| ƒt | Dt | No | ||||||||||||
| 3155 | 305 | 10.3 | 12" Schmidt Cassegrain | |||||||||||
| TRUE FIELD OF VIEW (arcminutes) | ||||||||||||||
| APPARENT FIELD OF VIEW | ||||||||||||||
| ƒe | EP | Mt | 30 | 40 | 45 | 50 | 55 | 60 | 65 | 70 | 80 | |||
| Eyepiece Brand | Nominal AFOV | |||||||||||||
| 55 | 5.3 | 57 | 31.4 | 41.8 | 47.1 | 52.3 | 57.5 | 62.8 | 68.0 | 73.2 | 83.7 | Edmund Hastings | 30 | |
| 50 | 4.8 | 63 | 28.5 | 38.0 | 42.8 | 47.5 | 52.3 | 57.1 | 61.8 | 66.6 | 76.1 | |||
| 45 | 4.4 | 70 | 25.7 | 34.2 | 38.5 | 42.8 | 47.1 | 51.3 | 55.6 | 59.9 | 68.5 | UO Ortho | 41 | |
| 40 | 3.9 | 79 | 22.8 | 30.4 | 34.2 | 38.0 | 41.8 | 45.6 | 49.4 | 53.2 | 60.9 | UO Ortho HD | 42 | |
| 36 | 3.5 | 88 | 20.5 | 27.4 | 30.8 | 34.2 | 37.7 | 41.1 | 44.5 | 47.9 | 54.8 | |||
| 32 | 3.1 | 99 | 18.3 | 24.3 | 27.4 | 30.4 | 33.5 | 36.5 | 39.6 | 42.6 | 48.7 | Celestron | 43 | |
| 31 | 3.0 | 102 | 17.7 | 23.6 | 26.5 | 29.5 | 32.4 | 35.4 | 38.3 | 41.3 | 47.2 | Russell Military Erfle | 43 | |
| 30 | 2.9 | 105 | 17.1 | 22.8 | 25.7 | 28.5 | 31.4 | 34.2 | 37.1 | 39.9 | 45.6 | VS Brandon | 44 | |
| 28 | 2.7 | 113 | 16.0 | 21.3 | 24.0 | 26.6 | 29.3 | 31.9 | 34.6 | 37.3 | 42.6 | Pentax XO | 45 | |
| 26 | 2.5 | 121 | 14.8 | 19.8 | 22.3 | 24.7 | 27.2 | 29.7 | 32.1 | 34.6 | 39.6 | |||
| 25 | 2.4 | 126 | 14.3 | 19.0 | 21.4 | 23.8 | 26.1 | 28.5 | 30.9 | 33.3 | 38.0 | Edmund RKE | 48 | |
| 24 | 2.3 | 131 | 13.7 | 18.3 | 20.5 | 22.8 | 25.1 | 27.4 | 29.7 | 31.9 | 36.5 | Russell RKE | 48 | |
| 23 | 2.2 | 137 | 13.1 | 17.5 | 19.7 | 21.9 | 24.1 | 26.2 | 28.4 | 30.6 | 35.0 | Tele Vue Plossl | 49 | |
| 22 | 2.1 | 143 | 12.6 | 16.7 | 18.8 | 20.9 | 23.0 | 25.1 | 27.2 | 29.3 | 33.5 | Takahashi LE | 50 | |
| 21 | 2.0 | 150 | 12.0 | 16.0 | 18.0 | 20.0 | 22.0 | 24.0 | 26.0 | 28.0 | 31.9 | Vixen NLV | 51 | |
| 20 | 1.9 | 158 | 11.4 | 15.2 | 17.1 | 19.0 | 20.9 | 22.8 | 24.7 | 26.6 | 30.4 | Russell Superwide XL | 52 | |
