NGC 2324, also known as Herschel 87, is an open cluster in the Monoceros constellation, a faint constellation which sits near the celestial equator. It has a right ascension of 07:04:10, a declination of 01:02:17 and coordinates 07 04 07.9 +01 02 46. This cluster is fairly young, as well as metal poor. It has an apparent size of approximately 8.7 arcmin. It was discovered on December 27, 1786. Said discovery is attributed to William Herschel, a famous German-born British astronomer, who made multiple contributions to the field. He is perhaps most famous for his discovery of Uranus, but he also catalogued thousands of celestial objects and discovered infrared radiation, amongst other things. Despite this, thereās a general lack of information on this cluster in particular.Ā It is 13.8 kpc away from Earth and has an apparent magnitude of 8.4.
Reddened and de-reddened colour images of NGC 2324, taken using Skynet and put together using Afterglow. Itās difficult to see the difference.
Itās one of the objects featured in the Herschel 400 catalogue. Said catalogue is a small fraction of 400 deep sky objects from William Herschelās Catalogue of Nebulae and Clusters of Stars, created in 1980 by Brenda F. Guzman (Branchett), Lydel Guzman, Paul Jones, James Morrison, Peggy Taylor and Sara Saey. All of the objects featured in the catalogue are New General Catalogue objects (NGC), are all visible around latitudes 30Ā°-60Ā° (mid-northern), and are all visible in 150 mm or larger telescopes.
The constellation itās situated in, Monoceros, is often called the Unicorn due to its shape. Itās situated right between Canis Minor and Major.
A picture of Monoceros in Stellarium, with constellation lines enabled. NGC 2324 is highlighted.
A nearly two decades old study from 2004 by Piatti et al found out that NGC 2324 is a ārelatively young, metal-poor and distant open cluster located beyond the Perseus spiral armā. (2004) They deduced that the E(B-V) value of the cluster is 0.25 Ā± 0.05 and that its distance from the Sun is 3.8 Ā± 0.5 kpc.Ā
To study this cluster, learn about the relationship between the different qualities of a star cluster, and make some pretty images, I needed to take photos. For this I used the Prompt5, PROMPT-USASK, PROMPT-MO-1, and Prompt2 telescopes through Skynet, though only the Prompt5 and PROMPT-USASk ended up taking any pictures. Using the R, B and V filters, I took 5 photos each: an exposure time of 30.49s for the R filter, 73.17s for B, and 42.68s for V (using Prompt5 exposure times).
During my analysis of the star cluster I used Afterglow for photometry and the Skynet Plotting site to easily analyze the data and create an isochrone. I determined that NGC 2324 had a motion in Right Ascension (RA) of -0.32 Ā± 0.08 mas/yr, a motion in Declination (Dec) of -0.1 Ā± 0.1 mas/yr, a distance from the Sun of 3.8 kpc Ā± 20%, about 90 stars, a log(Age) of 9.32 log(yr), a metallicity of -1.77 solar, and an E(B-V) value of magnitude 0.2.
Using GAIA and 2MASS data along with values obtained by Kharchenko et al (2013), I received an alternative, more accurate isochrone, as well as more accurate values. This isochrone has a motion in RA of -0.32 Ā± 0.08 mas/yr, a motion in Dec of -0.1 Ā± 0.1 mas/yr, a distance from the Sun of 3.842 kpc Ā± 20%, a log(Age) of 8.68 log(yr), a metallicity of -0.17 solar, and an E(B-V) value of magnitude 0.239.
Interestingly, most of the values are pretty close to each other. One thing to note is that both my results and the Kharchenko et al results show that the two decade old study was correct in its approximation of NGC 2324ās E(B-V) value and distance value. Both these results fall into the error ranges.
My isochrones and the GAIA/2MASS data isochrones with MWSC values. Overall, the second set is a better fit, thought both end up not capturing some stray blue stars. These may be blue stragglers.
This project was incredibly interesting. While the highlight of the project for me was probably creating colour images of clusters with Afterglow, the entire thing was really fun and Iām glad I did it.
Another image of Monoceros in Stellarium, with the constellation lines and art enabled. NGC 2324 is highlighted. Thereās no reason to include this, I just thought the art was nice and wanted to share.
References:
https://en.wikipedia.org/wiki/Open_cluster
https://en.wikipedia.org/wiki/Monoceros
https://ui.adsabs.harvard.edu/abs/2004A&A…418..979P/abstract?bbbRedirect=1
https://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+2324&submit=SIMBAD+search
https://telescopius.com/deep-sky/object/3254/ngc-2324/open-cluster
https://theskylive.com/sky/deepsky/ngc2324-object
http://ngcicproject.observers.org/NGC/NGC_23xx/NGC_2324.htm
https://commons.wikimedia.org/wiki/Category:NGC_2324
https://en.wikipedia.org/wiki/Herschel_400_Catalogue
https://en.wikipedia.org/wiki/William_Herschel