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 Astronomical Catalog portion of CDBS contains several atlases consisting of both observed and model stellar,galactic, and emission line object spectra as well as HST standard stars spectra are available in STSDAS table format for use in the calibration of HST instruments, with synphot, with the exposure time simulators, or for any other purpose. this is it There are two independent directories containing the spectra of ultraviolet and optical standard stars. ... For details see K93MODELS . ...

... 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. ...

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. ... contains wavelengths, gf and A values for each transition. Wavelengths are based on experimental level energies where available; wavelengths calculated from theoretical energies are less accurate and are given as negative values. ...

... Forms . ... This page explains how you can embed input forms into wiki pages. ... Forms processing can be found in the Cookbook (see below). ... input text name value size= n :) (: input hidden name value :) (: input password name value :) (: input search name value :) (: input number name value min=x max=y step=z:) (: input email name value :) (: input url name value :) (: input date name value :) (: input radio name value label checked=checked:) (: ...

... Data Handling and Products > Data Reduction FAQ > The spectrum of my MOS flux standard star is shifted in wavelength by several pixels. Why is that and how can I correct for it? ... Observing with ESO Telescopes . ... The shift of the flux standard spectrum is caused by a combination of bad centering within the slit and possible wavelength calibration issues. To align the spectrum to the tabulated flux, use the parameter --resp_shift in vmmosscience when determining the response curve. ...

. To redirect the standard output from a command use the > (greater than) symbol followed by the name of the output file. If the file that you redirect standard output to does not already exist it will be created. For example: grep Smith /etc/passwd > popular . This redirects the standard output from the grep command so that it goes to the file popular . This file will contain all occurrences of the string Smith that were found in the /etc/passwd file. **Caution** . Did You Know? .

... Standard Commands . ... TwistedActor.Actor is core code for writing an actor: an instrument control computer (ICC) or hub-based script that does something useful. This manual describes the standard commands and keywords that any actor based on TwistedActor.Actor will support. All actors based on TwistedActor typically support the following standard commands (plus additional device-specific commands documented in that actor's manual). ... Connect one or more devices (if not already connected). ...

... Briefly, the count rate at the detector from a source at a redshift z is . ... Another possible way that could lead to arising diverse peculiarities in the - distribution induced by the sources evolution is connected with a possible non-monotonic character of the star formation rate in galaxies. ... The most prominent feature of the obtained theoretical - is a notable sharp increase at low count rates due to evolutionary effects. ...

... This routine is designed to read in the current correlator set-up, go to the chosen source, and then take data pointing directly at the specified source. This routine will automatically wait until you are on source before beginning to take data. ... Additionally, this routine allows you to take an ON/OFF calibration pair (one 10s scan with the noise diode on, followed by a 10s scan with the diode off), using the chosen noise diode configuration (see Section 1.6 . ...

Emission Line Diagnostics in a ``No UV Bump'' Quasar PHL909 Smita Mathur, Belinda Wilkes, Martin Elvis and Jonathan McDowell Abstract PHL909 is a quasar with unusually low ultraviolet luminosity (blue bump strength C UV=IR = \Gamma0:20 compared to an average value of 0:4 (McDowell et al. ... The intrinsic continuum of PHL909 ( i.e. as seen by the BELR ) may thus be similar to the `standard' continuum, with a big blue bump, reddened along the line of sight. ...