Graduate Student Savanah Turner Publishes Study of over 300 L and T dwarfs

BYU Astronomy Research Group Joins the Astrophysical Research Consortium (ARC)

As of January 2021 BYU will be a member of the ARC Consortium (Link to Consortium) with access to the ARC 3.5-m telescope and the 0.5-m ARCSAT telescope.  The primary use of the ARC 3.5-m telescope time is for graduate student projects.  This provides a wide array of instrumentation that is currently being used to study objects in the solar system all the way to studies of the large scale structure of the Universe.

Other BYU Astronomy Facilities

In addition to our telescope time from the ARC consortium, we operate a number of our own astronomical facilities

West Mountain Observatory (West Mountain)

This is our mountain observatory at about 6600 ft above sea level.  This consists of three telescopes: 0.9-m, 0.5-m, and a 0.32-m. It is a 40 minute drive that ends in a 5 miles drive up a dirt road. The mountain itself can be seen from campus. We don't provide any tours of this facility.

Orson Pratt Observatory

The Orson Pratt Observatory is named for an early apostle of the Church of Jesus Christ of Latter-Day Saints.  It is our campus telescope facility and contains a wide variety of telescopes for student research and public outreach. We operate a 24" PlaneWave telescope in the main campus dome, plus a 16", two 12", one 8", and a 6" telescope on our observation deck.  The telescopes are all fully robotic. Beyond this we have a large sections of telescopes used on public nights.

Royden G. Derrick Planetarium (Planetarium)

This is a 119 seat, 39" dome planetarium with acoustically treated walls to allow it's use as a lecture room. Recently we upgraded to an E&S Digistar7 operating system with 4K projectors.  The planetarium is used for teaching classes, public outreach, and astronomy education research projects.





Selected Publications

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The consistency of stromgren-beta photometry for northern galactic clusters. IV. Praesepe revisited and the pleiades
New Stromgren-beta Pleiades data on a zero point defined by the Hyades and Coma are presented. The new data and counterparts from four extant sources are compared to measurements published by Crawford & Perry in 1976. The only statistically significant problem found in this way is a 4 mmag offset obtained b - y from a data set published by McNamara in 1976. Results of similar comparisons published previously for Praesepe are updated by including three additional sets of published data. In this case, comparisons are made to measurements published by Crawford & Barnes in 1969. Two of the data sets (including one published by Joner & Taylor in 1995) yield accordant, statistically significant formal corrections to the b - y m(1) measurements of Crawford & Barnes. In addition, results from a third data set are consistent with those derived from the data of Joner & Taylor. However, this pattern is either partly or entirely absent from the offsets yielded by the other three data sets. Because the measurements of Joner & Taylor are still the only ones known to have been derived from direct comparisons among the Hyades, Coma, and Praesepe, it is concluded that the balance of evidence presently favors the offsets obtained from those data. In addition, it is noted that the data of Joner & Taylor do not imply that the data of Crawford & Barnes require corrections that depend on color. With these interim conclusions drawn, it is then suggested that further Praesepe measurements should be brought to bear on the problem.
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Deriving color-color transformations for VRI photometry
In this paper, transformations between Cousins R - I and other indices are considered. New transformations to Cousins V - R and Johnson V - K are derived, a published transformation involving T-1-T-2 on the Washington system is rederived, and the basis for a transformation involving b-y is considered. In addition, a statistically rigorous procedure for deriving such transformations is presented and discussed in detail. Highlights of the discussion include ( 1) the need for statistical analysis when least-squares relations are determined and interpreted, ( 2) the permitted forms and best forms for such relations, ( 3) the essential role played by accidental errors, ( 4) the decision process for selecting terms to appear in the relations, ( 5) the use of plots of residuals, ( 6) detection of influential data, ( 7) a protocol for assessing systematic effects from absorption features and other sources, ( 8) the reasons for avoiding extrapolation of the relations, ( 9) a protocol for ensuring uniformity in data used to determine the relations, and ( 10) the derivation and testing of the accidental errors of those data. To put the last of these subjects in perspective, it is shown that rms errors for VRI photometry have been as small as 6 mmag for more than three decades and that standard errors for quantities derived from such photometry can be as small as 1 mmag or less.
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Homogeneous photometry for the Hyades: Scale-factor and zero-point tests of previously published BV(RI)(C) photometry
Michael D. Joner, Benjamin J. Taylor, and C. David Laney (et al.)
New BV(RI)(C) observations of 77 stars in the Hyades are reported and discussed. The new observations are used to test published magnitudes and color indices for that cluster. For values of (V-R)(C) and (R-I)(C) published previously by Taylor & Joner, the tests reveal no detectable scale-factor problems. In addition, the tests show that possible zero-point corrections to the published data can be no larger than a few millimagnitudes. These test results indicate that future studies requiring precision photometry for Hyades stars would be well served by selecting data samples from sources as close as possible to the native Cousins system. Tests of B-V photometry published by Johnson & Knuckles reveal a zero-point ambiguity of approximately 8 mmag in the new data that will require further measurements to resolve.
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Physical Science Foundations, 2nd Edition
J. Ward Moody, M. Jeanette Lawler, Juliana Boerio-Goates, R. Steven Turley, David V. Dearden, Bart J. Kowallis, and Michael D. Joner
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A catalog of temperatures and red Cousins photometry for the Hyades
Using Hyades photometry published by Mendoza and other authors, Pinsonneault et al. have recently concluded that Cousins V - I photometry published by Taylor & Joner is not on the Cousins system. Extensive tests of the Taylor- Joner photometry and other pertinent results are therefore performed in this paper. It is found that in part, the Pinsonneault et al. conclusion rests on ( 1) a systematic error in Mendoza's ( R - I)(J) photometry and ( 2) a small error in an approximate Johnson- to- Cousins transformation published by Bessell. For the Taylor- Joner values of ( V - R)(C), it is found that there are possible ( though not definite) differences of several mmag with other results. However, the Taylor- Joner values of ( R - I)(C) data are supported at the 1 mmag level. Using the ( R - I)(C) data and other published results, an ( R - I)(C) catalog is assembled for 146 Hyades stars with spectral types earlier than about K5. For single stars with multiple contributing data, the rms errors of the catalog entries are less than 4.4 mmag. Temperatures on the Di Benedetto angular- diameter scale are also given in the catalog and are used to help update published analyses of high- dispersion values of [ Fe/ H] for the Hyades. The best current mean Hyades value of [ Fe/ H] is found to be + 0.103 +/- 0.008 dex and is essentially unchanged from its previous value. In addition to these numerical results, recommendations are made about improving attitudes and practices that are pertinent to issues like those raised by Pinsonneault et al.
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Physical Science Foundations, 1st Edition
J. Ward Moody, M. Jeannette Lawler, Juliana Boerio-Goates, R. Steven Turley, David V. Dearden, Bart J. Kowallis, and Michael D. Joner