C2023 A3 - October 15, 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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Analyses of archival [Fe/H] results for cool evolved stairs. II. [Fe/H] standard stars
This paper is the second in a series based on published values of [Fe/H] for late-type evolved stars. Only high-dispersion results are considered here. Such data are used to derive mean values of [Fe/H] for stars that have often been used as [Fe/H] standard stars. For epsilon Vir and beta Gem, the mean values of [Fe/H] obtained here are +0.04 +/- 0.04 dex and 0.00 +/- 0.03 dex, respectively. For alpha Boo, [Fe/H] is found to be -0.55 +/- 0.02 dex. For the Hyades, a mean value of [Fe/H] obtained for giants can be combined with a counterpart published previously for dwarfs. The result is +0.10 +/-. 0.01 dex. Using available evidence, 0.049 dex is the smallest [Fe/H] difference that can be detected between Hyades giants and Hyades dwarfs. No such difference is found.
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Multicolor, two-dimensional photometric study of galaxies in rich Abell clusters .1. Observations and reductions
We have embarked on a long term project to obtain high precision photometry on individual galaxies in 45 rich clusters of galaxies. Data from the first set of six clusters have yielded BVRI photometric information on 961 galaxies and 384 stars. These objects come from the central one Mpc of Abell 576, 957, 1185, 1377, 2063, and 2657, each of which is of richness class R greater than or equal to 1. Each object was examined with two radial surface brightness fitting functions, and an asymptotic magnitude was determined. One fitting function produced a shape parameter beta which, when taken in. combination with the color index (B-I), shows a breakdown of the three basic morphological types (E, S0, and S) into four beta types and a set of peculiar galaxies. Our results match previous studies well, and also provide some new insights into the clusters. In addition, we have examined the effects of plate scale on the determination of these photometric parameters. All parameters were found to repeat across plate scale differences. We also examined the effects of co-adding frames in an attempt to understand the degradation or improvement of the photometric parameters with increasing signal-to-noise. (C) 1997 American Astronomical Society.
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The consistency of Stromgren-beta photometry for northern galactic clusters .3. M67

We have measured M67 stars in a Stromgren-beta system based ultimately on data for the Hyades and Coma clusters. By comparing our results to previously published data, we have derived formal corrections required to put the other data on our system. Corrections which are Statistically significant by our criteria are found for Stromgren measurements made by Strom et al. (1971, PASP, 83, 768). Those corrections range between 36 and 61 mmag. In addition, corrections of 17 and 8 mmag, respectively,are found for beta measurements made by Eggen (1981, ApJ, 247, 503) and Nissen et al. (1987, AJ, 93, 634). In addition to considering M67, we have updated earlier work of ours which was done on Praesepe and NGC 752. After revising our criterion for statistical significance, we have changed our judgment about two corrections which we had derived for published data for those clusters. Further work will be required to verify the reality of those corrections. We have also compared our results to closely similar work which was done by Nissen (1988, A&A, 199, 146) and which had previously escaped our notice. Differences between our results and those of Nissen appear Is exist for beta in Praesepe and for c(1) in NGC 752. Independent measurements support our Praesepe result. but the problem for NGC 752 remains unresolved.

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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.