... Each diode of the linear array (containing 512 diodes, diodes 7-506 are science diodes) was independently monitored via its own electronics chain. ... In practice, the threshold voltage for anomalous diode was set to a high value so that it did not detect electrons from the photocathode. ... Large background diode (50% peak +3) . ... Large background diode (50% +3) . ... Flaky: intermittently strong (see GHRS ISR 080). ... Table 37.4 lists diodes that are occasionally seen as flaky in data after...

... 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. ...

Next: The STScI NICMOS Calibration Up: No Title Previous: CONICA: The high resolution . The STScI NICMOS Calibration Pipeline . Introduction . ... Dark Current Subtraction . ... Input Data . ... Scalar Background Subtraction . 2-D Background Subtraction . ... Status and Goals of the NICMOS Calibration Plan . ... Photometry . ... Photometric Performance of NICMOS . ... NICMOS Photometry. ... ST-ECF Grism Spectrum Software for NICMOS Grism Data . ... Analysis . ... STScI NICMOS Software . ...

... Laboratory and theoretical modelling of the UV bump on the interstellar extinction curve is a very popular topic in dusty investigations. ... feature is illustrated by Fig. 10 where the profiles were calculated using the model of graphite spheres. Figure 10: Normalized extinction efficiencies for graphite spheres. ... The lower panel shows the summary extinction of two graphite spheres with radii and (from upper panel) taken in equal proportions. ...

Timing Mo de low-energy background (OCR-1762) Michael Freyb erg, Vadim Burwitz, MPE Motivation (status June 2006 ): · for analysis of serendipitous science (not only!) or faint sp ectral features there should b e detailled knowledge on camera ... MF + VB MPE Garching XMM-Newton EPIC Calibration Meeting, Mallorca, 26 Oct 2006 5 TI mo de: 0503 0125910901 PNS014 Sp ectrum and two-comp onent low-energy fit for 0503 0125910901 PNS014. ...

... We are using Canadian Galactic Plane Survey l 74.2њ, -3.6њ < b This poster gives preliminary results for a full-fledged analysis of the gas properties and distribution of HISA features in the CGPS. ... where T ON and T OFF are observed brightnesses on and off the HISA feature, T S is the spin or excitation temperature of the HISA gas, tau is its optical depth, T C is the continuum intensity, and p is the fraction of H I emission lying behind the HISA feature. ... GIF | ...

... A typical spectrum (such as Figure 1) shows the classic triple-peaked spectrum, which is associated with masers located in a circumnuclear disk (e.g. NGC 4258, Nakai et al., ... The Circinus galaxy megamasers are known to be variable on timescales of weeks and months with individual maser features having a lifetime of around one year. ... Most of the masers observed showed some degree of variability over an hour while one feature displayed a doubling of its flux density over about 10 minutes. ...

... Cosmic Adventures . ... Iт??ve read about background radiation fields that fill the universe. Is the infrared radiation as ancient as the microwave, and are there other cosmic fields of radiation besides these two? ... ESA/Planck consortium The cosmic background radiation currently emits mainly at microwave wavelengths. ... When the universe was 1 million years old, the cosmic background was mostly infrared radiation. ... Get instant access to subscriber content on Astronomy.com! ...

Previous Next Table of Contents . The Sparkle plug-in has a number of user controlled features to manipulate images: . ... Levels for the pixel intensity threshold, the intensity of the flares which radiate out from the center of the sparkle, and the opacity (the amount the sparkle will blend with the original image). ... Variable or constant saturation for spikes. Length of spike. ... All of these features is discussed at length in the section titled The Sparkle Dialog Box . ...

... We have developed a new extraction software package called aXe that was specifically designed to handle the ACS spectrophotometric data. ... The aXe software was designed to extract spectra in a consistent manner from all the slitless spectroscopy modes provided by the Advanced Camera for Surveys (ACS) that was installed on the Hubble Space Telescope in February 2002. ... The extraction process is a set of well isolated steps that can be individually applied and tweaked by the user (Figure 1 ). ...

... In most astronomical observations the image intensity consists of contributions from both object and sky background. Depending on the complexity of the field and the type of object, different methods are used to estimate and subtract the background intensity. ... Non--linear filters are often used to remove stellar images and other sharp features (see Section ) while extended objects are very difficult to eliminate automatically. ...

