... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. November 28, 1998 . A Lonely Neutron Star . ... Explanation: How massive can a star get without imploding into a black hole? ... Assuming that the object is a neutron star of typical mass, some previous theories of neutron star structure would have predicted an implosion that would have created a black hole . ... About APOD > . ...

... Assured of a reliable method of solving the normal equations, we now consider the equations of condition. The observed magnitude m of a star at M air masses with true instrumental magnitude is modelled as ([ 10 ], [ 28 ]) . ... The effective extinction coefficient depends on the effective spectral gradient [ 29 ] of the star, for which we use some color index, affected by half the atmospheric reddening ([ 26 ], [ 10 ]): . ... Thus, for the B band of UBV, we use the (U-V) color. ...

... CIMAFITS is the name for the Arecibo FITS-file format. ... This is a list of (fairly) up-to-date documents describing CIMA and CIMAFITS: . The CIMA version history log which is the most up-to-date page listing all changes made to the different versions of CIMA . ... The CIMA user's log which chronologically lists changes made to CIMA that may be relevant to an observer. The CIMA engineering log which lists engineering changes made to CIMA that probably are of less interest to an observer. ...

... ESO, the European Southern Observatory . ... Travel and Contacts . ... Green ESO . ... Survey Telescopes . ... 2002 . ... Images of Titan taken on November 26, 2002 through nine different filters to probe different altitudes, ranging from the stratosphere to the surface. ... Due to these good observing conditions, Titan's trailing hemisphere was observed with contrasts of about 40%, allowing the detection of several bright features on this surface region, once thought to be quite dark and...

... Let us first find out which way -- rise in spectral resolution with some loss in the S/N ratio or increase in the S/N ratio with a fixed spectral resolution -- is better for the purpose of reduction of equivalent width determination errors. ... N -- number of counts for 1 ? ... line equivalent width, . ... Thus if the spectral resolution is managed to be increased (i.e. to decrease )without loss in the number of counts falling at 1 ?, the equivalent width measurement error is then proportional to . ...

Describes how spatial region boundaries are handled. The golden rule for spatial region filtering was first enunciated by Leon VanSpeybroeck in 1986: . ... With this in mind, the rules for determining whether a boundary image pixel or table row are assigned to a region are defined below. For image filtering, pixels whose center is inside the boundary are included. ... That is, an row is inside the boundary without regard to its integerized pixel value. ...

... Images obtained using the Faulkes Telescope South, operated by Las Cumbres Observatory. ... The Faulkes Telescope Project and Las Cumbres Observatory Global Telescope Network had kindly given us the opportunity to use these telescopes and the observatory had booked us four sessions of controlling the telescope in order for us to make some observations on NEOs. ... Just before our first observing session on Friday, we were given a tour of the observatory building and its telescopes, by John McFarland...

spaceweb@oulu.fi - last update: 27 November 1998, 1900 UT (RR) . Tailward fast plasma flows with dipolar Bz signatures (north-then-south turning of B) observed within plasma sheet are called plasmoids (e.g., Hones et al., ... Most plasmoids have also helical magnetic field structures (large By fields), called "flux ropes" (Hughes and Sibeck, 1987; Slavin et al., ... 1998). ... Observations of plasmoids are highly correlated with substorm onsets (Moldwin and Hughes, 1993; Nagai et al., ... Lett. ...

The conference program included eleven one-hour talks and four free discussions. ... The talk also discussed different models for Internet traffic and quality of Service measures. ... The talk by Nikolai Vereschagin (Moscow State University) "The Kolmogorov complexity of approximate descriptions" discussed different notions of descriptive complexity of computable sequences which can be used in Internet measurements. ... What mathematics does Internet need?" ...

Next: The Scenario Machine: Operational Up: Evolution of Magnetic Rotators Previous: Ejector-propeller hysteresis . ... The length of this segment is determined by the eccentricity. ... In this case no hysteresis occurs and transitions E -- P and the reverse take place in symmetrical points of the orbit. ... Here EP means a mixed state of the rotator at which it is in the ejector state during one part of the orbit, and in the propeller state during the rest of the orbital cycle. ...

