| 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.