79 research outputs found
ESI, a new Keck Observatory echellette spectrograph and imager
The Echellette Spectrograph and Imager (ESI) is a multipurpose instrument
which has been delivered by the Instrument Development Laboratory of Lick
Observatory for use at the Cassegrain focus of the Keck II telescope. ESI saw
first light on August 29, 1999. ESI is a multi-mode instrument that enables the
observer to seamlessly switch between three modes during an observation. The
three modes of ESI are: An R=13,000-echellette mode; Low-dispersion prismatic
mode; Direct imaging mode. ESI contains a unique flexure compensation system
which reduces the small instrument flexure to negligible proportions.
Long-exposure images on the sky show FWHM spot diameters of 34 microns (0.34")
averaged over the entire field of view. These are the best non-AO images taken
in the visible at Keck Observatory to date. Maximum efficiencies are measured
to be 28% for the echellette mode and greater than 41% for low-dispersion
prismatic mode including atmospheric, telescope and detector losses. In this
paper we describe the instrument and its development. We also discuss the
performance-testing and some observational results.Comment: 10 pages, 14 figures, 8tables, accepted for publication in PASP, 15
April 200
Computational and Serologic Analysis of Novel and Known Viruses in Species Human Adenovirus D in Which Serology and Genomics Do Not Correlate
In November of 2007 a human adenovirus (HAdV) was isolated from a bronchoalveolar lavage (BAL) sample recovered from a biopsy of an AIDS patient who presented with fever, cough, tachycardia, and expiratory wheezes. To better understand the isolated virus, the genome was sequenced and analyzed using bioinformatic and phylogenomic analysis. The results suggest that this novel virus, which is provisionally named HAdV-D59, may have been created from multiple recombination events. Specifically, the penton, hexon, and fiber genes have high nucleotide identity to HAdV-D19C, HAdV-D25, and HAdV-D56, respectively. Serological results demonstrated that HAdV-D59 has a neutralization profile that is similar yet not identical to that of HAdV-D25. Furthermore, we observed a two-fold difference between the ability of HAdV-D15 and HAdV-D25 to be neutralized by reciprocal antiserum indicating that the two hexon proteins may be more similar in epitopic conformation than previously assumed. In contrast, hexon loops 1 and 2 of HAdV-D15 and HAdV-D25 share 79.13 and 92.56 percent nucleotide identity, respectively. These data suggest that serology and genomics do not always correlate
The DEIMOS spectrograph for the Keck II telescope:
The DEIMOS spectrograph is a multi-object spectrograph being built for Keck II. DEIMOS was delivered in February 2002, became operational in May, and is now about three-quarters of the way through its commissioning period. This paper describes the major problems encountered in completing the spectrograph, with particular emphasis on optical quality and image motion. The strategies developed to deal with these problems are described. Overall, commissioning is going well, and it appears that DEIMOS will meet all of its major performance goals
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