And I thought that locating the terrible Terzan’s were difficult…
Here is my candidate for the Globular Cluster AM-4, a loose and faint cluster discovered by Madore & Arp in 1982. According to an
article by Giovanni Carraro 2009, The Astronomical Journal 137 3809 , AM-4 is a candidate for being a young globular associated with the Sgr Dwarf Spheroidal galaxy.
I became attracted to this challenging target from the details provided at the
astronomy-mall website.
Last night (18th May 2013) I grabbed 20 x 5 min exposures with the Mewlon 180 F12 operating at F9.6 with the Tak x0.8 Reducer/Flattener and an SBIG ST2000XM CCD camera. These images were then calibrated, aligned and stacked in CCDStack then finished in CS6.
The LRGB image is made up of 3 x 10 minutes each LRGB data from the previous evening (17th May 2013) after my first attempt to record AM-4 and is provided for reference only as AM-4 is barely hinted at in the original Luminance data. The FOV is approx. 22x17 arc min at 0.83 arcsec/pixel.
Here is a
link to the reference image that I used, taken at the Las Campanas Observatory, using the 1.0 m Swope telescope equipped with the Site 3 2048 × 3150 CCD camera. The field of view is about 14.′8 × 22.′8 with a scale 0.435 arcsec pixel.
Although I did not manage to resolve the globular unambiguously, I think that the “cluster of grains” that I did manage to record is a good candidate for AM-4. It would probably require a dark sky site and more aperture to improve on these results. The 1st Quarter Moon was some 60 degrees away during the imaging session.
The attached animation shows some respectable correlation despite the BG noise...
AM-4 details from SKyTools 3 Professional:- Globular Cluster
- R.A.: 13h56m21.0s Dec.: -27°09'42" (2000) in Hydra
- Magnitude: 15.90
- Size: unknown