... The concerns here are similar to those for observing bright targets; saturation and blooming of the bright companion PSF must not impact the faint target. Also, one may need to consider subtracting the PSF of the bright object, and effects which limit the accuracy of that subtraction. If the bright companion will saturate and bloom, it will be necessary to rotate the CCD so that blooming along the CCD columns does not obliterate the faint target. ...

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• WFPC2 Instrument Handbook Update
• Spectroscopy of Planetary Nebulae
• If I need to observe a field containing bright stars, do I risk damage to the

... A detailed study of two consecutive bright points observed simultaneously with CDS, EIT and MDI is presented. The analysis of the evolution of the photospheric magnetic features and their coronal counterpart shows that there is a linear dependence between the EIT Fe XII 195? flux and the total magnetic flux of the photospheric bipolarity. ... In a follow-up study, we used wide slit (90arcsec240arcsec) movies of four EIT coronal bright points (BPs) obtained with CDS. ...

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• Armagh Observatory
• Coronal Bright Points: Another Oscillating Environment
• Leonid Press Release

The CHIANTI database consists of 4 primary ASCII files for each ion in the database. contains the energy levels in cm^(-1) It includes both experimental data and theoretical values of the levels energies. References: %observed energy levels (n=2): Fuhr, J.R., et al., NIST Atomic Spectra Database" ver. ... NIST Physical Reference Data %observed energy levels (12,19,23-26,65-67,69,70,72-74,78-82,84,85): Fuhr, J.R., et al., ...

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In this gallery are many images of Low Surface Brightness Galaxies which have recently been discovered and analyzed. ... The central surface brightness of this galaxy is 24.28 . Malin 2 This galaxy is another huge disk galaxy with a scale length of 15 kpc and a redshift of 15000 km/a. The high surface brightness knot in one of its spiral arms actually has the same color, luminosity and H-alpha equivalent width as the entire Large Magellanic Cloud . ... Truly it is a Low Surface Brightness Galaxy. ...

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• Astro-2 and the UIT Experiment
• Power Spectrum of Galaxies
• CCD Astronomy Magazine Article Page 4

Next: This Work Previous: Rotation Periods of ZAMS Stars . ... There are currently several groups involved in the studies of the rotation periods of PMS stars. ... Overall, there are about 100 rotation periods known for PMS stars. ... Furthermore, the stars with periods near 8 days also tend to have infrared excesses which can be interpreted as arising from disks. ... In the first interpretation, the gap occurs because locking mechanism holds stars at a eight day rotation period. ...

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• Period Criteria
• Project Tanagra
• ChaMPlane Bulge Windows Survey

... Science User Portal . ... ESO, the European Southern Observatory . ... Travel and Contacts . Travel to ESO Headquarters . ... Travel to E-ELT Armazones . ... Survey Telescopes . ... Star Clusters . ... Stars@ESO . ... ESO Science Newsletter . ... ESO 3.6-metre telescope . ... MPG/ESO 2.2-metre telescope . ... ESO 1-metre Schmidt telescope . ... ESO Science Outreach Network . ... This chart shows the brightness variation ("light-curve") of the star OGLE-TR-3 obtained during the OGLE observations. ...

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• Observed Brightness Variation of OGLE-TR-3 | ESO Australia
• Observed Brightness Variation of OGLE-TR-3 | ESO Ireland
• Observed Brightness Variation of OGLE-TR-3 | ESO United States

SAS home . ... This thread contains a step-by-step recipe to extract PN spectra of a point-like source observed in Imaging mode and to create associated response matrices, starting from a calibrated, concatenated event list (either produced with epproc or available as PPS product; here it has the assumed file name PN.fits ). ... The users should note that the SAS metatask xmmselect allows them to interactively define source and background regions (via ds9) and to run backscale on the fly. ...

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• How to extract MOS spectra of a point-like source and associated matrices
• Description
• XMM Science Objectives

The Sun is our nearest star and the source of energy for life on Earth. ... For centuries astronomers wondered whether they were clouds floating in the Sun's atmosphere, but we now know that they really are huge regions of magnetic field, about as intense as the field at the poles of an iron magnet. ... Such abrupt events were named solar flares , and what made them especially interesting was that occasionally, after a prominent flare, a magnetic storm would erupt on Earth. ...

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• Electric Currents from Space
• Close-up of the Aurora
• Solar Energetic Particles

... The Galactic low-mass X-ray binary GS 2023+338 was discovered during the burst on May 22, 1989 with the Japanise satellite Ginga (aka Galaxy). The flux reached 17 crabs (this unit of flux measurement is an bright X-ray source, Crab Nebula) at 10-35 keV. ... No other radio telescope worldwide carried out multi-frequency measurements. ... Upon 14 days the radio flux fell below the detection level at the RATAN-600 in relation to the decrease of the X-ray flux. ...

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• CH Cyg
• Measurement of the dark halo shape in polar ring galaxies
• Galaxy sector, archive 1994

... OOF . ALMA . ... OOF Index . Zernike Polys . GBT example . ... Observed data and analysis . The observed beam maps are shown in the first row of the table below. ... We show the best-fitting aperture and the best-fitting beams as the number of Zernike orders used for the fitting is increased. A sample OOF observed data set (top row) and the results of analysis with increasing number of Zernike polynomials used to parameterise the aperture. ... In-focus beam . ... Observed beams . ...

