One of my on-going research interests concerns the dust shells of proto-planetary nebulae or PPNs (also called pre-planetary nebulae, transition objects, and post-AGB objects in the literature; the latter term also applies to a wider selection of objects such as RV Tauri stars), especially the carbon-rich ones that show the unidentified "21 micron' emission feature. ... I am working to find a complete sample of proto-planetary nebulae in these satellite galaxies from the millions of detected stars. ...

... Laboratory and theoretical modelling of the UV bump on the interstellar extinction curve is a very popular topic in dusty investigations. ... feature is illustrated by Fig. 10 where the profiles were calculated using the model of graphite spheres. Figure 10: Normalized extinction efficiencies for graphite spheres. ... The lower panel shows the summary extinction of two graphite spheres with radii and (from upper panel) taken in equal proportions. ...

... November 8, 1997 . Aristarchus' Unbelievable Discoveries . Credit: Space Shuttle Columbia , STS58 , NASA . ... Aristarchus, who lived from 310 BC to 230 BC, postulated that the planets orbited the Sun - not the Earth -- over a thousand years before Copernicus and Galileo made similar arguments. ... Aristarchus' discoveries remained truly unbelievable to the people of his time but stand today as pillars of deductive reasoning. ... About APOD > . ... NASA Technical Rep.: ...

Next: Analysis Tools for Nebular Emission Lines . ... Extracting spectra from a large number of NICMOS grism images requires a convenient interactive tool which allows a user to manipulate direct/grism image pairs. ... The direct image is used to locate objects of interest, to find the position of the appropriate spectra in the grism image, to determine the optimal extraction technique to use, and to calibrate the wavelength range of the extracted spectra. ... Figure 1: The NICMOSlook User Interface . ...

... Цвет: фиолетовый . Коллекция: Осень-зима 2015/2016 . Материал верха: нейлон, спилок . ... Материал подошвы: резина . ... Пол: Мужской . Кроссовки Umbro. ... Материал: нейлон, спилок. Сезон: Осень-зима 2015/2016. ... Исследование причин нескольких крупнейших в истории авиации катастроф помогли сделать современные авиаперелеты самым безопасным способом передвижения. ... Цвет: серый . Коллекция: Весна-лето 2016 . ... Пол: Женский . ... Сезон: Весна-лето 2016. ... Цвет: розовый . ...

... The first identified compact galaxy group, Stephan's Quintet is featured in this stunning image from the newly upgraded Hubble Space Telescope. ... The bright clusters and nebulae of planet Earth's night sky are often named for flowers or insects, and NGC 6302 is no exception. ... First discovered by an amateur astronomer Anthony Wesley on 2009 July 19, the impact was quickly confirmed and even imaged by the Hubble Space Telescope the very next day. ... Despina, Moon of Neptune . ... August . ...

... ESO, the European Southern Observatory . ... Travel and Contacts . Travel to ESO Headquarters . ... ESO . ... Survey Telescopes . ... ESO Supernova . ... Star Clusters . ... Stars@ESO . ... ESO 3.6-metre telescope . ... MPG/ESO 2.2-metre telescope . ... ESO 1-metre Schmidt telescope . ... Future Projects . ... This NASA/ESA Hubble Space Telescope image shows the positions of the past, present and predicted future appearances of the Refsdal supernova behind the galaxy cluster€а MACS J1149+2223 . ...

... A2329 Date Received: 2007-May-30 06:16:37 Technical Page Proposal Type: General Category: Sub-Category: Observation Category: Total Time Requested: Minimum Useful Time: Prop osal Title: ABSTRACT: Regular Astronomy Spectroscopy Galactic 9 Hours 30 min between 19:30 and 20:30 Smiths Cloud: A High-Velocity Cloud Entering the Galactic Plane Smith's Cloud has been knonw since its discovery in 1963 as a large (10 degree across) elongated HI feature in the inner Galaxy of unknown origin. ...

... Tonight's Sky . ... SUN MOON MERCURY VENUS MARS, JUPITER SATURN . ... Moon . ... The Magazine . ... Observing . ... Gravitational wave search provides insights into galaxy evolution and mergers . ... The double star 54 Leonis, spiral galaxy NGC 3198, and emission nebula NGC 3199 . ... Astronomy for Kids . ... More UFOs identified . ... Get instant access to subscriber content on Astronomy.com! ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter....

