful tilings of the TF plane with true parallelograms (true to the extent that the DPSS define a truly rectangular region in the TF plane). ...

... Does the time it takes different methods to create all the elements coincide with the universeт??s accepted age? ... Illinois Urbana-Champaign) Different kinds of stars create elements at different rates, all of which are consistent with the age of the universe. Get instant access to subscriber content on Astronomy.com! ... Registration is FREE and takes only a few seconds to complete. If you are already registered on Astronomy.com, please log in below. ...

SINCom - the new program package for combined processing of space geodetic observations O. Brattseva, I. Gayazov, S. Kurdubov, V. Suvorkin IAA RAS, Saint Petersburg, Russian Federation, ipa@ipa.nw.ru The SINCom software package is developed for combined processing of different space geodesy observations. ... Header line) +(BLOCK TITLE) .. ... Further iterative improvement of satellite orbit parameters is also possible - single-technique combination ("horizontal" scheme) of daily solutions. ...

... In order to disentangle the effects of different climate variables on tree-ring growth rates of different species, and to explore the possibility that more than one species could improve the accuracy of the reconstructions of climate using tree rings, a methodical study of trees in close proximity to the Armagh Observatory climate station was initiated together with Ana Maria Garc?a Su?rez, and continued as part of the latter's PhD thesis with John Butler and Professor Mike Baillie (QUB). ...

... ESO Press Photo 19/98 . ... This is a colour photo from the VLT that shows NGC 4650A , a member of the so-called Centaurus chain of galaxies in the southern constellation of that name. ... As it is clear from this high-resolution picture, there are two main components, a lenticular-shaped galaxy (of type S0), surrounded by a knotty extended ring-like distribution of stars, dust and gas , nearly perpendicular to each other. ... This is the caption to ESO PR Photo 19/98 [JPG, 112k] . ...