Grazing Occultation of 810 S B7 Magnitude 1.6 [Red = 1.7] ZC 810 = El Nath = beta Tauri Date: 2025 Mar 07 4h 44m, to 2025 Mar 07 5h 21m Nominal site altitude 0m E. Longit. Latitude U.T. Sun Moon TanZ PA AA CA o ' " o ' " h m s Alt Alt Az o o o Location with elevation (h) in feet given -121 0 0 35 6 15.4 4 44 11 61 267 0.55 2.8 5.84 5.42N -120 45 0 35 2 13.5 4 44 38 61 267 0.56 2.8 5.91 5.50N -120 30 0 34 58 8.4 4 45 4 61 267 0.56 2.9 5.99 5.58N -120 15 0 34 53 59.9 4 45 31 60 268 0.57 3.0 6.07 5.66N ***Santa Maria, CA h=240ft *** R. Nolthenius -120 0 0 34 49 48.1 4 45 57 60 268 0.58 3.1 6.15 5.74N -119 45 0 34 45 33.1 4 46 23 60 268 0.58 3.2 6.22 5.81N -119 30 0 34 41 14.7 4 46 50 59 269 0.59 3.2 6.30 5.89N -119 15 0 34 36 53.1 4 47 16 59 269 0.60 3.3 6.38 5.97N -119 0 0 34 32 28.1 4 47 42 59 269 0.61 3.4 6.45 6.04N -118 45 0 34 27 59.9 4 48 8 59 270 0.61 3.5 6.53 6.12N -118 30 0 34 23 28.5 4 48 34 58 270 0.62 3.5 6.60 6.19N ***Santa Clarita, CA h=1200ft best from L.A. -118 15 0 34 18 53.7 4 49 0 58 270 0.63 3.6 6.68 6.27N -118 0 0 34 14 15.7 4 49 26 58 271 0.63 3.7 6.75 6.34N -117 45 0 34 9 34.5 4 49 52 57 271 0.64 3.8 6.82 6.41N -117 30 0 34 4 50.0 4 50 18 57 271 0.65 3.8 6.90 6.49N ### n. Riverside, CA h=1100ft -117 15 0 34 0 2.3 4 50 44 57 272 0.66 3.9 6.97 6.56N -117 0 0 33 55 11.4 4 51 10 56 272 0.66 4.0 7.04 6.63N -116 45 0 33 50 17.3 4 51 36 56 272 0.67 4.0 7.11 6.70N -116 30 0 33 45 19.9 4 52 2 56 273 0.68 4.1 7.18 6.77N s. Palm Springs, CA h=750ft -116 15 0 33 40 19.4 4 52 27 56 273 0.69 4.2 7.25 6.84N ***Palm Desert, CA h=+350ft [ALREADY DONE] -116 0 0 33 35 15.7 4 52 53 55 273 0.69 4.2 7.32 6.91N Thermal, CA h=-150ft -115 45 0 33 30 8.8 4 53 18 55 274 0.70 4.3 7.39 6.98N -115 30 0 33 24 58.7 4 53 44 55 274 0.71 4.4 7.46 7.05N -115 15 0 33 19 45.5 4 54 9 54 274 0.72 4.5 7.53 7.12N -115 0 0 33 14 29.1 4 54 35 54 274 0.73 4.5 7.60 7.19N -114 45 0 33 9 9.6 4 55 0 54 275 0.73 4.6 7.66 7.26N -114 30 0 33 3 47.0 4 55 25 53 275 0.74 4.7 7.73 7.32N -114 15 0 32 58 21.2 4 55 50 53 275 0.75 4.7 7.80 7.39N Hwy US95 n. of Yuma, AZ h=750ft -114 0 0 32 52 52.4 4 56 16 53 275 0.76 4.8 7.86 7.45N -113 45 0 32 47 20.4 4 56 41 52 276 0.77 4.9 7.93 7.52N ## Growler Norton, AZ, near I-8 h=300ft -113 30 0 32 41 45.4 4 57 6 52 276 0.78 4.9 7.99 7.58N -113 15 0 32 36 7.3 4 57 31 52 276 0.78 5.0 8.06 7.65N -113 0 0 32 30 26.2 4 57 56 52 277 0.79 5.0 8.12 7.71N ***Hwy AZ85 n. of Ajo, h=1450 ft *** best from Phoenix -112 45 0 32 24 42.0 4 58 20 51 277 0.80 5.1 8.18 7.77N -112 30 0 32 18 54.8 4 58 45 51 277 0.81 5.2 8.25 7.84N -112 15 0 32 13 4.6 4 59 10 51 277 0.82 5.2 8.31 7.90N ## Maish Vaya, AZ, h=2500ft -112 0 0 32 7 11.4 4 59 34 50 278 0.83 5.3 8.37 7.96N -111 45 0 32 1 15.2 4 59 59 50 278 0.84 5.4 8.43 8.02N ## Hwy AZ86 w. of Tucson, h=3150ft -111 30 0 31 55 16.1 5 0 23 50 278 0.85 5.4 8.49 8.08N ### s. of Kitt Peak, AZ, h=6600ft -111 15 0 31 49 14.0 5 0 48 49 278 0.86 5.5 8.55 8.14N -111 0 0 31 43 9.0 5 1 12 49 279 0.87 5.5 8.61 8.20N ## ***I-19, Arivaca Jctn, AZ, h=3050ft - s. of