... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . ... Risks Comparable to NEOs . ... The Increasing Rate of Discovery of Asteroids . ... Comet and Asteroid Collision Probabilities . ... Extreme albedo comets and the impact hazard (PDF Format) . ... Asteroid Impact Animations . ... Workshop on Scientific Requirements for Mitigation of Hazardous Comets and Asteroids - 2002 . ... The Spaceguard Survey Report, 1992 (PDF) . Tsunami from Asteroid/Comet Impacts . ...

M1 image More About M1 Nice Color Picture . ... M16 image More About M16 HST image . ... M31 image More About M31 Nice Color Picture . ... M42 image ; M43 image More About M42/43 Nice Color CCD Picture . M51 image More About M51 Color Image of M51 M51 Supernova . M57 image More About M57 Nice Color CCD Picture Very Deep M57 Image . ... M81 image More About M81 M81 Supernova Ultraviolet Image of M81 More about Ultraviolet Imaging . M82 image More About M82 M82 False Color M82 True Color . ...

... Data . ... Both the FUVOP and the NUVOP disperse the beam in a direction roughly parallel to the decreasing line number direction with angles of approximately 8 degrees and 11 degrees from the -L direction respectively. This dispersion angle can be seen clearly in Figures 8.2 and 8.3 which show f /96 images taken with the FUVOP and the NUVOP respectively. ... The wavelengths determined from objective prism spectra using these dispersion curves should have a / error of <1% for f /96 spectra. ...

... The STECF IRAF layered package impol provides five tasks specifically aimed at reduction of HST imaging polarimetry data for ACS, FOC, NICMOS and WFPC2. ... Reduction of HST polarimetry data and simulation of raw polarimetry images, together with polarization vector plotting, are covered. ... hstpolsim -- Produce simulated polarization input data frames for HST instruments from images of the total signal, the linear polarization and the position angle of the polarization vectors. ...

Next: Analysis Tools for Nebular Emission Lines . ... Extracting spectra from a large number of NICMOS grism images requires a convenient interactive tool which allows a user to manipulate direct/grism image pairs. ... The direct image is used to locate objects of interest, to find the position of the appropriate spectra in the grism image, to determine the optimal extraction technique to use, and to calibrate the wavelength range of the extracted spectra. ... Figure 1: The NICMOSlook User Interface . ...

slitless -- Extract a spectrum from a direct/GRISM image pair slitless image grism output PARAMETERS . ... A two dimensional direct image to be used to select an object. grism . A two dimensional GRISM image containing slitless spectra of objects present in the direct image. output . ... Toggle whether or not a background estimate is subtracted from the extracted object spectrum. mingood = INDEF . Pixels of the grism image with values smaller than this are ignored. maxgood = INDEF . ...