AP 24

21P/ Comet Giacobini-Zinner

gz21 0042 0908

Discovered by Michel Giacobini in 1900 and recovered by Ernst Zinner in 1913. Orbital period of 6.5 years and source of the Draconid meteor shower. Imaged here at 0042 IST on Aug 9 2018, at est mag 9.1 and Earth distance 49m miles. Perihelion Sep 10. With (a) mag 8.7 HIP 6156 in Cassiopeia. [24th observed comet]

Asteroids (27) Euterpe and (115) Thyra

euterp thyra sep28

Left: discovered by Hind in 1853; mag 10.4, diameter 60 ml, Earth distance 130m miles. With (a) mag 8.2 HIP 112071 in Aquarius. Sep 28 2018, 2225 IST. Right: discovered by Watson in 1871; mag 10.3, diameter 35 ml, Earth distance 110m miles. With (a) mag 7.9 HIP 108855 in Pegasus. Sep 28 2018, 2226 IST. [32nd, 33rd observed asteroids]

Birr Castle

scope1 leviath

The 72 inch Leviathan constructed by William Parsons, 3rd Lord Rosse. First light 1845; the world’s largest telescope until 1917. Reconstructed in 1997.

ilofar demesne

The ~7000 m2 I-LOFAR radio telescope, incorporating 3,000 individual antennae and 55km of cabling. Both images from Aug 10 2018.

64P/ Comet Swift-Gehrels

swift gehrels 64p

Discovered by Lewis Swift in 1889 and recovered by Tom Gehrels in 1973. Orbital period of 9.2 years and seen to best advantage at this year’s apparition. Imaged at 2342 UT on Nov 1 2018, 2 days before perihelion, at est mag 10.7 and Earth distance 40m miles. With (a) mag 7.9 HIP 3740 in Andromeda. [25th observed comet]

Asteroids (42) Isis and (12) Victoria

isvct jnw519h

Left: discovered by Pogson in 1856; mag 10.7, diameter 62 ml, Earth distance 130m miles. With (a) mag 6 HIP 15850 in Taurus. Nov 30 2017, 2156 UT. Right: discovered by Hind in 1850; mag 10.2, diameter 70 ml, Earth distance 135m miles. With (a) mag 7.8 HIP 18326 also in Taurus. Nov 18 2018, 2232 UT. [First 20 discovered asteroids now imaged, total 35]

Venus and Spica

spica venus 19118

The Morning Star dazzles at mag -4.5, 1.9° SE of and 170 times brighter than mag 0.95 Spica, Alpha Vir (s); and 8,000 times brighter than h Vir, 18′ NE. However both these stars are located ~1500 trillion miles distant, some 50 million times further than Venus. Nov 19 2018, 0644 UT.

38P/ Comet Stephan-Oterma

stephoterm 9nov18

Discovered by Jérôme Coggia in 1867 but named after Édouard Stephan and recovered by Liisi Oterma in 1942. Orbital period of 38 years. Imaged here at 0011 UT on Nov 9 2018 – the day before perihelion. Est visual mag 10.8 and Earth distance 83m miles. 15′ NW of mag 9.8 planetary nebula NGC 2392 in Gemini (the Eskimo Nebula), discovered by William Herschel in 1787 (E). With (a) mag 5.2 63 Gem. [26th observed comet]

Total Lunar Eclipse, Jan 21st 2019


Pre-eclipse Moonlit panorama

prtlclp jn21stnt

Partial phase; left – 0359 UT, 25 minutes after commencement; right – 0429 UT, 12 minutes before totality.

ttleclp 0441jy91

0449 UT, 8 minutes into totality – imperfect but acceptable sky conditions. Star ½ a degree to the SE is mag 7.6 HIP 39816 in Cancer.

eclpscam pzt1

3 minutes after end of totality…


The first meteor impact on the Moon during a total eclipse was famously recorded by several observers. A probable 10kg cometary fragment travelling at 38,000 mph generated an explosion equivalent to 0.5 tons of TNT, resulting in a ~10m pockmark close to 55-mile diameter Byrgius crater.