... To be read in conjunction with Section 4.11 of the WFPC2 Instrument Handbook , -Version 4.0. ... 1 The second study found evidence that CTE loss for faint stars has increased with time (Whitmore, 1998). The primary observational consequence of CTE loss is that a point source at the top of the chip appears to be fainter than if observed at the bottom of the chip, due to the loss of electrons as the star is read out down the chip (see Figure 1 ). ... Last updated: 06/16/98 10:38:00 . ...

... 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. ...

... In the three intervening decades there have been many observations of this diffuse emission over a wide range of x-ray energies. ... During the 1970's researchers at the University of Wisconsin, lead by Dr. William Kraushaar, used a series of sounding rocket flights to map the diffuse x-ray emission from the sky in several bands. ... University of Wisconsin Sky Survey map of the B-band (0.13-0.188 keV) x-ray intensity. ... University of Wisconsin Sky Survey map of the 2-6 keV band x-ray intensity. ...

... Meta Index / Home Page / Description / Soft flare rejection for . The EPIC-pn fast timing mode was designed so that a time resolution of 0.029 milliseconds can be achieved. ... Below this energy the data is affected by so-called soft flares which are caused by stack overflows generated by high energy particles. These so-called soft flares have sharp rise (from 0 counts/sec to several thousand counts/sec in 0.10-0.15 sec) then decaying back 0 counts/sec slightly slower in about 0.3-0.4 sec). ...

... Usually, H I is seen as bright emission against a darker background, but under the right viewing conditions, it can also be seen as dark absorption against a brighter background. In the case where the background is itself H I emission, the hydrogen is said to be self-absorbed, and the radiative transfer process is termed H I self-absorption (HISA). ... Shown below is a single CGPS H I 21cm spectral line channel at a radial velocity of -41 km/s in the Local Standard of Rest, at l =140њ, b =+1њ. ...

... This paper describes the main algorithms used by the Einstein Level One processing to create the exposure masks and the background maps for Einstein IPC images, and how these algorithms were recreated in the IRAF environment. Our goal was to recreate the algorithms used by the Level One Processing to create exposure masks and background maps for Einstein Image Proportional Counter (IPC) data (cf. sections 2.5 and 2.7 of Harnden et al. ...

... Observers in Europe observed a sharp peak in the number of meteors visible around 0210 UTC during the early morning hours of November 18. ... Early morning risers around the world have enjoyed the sight of bright planets in this week's predawn skies - further enhanced by the celestial spectacle of the waning crescent Moon. From some locations the Moon was seen to pass in front of Jupiter or Venus, a lunar occultation. ... What are those bright objects in the morning sky? ...

... Tonight's Sky . ... The Magazine . ... Observing . ... The double star 54 Leonis, spiral galaxy NGC 3198, and emission nebula NGC 3199 . ... Astronomy for Kids . ... Observing springtime deep-sky objects with a large telescope . ... Bright planets meet at dusk . ... Astronomy magazine subscribers can read the full article for free. ... Get instant access to subscriber content on Astronomy.com! ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter....

... A1 centered at 2500 angstroms with a width of 1200 angstroms . ... M63 or NGC 5055 is a pleasant spiral galaxy with multiple arms and a bright inner region. The exposure times were 1149 seconds through B1 and 576 seconds through A1. NGC 752 a galactic stellar cluster was observed for 777 seconds through B5 . ... NGC 1365 is a prominent spiral galaxy in the Fornax Cluster. ... The galaxy fits comfortably into one UIT frame and this exposure was for 1360 seconds through A1 and B1. ...

Next: Basic Properties Up: R Coronae Borealis Stars Previous: Introduction . RCB stars are named after a star just visible to the naked eye in the constellation of Corona Borealis. RCrB was discovered by Edward Pigott, an English amateur astronomer, who had been observing a star in the `Northern Crown' for over a decade. ... Since 1795, other RCB stars have been discovered and their properties have been carefully observed. ...

