Vol. 10 No. 1 January 1, 2014 Journal of Double Star Observations Page 12 Double Stars at the U.S. Naval Observatory Alan L. Behall1 U.S. Naval Observatory 3450 Massachusetts Avenue, NW, Washington, DC, 20392-5420 Abstract: Micrometer measures of double stars made with the 24-inch reflector and the 26- inch refractor of the U.S. Naval Observatory from 1973 to 1990 are presented. Introduction Alan Behall (1940-2009) worked at the US Naval Observatory from 1963-1975 in the Astronomy & As- trophysics Department in work primarily involving double stars. From 1968 to 1970, he made measures of 159 pairs with the 12 inch Clark refractor on the roof of Building 1 and obtained 68 mean positions with a medi- an separation of 1.39 a.s. After his “training” period with the 12 inch, Alan began work with the 26 inch Clark refractor. From 1970 to 1974 he made measures of 1295 pairs with the 26 inch and obtained 370 mean positions with a median separation of 1.20 a.s. In 1974 he also made measures of 60 pairs with the 24 inch Boller & Chivens reflector, resulting in 24 mean posi- tions with a median separation of 1.01 a.s. All of these measures are found in the second series of USNO Pub- lications (Behall 1977). However, his in-depth analysis of orbit pairs is probably of greater significance. In 1963 he determined a very accurate orbit for 13 Ceti (Behall 1963), and re- turned to it a decade later (Gatewood & Behall 1975) with George Gatewood to investigate the residuals in parallax measures due to the unseen spectroscopic com- panion in this overluminous star. He later collaborated with Charles Worley (Worley & Behall 1973), deter- mining the orbit of the faint red double L726-8 ob- served with the 61 inch parallax program. He continued his work on this pair, collaborating with Bob Harring- ton (Harrington & Behall 1973) determining their mass Figure 1. Alan Behall, USNO staff photo (August 1968). ratio. Also with Harrington (Harrington & Behall 1976), he investigated the Keplerian perturbation of the 1Deceased: 11 June 2009 Vol. 10 No. 1 January 1, 2014 Journal of Double Star Observations Page 13 Double Stars at the U.S. Naval Observatory Table 1. Statistics of Samples Name Dataset Years Behall 1977 462 4.1 125 157 faint red dwarf pairs, G96-45 and G146-72, determin- ing orbits that are still the standard. This was done in conjunction with his work on the parallax program (Harrington et al. 1976). After Alan retired, he had subsequent careers as a computer programmer for two other branches of the Federal Government, the Office of Personnel Manage- ment and the Veteran Administration. But even after Alan left the USNO, he maintained an interest in dou- ble star research and returned periodically from 1984 to 1990 to observe and make micrometer measures. His observing program on the 26 inch only ended when the USNO mothballed it’s visual micrometry program in favor of speckle interferometry. Results After the cutoff date of his earlier publication (Behall 1977), additional measures were made before he left the USNO: 36 mean positions with a median separation of 1.13 a.s. with the 24 inch and 231 mean positions with a median separation of 0.82 a.s. with the 26 inch. The final set of “post-retirement” measures were delayed for some time. Of the 44 nights he observed Figure 2: Alan Behall, USNO luncheon from 1984 to 1990, Alan retained observing reports (September 2002). for only 12 of them. The reports for the remaining nights were apparently mishandled and the publication of these data have been delayed in a vain search umn nine is reserved for notes which are listed at the through the USNO archives and double star papers of end of the table. Charles Worley, who was in charge of the visual dou- Compilation of the measurements and brief de- ble star program. scription prepared by Brian Mason. All of the mean positions in the “pre” and “post” retirement are presented in Table 2. In this table, the References first two columns identify the system by providing its Behall, A.L. 1963, AJ 68, 