Life from Mars: . The Discovery . ... Meteorite Yields Evidence of Primitive Life on Early Mars (August 7, 1996) . Life from Mars: Video Animations . ... The NASA-funded team found the first organic molecules thought to be of Martian origin; several mineral features characteristic of biological activity; and possible microscopic fossils of primitive, bacteria-like organisms inside of an ancient Martian rock that fell to Earth as a meteorite. ... Mars Life? Microscopic Structures . ...

... Ж.Ф. Родионова, А.А.Карлов, Т.П. Скобелева и др. ... Sternberg State Astronomical Institute, 119899, Moscow, Russia; jeanna@sai.msu ru. ... Moscow State University, Vorobjovy Gory, 119899, Moscow, Russia. Brown University - Vernadsky Institute Microsymposium 34, October 8-9, 2001, Moscow, Russia . ... Rodionova J1., ... Sternberg State Astronomical Institute, Moscow University, jeanna@sai.msu.ru . ... 1 Sternberg State Astronomical Institute Lomonosov Moscow University, Russia; marss8@mail.ru . ...

Automatic Classification of Sunspot Groups Using SOHO/MDI Magnetogram and White Light Images David Stenning March 29, 2011 1 Introduction and Motivation Although solar data is being generated at an unprecedented rate, the majority of sunspot classification is done manually by experts. ... This is to smooth the "white" areas in the magnetograms. ... Left: Inverse Magnetogram Right: "Opened" Inverse Magnetogram 6 Using the cleaned images, sunspot active-region "seeds" are obtain by thresholding. ...

... Among the objectives of Principal Components Analysis are the following. dimensionality reduction; љ . the determining of linear combinations of variables; љ . ... identification of groups of objects or of outliers. ... Finding a set of principal axes allows the objects to be adequately characterised on a smaller number of (artificial) variables. ... Reduction of dimensionality is practicable if the first new axes account for approximately 75 % or more of the variance. ...

Next: Feature enhancement: filtering Up: No Title Previous: Commentary . A sharp contrast is seen between the `crowded' energy map of the modulated oscillations (individual minima and maxima of the signal identified by the Mexican hat wavelet) in section 13 and and the `smooth' presentation of the norm-Morlet transforms of the same data in section 15. ... construct an energy map based on individual events. smooth the map by merging the events that are `close enough' to each other. ...

... The search for distant objects which can be both galaxies and quasars is one of the most important problems of observational astrphysics, because it allows one to determine cosmological parameters connected with the time of appearence and evolution of stellar systems, large scale structure of the Universe. ... Radio galaxies are important objects to be studied because they are sources of infrared-optical-ultraviolet continuum, emission lines and continual radio emission. ...

Figure 1: An averaged OH 1612-MHz spectral profile of V1018 Sco, from 36 separate epochs of observations at Parkes. ... V1018 Sco (IRAS 17317-3331, OH354.88-0.54) is a well known OH/IR star with strong infrared and radio maser emission. The OH 1612-MHz maser spectrum of V1018 Sco, shown in Figure 1, has a double-peaked profile that is characteristic of asymptotic giant branch (AGB) stars where the maser emission occurs from the outer regions of an expanding circumstellar envelope. ...

Next: Imaging Polarimetry with NICMOS Up: NICMOS Data Calibration and Previous: The Photometric Performance of . ... NICMOSlook and Calnic C . ... Extracting spectra from a large number of NICMOS grism images requires a convenient interactive tool which allows a user to manipulate direct/grism image pairs. ... NICMOSlook and Calnic-C are two programs that were designed to take advantage of the fact that the NICMOS grism mode typically consists of taking both a direct and a grism image. ...

... The variability of the spectrum of the optical component of the IR-source IRAS01005+7910 was discovered for the first time in the BTA spectra [1]. ... The spectral features include absorptions that form in near-photospheric layers, narrow envelope emissions, and emission-absorption profiles that form in photosphere-to-envelope transition layers (the wind). ... Discovery of spectral variation in the optical counterpart of IRAS01005+7910. ... Dashed line - envelope curve of all the SiII 5979 profiles ...

... 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.. ...

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 . ...