Chapter V: Section IV: The Sidereal Heavens

_Frontispiece_—NEBULA IN ANDROMEDA 31 MESSIER 398

1.— STARS VISIBLE IN THE NORTHERN HEMISPHERE 401
2.— STARS VISIBLE IN THE SOUTHERN HEMISPHERE 403
3.— DIAGRAM SHOWING “SOLAR APEX” AS ROUNDLY COMPUTED 429
4.— APPARENT ORBIT OF ZETA HERCULIS 436
5.— APPARENT ORBIT OF THE COMPANION OF SIRIUS 439
6.— APPARENT ORBIT OF 70 OPHIUCHI 443
7.— TRIPLE STARS 451
8.— THE TEMPORARY STAR OF 1572 481
9.— THE DOUBLE STAR CLUSTER IN PERSEUS 503
10.— STAR CLUSTER IN GEMINI 504
11.— 37 MESSIER 505
12.— STAR CLUSTER IN HERCULES 507
13.— THE STAR CLUSTER, OMEGA CENTAURI 512
14.— THE ORION NEBULÆ 521
15.— THE NEBULA ROUND ETA ARGUS 523
16.— THE TRIFID NEBULA, SAGITTARIUS 525
17.— SPIRAL NEBULA, 51 MESSIER 533
18.— MAGELLANIC CLOUDS 537
19.— PHOTOGRAPH OF MILKY WAY, SAGITTARIUS 555
20.— THE MILKY WAY 557

ASTRONOMY

THE OBSERVATORY AT NICE.

[_See page 192_
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