Tucson -110 45 0 31 37 1.0 5 1 36 49 279 0.88 5.6 8.67 8.26N ### Hwy AZ82 n. of Patagonia, h=4300ft ### -110 30 0 31 30 50.2 5 2 0 48 279 0.89 5.6 8.72 8.32N -110 15 0 31 24 36.4 5 2 24 48 279 0.90 5.7 8.78 8.37N ***Hwy AZ92, s. of Sierra Vista ***V. Sempronio*** -110 0 0 31 18 19.8 5 2 48 48 280 0.91 5.8 8.84 8.43N crosses Mexican border; -109 45 0 31 12 0.4 5 3 12 48 280 0.92 5.8 8.89 8.49N no USA land crossed east of here -109 30 0 31 5 38.1 5 3 36 47 280 0.93 5.9 8.95 8.54N -109 15 0 30 59 13.1 5 4 0 47 280 0.94 5.9 9.00 8.60N -109 0 0 30 52 45.2 5 4 23 47 281 0.95 6.0 9.06 8.65N -108 45 0 30 46 14.6 5 4 47 46 281 0.96 6.0 9.11 8.70N -108 30 0 30 39 41.2 5 5 10 46 281 0.97 6.1 9.16 8.76N -108 15 0 30 33 5.0 5 5 33 46 281 0.98 6.1 9.22 8.81N -108 0 0 30 26 26.2 5 5 57 45 281 0.99 6.2 9.27 8.86N -107 45 0 30 19 44.7 5 6 20 45 282 1.00 6.2 9.32 8.91N -107 30 0 30 13 0.5 5 6 43 45 282 1.01 6.3 9.37 8.96N -107 15 0 30 6 13.7 5 7 6 44 282 1.02 6.3 9.42 9.01N -107 0 0 29 59 24.2 5 7 28 44 282 1.03 6.4 9.47 9.06N -106 45 0 29 52 32.2 5 7 51 44 283 1.04 6.4 9.52 9.11N -106 30 0 29 45 37.5 5 8 14 43 283 1.06 6.5 9.57 9.16N -106 15 0 29 38 40.3 5 8 36 43 283 1.07 6.5 9.61 9.21N -106 0 0 29 31 40.6 5 8 59 43 283 1.08 6.6 9.66 9.25N -105 45 0 29 24 38.4 5 9 21 42 283 1.09 6.6 9.71 9.30N -105 30 0 29 17 33.7 5 9 43 42 284 1.10 6.7 9.75 9.35N -105 15 0 29 10 26.5 5 10 5 42 284 1.12 6.7 9.80 9.39N -105 0 0 29 3 17.0 5 10 27 42 284 1.13 6.8 9.84 9.44N -104 45 0 28 56 5.0 5 10 49 41 284 1.14 6.8 9.89 9.48N -104 30 0 28 48 50.6 5 11 11 41 284 1.15 6.8 9.93 9.52N -104 15 0 28 41 33.8 5 11 32 41 285 1.17 6.9 9.97 9.57N -104 0 0 28 34 14.8 5 11 54 40 285 1.18 6.9 10.01 9.61N -103 45 0 28 26 53.4 5 12 15 40 285 1.19 7.0 10.06 9.65N -103 30 0 28 19 29.7 5 12 37 40 285 1.21 7.0 10.10 9.69N -103 15 0 28 12 3.9 5 12 58 39 285 1.22 7.1 10.14 9.73N -103 0 0 28 4 35.7 5 13 19 39 286 1.24 7.1 10.18 9.77N -102 45 0 27 57 5.4 5 13 40 39 286 1.25 7.1 10.22 9.81N -102 30 0 27 49 33.0 5 14 0 38 286 1.26 7.2 10.25 9.85N -102 15 0 27 41 58.4 5 14 21 38 286 1.28 7.2 10.29 9.89N -102 0 0 27 34 21.7 5 14 41 38 286 1.29 7.2 10.33 9.92N -101 45 0 27 26 42.9 5 15 2 37 287 1.31 7.3 10.37 9.96N -101 30 0 27 19 2.1 5 15 22 37 287 1.32 7.3 10.40 10.00N -101 15 0 27 11 19.2 5 15 42 37 287 1.34 7.4 10.44 10.03N -101 0 0 27 3 34.4 5 16 2 36 287 1.36 7.4 10.47 10.07N -100 45 0 26 55 47.6 5 16 22 36 287 1.37 7.4 10.51 10.10N -100 30 0 26 47 58.9 5 16 42 36 287 1.39 7.5 10.54 10.13N -100 15 0 26 40 8.3 5 17 1 35 288 1.41 7.5 10.57 10.17N -100 0 0 26 32 15.8 5 17 20 35 288 1.42 7.5 10.60 10.20N - 99 45 0 26 24 21.5 5 17 40 35 288 1.44 7.6 10.64 10.23N - 99 30 0 26 16 25.4 5 17 59 34 288 1.46 7.6 10.67 10.26N - 99 15 0 26 8 27.5 5 18 18 34 288 1.47 7.6 10.70 10.29N - 99 0 0 26 0 27.9 5 18 37 34 288 1.49 7.6 10.73 10.32N - 98 45 0 25 52 26.5 5 18 55 34 289 1.51 7.7 10.76 10.35N - 98 30 0 25 44 23.5 5 19 14 33 289 1.53 7.7 10.79 10.38N - 98 15 0 25 36 18.8 5 19 32 33 289 1.55 7.7 10.81 10.41N - 98 0 0 25 28 12.6 5 19 50 