Sky Sketcher's Post Mortem 3

SKY SKETCHERS POST MORTEM

By Scott Mellish

PHOENIX-LEPUS-TUCANA

I have selected three objects for this Post Mortem which I have observed over the last few months at the ASNSW dark sky observing site Wiruna which I thought may be of interest for keen observers.

NGC 1904 (M79)

The first object I will discuss is the rather impressive globular cluster NGC 1904 (M79). I rather enjoyed the view of this object in the 56cm dob at 354x mag as the 100° FOV in my new 8mm Ethos eyepiece made this globular cluster look quite crisp in appearance.

The central core of this cluster was only partially resolved, but quite dense and had a rather grainy appearance. However most of the outlying stars were quite pretty, and enhanced the visual appearance. The cluster was discovered in 1780 by Pierre Francois Andre Mechain (1744-1804) and is around 8.7' with a visual mag of 7.7.

Steve Gottlieb describes his observations of NGC 1904 as follows:"17.5" (1/9/99): at 280x, this globular is well resolved into several dozen stars. Contains a sharply concentrated intense core, ~2' in diameter which is clumpy, mottled and partially resolved at its periphery. The inner part of the halo is peppered with faint stars. The background haze drops off significantly towards the outer portion of the halo but a number of brighter stars are resolved including a nice arc of stars along the following edge of the halo. An evenly matched close pair is on the NE side and a mag 12 star is at the N edge. Located 35' NE of naked-eye 5th magnitude h3752 (5.5/6.7 at 3")."

NGC 360

We shift our focus now to the constellation Tucana and a rather nice edge on galaxy NGC 360. These types of galaxies are always a treat to observe in the eyepiece as their acute line of sight orientation always provides a novel view. The 56cm dob. shows the galaxy as a crisp streak covering around 10' of the 17' eyepiece field. The galaxy was discovered in the year 1834 by John Frederick William Herschel (1792 - 1871) and is around 10' x 1' in size, with a visual mag of about 13.0. NGC 360 is not a well known edge-on object hence observing reports are rather scant.

ESO 243-35, ESO 243-37, ESO 243-38

The final object in this Post Mortem is a somewhat faint but interesting grouping of galaxies in the constellation of Phoenix. I was intrigued by the unusual formation these four galaxies presented in the eyepiece of the 56cm at 314x mag. Whilst they were small and faint they were bright enough to be easily visible without the use of averted vision. As you can see in the sketch, this nice little combination consists of from top right ESO243-35 then just below and to the left is an anonymous galaxy. At the bottom and the most prominent galaxy is ESO 243-37, and about 2.0’ above is the diffuse ESO 243-38. This is a very unusual little galaxy group and it is worthy of close scrutiny.

Clear Skies