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• Example of an OOF analysis for the GBT Bojan Nikolic web pages (r. 329)
• Inference of Coefficients for Use in Phase Correction Bojan Nikolic web pages
• Bojan Nikolic -- Memo on inference of phase correction coefficients

NMW survey overview . Access image archive . ... The New Milky Way survey aims to detect bright (V<13.5) optical transients near the Galactic plane using an automated wide-field (8x6 deg.) system capable of surveying the whole Milky Way area visible from the observing site in one night. ... All images obtained during the transient search survey are available online (please use the image archive access form ). ... Images per field: . ... Images per night: . ... Milky Way imaging time: . ...

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... Cross-shaped galaxy ZGC 2315+03 (Fig.1) has been described by Zwicky (1971) as ``post-eruptive or the result of the crossing of a compact galaxy through an edge-on spiral'' . This object was included in the Polar-Ring Catalog (C-71) by Whitmore et al. (1990) as a possible candidate for Polar-Ring Galaxies (PRG). ... One of them is galaxy 'disk' and the other is 'polar-ring'. ... The facts against the polar-ring nature of ZGC 2315+03 can be summarized as follows: . ...

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• Linear polarization: wavelength dependence
• Wavelength dependence

... For us to see them from such great distances, quasars must be producing enormous energy -- they are about 1000 times brighter than an average galaxy! ... One of their choices for the energy source of quasars was a black hole. ... On the one hand, it may seem difficult to think that mere friction between bits of matter could account for the energy of a quasar, but, on the other hand, gravity is unimaginably strong near a black hole. ... How does matter actually rush towards the black hole? ...

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• ASP: Star Science in the Autumn Sky
• ASP: Guest Observer
• ASP: Monster Comet Promises Big Show

... Tonight's Sky . ... The Magazine . ... Observing . ... The double star 54 Leonis, spiral galaxy NGC 3198, and emission nebula NGC 3199 . ... Astronomy for Kids . ... Observing springtime deep-sky objects with a large telescope . ... Bright planets meet at dusk . ... Astronomy magazine subscribers can read the full article for free. ... Get instant access to subscriber content on Astronomy.com! ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter....

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• Astronomers report most т??outrageously luminousт?? galaxies ever observed |
• Understanding brightness | Astronomy.com
• New theory explains supernovae behavior | Astronomy.com

... ATNF Home . About ATNF . ... About ATNF overview . ... Australia Telescope Steering Committee . ... Australia Telescope User Committee . ... Murchison Radio-astronomy Observatory . ... Parkes radio telescope . Australia Telescope Compact Array . Mopra radio telescope . ... Australia Telescope Online Archive (ATOA) . ... Parkes | ... Australia Telescope 20GHz Survey . ... Visiting Parkes radio telescope . ... Parkes radio telescope webcam . ... X-Ray Microlensing of Bright Quasars . ...

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• Flux density bootstrapping
• Pulsar Group Observing/Dfb-fold
• HIPASS Bright Galaxy Catalog

... In 1610, Galileo turned his telescope to the heavens and discovered that the planet Jupiter had four bright moons. ... Jupiter's Rings . ... Unlike Saturn's bright rings which are composed of chunks of rock and ice, Jupiter's rings appear to consist of fine particles of dust. ... Exploring Saturn's Rings . ... Saturn's spectacular system of bright rings has been the subject of study and wonder since Galileo first turned his telescope on the ringed planet in 1610. ... M57: The Ring Nebula . ...

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... Calibration and analysis of this observation posed very interesting challenges for the authors, in particular dealing with an exciting new instrument whose on-orbit calibration was not yet well defined. ... Five mosaic positions were observed during five consecutive orbits as well as observations for dark and flat calibration. ... Darks and flats had to be created from contemporaneous reference observations and problems within the calibration process had to be resolved. ...

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• Classification of Objects in the Guide Star Catalog
• AIRY: Astronomical Image Restoration in interferometrY
• The Removal of Periodic Read-Out Patterns from Science Frames

Galactic Spiral Structure in H I Emission and Self-Absorption S. J. Gibson (NAIC) H I Self-Absorption (HISA) occurs when cold H I lies in front of warmer H I emission (HIE) at the same radial velocity. The map and spectra AT LEF T show HISA in the Perseus spiral arm in the Canadian Galactic Plane Survey (CGPS; Taylor et al. ... The basic components of the model are shown AT LEF T with all 3 types of CNM cells (shock-induced, local, ambient disk), but without lumpy dispersion in the velocity field. ...

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• NAIC-NRAO Single Dish Summer School 2005 NAIC-NRAO Single Dish Summer School
• CIMA Auto-Observing
• HISA Science Overview

... For more distant stars we must use other techniques. ... Hence if we see a distant galaxy and can pick out any cepheids lying within it, we can calculate its distance. ... Here then is another method to gauge the size of the Universe and there are yet more. volume at high enough temperature a nuclear fusion reaction sweeps across the white dwarf's surface and eventually we will see a spectacularly bright new star (hence nova) in our skies. ... Why is this relevant to the size of the Universe? ...

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• Leonid meteors 2011 | Astronotes
• Stargazing in May | Astronotes
• Astro Topics

You Can Make Stellar Images Brighter . Articles | ... A few months ago I wrote an article titled "You Can’t Make Them Brighter". So why am I now writing that you can make them brighter. ... The image of a focused star is actually a small disk called the Airy disk, named after the 19 th century scientist Sir George Airy. ... For a given aperture, a smaller Airy disk means that the light is focused to a smaller disk and is therefore brighter. ... www.astronomy.net . About Astronomy Net | ...

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• Astronomy articles, forums, listings, and other resources about Astronomy.
• Finding Himalia, The Fifth Brightest Moon Of Jupiter - an Astronomy Net Article
• Observe Every Photon's Size Experiment - an Astronomy Net Education Forum