Lowell Telescope Specification chart

Perkins 72" Hall 42" LONEOS 31" 21"
Longitude 111° 32' 09.3" 111° 32' 07.9" 111° 32.2' 111° 32' 09.0" 111° 39' 59.2"
Latitude +35° 05' 48.6" +35° 05' 48.3" +35° 05.8' +35° 05' 54.6" +35° 12' 10.4"
Altitude 7236ft. (2206m) 7236ft. (2206m) 7236ft. (2206m) 7243ft. (2208m) 7260ft. (2213m)
Dp 72" (1.8m) 41" (1.04m) * 31/29.5" (0.79/0.75m) 20.78 (0.53m)
F/# 17.5 8.06 * 15 15.9
EFI 1256.5" (31.93m) 330.39" (8.392m) * 464" (11.78m) 332.5" (8.44m)
Scale ("/mm) 6.45 24.58 * 17.5 24.3
BFI 51.5" (1.30m) 29.9" (0.759m) * 25" (0.63m) 20" (0.51m)
Fp/# 4.18 4.05 * 5.0 3.4
FLp 300.6" (7.635m) 166.06" (4.218m) * 155" (3.94m) 70.0" (1.77m)
Dsa 16.3" (0.41m) 16.6" (0.422m) * 9.0" (0.22m) 4.6" (0.12m)
Is 284.1" (7.22m) 130.43" (3.313m) * 134.9" (3.43m) 72.7" (1.85m)
Os 68.0" (1.72m) 65.51" (1.664m) * 45.1" (1.14m) 15.3" (0.39m)
Ms 232.6" (5.91m) 100.56" (2.554m) * 109.9" (2.79m) 54.7" (1.39m)
mag 4.2 1.990 * 3.0 4.7
K1 -1.0 -1.306 * -1.00 -1.00
K2 -3.65 -14.945 * -5.01 -3.35

1) Longitude and latitude are good to about 0.2.
2) The altitudes are good to about 1 meter.
4) The Hall F/8 is a Ritchey-Chretien telescope.
5) The 31inch primary if F/5. However, it is stopped down to 29.5 inches.
6) Only the Hall F/8 has a known optimum back focal distance.
7) The conic constant is defined such that 0 is a circle and -1 is a parabola.
8) Dsa is the diameter of the axial cone at the secondary. The diameter of the secondary is 1 to 2 inches larger than Dsa.