Utah Aurora - May 10/11 2024

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 colours of the Sun
B. J. Taylor (et al.)
In this paper, arguments are developed for treating (R-l)(C) as the most important colour to be derived for the Sun. The solar value of (R-I)(C) is then found to be 0.335 +/- 0.002 mag. This result updates a counterpart given by Taylor in 1992.
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The cousins VRI system: A consistency test of equatorial and southern standard stars
We present new VRI measurements of southern-hemisphere stars which are on the standard-star system of Landolt [AJ, 88, 439 (1983)]. Using our data and previously published data, we study the relationship between Landolt and ''SAAO'' standards in the Cousins VRI system. Our work expands on a study done by Menzies et al. [MNRAS, 248, 642 (1991)] and extends also to the standard stars of Graham [PASP, 94, 244 (1982)]. To within moderate errors, the Graham and SAAO systems turn out to be identical. A zero-point difference in V between the data of Landolt and Menzies er al. is found to be in the latter data set. For relatively blue stars in V-R, we confirm a deduction by Menzies et al. that there is a scale-factor difference between the Landolt and southern-hemisphere standards. Especially when recent work by Bessell [PASP, 107, 672 (1995)] is considered, the red-star V-R transformation of Landolt's data turns out to be uncertain. At a given Landolt color for red stars, the range of possibilities for transformed colors is about 30 mmag. For R-I, we find that if data used by Bessell for very red stars are excluded, all standard-star data we have tested adhere very closely to a single system. Our work adds to the list of photometric data sets for which rms errors per datum are known to be decisively less than 10 mmag, and we therefore suggest that ''millimagnitudes'' should become a generally accepted unit in photometry. We conclude our discussion by suggesting that the ''Landolt subsystem'' should be retained at present, and that it should be tested further before a definitive conversion is made to the SAAO system. (C) 1996 American Astronomical Society.
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Supermetallicity at the quarter-century mark: A conservative statistician's review of the evidence
Available high-dispersion data show that [Fe/H] similar to +0.25 +/- 0.04 dex for mu Lee, which has often been regarded as the prototypical super-metal-rich( SMR) star. Neither mu Leo nor any other giant is known to be SMR at present (by this paper's definition: [Fe/H] > 0.2 dex). This conclusion applies to both nearby giants and those in Baade's Window. Up to the level of feature-strength enhancement found in mu Lee, low-resolution data for candidate SMR giants are usually consistent with high-dispersion results. Beyond mu Lee's enhancement lever, high-dispersion analyses do not yield metallicities that are high enough to explain the low-resolution data readily. This problem does not rule out supermetallicity as an explanation for very strong lined stars, but it does interfere with an appeal to that explanation at present. Seven class IV-V stars seem to be firmly established as SMR stars. A number of stars besides these would likely repay further study. The stars (of all luminosity classes) that most require further work are HR 1779 AB, 18 Lib AB, 20 Cyg, HR 8924, and HR 1614. In a supporting analysis, it is found that the anomalous strong-feature weakening derived in a previous paper for Hyades dwarfs is also seen in Hyades giants.
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Analyses of Archival Data for Cool Dwarfs. VI. The 1993 Versions of the Temperature and [Fe/H] Catalogs

This paper contains supplements to two catalogs which have previously been published by the author. One of the supplements updates a catalog of temperatures for FGK dwarfs (see Taylor, PASP, 106, 452, 1994). The other supplement updates a catalog of averaged values of [Fe/H] for the same stars (see Taylor, PASP, 106, 704, 1994). The combined catalogs and supplements include values of [Fe/H] published through the end of 1993. Detailed instructions are given for catalog users, including an algorithm for adding data to the [Fe/H] catalog. For recent sources of [Fe/H] which require comment, discussions of issues such as data editing and zero-point corrections are given. A review is also given of a problem described by Gray (PASP, 106, 1248, 1994), who finds that his spectroscopic temperatures and photometric temperatures from Paper II scatter more around their mean relation than one would expect from the contributing rms errors. It is found that near-Sun reddening (which is Gray's preferred solution of the problem) is not a defensible explanation for this scatter. For the moment, the real source of the scatter remains unknown.

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The Consistency of Strömgren-Beta Photometry for Northern Galactic Clusters. II. Praesepe and NGC 752

We have measured stars in Praesepe and NGC 752 in an internally consistent Stromgren-beta system. This system is based in large part on published Hyades and Coma measurements. On comparing our Praesepe results to those of Crawford and Barnes (1969, AJ, 74, 818), we find that the published color indices require corrections of 10-18 mmag to put them on the Hyades-Coma syslem. This deduction applies for b - y, m(1), and beta (but not c(1)). For the NGC 752 data of Crawford and Barnes (1970, AJ, 75, 946), we obtain a nonzero correction only for beta. This correction is about 9 mmag. Also for NGC 752, we find that the data of Twarog (1983, ApJ, 267, 207) require corrections ranging from 4-17 mmag, with all Stromgren indices being affected and the largest correction being for m(1). These corrections resolve the long-standing problem posed by the differences between the Twarog and Crawford and Barnes data. For three published sources of V magnitudes, we obtain offsets ranging from -14 to +27 mmag relative to our zero point, and we suggest that such offsets are fairly common in published photometry for galactic clusters. For Praesepe, we use new and corrected data to test for a c(1) anomaly. Unlike Crawford and Barnes, we find that Praesepe does not have such an anomaly and is indistinguishable from Coma in that regard.

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A close look at the c(1) anomaly

In a recent paper, Eggen has suggested that the Hyades cl anomaly is an instrumental effect. Using results published by Taylor and Joner, we show that Eggen's conjecture is incorrect. Taylor and Joner report formal corrections of published Coma photometry to a system defined in part by Hyades measurements. If the Taylor-Joner corrections are not adopted, the existence of the Hyades anomaly (relative to Coma) can be established at >99.9% confidence. if the corrections are adopted, the anomaly exists at 99.6% confidence.