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26. F8

The spectral type is determined from the ratios lambda 4045: Hdelta and lambda 4226: Hgamma. The most sensitive criterion of absolute magnitude is probably the ratio lambda 4077: lambda 4226 for normal giants and dwarfs; while in the range from supergiants to giants the ratios lambda 4077: Hdelta and lambdalambda 4171-4173: lambda 4226 allow a very accurate luminosity classification to be made.

TABLE 21
STANDARDS AT F8

Star MKK a delta m HD

50 And.... F8 IV 01:30 +40°54' 4.2 G0
36 UMa... F8 V 10:24 +56 30 4.8 F5
beta Vir...... F8 V 11:45 +02 20 3.8 F8
theta Dra...... F8 IV 16:00 +58 50 4.1 F8
upsilon Peg...... F8 III 23:20 +22 51 4.6 G0

Plate 36. Normal Giants F8 - K5
Plate 36
High resolution image

Plate 37. Luminosity Effects at F8
Plate 37
High resolution image

Plate 38. High Luminosity Stars at F8
Plate 38
High resolution image

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