Next: Examples Up: Better HST Point-Spread Functions: Previous: What Is Phase . I have been using a new phase retrieval iteration that is derived from the maximum likelihood equation for Poisson statistics in the data. The joint likelihood of getting the observed counts in each pixel given the expected counts is . ... If we allow the amplitude of the complex pupil function to vary, then the maximum likelihood solution occurs where all partial derivatives of with respect to are zero: . ...

... Bojan Nikolic web pages (r. 329) . ALMA . ... LibAIR is the atmospheric inference library that is the main core of the algorithms for phase correction of ALMA data using water vapour radiometers that we are developing in Cambridge. ... The library and algorithms are documented in the series of memo?s which are being posted at page on inference of coefficients for use in phase correction. ... ALMA WVR phase correction algorithms and software . ... Introduction to phase correction for ALMA . ...

Next: Computation Up: Image Deconvolution Previous: Computation . ... The Maximum Entropy Method (MEM) is not procedural. ... Typically this is a flux constraint, which ensures that the flux density in the maximum entropy image is correct. That is, the flux density of the maximum entropy image, . ... This is quite a useful constraint. Although the maximum entropy task, described below, does not force you to give a flux constraint, you should attempt to, if at all possible. ... Computation . ...

SKA ­ TDT Group On Phase Computation during Folding C.Baffa, E.Giani January 2014 The last part of pulsar search algorithm, as in the SKA TDT group approach, is the verification and optimization of pulsar parameters candidates identified in the previous phases. ... As the phase errors are expressed as fractions of the full period (in our case 44 measurement of 50 s), it is evident that the maximum integration time compatible with single precision phase computation is very short. ...

... Bad Astronomy . ... Bitesize Astronomy . ... Keep Bad Astronomy close to your heart, and help make me filthy rich. ... When Venus is on the far side of the Sun, we see the entire near side lit by the Sun. ... When it is on the near side of the Sun, it shows a beautiful thin crescent, because it is between us and the Sun and we see the mostly unlit dark half. ... To see this for yourself, draw a circle one centimeter across, then, next to it, draw a circle 6 centimeters across. ... 2008 Phil Plait. ...

Once students get the hang of it, they can find and measure the brightness of Delta Cephei in a few minutes. ... of Delta Cephei . ... Oct. ... The following table lists the measurements of Delta Cephei made by one amateur astronomer in autumn 1990. ... 4.0 . ... This activity is a simplified version of one that appeared in Hands-On Astrophysics, a series of activities prepared by the American Association of Variable Star Observers with support from the National Science Foundation. << previous page | ...

Next: Astrometry Up: Calibrate data Previous: Calibrating amplitude errors Contents . There are three unwrapping algorithms available under C ALIBRATE V ISIBILITY T RIPLE . ... Rewrapping here shall mean the rotation of the complex visibility by a specified angle so that the entire range of phases fits into the interval degrees. ... If the phase is wrapping more rapidly, one should plot the (calibrated) triple phase, and fit a low order polynomial to a stretch which does not wrap (use FIT). ...

... Positive iterative deconvolution is an algorithm that applies non-linear constraints, conserves energy, and delivers stable results at high noise-levels. This is also true for Richardson-Lucy like algorithms which follow a statistical approach to the deconvolution problem. ... All algorithms resolve the objects, as shown by the reconstructions by Richardson-Lucy in Figure 2 on the right, the algorithm by M?ller in Figure 3 on the left and positive iterative deconvolution in Figure 3 on the right. ...

. XMM-Newton Science Analysis System . phasecalc (dscalc-2.6) [xmmsas_20080701_1801-8.0.0] . Meta Index / Home Page . read ephemeris open table if( cannot calculate absolute event time ) error call selectlib with table and phase formula . XMM-Newton SOC/SSC -- 2008-07-02

Next: Source Positions Up: Observations and Analysis Previous: Maximum Likelihood Application . ... Any excess above the diffuse model which showed a 3 was initially retained as a candidate source. A cross-comparison of the candidate sources was made in order to eliminate cases in which the same source was assigned different positions in different observations. From this comparison, a list of candidate sources was derived. ...

