1 Attachment(s)
Object Of The Week February 16, 2020 – NGC 1566
NGC 1566, ESO 157-20, LEDA 14897
Seyfert 1 Galaxy
Constellation: Dorado
RA: 04 20 00.40
DEC: -54 56 16.58
Visual magnitude: 9.73
Dimensions: 8.51' x 5.37'
NGC 1566 was discovered by James Dunlop on May 28, 1826. Originally from Scotland, Dunlop moved to Australia in 1821 to work as an astronomical assistant at the Parramatta observatory (which was spelled Paramatta back then). From Wikipedia:
Between June 1823 and February 1826 Dunlop made some 40,000 observations and catalogued some 7,385 stars, of which included 166 double stars and references to several bright deep-sky objects near the bright stars he catalogued. By the beginning of March 1826, he left the Paramatta Observatory and continued working at his own home in Hunter Street, Paramatta. For there he began organising his own observations of double stars and deep-sky objects for the next 18 months, in which he constructed telescopes and other equipment for his dedicated southern sky survey.
It was then that he discovered NGC 1566. In 1828 he published A catalogue of nebulae and clusters of stars in the southern hemisphere, observed at Parramatta in New South Wales with descriptions contains 629 southern deep-sky objects.
Attachment 3796
Image of NGC 1566 taken by the Star Shadows Remote Observatory.
NGC 1566 bears the nick name "The Spanish Dancer" due to it's striking spiral arms that, I suppose, resemble a twirling dress. It is classified as a Seyfert I galaxy, which is a class of active galaxies that do not have bright optical cores but do emit a lot of radiation in UV and X-Ray.
It also is the brightest and dominant member of the Dorado Group, which lies at some 18 Mpc from Earth. According to WikiPedia, a 2005 study some 26 galaxies are part of the group: NGCs 1515, 1522, 1533, 1536, 1543, 1546, 1549, 1553, 1566, 1574, 1581, 1596, 1602 and 1617, ICs 2032, 2038, 2049, 2058 and 2085, ESOs 157-030, 157-047, 157-049 and 118-019, faint irregular galaxies LSBG F157-081, APMBGC 157+016+068 and Abell 3202. Funny enough both Simbad and NED don't have any references to galaxies in this group, apart from NGC 1549 in Simbad.
As I mentioned before, NGC 1566 has very striking spiral arms and lots of details close to its center where the arms meet the bulge. I observed this galaxy last Friday, February 14, with my 12" dob at varying magnifications. Since the dob is not a goto, I had to star hop and started at the star Alpha Doradus. From there I also observed Dorado Group members NGC 1617, NGC 1602 and NGC 1596 though I managed to overlook NGC 1581. My notes read:
The 35 mm Panoptic eye piece yields a FOV of over 1.5 degrees and immediately a glow appears next to Alpha Doradus: NGC 1617. Using the 10 mm Ethos (150x, 40') we saw a very bright stellar core surrounded by a large, oval glow. One striking feature was the contrast between the very bright core and the oval glow, particularly right adjacent to the core.
Continiung the star hop with the 17 mm Ethos (88x, 1º14') we end at another glow. And to paraphrase Iron Maiden's Rhyme Of the ancient Mariner: "Wait, but there's two!". NGC 1596 has a stellar core and and a thin, almost needle-like, halo. NGC 1602 shows a very faint oval glow which only seems a little bit smaller than NGC 1596. Photo's of this galaxy show a bright starforming region at the end closest to NGC 1596 but we didn't see it. I'll revisit this galaxy with my 20" telescope.
Continuining the star hop with the 17 mm Ethos we end up at NGC 1596. At 88x the spiral structure is plainly visible and very pleasing. With the 10 mm Ethos we see a beautiful spiral galaxy of which we can follow the spiral arms over 1/3 around the core. Using the 8 mm Ethos (188x, 35') lots of details around the core become visible. This is a very spectacular spiral galaxy that I will revisit with my 20" dob.
As always,
"Give it a go and let us know!
Good luck and great viewing!"
