GLORY OF STARS

New Zealand Herald, Volume LXXIII, Issue 22512, 1 September 1936, Page 8

GLORY OF STARS

HEAVENS IN SEPTEMBER PELTIER'S COMET AN INTERESTING VISITOR

BY CRUX AUSTRALIA

Peltier's comet, in the course of its rapid passage across the southern sky, has undoubtedly provided amateur astronomers with a great deal to stir the interest and imagination, as it is only the fourth comet since 1910 to possess d prominent tail and to be at its brightest stage easily visible to the eye without the aid of a telescope. The Southern Hemisphere seems to be particularly well favoured by bright comets. The comet of 1901, the daylight comet of 1910, and Hal ley's comet in the same year all provided much better spectacles in this hemisphere than in their northern paths. Seventeen years passed before another brilliant comet was visible. In 1927 Skjellerup's comet provided for a week a brilliant spectacle in the dawn in this hemisphere, while remaining completely hidden from northern observers. After a wait of a further nine years Peltier's comet has provided what might bo termed a moderate display, being again brighter in the southern sky than in the north, and providing for southern observers a splendid tail. Discovery of Comet This comet was the fifth to be discovered by Peltier, an amateur astronomer ot Delphos, Ohio, who was also fortunate last June in discovering a new star. By day Mr. Peltier works in a garage —by night he is an assiduous observe#" of variable stars, and his keenness for astronomical observation is revealed not only by these sensational discoveries, but also by the large amount of routine observation ho carries out. .

When first discovered the comet was in high northern declination, and it was moving so slowly that there was difficulty in deciding on its cometary nature. So slow was its motion that computers had great difficulty in calculating its exact orbit in space, and some rather discordant data were published. Although it way known from the first tliat the comet would eventually pass into the southern sky, it was not expected to arrive so soon or to Ibe as bright as it was. Actually, the comet reached a position where it could be seen by New Zealanders some days before the information reached here by cablegram. Passage Close to Earth When first observed in New Zealand, about the middle of the first week in August, the comet was making its closest approach to the Sun, and was also at the time much closer to tbe Earth than comets usually lie, being less than 3,6,000,000 miles distant. It was mainly owing to its proximity chat the comet appeared to travel so swiftly across the sky. News of its prior appearance in the northern hemisphere has not yet reached us, but it is certain that no tail was visible in the period August 3 to 7. Of course, if a tail was present, then it would have been directed almost directly away from us, and therefore would not have been seen. /The full moou was also a factor in hiding any faint extension of its light. On the morning of August 8, however, a splendid tail, over a degree long, was visible in the strong moonlight, and that night its measured length was 2i degrees, or five times the Moon's apparent diameter. The starlike nucleus of the comet was of a distinctly or.mee hue, enveloped in a parabolic nebulositj' which streamed away in a perfectly straight tail. During thfe month Peltier's comet has steadily waned in brightness, passing beyond the range of naked-eye vision about August 20. At present it is visible only in telescopes, and - although a tail is still present this is now less than half a degree in length. The comet will not much longer remain visible telescopically. Phenomena lor September

The Sun is- at present in the constellation Leo. On the 17th it will pass into Virgo, the vernal equinox occurring on the 23rd. The Sun's noon altitude at Auckland will increase during the month from 44 i degrees to 55 J degrees. The Moon will be in conjunction with tha' various planets as follows: Saturn, 2nd. 10.30 p.m.; Mars, 13th, 8.30 p.m-j Mercury, 18th, 5.30 a.m.; Venus, 18th, 9.30 a.m.; Jupiter, 23rd, 7.30 a.m.; Saturn, 30th, 7 a.m. Mercury is at present prominently visible in the evening sky, attaining its greatest elongation from the Sun on the 4th. Venus, also in the evening sky, will be in conjunction with Mercury on the 16th, when the two planets will be 5 degrees apart. Mars is in the morning sky and not favourably placed for observation. It. will be less than a degree north of Regulus oil 24th. Jupiter remains favourably situated for observation, being nearly overhead at the end of twilight and setting about midnight. Saturn will be in its most favourable position, in opposition to the Sun, on the 12th. Wising about sunset, it will be highest in the sky near midnight, and presents its famous ring-system at a very narrow angle to our vision. Now is the time to observe the planet teleecopically and to note the extreme thinness of its unique rings.