... Stellar Evolution is driven entirely by the never ending battle between Pressure and Gravity . As imbalances are reached, the star is driven to find a new Energy source. ... Pressure and gravitational forces are equal, the star is stable and its core is sufficiently hot to fuse Hydrogen into Helium More about main sequence stars . ... The luminosity generated by the core fusion of Helium into Carbon is far greater than the shell luminosity associated with the fusion of Hydrogen into Helium. ...

Next: Reduction procedure Up: Extinction and transformation Previous: Strategy . Standard stars can be included in the extinction solution, if one is careful. The problem is that there are usually appreciable ``conformity errors'' due to mismatch between the instrumental and the standard passbands [ 16 ]. ... Thus, it is wrong to assume that the transformation between the instrumental system and the standard system is exact, even if there were no measurement error in either system [ 1 ]. ...

... The procedure simply observes ON your source for x minutes and then takes a `blank sky' observation OFF your source for the same amount of time and tracking the same azimuth and zenith angle range. ... Typically, observing times are kept to within 5 minutes (with 5 minutes as the most efficient, and therefore default, choice). ... If your scans are for 5 minutes or less, your wait time should be set to 1 minute (the default setting). ... A 5 minute ON/OFF + 10s CAL takes 11.3 minutes. ...

Next: Examples of Setup Files Up: Setup Files Previous: Setup Files Contents . Over 200 standard setup files have been created, covering many of the normal modes of observing. ... These especially include precisely defined, and somewhat complex cases like the Mark III standard modes (although MarkIII went the way of the dinosaur long ago. ... v '' files: . These are setup files for VLBI observations using VLBA recording formats. ... These are setup files for Mark III observations. ...

... The absolute flux calibration of NICMOS will be calculated from observations of standard stars with known flux distributions F( ). ... In order to expand the set of IR standard stars in the appropriate flux range for NICMOS, M. Rieke, R. Thompson, and collaborators at the University of Arizona are making photometric observations of solar-analog stars, which will be used to normalize the solar spectrum to the observed IR magnitudes. ... Relative flux references accurate to 1.5% for standard...

... Science . ... Science Users Information > Observing with ESO Telescopes > Observing Tools and Services > Standard Stars Catalogues > Standard Star Catalogue Search Tool . ... Publications with ESO Data . ... ESO Data . ... This tool searches the standard star catalogues for standards that are within dX airmasses of the target at a given LST. ... In this case put the LST when the target was observed in the TargetLST box as before, and put the LST of the standard star observation in the StdObs LST box...

Peremennye Zvezdy ( Variable Stars ) 26 , No. ... Our BVR CCD photometric study of the globular cluster NGC 7006 permitted us to find two new suspected RR Lyrae variables. A cluster chart is presented with the position of known and suspected variables marked. ... According to the Catalogue of Variable Stars in Globular Clusters (Clement et al., 2001), it contains 76 variables, most of which are RR Lyrae variables, the RR1 to RR0 ratio being 8:55. ... for suspected and some of known variable stars. ...

Last updated 5 November 2003 by JMD . Last link checked 9 October 2003 by JCB . Data from 191 observations of stars with the ARCES were analyzed to calculate exposure times to reach particular signal-to-noise values for bright standard stars. ... An exponential fit to the data shows pretty good agreement and allows for forecasting to fainter stars beyond the limit of the data set ( V ~ 12). The fit was used to calculate the exposure times in the table below: . ...

... The J, H and K bands are characterized by a bright background, such a background is mainly due to the emission of atmospheric lines and of thermal radiation. ... If the source cover a large fraction of the slit, spectra off-source must be observed to adequately sample the sky background. ... The on chip integration time (time spent in each position of the slit) must not exceed 40 seconds in J and H bands and 60 seconds in K band. ... We suggest a sequence of 10 for each elementary integration time. ...

STEP INTO THE BLUE - MEADE INSTRUMENTS PRODUCT GUIDE . ... Telescopes . LX850 Series . ... Superb optical performance coupled with time proven computerized pointing and tracking has made the LX200 ACF series a best-seller in the high-performance telescope class. ... LX70 Series . ... Meade's revolutionary LS LightSwitchтДв series of telescopes use advanced technologies to do what no other consumer telescopes have done before: take all the hassle out of using a telescope. ... LightBridge Series . ...