33 289 1.57 7.8 10.84 10.44N - 97 45 0 25 20 4.7 5 20 9 32 289 1.59 7.8 10.87 10.46N - 97 30 0 25 11 55.3 5 20 26 32 289 1.61 7.8 10.89 10.49N - 97 15 0 25 3 44.3 5 20 44 32 290 1.63 7.8 10.92 10.51N - 97 0 0 24 55 31.9 5 21 2 31 290 1.65 7.9 10.95 10.54N Path coordinates are referred to WGS84 (as used by GPS), with the nominal site altitude being referenced to Mean Sea Level. The path is adjusted for the effects of refraction at low moon altitudes. Projected diameter of star 2 meters [CHARM2/CADARS, 7 measures] El Nath has been suspected of being a close double from gradual phenomena seen visually at past occultations, but this has not been confirmed and the observed effects were' likely due to Fresnel diffraction rather than duplicity. El Nath has been measured relative to several very faint nearby stars for 19th-century attempts to measure proper motion, but these stars are all too faint to be seen near the Moon. Librations Long +5.04 Lat -6.65 P +8.49 D +7.62 Illumination of moon 55%+ Elongation of Moon 96 Vertical Profile Scale approx. 1.88 km/arcsec at mean distance of moon Horizontal Scale Factor 1.55 deg/min At longitude -109.00: Limiting Magnitudes for various telescope apertures (in cm) CA\Tdia 5 10 15 20 25 30 35 4.6 5.7 7.2 8.0 8.5 8.9 9.2 9.4 6.6 5.8 7.2 8.0 8.5 8.9 9.2 9.4 8.6 5.8 7.2 8.0 8.6 8.9 9.2 9.4 10.6 5.8 7.2 8.0 8.6 8.9 9.2 9.4 12.6 5.8 7.3 8.1 8.6 9.0 9.2 9.4 ------------------------------------------------------------------------------ Results of Observer Scan UT Site Long. Lat. Dist. h m s Alamogordo NM -106.0 32.9 329km 5 9 3.2 Amado AZ -111.1 31.7 3km 5 1 2.7 Bakersfield CA -119.0 35.4 86km 4 47 39.8 Berkeley CA -122.3 37.9 258km 4 41 56.0 Brownsville TX -97.5 25.9 67km 5 20 26.4 Chihuahua MX -106.1 28.6 91km 5 8 51.3 CiudadJuarez MX -106.5 31.7 189km 5 8 15.3 Crps Christi TX -97.4 27.8 251km 5 20 33.8 El Paso TX -106.5 31.8 195km 5 8 15.0 Flagstaff AZ -111.7 35.2 319km 5 0 8.4 Fresno CA -119.8 36.7 205km 4 46 19.5 Hermosillo MX -111.0 29.3 247km 5 1 13.5 Kingsville TX -97.8 27.5 202km 5 20 2.5 Laredo TX -99.5 27.5 117km 5 17 58.2 Las Cruces NM -106.7 32.3 241km 5 7 53.0 Las Vegas NV -115.1 36.2 292km 4 54 20.1 Livermore CA -121.7 37.7 250km 4 42 52.1 Long Beach CA -118.2 33.8 55km 4 49 6.8 Los Angeles CA -118.2 34.1 27km 4 49 1.3 Monterey MX -100.3 25.7 99km 5 16 55.9 Oakland CA -122.3 37.8 250km 4 41 56.7 Pasadena CA -118.1 34.1 14km 4 49 11.3 Phoenix AZ -112.1 33.5 131km 4 59 26.9 Quartzsite AZ -114.3 33.7 69km 4 55 50.3 Sacramento CA -121.5 38.6 352km 4 43 18.7 San Antonio TX -98.5 29.4 348km 5 19 14.9 San Bernrdno CA -117.3 34.1 10km 4 50 39.9 San Diego CA -117.2 32.7 130km 4 50 53.9 San Jose CA -121.9 37.3 211km 4 42 36.7 SanFrancisco CA -122.4 37.8 244km 4 41 41.0 Santa Cruz CA -122.0 37.0 169km 4 42 22.7 SantaBarbara CA -119.7 34.4 34km 4 46 28.8 Simi Valley Calif -118.8 34.3 21km 4 48 3.3 Stockton CA -121.3 38.0 292km 4 43 40.7 Tucson AZ -111.0 32.2 51km 5 1 14.9 Victoria TX -97.0 28.8 365km 5 21 2.9 Yuma AZ -114.6 32.7 40km 4 55 12.8