Sand and Stars

Dorado’s Other Cloud

A Dorado diving into turbulent water. Image credit Wikimedia Commons

3 Feb 2017

Dorado, the gorgeous fish gracing our southern skies, appears as if it is diving into a great froth of turbulent water represented by the Large Magellanic Cloud. And it’s hard not to follow suit when one is observing in Dorado because the Large Magellanic Cloud dominates the constellation… and then some! However, Dorado is home to another cloud… the cloud of galaxies known as the Dorado Group of galaxies; a loose group comprised of an estimated 70 galaxies and located roughly 60 million light-years away. The Dorado Group is much larger than the Local Group in which we live (it contains around 30 galaxies) and approaches the size of a galaxy cluster. Galaxy clusters are the largest groupings of galaxies (and indeed the largest structures of any type) in the universe to be held together by their gravity.

I spent last night wandering around the Dorado Group with my telescope. In these gloriously dark, clear and steady Kalahari skies a horde of its galaxies were visible; among them some truly gorgeous beauties – a magnificent spiral galaxy that is also a Seyfert galaxy (and not just any old Seyfert galaxy at that, it is the second brightest Seyfert galaxy known), a pair of interacting galaxies, an edge-on galaxy, a lenticular galaxy, an elliptical galaxy… it was a breath-taking galaxy voyage.

NGC 1566 Galaxy 

RA 04 20 00.8   Dec -54 56 14   Mag 9.7   Size 8.3’ x 6.6’   SB 13.9
Image credit Hubble
NGC 1566. Image credit Hubble

Wow! Stunning! A big round glow – very bright – that brightens to a very bright nucleus. A little brighter mottling in the halo and with averted vision there is the slightest hint of a spiral. A very handsome galaxy!

NGC 1515 Galaxy 

RA 04 04 02.2   Dec -54 06 10   Mag 11.2   Size 5.4’ x 1.3’   SB 13.2

DSS image
NGC 1515. DSS image

A lovely edge-on galaxy! Long and thin and bright and tapering to points at both ends; elongated NNE – SSW. It has a central bulge that brightens to a stellar nucleus. No sign of NGC 1515a.

NGC 1672 Galaxy 

RA 04 14 36.8   Dec -54 06 10    Mag 11.2   Size 5.4’ x 1.3’

Image credit Hubble
NGC 1672. Image credit Hubble

A gorgeous galaxy! It appears as a bright, very roundish oval glow, elongated E-W. It brightens to a very slightly oval nucleus. Averted vision shows a very faint outer halo and a hint of structure! – a very flimsy hint of a spiral off the east end.

NGC 1549 Galaxy 

RA 04 15 45.0   Dec -55 35 31   Mag 9.8   Size 4.9’ x 4.1’   SB 13.0

NGC 1553 Galaxy 

RA 04 16 11.5   Dec -55 46 51   Mag 9.4   Size 4.5’ x 2.8’   SB 12.0

DSS image
NGC 1649 & NGC 1553. DSS image

A lovely pair of galaxies. NGC 1549 appears as a round, bright smooth glow, brightening to a stellar nucleus. NGC 1553 appears as a beautiful bright oval glow, brightening to a small but very bright nucleus.

NGC 1533 Galaxy 

RA 04 09 52.5   Dec -56 07 09   Mag 10.7   Size 2.8’ x 2.3’   SB 12.6

DSS image
NGC 1533. DSS image

This galaxy appears as a bright, round, small, hazy glow that brightens to the centre.

NGC 1546 Galaxy 

RA 04 14 36.8   Dec -56 03 36   Mag 10.9   Size 3.0’ x 1.7’   SB 12.6

DSS image
NGC 1546. DSS image

A small, quite bright, smooth and soft elongated glow elongated NNW-SSE. It brightens to a tiny stellar nucleus. . A lovely little galaxy!

NGC 1617 Galaxy 

RA 04 31 40.3   Dec -54 36 12   Mag 10.4   Size 4.3’ x 2.1   SB 12.7

DSS image
NGC 1617. DSS image

A lovely galaxy! It appears as a very bright, oval glow elongated WNW-ESE. Smooth, even glow; no sign of mottling or knots in the silky smoothness. It brightens to a bright stellar nucleus embedded in a bright core.

IC 2058 Galaxy 

RA 04 17 54.5   Dec -55 56 00   Mag 13.2   Size 3.0’ x 0.4’   SB 13.2

DSS image
IC 2058. DSS image

All I could see of this gorgeous razor-thin edge-on galaxy was a very small round faint glow with an exceedingly thin, short streak of  exceedingly faint light elongated NNE-SSW.

Copyright © Susan Young 2017