Prospects for a Broad-Band Effective Area Standard Candle Steve Sembay EPIC - MOS Calibration Manager XMM EPIC MOS Steve Sembay ( sfs5@star.le.ac.uk ) ICWG 15/06/06 Compact MS2137 Crab Stable Simple BroadBand G21.5 Vela PWNe Steve Sembay ( sfs5@star.le.ac.uk ) ICWG 15/06/06 XMM EPIC MOS Some Clusters Observed by Chandra All Chandra Images/Movies courtesy of... http:// ... No Yes Yes G21.5 Vela PWNe XMM EPIC MOS Steve Sembay (sfs5@star.le.ac.uk) ICWG 15/06/06 ...

... We describe a tool in the PCIPS environment for finishing the job of globular cluster photometry started by DAOPHOT II: starting with the instrumental magnitudes derived by DAOPHOT II, DASHA can automatically produce final color-magnitude diagrams. ... DASHA can automate the whole process of globular cluster photometry, from instrumental magnitude lists produced by DAOPHOT II, to final color-magnitude diagrams. ... DASHA is oriented towards star lists produced by DAOPHOT II as source data. ...

... The study of the Large-scale structure of the Universe and measurements of the Dark Energy equation of state; The exploration of the growth and cosmological evolution of supermassive Black holes in the Universe. ... In course of the all sky survey SRG will discover about 100 000 galaxy clusters and 3 million AGNs. Galaxy clusters are the largest gravitationally bounded objects in the Universe and are best explored through the study of X-ray emission from the hot intergalactic gas. ... 2016 IKI RAN ...

Next: The Formation and Evolution Up: NICMOS Science Previous: NICMOS Observes the Galactic . ... We have taken diffraction-limited ( 0.15") near-infrared F160W (henceforth H-band, for convenience) images with NICMOS on HST of the center of the R136 cluster (age 3.5 Myr) in the core of the 30 Dor giant HII region in the Large Magellanic Cloud. ... 1996, ApJ 466, 274) can sample only M >2M , while previous V and I band HST images with WFPC2 (Hunter et al. ...

... Optical photometric data were taken of fields encompassing all these sources during a total of seven telescope runs. ... The initial goal of the photometric observations is to follow up the X--ray sources, assign them colors in a standard system, so that the observed objects can be placed on a color--magnitude diagram. This can be used to verify that the X--ray sources are indeed PMS stars. ... Aperture photometry was performed using the APPHOT package in IRAF. ...

... The material in "From Stargazers to Starships" meets several important requirements of the national standards. Pages cited below are from National Science Education Standards National Academy Press, Washington 1995. ... For example: the sections on astronomy not only describe calendars and sundials (including their construction), but also the astronomy of the ancient Greeks, including two different ways in which ancient Greeks estimated the distance to the Moon. ...

Bridge World Standard Bridge World Standard (BWS) is a system based on the majority preferences of approximately 125 leading experts and thousands of Bridge World readers. ... Jacoby transfers (splinter rebids; game raise is slam try; two diamonds plus two spades forcing only one round); two spades shows minors; three hearts invitational, major two-suiter; Texas transfers; Stayman (two-spade rebid invitational; two-heart rebid weak; minor rebid forcing); Smolen; three of a minor invitational; Gerber. ...

... A theory suggests that a certain sub-class of gamma-ray bursts all have the same absolute magnitude. ... The author claims that this absolute magnitude is so different from that in the previous sample that this must belong to a new sub-class of gamma-ray bursts. ... To do this, there needs to be some feature in their spectra which correlates with their absolute magnitude. ... Consider a telescope which is continually monitoring a star, looking for transits due to planets orbiting this star. ...

Pulkovo NEO Page . ... NEA Accuracy Estimation . ... The estimation of accuracy of the current CCD observations of asteroids and comets is constantly performed at Pulkovo Observatory. ... The (O-C) values, so called "Observed" minus "Calculated" positions, characterize numerically the observations of any observatory, both professional and amateur, during a short period (one or several close nights). ... So the (O-C) values for these objects nearly entirely define the errors of observations. ...

The software package ERA (Ephemerides for Research in Astronomy) is a problem-oriented software system for solving heterogeneous calculating tasks of Ephemeris and Dynamical Astronomy. The package makes it possible to produce ephemeris calculations needed for both planning various observational programs and processing the resulting observations. ... The system includes packages of processing the position observations by both the Least Squares Method and by Kalman filtering. ...