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View Full Version : Object of the Week October 26, 2014 - Wolf-Lundmark-Melotte



FaintFuzzies
October 25th, 2014, 11:32 PM
Wolf-Lundmark-Melotte aka WLM – Dwarf galaxy in Cetus

RA: 00h 01m56s
Dec center: -15° 27’ 21”
Size: 11.6 x 4.0’
Mag: ~10.4

This “extended” local group dwarf galaxy was discovered by Max Wolf in 1909, but apparently he didn’t know what it was until in 1926. Lundmark and Melotte figured it out and determined that it was an external galaxy.

I’ll just cut straight to the chase on what to look for in this object other than some ill-defined large glow, like many dwarfs in a small telescope. There is one known globular cluster and one marked OB region. I’m sure there are more OB regions, but I’ve marked only one as it is observable in a modestly large amateur telescope.
GC-1 is a mag 16.1 globular cluster that is visible as a very faint “fuzzy” star about 1’ west of WLM. A mag 15.2 star lies about 40” north of GC-1 forming a double star. The key of successful observing of GC-1 is magnification; need at least 300 to 400x. There is a paper of the study of this globular with the Hubble Space Telescope. The article is here (http://iopscience.iop.org/0004-637X/521/2/577).

The OB region, A3, was not detected with my 22” telescope under nearly pristine skies at Shot Rock, NELM was at 7.2. Has anyone seen A3? Let’s hear it.
For those who likes to look for very faint galaxies, there are three nearby MAC galaxies; MAC 0002-1525, -1525A, -1527. I didn’t see -1527, but caught -1525 and -1525A as a very faint double galaxy that sometimes appears to be merged. It was held only 50% of the time. Once I cranked the magnification to 458x, it was a little easier to see as separate galaxies. Pretty tough.


1406
Detailed DSS image of WLM with labeled non-stellar objects


1407
Here is an image put together by Knut Olson of CTIO/NOAO. Note: This image was cropped and reduced size. For the full image, see here (http://www.ctio.noao.edu/images/download_pict/local_group_survey.htm) (and scroll down to WLM)




So…
"GIVE IT A GO AND LET US KNOW"

Uwe Glahn
October 31st, 2014, 09:56 PM
4", 31x, NELM 6m5+
faint glow 1° NE 1 Cet; can hold glow with averted vision; 3:1 N-S elongation indicated

16", 100x-257x, NELM 7m+
with searching eyepiece faint 3:1 - 4:1 N-S glow; best view with EP 4mm (100x); easy to hold glow with averted vision; central 15mag star; with higher magnification 46" NW of the star a faint but clearly observable small glow (HII WLM8/9 = A3) is visible; 78" NW another faint stellar glow can be seen with difficulties (HII WLM 6), no sure observation; W of the galaxy two 15mag stellar peaks are visible, southern peak is the GC WLM 1; GC remains stellar even with very high magnification
http://www.deepsky-visuell.de/Zeichnungen/WLM.jpg

27", 113x-172x, NELM 6m5+
quick and dirty observation; astonishingly faint with 27" aperture; remains faint but just direct vision object; GC easy to hold but remains stellar; did not try the HII regions and the neighbor galaxies