... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2006 April 24 . Star Clouds over Arizona . ... Explanation: The clouds in the foreground are much different than the clouds in the background. ... Contrast between the water clouds and the star clouds has been digitally enhanced . ... About APOD | ... NASA Web Site Statements, Warnings, and Disclaimers . NASA Official: Jay Norris. ...

Astronomy Picture of the Day . ... 24.04.2006 . ... Far in the distance, however, are star clouds from the disk of our Milky Way Galaxy . ... Contrast between the water clouds and the star clouds has been digitally enhanced . ... April . ... April 2006 . ... NASA Web Site Statements, Warnings, and Disclaimers . ... Publications with keywords: Milky Way . Publications with words: Milky Way . ... A Milky Way Band . Jupiter, Vesta, and the Milky Way . The Milky Way Near the Southern Cross . ...

... ATNF Home . ... About ATNF overview . ... Australia Telescope Steering Committee . ... Australia Telescope User Committee . ... Astrophysics graduate student programs . ... Facilities . ATNF facilities . ... Australian Square Kilometre Array Pathfinder . Murchison Radio-astronomy Observatory . ... Parkes radio telescope . Australia Telescope Compact Array . ... Visiting Parkes radio telescope . Visiting Australia Telescope Compact Array . ... Parkes radio telescope webcam . ...

... In most astronomical observations the image intensity consists of contributions from both object and sky background. Depending on the complexity of the field and the type of object, different methods are used to estimate and subtract the background intensity. ... Non--linear filters are often used to remove stellar images and other sharp features (see Section ) while extended objects are very difficult to eliminate automatically. ...

The Mars Flag has a different design on the reverse side. obverse side of flag . ... The orbit lines on the obverse cross the Sun on the lower half of the flag and appear to go behind the Sun on the upper half of the flag. The reverse side has the orbits lines continuing around the Sun on the upper half of the flag. ... The Mars Flag reverse side is a continuation of the obverse side and not just a different design on the back and not a mirror image of the obverse. Main Flag Background Color . ...

... subroutine omlcbuild read parameters loop i=0, nSources get handle on source rates file get handle on source region file if (exposure IDs are different) issue warning get handle on background rates file get handle on background region file if (exposure IDs are different) issue warning if (exposure ID source != exposure ID background ) call fatal get source extraction radius = s_radius get ...

This is the homepage of Andrew Fruchter, an astronomer on the staff of the Space Telescope Science Institute . ... Here you can look at an HST images of the optical counterparts of gamma-ray bursts and their host galaxies. ... Therefore, substantial information on the fine scale structure of objects can be obtained by offsetting the pointing of the telescope between exposures and then combining these "dithered" exposures into a single image. ...

A visual impression of the data used in the study. The relevant extra-galactic maps are represented as shells of increasing distance from Earth from left to right. ... After this are six shells containing maps of the millions of distant galaxies used in the study. These maps are produced using different telescopes in different wavelengths and are color-coded to show denser clumps of galaxies as red and less dense regions as blue. There are holes in the maps due to data quality cuts. ...

Since the light from galaxies represents the integrated contribution of its consitutient stars, then we can learn about stellar populations in galaxies by modelling their light by summing up individual stellar spectra for different kinds of stars. ... The data cover the wavelength range 3500 - 9000 angstroms. ... Retrieve Digital Stellar Spectra Click on the appropriate spectral type. ... Note that the designation V means main sequence, IV means subgiants, III means giants, I means supergiant. ...

... Slide 2 . ... Smooth Accretion of Intergalactic Gas . Mergers and Satellite Accretion . Galactic Fountain Material . HIPASS = HI Parkes All-Sky Survey . A typical HIPASS data cube . HIPASS was designed to be an extragalactic survey . ... Different types of HVCs in different environments? ... HVCs and Galactic Emission . ...

Some recent results ( see ) attracted the attentions of astronomers working on field which could benefits from photon counting techniques with high speed and spatial resolutions as adaptive optics. ... Fasti has been designed to be fast and largerly configurable. ... The data rate attined in the best case (30 Mhz), give no impossible load to the digital acquisition in the photon counting mode, since data are 1 bit only, they can be parallelized, giving a maximum speed of about 940.000 32 bit word/sec. ...

