... To be read in conjunction with Section 4.11 of the WFPC2 Instrument Handbook , -Version 4.0. ... 1 The second study found evidence that CTE loss for faint stars has increased with time (Whitmore, 1998). The primary observational consequence of CTE loss is that a point source at the top of the chip appears to be fainter than if observed at the bottom of the chip, due to the loss of electrons as the star is read out down the chip (see Figure 1 ). ... Last updated: 06/16/98 10:38:00 . ...

The process of determining the number and characteristics of sources in astronomical images is so fundamental to a large range of astronomical problems that it is perhaps surprising that no standard procedure has ever been defined that has well understood properties with a high degree of statistical rigour on completeness and reliability. ... In this analysis we present results from testing such algorithms as implemented in the SExtractor, Selavy (Duchamp), and sfind tools on simulated data. ...

... July 6, 1996 . Edmond Halley's Greatest Discoveries . Explanation: Sir Edmond Halley was quite a discoverer. Born in 1656, he computed in 1705 that a bright comet was periodic and would make another appearance in 1758. The comet appeared as predicted and is now known as Comet Halley . ... Perhaps Halley's greatest discovery, however, was that his contemporary Isaac Newton had discovered a powerful mathematical formulation of gravity. ... About APOD | ...

Next: Star Formation and Stellar Up: Stellar Astrophysics Previous: The Chemical Evolution of . Amir Ahmad and Simon Jeffery have been studying some rare stars known, loosely, as helium-rich subdwarfs. ... Further study showed that PG1544+488 is in fact a double star with both stars having extremely helium-rich surfaces -- the first case known. ... Next: Star Formation and Stellar Up: Stellar Astrophysics Previous: The Chemical Evolution of M.E. Bailey . ...

... Bad Astronomy . ... Bitesize Astronomy . ... Last week's Snack talked about how black holes can affect the environment around them in such a way as to be very bright . ... It's a common misconception that black holes always have matter swirling into them. ... As this matter gets closer and closer to the black hole it piles up and a large, fairly flat disk forms. This is called the accretion disk , because matter from this disk accretes (that is, falls in) on the black hole. ... 2008 Phil Plait. ...

Astronomy Picture of the Day . Edmund Halley's Greatest Discoveries . ... 6.07.1996 . ... Born in 1656, he computed in 1705 that a bright comet was periodic and would make another appearance in 1758. The comet appeared as predicted and is now known as Comet Halley . ... Perhaps Halley's greatest discovery, however, was that his contemporary Isaac Newton had discovered a powerful mathematical formulation of gravity. ... July 1996 . ... NASA Web Site Statements, Warnings, and Disclaimers . ...

... Donate to Support Science Literacy . ... 2016 Annual Awards . The ASP is accepting nominations for the organizationтАЩs national annual awards which recognize special achievements in astronomy research, technology, education, and public outreach. ... Shop the AstroShop . ... The Astronomical Society of the Pacific (ASP) is accepting nominations for the organizationтАЩs national annual awards which recognize special achievements in astronomy research, technology, education, and public outreach.. ...

... Tonight's Sky . ... Sky this Month . ... Star Atlas . ... stars . ... The Sky This Week: April 1 - 10 . ... Observing springtime deep-sky objects with a large telescope . ... Why do some stars appear to flash a variety of different colors when you look at them through a telescope? ... So, Earthт??s atmosphere will bend some colors from especially bright stars more so than others, which makes the source look like itт??s flashing colors. Get instant access to subscriber content on Astronomy.com! ...

... Posts tagged ?incompleteness? ... Comment . ... The notions of missing data are overall different between two communities. ... Astronomers?I?m not sure how they think but my impression so far is that a missing value in one attribute/variable from a object/observation/informant, all other attributes related to that object become useless because that object is not considered in scientific data analysis or model evaluation process. ... 2 Comments . ... Entries RSS . ... Entries (RSS) and Comments (RSS)...

The weather throughout this year was so extremely favorable that I have been able to observe the Sun clearly on 312 days; however, I counted only 34 groups of sunspots.. From my earlier observations, which I have reported every year in this journal, it appears that there is a certain periodicity in the appearance of sunspots and this theory seems more and more probable from the results of this year.. ... 244 . ... 149 . ... Exploration" home page (index) Glossary . Official GSFC Home Page .. ...