... A Colorful Moon . ... But small, measurable color differences have been greatly exaggerated to make this telescopic, multicolored, moonscape captured during the Moon's full phase. ... In most places on Earth, a lucky viewer.. Geminid Meteors over Teide Volcano . ... Gibbous Europa . ... In fact, this gibbous phase shows part of Jupiter's moon Europa. ... The Bubble Nebula . ... Cataloged as NGC 7635, it is also known simply as The Bubble Nebula. ... What will survive this battle of the galaxies? ...

ATNF Home . About ATNF . ... About ATNF overview . ... Governance overview . Australia Telescope Steering Committee . ... Australia Telescope User Committee . ... Our people overview . ... Staff list | Student list | ... Parkes radio telescope . ... Australia Telescope Online Archive (ATOA) . ... Parkes | ... VLBI . ... CSIRO ATNF Data Archives . ... Visiting Parkes radio telescope . ... Parkes radio telescope webcam . ... This message : [ Message body ] [ More options ( top , bottom ) ] . ...

... We also identified two other spectrally unique terrains, corresponding to the northern polar ice cap, and to the southern winter polar hood. Comparisons with mineral spectra indicate the possibility of different H 2O- or OH-bearing (i.e., hydroxides and/or hydrates) minerals existing both in northern Acidalia and in the nearby intermediate albedo terrain. Hydrated minerals do not appear to be spectrally important components of the southern hemisphere dark terrains imaged by HST in 1997. ...

... There are 6 different analysis options: . 0:all : all the exposures corresponding to the chosen observation are reduced to calibrated event lists, unless disabled via the corresponding parameter ( PN , MOS , RGS , OM , all set to "yes" by default). ... The EPIC data is then searched for source detections, via edetect_chain . By default, for the EPIC data, if more than one exposure is present, these actions are taken over the event list corresponding to the longest observation. ...

Astronomy Discussion Forums . Forums: . ... Discussion Forums . ... Total Lunar Eclipse, November 8-9 . Forum List | ... Post Message | ... Posted by Guillaume DИtretat on November 15, 2003 00:18:41 UTC . ... www.astronomy.net . About Astronomy Net | Advertise on Astronomy Net | ... Forum posts are Copyright their authors as specified in the heading above the post. "dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET" . ...

... November 5, 1997 . The Milky Way's Gamma-Ray Halo . Credit: D. Dixon ( UCR ), D. Hartmann ( Clemson ), E. Kolaczyk ( U. Chicago ), NASA . Explanation: Our Milky Way galaxy appears to be surrounded by a halo of gamma rays . Gamma rays are the most energetic form of electromagnetic radiation , with more than a hundred thousand times the energy of visible light, but known gamma-ray sources don't account for the diffuse distribution of this high-energy glow. ... About APOD > . ...

If necessary, the observations and corresponding O – C values belonging to some observatory can be separated from the other data. Besides, O – C satisfying some conditions imposed on their value can be separated. ... To separate O – C by value, mark O – C check box and enter positive numbers limiting absolute values of O – C from above or from bottom or both and click on Run . ... The restrictions imposed on observatory code and on O – C values are indicated in status bar. ...

In the recent years, the interest on studying the outer parts of spiral galaxies is rising. ... During this talk I will speak about my current work as part of my PhD project focused on the stellar content in these outer regions. ... I will finish showing the effect that satellite accretion has on shaping the chemical and kinematic properties of the outskirts of simulated galaxies, as well as the effect of such accretion in the shape of the stellar age profile as shown by the RaDES set of galaxies. ...

... the time of observation . ... Observing the Changing Position of the Sun To Establish Cardinal Directions . ... Observations of the Sun's apparent movement across the sky and its pattern of rising and setting in the east and west horizon helped to establish the cardinal directions. ... The final stage of the Sun's return was marked by the observation that the Sun had reached its highest altitude when the full width of your mitted hand could fill the gap between the Sun and the horizon. ...

... I would several points which we faced during our everysolved for better quality of individual ACs' and EOP products · There are two main EOP products provided by two IERS Product Centers on Earth Orientation (Earth Orientation Center (EOC) and Rapid Service/ Prediction Center (RSPC)). ... However, the latter is not provided by the IERS. ... ITRF · Using ITRF in computation of EOP series produced by various ACs seems to be a necessary condition to provide the consistency between the IERS products. ...