20. F2
The ratio of intensity 
4030-4034:
4128-4132 is greater than in
the corresponding luminosity class at F0. A shading is observed
degrading toward the red from 4300. The luminosity class is
determined from the ratios
4171: 4226 and
4077:
4045.
| Star | MKK | a |  | m | HD |
Cas..... | F2 III | 00:03 | +58°36' | 2.4 | F5 |
| Gem..... | F2 IV | 07:14 | +22 10 | 3.5 | F0 |
 UMa..... | F2 III | 09:43 | +59 31 | 3.9 | F0 |
| 78 UMa... | F2 V | 12:56 | +56 54 | 4.9 | F0 |
 Boo...... | F2 V | 14:30 | +30 11 | 4.5 | F0 |
Ser....... | F2 IV | 17:55 | -03 41 | 4.6 | F0 |
 Sgr...... | F2 II | 19:03 | -21 11 | 3.0 | F2 |
 |
| High resolution image |
