17. A5

The principal line ratio for determining the spectral type is 4030-4034: 4128-4132. The luminosity class is determined from the ratios 4417: 4481 and 4417: 4300.

TABLE 15
STANDARDS AT A5

Star	MKK	a		m	HD
Cas....	A5 V	01:19	+59°43'	3.0	A5
Ari.....	A5 V	01:49	+20 19	2.7	A5
Tri......	A5 III	02:03	+34 31	3.1	A5
g UMa....	A5 V	13:21	+55 31	4.0	A5
a Oph.....	A5 III	17:30	+12 38	2.1	A5

Plate 26. Luminosity Effects at A5

High resolution image

Plate 27. The Spectrum of 17 Leporis

High resolution image