Data and Phase Links . The maximum scientific data rate of downlink is 128 Mbit/s (total rate 144 Mbit/s). Data transmission is being done by VIRK communicationsystem through the high gain antenna at frequency 15.000 GHz. The downlink data stream is divided into frames each being 20 000 bytes long. ... Ground Support of the RadioAstron . ... Data Processing . ... Progress of the RadioAstron Project in Pictures . ...

... High-pressures experiments are mostly aimed at studying phase transformations in solids, synthesising new phases and studying their composition, crystal and magnetic structure, physical and thermodynamical properties. ... The specific feature of investigations at LHPP that distinguishes it from most other high-pressure laboratories is combining in situ measurements with studies at ambient pressure of new high-pressure phases fixed by quenching to liquid nitrogen temperature. ...

... The eclipse will be partial for viewers in Northern Ireland with almost 20% of the Sun obscured by the Moon at the maximum phase. ... The maximum duration of totality, when the Moon completely covers the Sun, is 2 minutes and 27 seconds, and will occur shortly after the track crosses the northern coast of Russia. For Northern Ireland viewers, the partial eclipse will last from 09:23 until 11:04 (BST), with the Sun moderately high in the southeast. ... Last Revised: 2008 July 24th . ...

... 8, ``Celestial Mechanics'', 2002 First results of GPS orbit determination with GRAPE package using a square--root information filter M. O. Keshin Institute of Applied Astronomy, St. Petersburg, Russia The zero--differenced carrier phase measurements contain the distance be­ tween the phase centres of receiver and transmitter antennas biased by unknown integer number of cycles (phase ambiguities). ... In the case of GPS the problem of solar radiation pressure modelling is of primary importance. ...

... reference to the following paper: Karakas Lattanzio (2007, PASA, submitted) Each file contains: 1) pulse number 2) the core mass , Mcore ( Msun ) 3) maximum mass of the intershell convection zone, M_csh ( Msun ) 4) duration of intershell convection , t_csh (years) 5) mass dredged into the envelope, D_dredge ( Msun ) 6) lambda 7) lambda_dup defined by Goriely Mowlavi (= lambda x (DMh/Mpulse) where Mpulse is the maximum ...

... country name . ... Query " Moscow's celebrations hotel Moscow, Russia" would failed if search attributes separately, but could be succeeded if search their concatenation. ... hotel". ... Simple search for "Moscow": # select name, country, place, rank( idx, ftsquery ) as r from hotels, to_tsquery('Moscow') as ftsquery where idx @@ ftsquery order by r desc; name | ... Query "Moscow hotel" (rewritten by hand): # select name, country, place, rank( idx, ftsquery ) as r from hotels, to_tsquery('Moscow | ...

... Posts tagged ?maximum entropy? ... I happened to observe a surge of principle component analysis (PCA) and independent component analysis (ICA) applications in astronomy. The PCA and ICA is used for separating mixed components with some assumptions. ... Such assumptions allow to set dissimilarity measures and algorithms work toward maximize them. ... Tags: component separation , ICA , maximum entropy , PCA . ... 2 Comments . ... Entries RSS . ... Entries (RSS) and Comments (RSS) . ...

... The growth phase starts the substorm process. ... Furthermore, a thin current sheet (TCS, down to 0.1 Re) forms just tailward of the dipole-like field lines (6-15 Re). This can be important for the triggering of the substorm (onset of the expansion phase). ... Res. ... Kaufmann, R. L., Substorm currents: growth phase and onset, J. Geophys. ... Kirkwood, S., and L. Eliasson, Energetic particle precipitation in the substorm growth phase measured by EISCAT and Viking, J. Geophys. ...

... The Phases of Venus . ... 10.01.2006 . ... Just like our Moon , Venus can appear as full as a disk or as a thin as a crescent . ... The above time-lapse sequence , however, was taken over the course of many months and shows not only how Venus changes phase but how it's apparent angular size also changes. In the middle negative image, Venus is in a new phase, the same phase that occurred during its rare partial eclipse of the Sun in 2004. ... Publications with keywords: Venus - phases . ...

A superfine grid was started 21jun10 on position A0, focus=0 with .37 amin steps (31x31 points).The source J1330+251 was tracked. The postioning code used rick fischer's computation that iterated to find the correct offset position for the telescope. The 1st plots shows the az,za covered as well as the changes to the offsets from rick's code (.p s) ( .pdf ) . az,za covered . the standard positions visited in the grid (black) as well as the new offsets (blue) . ...