... 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. ...

A number of different choices are possible on WFPC2 in order to approximate the Johnson-Cousins system often used in ground based observing. These choices differ in throughput, wavelength fidelity, color transformability, and cosmetics. The HST science program as a whole benefits if a standard set can be agreed upon by the community for broad band photometry. ... These filters form the basis for the WFPC2 broad band photometric system. ... Space Telescope Science Institute . ...

... Standard magnitudes can only be computed for the U, B and V filters and hence the only standard colours that can be calculated are U-B, B-V and U-V. An important point to note, is that these standard colours can be computed using the following instrumental colours - U-B, B-V, U-V, (UVW1-U), (UVW1-B), (UVW1-V), (UVW2-B) and (UVW2-V). Omsrclistcomb computes all possible standard magnitudes for each of the U, B and V filters and displays them in a vector column. ...

Next: AXAF Recipes Up: ROSAT HRI Recipes Previous: Quantum Efficiency Correction (a.k.a. For some observations, a significant amount of data may have been rejected during SASS processing because the background level was higher than the calculated threshold for rejection. ... REJECTED EVENTS . ... The recipe will allow the user to include rejected events in the generation of a new qpoe file and filter on the background level. ... This creates a qpoe file with standard + rejected events. ...

A computer controlled low light photometer for nightglow observations. Hardware units of portable photometer for low light measurements, especially night glow emission is described. ... Interface card contain three channels of 24 bit counter, 4 channels of 12 bit ADC and the buffer bus for the controlled motors of the altazimuthal fork mounting and filters wheel, the position encoders. ... Where N( ) is output signal photometer generated input light flux F( l ) . ... PMT # . 599 . ...

Astronomers usually measure the flux of an object by collecting light with a telescope, sending it through a known filter, and then determining the power. ... But astronomers usually give their photometric results in terms of magnitudes. ... Astronomers define an absolute magnitude that is independent of the distance of a star and only depends on the intrinsic properties of the object: the absolute magnitude is the magnitude the star would have if it were 10 parsecs away from the Earth. ...

RTT150 . Russian-Turkish 1.5-m Telescope . ... Until 2002 observations were mostly performed with ST-8E CCD in the 1:7.7 Cassegrain focus. ... In April, 2003 telescope was equipped with a larger-size CCD Andor DW436 . ... 2048 x 2048 pixels, . ... Since summer of 2002 the main focal detector of the RTT150 telescope was AP47p CCD in 1:7.7 Cassegrain focus. ... During September 3-13, 2002 works on installation of new autoguiding system ( photo 1 ) were carried out on RTT150 telescope. ...

... New IRAF tools for the photometric calibration of optical/IR images are presented. The new tools are standard star catalog and world coordinate driven, requiring both accurate standard star catalog coordinate and accurate image coordinate data. Network access to standard star catalog servers is supported. ... The photometric calibration software will automatically convert the standard star coordinates from the standard star coordinate system to the image coordinate system. ...

... The first step to improve the FORS calibration is therefore to obtain data to allow a computation of the illumination correction across the field. ... Another limitation on the calibration accuracy has been the brightness of the Landolt standards which have forced the use of extremely short exposures introducing small but non-negligible shutter-time errors and also resulting in a very small number of useful standards per frame. ...

... Fortranљ66 . ... Fixed form . ... Whole Fortranљ66 . ... Continuation line indicated in column 6 . ... Blank line as comment . ... Extension in Unix .f .f .f .f90 .f .f90 . Extension in DOS .FOR .FOR .FOR .F90 .FOR .F90 . ... This applies to both fixed form and free form source code. ... Fixed form of the source code is discouraged in Fortran 95! ... In UNIX there is no concept called extension, and the extensions are not specified in the Fortran standard, but in informal manufacturer standards. ...

... mar05: filter bank installed but left in wide band mode. 05apr05: 10db amps placed in pixel 2a,2b path in front of the filter bank. 08apr05: 10db amps placed in front of filter bank for all alfa pixels. 12apr05: 6db attenuators placed before 10db amps. 25apr05: 10db amps are now only in the OH filter bath. ... This allowed the search of the data taken by P2030 (100Mhz bandwidth, cfr 1420Mhz, 64usec samples) between 01feb05 and 01may05 for signals of the aerostat radar. ...

... 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. ...

... I have compiled a list of throughput filter curves from a variety of telescopes, instruments, and surveys. Click on the name of the filter to download it. The first line of each filter is the zeropoint for that filter. If the filter is in the AB system, it is listed as 0.0 (or in otherwords -48.55). ... Filter . Effective Wavelength . ... A_V . ... 0.987 . ... 0.050 . ...

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. ...

. Position . Logical Name . Description . 0 . D . Stop . 948 . J . Standard Filter J (1.12-1.40?m) . 1896 . SJF . BandPass Filter (0.91-1.12?m) . 2844 . F1 . Hole . 3792 . EPS . LongPass Filter (1.65-2.55?m) . 4740 . H . Standard Filter H (1.48-1.82?m) . 5688 . FHK . BandPass Filter (1.76-2.12?m) . 6636 . K . Standard Filter K (2.00-2.41?m) .

... 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. ... MeadeтАЩs new LX70 Series offers high-quality German equatorially mounted telescopes with slow-motion controls and heavy-duty steel tripods. ... For crisp wide-field observing and imaging, few optical designs match the performance of a true triple-element apochromatic refractor. ... Meade Standard Field Tripod #07020. ...

... U filter . UG1 - 1mm . S8612 - 2mm . WG295 - 2mm . ... BG37 - 3mm . BG39 - 1mm . GG395 - 1mm . ... GG495 - 2mm . BG40 - 3mm . ... OG570 - 3mm . KG3 - 2mm . ... RG9 - 2mm . WG305 - 3mm . Bessell, PASP 102 , 1181, (1990) . ... Bessell, PASP 107 , 672, (1995) . APO Filters Homepage ...

This library currently provides subroutines used to transform theoretical spectra to intermediate and broad-band photometric indices. ... Typical tasks are the response functions and transmission curves for various filters, mirrors and photomultiplier windows. ... The response is zero outside the given wavelength range. ... real . input . Wavelength in nanometres . PHOT_1P21 . ... PHOT_AIR . ... PHOT_ALUM . ... Inputs must be valid as for PHOT_FILTER, PHOT_AIR, PHOT_ALUM and PHOT_1P21. ...

... Telescopes . ... CCD photometer . ... One of the principal devices used in observations at the telescope Zeiss-1000 is a CCD photometer. ... The count rates (electron per second) for ADU = 1e - computed throughout the image for U = B = R = I = 20.0 for an object observed at air mass equal to 1.0 with the given version of CCD at the telescope Zeiss-1000 are presented in Table 1. Table 1: Quantum efficiency and count rate in the broad-band system of the CCD photometer of the telescope Zeiss-1000. ...

splitxyz - filter to divide (x,y,z[, distance ,heading]) data into (x,y,z) track segments . splitxyz [ xyz [ dh ] file ] -C course _ change [ -A azimuth / tolerance ] [ -D minimum _ distance ] [ -F xy _ filter / z _ filter ] [ -G gap _ distance ] [ -H [ nrec ] ] [ -M ] [ -N namestem ] [ -S ] [ -V ] [ -Z ] [ -: ] [ -bi [ s ][ n ] ] [ -bo [ s ] ] ... If xy _ filter is non-zero, the data is first divided into segments and then the x,y values of each segment are filtered separately. ...