Fornax Dwarf Galaxy’s Globular Clusters

16 Feb 2018

One of the oddest observing experiences is to observe a handful of globular clusters that reside in a galaxy around 530,000 light years away… while the galaxy itself stays resolutely invisible.

The Fornax Dwarf covers a 17’x13′ area of sky and has a magnitude rating of 9.3, which makes it sound like an easy catch, so it’s very odd to look in its direction and see nothing of it at all. Not even the mistiest hint of the galaxy is visible.

The galaxy’s brightest globular cluster, NGC 1049, was discovered in 1935 by John Herschel when he was at the Cape of Good Hope in South Africa cataloguing the southern skies. Its parent galaxy, was discovered a century later in 1938 by Harlow Shapley. He was also in South Africa, at the Boyden Observatory in Bloemfontein and discovered it on photographic plates taken by the observatory’s 24 inch (61 cm) Bruce refractor.

I used my 16″ Dobs at 228x and 330x to view these far distant globular clusters.

*I annotated a Digitized Sky Survey 2 image of the Fornax Dwarf Galaxy with its six globular clusters*

Fornax 1

RA 02 37 02.1 Dec -34 11 00 Mag 16.6 Size –

A very challenging globular! So challenging in fact, that it remained invisible.

Fornax 2

RA 02 38 44.2 Dec -34 48 30 Mag 14.5 Size 0.8′

Albeit very faint, this globular was visible with direct vision and stood out well against the background sky. It is a very small, very faint, round, even glow. A faint little mag 15 star lies just off the SW edge of the cluster.

Fornax 3 – NGC 1049

RA 02 39 48.1 Dec -34 15 28 Mag 13.4 Size –

John Herschel recorded his observation as “pretty bright; small; round; like a star 12th magnitude a very little rubbed at the edges, a curious little object and easily mistaken for a star, which, however, it certainly is not”. In my eyepiece it stood out well against the background sky – fairly faint, small, round; it had a tiny, almost stellar, brightish core surrounded by a thin even surface brightness halo, which indeed made it appear to be a little rubbed at the edges.

Fornax 4

RA 02 40 07.6 Dec -34 32 10 Mag 13.9 Size 0.3′

This globular appears very small and very faint and round, with an even glow. A faint mag 15 star lies just north of it.

Fornax 5

DSS image and NASA/ESA/S. Larsen (Radboud University, the Netherlands)

RA 02 42 21.1 Dec -34 06 05 Mag 13.4 Size 0.3′

This globular appeared as a very small, very faint, round, even glow.

Fornax 6

*DSS image and Legacy Survey Sky Viewer*

RA 02 40 06.9 Dec -34 25 19 Mag – Size –

Not even the slightest chance of seeing anything at all! I pointed my telescope in the direction in which it lies, not hoping to see it, but just because it’s cool to look at something that you know is there but that’s invisible to one’s eyes.