| 19 | 1.8 | 166 | 10.8 | 14.5 | 16.3 | 18.1 | 19.9 | 21.7 | 23.5 | 25.3 | 28.9 | |||
| 18 | 1.7 | 175 | 10.3 | 13.7 | 15.4 | 17.1 | 18.8 | 20.5 | 22.3 | 24.0 | 27.4 | UO Planetary | 54 | |
| 17 | 1.6 | 186 | 9.7 | 12.9 | 14.5 | 16.2 | 17.8 | 19.4 | 21.0 | 22.6 | 25.9 | |||
| 16 | 1.5 | 197 | 9.1 | 12.2 | 13.7 | 15.2 | 16.7 | 18.3 | 19.8 | 21.3 | 24.3 | Meade 5000 | 60 | |
| 15 | 1.5 | 210 | 8.6 | 11.4 | 12.8 | 14.3 | 15.7 | 17.1 | 18.5 | 20.0 | 22.8 | TMB Planetary II | 61 | |
| 14 | 1.4 | 225 | 8.0 | 10.6 | 12.0 | 13.3 | 14.6 | 16.0 | 17.3 | 18.6 | 21.3 | |||
| 13 | 1.3 | 243 | 7.4 | 9.9 | 11.1 | 12.4 | 13.6 | 14.8 | 16.1 | 17.3 | 19.8 | Denkmeier | 66 | |
| 12 | 1.2 | 263 | 6.8 | 9.1 | 10.3 | 11.4 | 12.6 | 13.7 | 14.8 | 16.0 | 18.3 | Vixen LVW | 65 | |
| 11 | 1.1 | 287 | 6.3 | 8.4 | 9.4 | 10.5 | 11.5 | 12.6 | 13.6 | 14.6 | 16.7 | Meade SWA | 66 | |
| 10 | 1.0 | 316 | 5.7 | 7.6 | 8.6 | 9.5 | 10.5 | 11.4 | 12.4 | 13.3 | 15.2 | |||
| 9 | 0.9 | 351 | 5.1 | 6.8 | 7.7 | 8.6 | 9.4 | 10.3 | 11.1 | 12.0 | 13.7 | Pentax XW | 70 | |
| 8 | 0.8 | 394 | 4.6 | 6.1 | 6.8 | 7.6 | 8.4 | 9.1 | 9.9 | 10.6 | 12.2 | UO WideScan | 73 | |
| 7.5 | 0.7 | 421 | 4.3 | 5.7 | 6.4 | 7.1 | 7.8 | 8.6 | 9.3 | 10.0 | 11.4 | BP Hyperion | 74 | |
| 7 | 0.7 | 451 | 4.0 | 5.3 | 6.0 | 6.7 | 7.3 | 8.0 | 8.7 | 9.3 | 10.6 | UO SWA | 75 | |
| 6.5 | 0.6 | 485 | 3.7 | 4.9 | 5.6 | 6.2 | 6.8 | 7.4 | 8.0 | 8.7 | 9.9 | |||
| 6 | 0.6 | 526 | 3.4 | 4.6 | 5.1 | 5.7 | 6.3 | 6.8 | 7.4 | 8.0 | 9.1 | UO UltraWide | 77 | |
| 5.5 | 0.5 | 574 | 3.1 | 4.2 | 4.7 | 5.2 | 5.8 | 6.3 | 6.8 | 7.3 | 8.4 | Explore Scientific N2 | 80 | |
| 5 | 0.5 | 631 | 2.9 | 3.8 | 4.3 | 4.8 | 5.2 | 5.7 | 6.2 | 6.7 | 7.6 | |||
| 4.5 | 0.4 | 701 | 2.6 | 3.4 | 3.9 | 4.3 | 4.7 | 5.1 | 5.6 | 6.0 | 6.8 | |||
| 4 | 0.4 | 789 | 2.3 | 3.0 | 3.4 | 3.8 | 4.2 | 4.6 | 4.9 | 5.3 | 6.1 | |||
| 3.5 | 0.3 | 901 | 2.0 | 2.7 | 3.0 | 3.3 | 3.7 | 4.0 | 4.3 | 4.7 | 5.3 | |||
| 3 | 0.3 | 1052 | 1.7 | 2.3 | 2.6 | 2.9 | 3.1 | 3.4 | 3.7 | 4.0 | 4.6 | |||