... Visible Distribution of Galaxies. ... Features of Elliptical, Lens-Shaped, Spiral and Irregular Galaxies. Galaxies with Bar. ... Distribution of Surface Brightness of Surface and Spiral Galaxies. ... Color Characteristics of Galaxies. ... Methods of Galaxies' Mass Determination. ... Hidden Mass of Spiral Galaxies. ... Features of Dark Matter Distribution in E and SO Galaxies. ... The Whole Number of Galaxies and Their Density by the Results of Observation on the 'Hubble' Space Telescope. ...

... Science . ... Data Handling and Products > Data Reduction FAQ > My MR+GG475 data show strong absorption features below 6000A. Where do they come from and how can I correct them? ... Observing with ESO Telescopes . ... Science Data Products Forum . ... The absorption comes from impurities in the GG475 filters and the first and third quadrant are most strongly affected (see plot - the black curve shows the spectrum of a featureless star observed in Q1, the green shows the same star observed in Q3). ...

Next: Coordinate Systems Up: IRAF/PROS Previous: Other Types of Files . A few new features and enhancements to the standard IRAF system have been introduced with the PROS software: . ... Default compound extensions are used by the PROS tasks when no extension is given for the output file name. Most PROS tasks allow the output file name to be defaulted, with the convention that the output file name will be composed of the input `root' name, plus the default extension specific to the task. ...

... Sun-aligned arcs are auroral features found within the polar cap , as opposed to the auroral oval where the more typical arcs reside. First global image of this phenomenon was reported by Frank et al. (1982); it consists of luminous belt reaching across the polar cap from noon to midnigh (that is why it is also called theta aurora; terms transpolar or polar cap arc are also known). ... Res., ... Antisunward decay of polar cap arcs, J. Geophys. ... The Creation of Theta-Aurora, by JHU/APL . ...

... Mystery Feature Now Disappears in Titan Lake . ... Credit Copyright: Cassini Radar Mapper , Cornell , JPL , ESA , NASA Explanation: What is that changing object in a cold hydrocarbon sea of Titan? ... When imaging the flat -- and hence radar dark -- surface of the methane and ethane lake called Ligeia Mare , an object appeared in 2013 July just was not there in 2007. ... The featured false-color image shows how the 20-km long object has come, changed, and gone. ... Publications with keywords: Titan ...

... Copyrightї1997 Bob Yen (byen@ix.netcom.com) (http://www.comet-track.com/hb/hb.html) . ... Information on Comet Hale-Bopp for the Non-Astronomer Hale-Bopp rotates about twice a day (3/14/97) . ... The Comet Observation Home Page was been selected to receive the Griffith Observatory Star Award for the week of February 2 - 8, 1997 for excellence in promoting astronomy to the public through the World Wide Web. ... Typically, about 1,000 individual users/computers access this page every day. ...

Next: Radial velocity of the Up: Optical spectrum of IRAS04296 Previous: Observations and spectra reduction . ... However, molecular emission features are only very rarely observed in the optical spectra of PPNe. ... On the other hand, it is well known that cometary nuclei spectra show prominent Swan band emission. In both spectra of IRAS04296 we have discovered strong emission in the (0;0) and (0;1) bands of the Swan system of the molecule. ... Now consider the case of IRAS04296. ...

Astronotes Armagh Planetarium's Stellar Blog! ... Armagh Planetarium . ... Stars . ... Space Flight . ... Monthly Sky Notes . ... NGC 6357's inner star forming region glows with the emission of ionized hydrogen gas. Image credit: ESO/VVV Survey/D. Minniti. ... Located around 8000 light years away in the constellation of Scorpius , NGC 6357 (sometimes called the Lobster Nebula ) is a typical stellar nursery, filled with vast clouds of gas and tendrils of dark dust. ... Subscribe to Astronotes . ...

... Flux density at 1 GHz (/Jy): 20 . ... Becker & Kundu 1975, AJ, 80, 679. NRAO 140-ft at 10.6 GHz (3'). ADS . ... 1975, AuJPA, 37, 39. Molonglo at 408 MHz (3': S=31.0 Jy) and Parkes 64-m at 5 GHz (4': S=9.1 Jy), no maps. ... 1975, A&A, 45, 239. ... VLA at 1.4 GHz (3".4?14".5). ... Whiteoak & Green 1996, A&AS, 118, 329. ... 2000, ApJ, 537, 875. VLA at 1.7 GHz for OH Zeeman splitting. ... CO observations of the vicinity. ... Spitzer observations. ... GBT at 1.6 and 1.7 GHz for OH masers. ...