For our northern contingent we will visit Gemini for a nice open cluster and winter staple planetary nebula. We will wrap up in the dimmer constellation Lynx where we will seek out the far removed globular cluster NGC 2419 which lay at an astounding 300 KLY distant from our galactic core. Our southern colleagues will pursue a fine open cluster in Carina, the stellar keep of the mythical ship Argo. Next they will look for the bright nebula NGC 2359, famously known as Thor’s Helmet, located in Canis Major. They will also have a globular as their last object for this month, in the celestial poop deck of the Argo – Puppis.
Northern Celestial Hemisphere:
NGC 2420 (Gemini, open cluster, mag=8.3, size=10.0’, class= I2r):
This small, but nice cluster is found just 2° 14’ ENE of the famous planetary nebula NGC 2392 (Eskimo Nebula), which is our second object this month. This cluster was discovered by William Herschel in 1783, who described it as "a beautiful cluster of many large and compressed small stars, about 12' diameter."
The cluster field is compact, and may even resemble a small globular cluster in smaller apertures. Put some aperture, and conditions permitting, higher magnification on it and one can resolve a rich field of little diamonds glistening in the winter sky. I feel this cluster deserves more attention than it typically receives from observers and imagers. So I encourage you to add this to your next outing.
NGC 2392 (Gemini, planetary nebula, mag=9.2, size=0.8’x0.7’, SBr=8.2):
This famous and bright planetary, sometimes referred to as the Lion Nebula, is a popular visual, sketching and imaging target during the northern winter months. While its former nickname was considered offensive and fallen out of favor, it does honor a great people and culture. Therefore I would like to tale some liberal license and re-christen it the "Inuit Nebula" in this article.
William Herschel discovered this curious object in 1787, but its annular nature was first detected by Lord Rosse’s assistant George Stoney in 1849. The magnitude 10.5 central star stands out well with direct vision and without a filter. Using an O-III filter (or alternatively a narrow-band nebula filter) tames this star providing more contrast for the nebula’s disk. It is not difficult to see this planetary using an 8x50 optical finder or binoculars as a stellar object where it looks like a wide double with the magnitude 8.2 field star just over 1.5’ to its north. Visual observers should not be afraid to push the magnification, as its high surface brightness will tolerate pushing your limits a bit.
NGC 2419 (Lynx, globular cluster, mag=10.3, size=4.6’, class=2):
The dimmer northern constellation representing a celestial lynx is home to this distant globular cluster. At a distance of around 300,000 light years it was given the erroneous nickname of “Intergalactic Wanderer” by Harlow Shapley in the 1940s when it was thought to have escaped the gravitational grasp of the Milky Way. Eventually that was disproved but the name stuck. This very distant cluster was discovered in 1788 by William Herschel.
It tends to not give up any resolution of its member stars visually, though with enough aperture it may appear slightly granular. It forms a curious conga line of three with two 7th magnitude field stars just to its west. Imagers should be able to obtain some resolution, though its core will likely remain tight. Give it a try and see what your eye or camera reveal to you.
Southern Celestial Hemisphere:
NGC 2516 (Carina, open cluster, mag=3.8, size=30.0’, class=I3r):
This delightful cluster is a bright and pretty grouping of stars that carries the nickname of the Southern Beehive. It is very evident along the southern side of a triangle of three 5th magnitude field stars. Discovered by Nicolas-Louis de Lacaille in the 1751 to 1752 timeframe, it can be seen with the naked eye in moderate to low light pollution areas and even an 80mm resolves it well into over 40 stars in a wedge shaped grouping (my experience).
I find it more attractive than M44 because it is more compact and to my eye more dynamic in character. Have a long look at this beauty, and if you image, it should be a wonderful target for you.
NGC 2359 (Canis Major, diffuse nebula, mag=8.0~, size=10.0’x6.0’, SBr=13.3~):
This beautiful emission nebula is known by the nickname of “Thor’s Helmet”, and less often as the “Duck Nebula.” Personally I think it looks more like a snail in images – but that’s just me. Discovered by William Herschel in 1769, it is a beautiful and delicate object exhibiting bubble, bow shock and filamentary structure. Fired by the Wolf-Rayet star WR7 it lies about 12,000 light years away from us.
Visual observers are helped by darker skies, and a narrow-band filter can be utilized to good result. From a dark site I have just glimpsed it in an 8x50 optical finder as a tiny non-stellar glow. Imagers will find this object a very interesting target as they try to draw out the details of its delicate streamers and of course its primary “helmet” structure.
NGC 2298 (Puppis, globular cluster, mag=9.3, size=5.0’, class=6):
This cluster is not particularly large in angular extent, but it is easily discerned as a globular. It definitely gets better as aperture increases. As a class 6 core concentration cluster, if it reveals any visual resolution at all, it will not be significant in amateur scopes.
Puppis is the 20th largest constellation in the sky, but was once part of the vast constellation Argo Navis. This ancient behemoth represented the mythical ship Argo used by Jason and the Argonauts during their search for the golden fleece. According to the book Star Names – Their Lore and Meaning (1963, Richard H. Allen), the constellation contained an outrageous number of naked eye stars – 829. It was this for this reason that Nicolas-Louis de Lacaille was the first to divide the constellation into the three constituents that we know today in his 1755 catalogue. Lacaille named the three components, Puppis (poop deck), Carina (keel) and Vela (sails). These were not officially adopted until 1928 when the IAU finally established boundaries and names for the 88 modern constellations.
So there are your February targets. I encourage all, regardless of skill level to attempt observation or imaging of those objects that you have access to based on your latitude. At the same time, don’t forget your January targets as they remain in play for a bit as well. As always, please report your results back here so we can all share the experience in order to learn and grow as observers/sketchers/imagers. Good luck and get on out there!
