These comments apply to the HST Call for Proposals dated May 1990. page 3, table 2-1: change HSP version from 1.1 to 3.0 page 30, table 11-1(c): delete 0.4 aperture (limiting mag is still about correct -- jwp) page 34: delete reference to 0.4 apertures change 50, 000 per second to 80, 000 per second replace sentence starting Brighter stars... with: Stars ...

... Apache HTTP Server Version 2.2 . ... This document describes the use of filters in Apache. ... The Filter Chain is available in Apache 2.0 and higher, and enables applications to process incoming and outgoing data in a highly flexible and configurable manner, regardless of where the data comes from. ... A wider range of applications are implemented by third-party filter modules available from modules.apache.org and elsewhere. ... There are two ways to use filtering: Simple and Dynamic. ...

... Submitted by Al Takeda on 05/14/2014 15:05:01 . Jellyfish Nebula (IC443) – Narrowband Hydrogen-alpha . While testing a new coupler/adapter for the STL6303E CCD camera, I imaged the Jellyfish supernova remnant using a 5nm narrowband Hydrogen-alpha filter. The bright star near the “head” is 7 – Eta Geminorum. 5nm Narrowband H-alpha filter, 10 images x 600-second sub frames, binned 1x1, Total= 1 hour and 40 minutes. ... Copyright (c) Amateur Telescope Makers of Boston, Inc. ...

adapted from Observe: Eclipses, published in 1979 by the Astronomical League and "Safe Solar Filters," by B. Ralph Chou, Sky and Telescope, August 1981) . ... Tape TWO pieces of film together into a sandwich, and tape this over the opening in the cardboard. ... The cardboard frame will act as a shade from the bright Sun, while you safely observe through the film sandwich. ... Undeveloped film is not safe. ... tape . ... At the end of one of the tubes, tape the aluminum foil, and make a tiny pinhole. ...

Galaxies are diffuse objects which are imaged against a background of finite brightness and noise. Galaxies which have the maximum contrast with respect to this background are the ones that are first discovered. ... These galaxies have been missed to date but active surveys for them are underway. ... In this page we present several examples of these newly discovered Low Surface Brightness galaxies as well as examples of high surface brightness galaxies. ...

... Archives . ... Differential Emission Measure [Eqn] . ... Astro 301, class 1, and it took all of 20 minutes of talk about stellar magnitudes to put that notion to permanent rest. ... Now, it turns out that the human eye perceives brightness on a log scale, so magnitudes are numerically similar to log (brightness). ... frac{5}{2}\log_{10}\left(\frac{f_{object}}{f_{standard}}\right) \,,$$ . ... frac{5}{2}\log_{10}\left(\frac{L_{object}}{4 \pi d^2}\frac{1}{f_{standard}}\right) \,.$ ... Chandra Blog . ...

XMM-Newton Science Analysis System . phasecalc (dscalc-2.6) [xmmsas_20080701_1801-8.0.0] . ... phasecalc is meant to be used in conjunction with evselect or xmmselect to perform second order filtering. phasecalc is not a general tool, in that it has a very specific knowledge of how to calculate the absoulte time of an event based on the XMM-Newton conventions. ... For a more generic tool to perform arbitrary math on binary tables see tabcalc ( ). XMM-Newton SOC/SSC -- 2008-07-02 ...

... Step thru 1120 - 1720 in 100 Mhz junks. At each step do 3 one second integrations with cal off and then 3 one second integrations with cal on. ... 1320-1420 filter 3 (1230-1470) . ... When the data was analyzed the 1320-1420 polB had jumps in the cal deflection (relative to Tsys on Absorber). ... This is the 1320-1420 Mhz band with filter 3 in. ... This jump was also seen in the lbw cal measurements done on 10jun05 while on absorber (see: caldeflection/Tsys for the 9 passes (.ps ) ( .pdf ). ...

m31 _B_00098_df.fits TARGET = ' M31 ' / target EXPTIME = 100 . / exposure time (seconds) FILTER = ' (2) B (375-490)' / filter DATE-OBS = ' 2012-11-22T00 :40:42.618' / date of observation (UT) m31 _B_00099_df.fits TARGET = ' M31 ' / target EXPTIME = 100 . / exposure time (seconds) FILTER = ' (2) B (3