... The Galactic low-mass X-ray binary GS 2023+338 was discovered during the burst on May 22, 1989 with the Japanise satellite Ginga (aka Galaxy). The flux reached 17 crabs (this unit of flux measurement is an bright X-ray source, Crab Nebula) at 10-35 keV. ... No other radio telescope worldwide carried out multi-frequency measurements. ... Upon 14 days the radio flux fell below the detection level at the RATAN-600 in relation to the decrease of the X-ray flux. ...

... The R , I photometric observations of SBS 0335-052W were obtained occasionally during the study of SBS 0335-052 with the 3.5m telescope in Calar Alto on 1991 October 6. ... Aperture photometry was performed on the standard star observations using MAGNITUDE/CIRCLE task with the same aperture for all stars. ... For photometry of extended objects, we used the package SURFPHOT as well as dedicated software for adaptive filtering developed at the Astrophysical Institute of Potsdam (Lorenz et al. ...

Once students get the hang of it, they can find and measure the brightness of Delta Cephei in a few minutes. ... of Delta Cephei . ... Oct. ... The following table lists the measurements of Delta Cephei made by one amateur astronomer in autumn 1990. ... 4.0 . ... This activity is a simplified version of one that appeared in Hands-On Astrophysics, a series of activities prepared by the American Association of Variable Star Observers with support from the National Science Foundation. << previous page | ...

We cannot observe the way the distant universe accelerates cosmic rays or produces energetic photons, but acceleration processes also occur on our Sun , though on a much more moderate scale. ... That is why such events are often missed by cosmic ray detectors near the equator, where the lowest energies are excluded by the Earth's magnetic field. The best detectors for observing solar particles are therefore those sensitive to the lowest energies of the cosmic radiation. ...

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: . ...

... Galaxies 99 Cosmic background with model of cloudy interstellar medium Yu. ... Figure 1: Averaged spectrum of the cosmic background I f in frequency range 0.25 200 MHz for the Galactic poles. ... First interpretation of the cosmic noise background spectrum at broad band frequency range 0.25 200 MHz with a model of the cloudy interstellar medium ISM is presented here. ... Synthesized background spectra I f for regions of the Galactic poles at the frequency range 0.25 200 MHz is presented in Fig. ...

... Science User Portal . ... ESO, the European Southern Observatory . ... Travel and Contacts . Travel to ESO Headquarters . ... Travel to E-ELT Armazones . ... Survey Telescopes . ... Star Clusters . ... Stars@ESO . ... ESO Science Newsletter . ... ESO 3.6-metre telescope . ... MPG/ESO 2.2-metre telescope . ... ESO 1-metre Schmidt telescope . ... ESO Science Outreach Network . ... This chart shows the brightness variation ("light-curve") of the star OGLE-TR-3 obtained during the OGLE observations. ...

... all new HIPASS galaxies (Table 2.4) that have no yet been observed with the ATCA . ... Table : Remaining ATCA target list (sorted by RA) -------------------------------------------------------------------------------- Name RA DEC ID Max mom0 mom1 mom2 w50 w20 -------------------------------------------------------------------------------- ZSS 13 07:33:16 -28:41:07 new -HIZSS013 0.151 9.2 2077.6 21.6 52.8 144.6 HIP 358 07:44:56 -41:47:02 ESO311-G006/7 0.262 30.9 1049.4 34.5 127.1 149.5 ...

... The bright supernova (hereafter SN) in the galaxy NGC 4527 was first sighted by S. Knight (USA) on April 13.17UT at magnitude ~14.0v. The report of the sighting was subsequently forwarded by phone to the AAVSO. ... SN 1991T. The galaxy NGC 4527 is an Sb(s)II type galaxy with an apparent Blue magnitude of 11.32 (Shapley-Ames, 1981). ... An analysis of this event utilizing visual observations by amateurs, plus a light curve is presented.. ... THE LIGHT CURVE: . ... ISN SN 1991T web page . ...

... 2002 March 7 . Comet Ikeya-Zhang Brightens . ... Explanation: In the last week , Comet Ikeya-Zhang has become bright enough to be just visible to the unaided eye. Based on its present activity, observers are optimistic that Ikeya-Zhang will become substantially brighter. This composite color image from March 3rd, captured with a wide-field telescope, shows this active comet's bright, condensed coma and a delightful array of subtle structures in its developing tail. ... About APOD | ...