Class 1 Introduction, Background History of Modern Astronomy The Night Sky, Eclipses and the Seasons Kepler's Laws Newtonian Gravity General Relativity Matter and Light Telescopes Class 2 Solar System Characteristics Formation Exosolar Planets Class 3 Stars The S un Stellar Evolution of Low and High Mass Stars Deaths of Stars Exotic Stars Class 4 Galaxies Galaxy Classification Formation of Galaxies Galactic ... Low mass stars live and die differently than high mass stars. ...

Scale-heights of the Galactic disk subsytems with different ages and metallicities . V.Marsakov & Yu. ... It is based on the fact, that all stars cross the disk plane several times during their Galactic orbital period. ... We have used our representative sample of nearby disk F2-G2 stars Marsakov & Shevelev (1995) in which fundamental stellar parameters was determined on the basis of published date on uvby-photometry, proper motion and radial velocities. ... Marsakov V.A., Shevelev Yu.G. Bull. ...

DIGITAL WDC EXCHANGE FORMAT . FOR OBSERVATORY 1.0 MINUTE VALUES 1. ... DATA-1 .. DATA-60 are 1-minute values of the given element for that hour. ... Typically, digital 1-minute values received by WDCs from organizations operating automatic magnetic observatory instruments are averages of more frequendy sampled values, e.g. 10-second point samples. ... If the method used to obtain 1-minute average values is important to a user, the WDC will assist in determining the exact procedure applied. ...

Next: Extragalactic Gravitational Wave Background Previous: Transparency of the Stochastic . Let the sky be observed with a detector having a pencil beam diagram across. The number of stars per frequency decade that is swept by the detector is a function of celestial coordinates (say, galactic coordinates l , b ): . ... It is clear from the figure that for an all-sky detector the Galaxy becomes transparent above the frequency  Hz. ...

... Science . User Portal . ... Science Users Information > Data Handling and Products > Data Reduction FAQ > Why do the flats in my data have different exposure times and how do I know which ones to use? ... Science Users Information . ... Observing with ESO Telescopes . ... Telescope Time Allocation . ... Science Data Products Forum . ... ESO Data . ... ESO Data Access Policy . ... ESO Science Newsletter . ... The exposure times of the flat fields depends on slit width and readout mode. ...

... Get used to using the mouse and its buttons for such tasks. Figure out the function of each of the three mouse buttons. ... Fire up textedit application and practice editing text files. ... Figure out basic options like cut and paste of text around the file, saving and loading files, searching for strings in the text and replacing strings. ... Familiarise yourself with other UNIX functions by creating various files of text etc. and trying out the various functions listed in handouts. ...

... The distribution of galactic RCB stars is controversial. Several authors have argued that they belong to a thick galactic disk, and are thus old Population I stars. However, they may alternatively belong to the even older galactic bulge (Population II). ... In either case, the populations are sufficiently old that RCB stars must have relatively low masses ( ). ... These are the only RCB stars for which a distance is known and hence for which an absolute magnitude can be deduced. ...

... Archives . ... If you do not mind the time predictor, it is hard to believe that this is a light curve, time dependent data. ... It?s hard to say this data set is designed for time series analysis apart from the complication in statistical inference due to measurement errors. How to design the statistical study with measurement errors, huge gaps in time, and unequal time intervals is complex and unexplored. ... The following is R output without measurement errors. ... Chandra Blog . ...

... sin f = y / r . cos f = x / r . ... They are now viewed as new definitions of the sine and cosine, for the polar angle f given by x and y ( a slightly different way of formulating this definition is described further below ). ... sin 2 f + cos 2 f = 1 . ... Angle . ... Many trigonometry texts define the sine and cosine slightly differently, using the so-called unit circle . ... Then the distance AB ("the sine line") equals sin a , and the distance OA ("the cosine line") equals cos a . ...