432 Behall, A.L. 1977, Pub. epoch-2000 coordinates and discovery designation. USNO 24, Pt.2 Behall, A.L. & Harrington, R.S. Columns three through seven give the parameters of 1976, PASP 88, 204 the mean position, the epoch of observation (expressed as a fractional Besselian year), the position Gatewood, G.D. & Behall, A.L. 1975, AJ 80, 1065 angle (in degrees), the separation (in seconds of arc), Harrington, R.S. & Behall, A.L. 1973, AJ 78, 1096 the magnitude difference (in visual, when determined), and the number of individual measurements in the Harrington, R.S., Dahn, C.C., Behall, A.L., Priser, mean. Column eight gives the telescope aperture in J.B., Christy, J.W., Riepe, B.Y., Ables, H.D., inches indicating either the 24 inch Boller & Chivens Guetter, H.H., et al. 1975, Pub. USNO 24, Pt.1 reflector or the 26 inch Clark refractor. Finally, col- Worley, C.E. & Behall, A.L. 1973, AJ 78, 1973 Vol. 10 No. 1 January 1, 2014 Journal of Double Star Observations Page 14 Double Stars at the U.S. Naval Observatory Table 2. Measurements of Double Stars WDS Desig. Tel. Aper. (inches) BU 281 AB BU 281 AB BU 281 AB 1.57 MLB 429 AB 1929 AC 3056 AB 3056 AB 1250 AB 251.7 114.3 BU 1026 AB BU BU BU J 217 1.67 J 217 151.8 181.7 19 25 AB 191.5 25 AB 1.33 25 AB BU D 2 AB BU 1.4 1.56 14 01137+0735 BU 1029 BC 1.35 Vol. 10 No. 1 January 1, 2014 Journal of Double Star Observations Page 15 Double Stars at the U.S. Naval Observatory Table 2 (Continued). Measurements of Double Stars WDS Desig. Tel. Aper. (inches) 9.1 251.7 1.37 BU 1.67 BU BU BU 202 AB 208 AB 1.78 112.2 1.95 181.6 119.2 BU 533 AB 1.73 BU 1.18 BU 536 AB BU 1.47 Vol. 10 No. 1 January 1, 2014 Journal of Double Star Observations Page 16 Double Stars at the U.S. Naval Observatory Table 2 (Continued). Measurements of Double Stars WDS Desig. Tel. Aper. (inches) 04139+0916 BU 547 AB 75.113 BU 75.113 531 318.1 1.10 75.113 1.72 75.113 75.151 BU 552 AB 75.159 BU 75.151 BU 75.151 1.3 75.151 75.151 181.4 1.6 670 AB 75.151 2 A,BC 75.151 161.5 847 BC 75.151 75.151 75.151 75.151 729 AB 75.151 1.97 1.2 749 AB 210.1 54 AB BU 75.159 75.159 152 75.159 1.8 156 157 75.159 75.159 173.3 1.47 BU 327 AB 74.717 BU 75.151 75.151 07067−1118 BU 328 AB 75.151 112.3 75.151 Vol. 10 No. 1 January 1, 2014 Journal of Double Star Observations Page 17 Double Stars at the U.S. Naval Observatory Table 2 (Continued). Measurements of Double Stars WDS Desig. Tel. Aper. (inches) 07176+0918 STT 170 07241+2127 75.151 07274+1519 07279−1133 BU 332 AB 112.9 1.76 2534 AB,C 74.157 74.157 BU J 76.1 1.97 KUI BU BU 591 09415+1753 1.10 10131+2725 1.6 10151+1907 10163+1744 215 186.1 10163+1744 215 75.159 184.1 75.159 1424 AB 75.159 124.1 1426 AB 1426 BC 13.5 10227+1521 75.159 Vol. 10 No. 1 January 1, 2014 Journal of Double Star Observations Page 18 Double Stars at the U.S. Naval Observatory Table 2 (Continued). Measurements of Double Stars WDS Desig. Tel. Aper. (inches) 10260+0256 A 74.691 J 1457 75.159 10417+1044 75.159 10417+1044 11.8 75.159 11.0 75.151 1.8 116.0 75.151 75.151 11182+3132 117.8 11182+3132 75.151 1527 75.151 1.65 1527 45.1 2776 AB 75.159 11239+1032 1.25 BU 11363+2747 75.151 11428+2105 75.159 11428+2105 11563+3527 1.87 12159−0759 141.9 1639 AB 75.159 1.55 12291+3123 251 1.47 12351+0727 1658 AB 12360+1124 1661 12372+2112 12372+2112 75.159 75.159 1.37 12417−0127 1670 AB 75.159 118.2 BU Vol. 10 No. 1 January 1, 2014 Journal of Double Star Observations Page 19 Double Stars at the U.S. Naval Observatory Table 2 (Continued). Measurements of Double Stars WDS Desig. Tel. Aper. (inches) 13091+2127 HU 572 75.452 13100+1732 2585 AB U 13347−1313 BU 932 AB 13347−1313 BU 932 AB 13375+3618 101.9 1.87 13375+3618 1816 1816 1819 Aa,Ab 255.1 1819 Aa,Ab 14158+1018 1823 AB,C 147.7 101.5 6.15 BU 14411+1344 1865 AB 1.01 1.47 14534+1542 1.76 15126+1523 15232+3017 16044−1122 1998 AB 16044−1122 1998 BC 7.19 16057−0617 BU 948 AB 113.6 16071+1654 BU 1.9 16235+3321 26 AB 16235+3321 BU 31.3 2054 AB 351.1 Vol. 10 No. 1 January 1, 2014 Journal of Double Star Observations Page 20 Double Stars at the U.S.