The Keck-I Cassegrain ADC

Phillips, Andrew C.; Miller, Joseph S.; Cowley, David J.; Wallace, Vernon

doi:10.1117/12.789930

Cited by 5 publications

(3 citation statements)

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“…Exceptions were usually at an airmass <1.2 or when the slit was positioned at a specific angle to include a second object (the host‐galaxy nucleus, a trace star, a second SN, etc.). In 2007 August, LRIS was retrofitted with an atmospheric dispersion corrector (ADC; Phillips et al ). With the ADC, differential light loss is substantially reduced regardless of position angle, even at high airmass.…”

Section: Observationsmentioning

confidence: 99%

Berkeley Supernova Ia Program - I. Observations, data reduction and spectroscopic sample of 582 low-redshift Type Ia supernovae

Silverman

Foley

Filippenko

et al. 2012

Monthly Notices of the Royal Astronomical Society

303

177

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In this first paper in a series we present 1298 low-redshift (z 0.2) optical spectra of 582 Type Ia supernovae (SNe Ia) observed from 1989 through 2008 as part of the Berkeley SN Ia Program (BSNIP). 584 spectra of 199 SNe Ia have well-calibrated light curves with measured distance moduli, and many of the spectra have been corrected for host-galaxy contamination. Most of the data were obtained using the Kast double spectrograph mounted on the Shane 3 m telescope at Lick Observatory and have a typical wavelength range of 3300-10,400Å, roughly twice as wide as spectra from most previously published datasets. We present our observing and reduction procedures, and we describe the resulting SN Database (SNDB), which will be an online, public, searchable database containing all of our fully reduced spectra and companion photometry. In addition, we discuss our spectral classification scheme (using the SuperNova IDentification code, SNID; Blondin & Tonry 2007), utilising our newly constructed set of SNID spectral templates. These templates allow us to accurately classify our entire dataset, and by doing so we are able to reclassify a handful of objects as bona fide SNe Ia and a few other objects as members of some of the peculiar SN Ia subtypes. In fact, our dataset includes spectra of nearly 90 spectroscopically peculiar SNe Ia. We also present spectroscopic host-galaxy redshifts of some SNe Ia where these values were previously unknown. The sheer size of the BSNIP dataset and the consistency of our observation and reduction methods makes this sample unique among all other published SN Ia datasets and is complementary in many ways to the large, low-redshift SN Ia spectra presented by Matheson et al. 2008 andBlondin et al. 2012. In other BSNIP papers in this series, we use these data to examine the relationships between spectroscopic characteristics and various observables such as photometric and host-galaxy properties.

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Section: Observationsmentioning

confidence: 99%

Berkeley Supernova Ia Program - I. Observations, data reduction and spectroscopic sample of 582 low-redshift Type Ia supernovae

Silverman

Foley

Filippenko

et al. 2012

Monthly Notices of the Royal Astronomical Society

303

177

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“…It is very easy to e-beam and appears to be moisture-resistant in our tests. We are currently evaluating protected Ag coatings using YF 3 and an oxide (HfO 2 , Zr-Ti oxide or Zr-Ta oxide). These coatings have reflectance R > 90% for λ > 340 nm, R > 95.5% for λ > 400 nm, and R ~ 98.5% at 2 μm.…”

Section: New Materialsmentioning

confidence: 99%

Progress toward high-performance astronomical coatings

Phillips¹,

Brown²,

Dupraw³

et al. 2010

SPIE Proceedings

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We present an update on efforts at University of California Observatories to develop improved optical coatings for astronomical telescopes and instruments. The main thrust has been in the areas of protected silver mirror coatings and sol-gel based anti-reflection coatings. We report on the performance of silver coatings used for several years in Keck and Lick instruments, as well as that on the Lick 1-m telescope. We discuss process improvements, including use of reactive ion-assisted deposition of oxides. Sol-gel based AR coatings have been exposed to cryogenic environments to test their suitability for IR instruments, with encouraging results. Finally, we describe our plans for future work.

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“…Maximum correction is when the prisms are spaced furthest apart; at zero spacing the system becomes a simple plate with no dispersion. The linear ADC can be made with simple prisms (for example, in the Keck Cassegrain ADC 5 ), although in this case it displaces the optical axis of the system as the prisms separate, so zero-deviation compound prisms are usually chosen (as in, for example, the Gemini Planet Imager 6 ). This design introduces a small amount of spherical aberration and some "constant" coma.…”

Section: Choice Of Adc Designmentioning

confidence: 99%

The Infrared Imaging Spectrograph (IRIS) for TMT: the atmospheric dispersion corrector

et al. 2010

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We present a conceptual design for the atmospheric dispersion corrector (ADC) for TMT's Infrared Imaging Spectrograph (IRIS). The severe requirements of this ADC are reviewed, as are limitations to observing caused by uncorrectable atmospheric effects. The requirement of residual dispersion less than 1 milliarcsecond can be met with certain glass combinations. The design decisions are discussed and the performance of the design ADC is described. Alternative options and their performance tradeoffs are also presented.

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The Keck-I Cassegrain ADC

Cited by 5 publications

References 0 publications

Berkeley Supernova Ia Program - I. Observations, data reduction and spectroscopic sample of 582 low-redshift Type Ia supernovae

Berkeley Supernova Ia Program - I. Observations, data reduction and spectroscopic sample of 582 low-redshift Type Ia supernovae

Progress toward high-performance astronomical coatings

The Infrared Imaging Spectrograph (IRIS) for TMT: the atmospheric dispersion corrector

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