2009-05-20 O.Hainaut There are many steps between the data coming out of a camera on a professional telescope and the final image that appears in magazines or on our web sites. ... preliminary: from the telescope to Photoshop. cleaning: remove the artifacts remaining in the image . ... In each filter, several images are acquired. ... Fig 1: a raw image (click for full scale) . ... At this stage, the images are still in FITS, the astronomical format, with one FITS file per filter. ... The final image. ...

Seven months ago, on Mar 19, 2008, at 09:12 Moscow time, a new star appeared on the sky. The Sun had already risen over the Russia, but people of the Western hemisphere might be able to see by their eyes a faint starlet near one of Bootes constellation stars. This starlet appeared and faded by an order of magnitude in a minute. Astronomers named it GRB080319B or, informally, the Naked-Eye Burst, as it was twice as bright as human eye can see a star. ... Royal Astronomical Society . ...

... Astrophysics Group . ... Pulsars . ... Stars ? ... The array was designed to detect compact radio sources such as these by virtue of the fact that they would scintillate (twinkle) when observed from the Earth through the interplanetary medium ? ... One of Antony Hewish?s research students, Jocelyn Bell, was set the task of operating the telescope and inspecting the daily charts for the kind deflections in the trace which occurred when a scintillating source passed over the array. ...

Supernova 1999cl in M88 . This page is devoted to information on Supernova 1999cl in M88 Basic information on this SN, including the last reported brightness, on this Supernova can be found on the main supernova page. Information on the original web pages for many of these images can be found on the Supernova links web page. ... M1 Supernova Search has a 1999cl page . ... Pedro Re' Animated gif image . ... DAX Observatory . ... vsnet-obs 21040 ] (fwd) Observation of Supernova 1999cl in M88 . ...

Umbriel . Uranus II . ... It is about the same size as Ariel and has about the same density. The surface appears to be old with large craters and does not change much from one location to another. ... Orbital period (days) . ... Visual geometric albedo . ... This image is a polar stereographic projection of the southern hemisphere of Umbriel. ... Dark regions are represented as red and bright regions are represented as blue. The two white regions are bright ejecta from two fresh craters. ...

... Комментариев нет 22 августа 2010, 13:58 Blogger , English , Астрономия . ... Neptune will finally complete its first full orbit of the sun since it was discovered in 1846a approximately one year from now, according to NASA estimates. ... Twitter Weekly Updates for 2010-08-21 . ...

Check out the new images (Jan 18-25) and (Jan 26-Feb 05) of the comet by Rob McNaught. ... Every few years a comet becomes bright enough to be easily seen with the naked eye but only every decade or so are these comparable with comets like Halley. ... Before Jan 13, the comet is not visible in the Australian sky after sunset. ... SOHO images . ... On Jan 12 at approximately 09:00 UT (8pm NSW time), comet C/2006 P1 McNaught appears at the 11 o'clock position in the images. ... STEREO images . ...

... Since the fast mode window is necessarily small, the source PSF fills much of the window (clearly evident for bright sources). ... As such, the source and background extraction apertures may be truncated by the window. ... While often there will be only one object in the image, one should check for spurious detections which could affect the analysis of the target source and also for missed sources or prominent objects in the window, which may contaminate the target. ...

The AstroGuide . ... AstroGuide Listing . ... See many more Astronomy Listings by: Category or Alphabet . Discovery Telescopes, Inc. has been manufacturing precision astronomical components since its inception in 1991. ... 949) 347-0142 . ... Web Site . http://www.discovery-telescopes.com/ . ... Web . ... Unless otherwise specified, web site content Copyright 1994-2016 John Huggins All Rights Reserved . dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET" . are trademarks of John Huggins ...

... The weather throughout this year was so extremely favorable that I have been able to observe the Sun clearly on 312 days; however, I counted only 34 groups of sunspots.. From my earlier observations, which I have reported every year in this journal, it appears that there is a certain periodicity in the appearance of sunspots and this theory seems more and more probable from the results of this year.. ... Year . ... Days when no . ... Observation Days . ... 273 . ... 282 . ... 244 . ... 149 . ...