Happy New Year everyone, and I hope you made it through 2023 relatively unscathed! Whenever I hear someone mention a constellation that they are anxious to see rise above the horizon every year. Or the one that they will get up in the pre-dawn hours sometimes for the pleasure of catching that first view every year. It is almost always Orion that they mention! It indeed seems to be one of the most loved of the 88 recognized constellations. This large and showy constellation was listed among the original 48 written about by the 2nd century astronomer, Ptolmey. Its stellar figure represents a great hunter from Greek mythology that Zeus (or Artemis) honored with placement amongst the stars.
(Orion as illustrated by Johann Bayer in Uranometria in 1603)
For us, it is one of the most beloved constellations in the stellar heavens. And rightly so, as it is home to some amazing deep sky objects (DSOs), from the in-your-face obvious to dim and challenging, and everything in between. It is well known for its DSO diversity, containing nebulae of the emission, reflection, dark and planetary varieties. There are beaucoup open clusters and myriad galaxies though the brightest of this category are in the 12th magnitude range. Unfortunately there are no known globular clusters in Orion. Nonetheless, there are ample observing opportunities within the “great hunter” to keep one busy for quite some time. If one also tosses double stars into the mix, then observing in Orion can almost turn into a full time career! (smiley)
I am posting this particular edition for two months because Orion will be front and center during both January and February, and also giving you all some time to work on the numerous objects that I will share with you for your pursuit. Whether you are purely a visual observer, a sketching enthusiast and/or an imaging aficionado, there should be plenty of interest for you here.
While everyone pursues the Messier objects within Orion (M42/43 and M78) regularly, to truly appreciate this large constellation (26th in terms of area) one should pursue at least some of the other stuff that it has to offer. That is exactly why I am omitting those regular showpieces from this edition about Orion. I am 100% sure you will make time to go after the Messier objects there, so I wanted to draw your attention to hopefully some objects that you may not have considered. My object selection for Orion runs the gamut from bright and easy to some dimmer challenges for you. To challenge ourselves as observers and imagers is always a good thing. It is through those personal challenges that we grow and develop our skills. And honestly, while the Messier objects are what Orion is predominantly known for, there is simply so much more there to feast your eyes upon.
For some if not many, I am sure that you have pursued some of the below objects previously. But hopefully I will provide at least a few new ones to add to your observing/imaging plans for a good number of you. I of course have not listed an exhaustive number of DSOs, but I hope that I have given you a very good sampling of what to expect within the great hunter’s stomping grounds! So with that, I will leave these in your capable hands. Enjoy the constellation of Orion for all of its brightness and beauty; its depth and variety; and its richness and rewards. It is indeed sitting up there just waiting for you to turn your eyes its way.
NGC 1977 (diffuse nebula, mag=7.0, size=20.0’x10.0’):
NGC 1973 (diffuse nebula, size=5.0’x5.0’):
NGC 1975 (diffuse nebula, size=10.0’x5.0’):
Just north of the Orion Nebula is this three piece nebula structure, collectively known as the “Running Man.” Personally I think it takes a bit more imagination than I have to see that figure in it. However, it does have a curious appearance, particularly from darker locations. There are a few brighter stars embedded in this complex, particularly 42 Orionis (mag 4.6) and 45 Orionis (mag 5.2). Take a look at this interesting nebula structure and see if you can pick up hints of someone running through your field of view!
NGC 2024 (diffuse nebula, mag=10.0, size=30.0’x30.0’):
Just northeast of the eastern most star in Orion’s belt, mag 1.8 Zeta Orionis (Alnitak), look for this elusive object, famously known as the Flame Nebula. Visually this is a challenging object for those under light polluted skies. While it is not so difficult from darker locations, its diaphanous structure will not knock you over as does M42/43. Use of a narrowband nebula filter will definitely boost contrast of this object, as will an O-III filter, though a little less so. A key detail to look for is a dark lane separating two main portions of the nebula’s glow.
IC 434 + Barnard 33 (diffuse nebula + dark nebula, mag=7.3, size=60.0’x10.0’):
Located just south of Alnitak and the Flame Nebula is the famous dark nebula, the Horsehead Nebula. The object IC 434 is a bright north-south nebula complex extending down from Alnitak. This nebula is what actually allows the Horsehead or Barnard 33, to be visible. It provides that illuminated backdrop for the dark nebula to become apparent. However, these can be very challenging objects for many, particularly those dealing with significant sky glow. In this case darker skies are your friend; as can having an H-Beta filter in your kit. In fact this type of filter is often called a Horsehead filter. If you enjoy true challenges, this may just be the one for you! One thing to remember as well is that when people do finally see the HH, they are surprised that it is larger than they were expecting!
NGC 2175 (diffuse nebula, mag=6.8, size=40.0’x30.0’):
NGC 2174 (knot within nebula, mag=unk, size=3.5’x2.0’):
The so-called Monkey Head Nebula is a nebula plus open cluster (Collinder 84). NGC 2174 is a brighter knot within the larger nebula. Often one will find NGC 2174 listed as the nebula and NGC 2175 as the cluster. However, that is incorrect. NGC 2174 is in the northwestern quadrant of the nebula complex. Another open cluster, Pismis 27, sometimes referred to as NGC 2175S, is found at the eastern edge of the nebula. Have a look and see what you can see.
(Image Credit: Don Goldman, Ph.D. [Astrodon])
NGC 1788 (reflection nebula, mag=9.0, size=8.0’x5.0’):
You can seek this nice object about 7° southwest of brilliant Mintaka, the westernmost star in Orion’s belt, near the border with Eridanus not quite 2° north of mag 2.8 Beta Eridani (Cursa). This reflection nebula is moderately bright, and as is typical of this type of nebula presents a soft and delicate glow. The two main stars involved are one of 10th magnitude in its central area and one of 9th magnitude at its northern edge. It has a bit of a ghostly, otherworldly appearance and in my book is a true visual treat off the beaten path.
NGC 2022 (planetary nebula, mag=11.6, size=18.0’x18.0’, SBr=10.4):
While there are numerous planetary nebulae within Orion, this object is the brightest of the lot and easiest to pin down. This small round disk typically appears whitish to the eye and lies about 2° southeast of the open cluster Collinder 69 (see below) which marks the head of Orion. For the most part the object appears as a smooth disk. With much larger apertures one may begin to pick up some hints of internal structure and maybe, just maybe, illusive hints of its dim mag 14.9 central star.
NGC 1980 (open cluster + diffuse nebula, mag=2.5, size=14.0’x14.0’):
This dual object is also known as Collinder 72 (cluster) and LBN 977 (nebula), and has been called the “Lost Jewel of Orion.” Immediately below Messier 42, this bright grouping is an interesting object in the eyepiece. The bright star Iota Orionis (mag 2.8) dominates the view of this field, with other stars of 4th to 8th and dimmer magnitudes scattered loosely around the area. The weak nebula associated with Iota can be quite difficult to differentiate from the bright glare of the primary star.
NGC 1981 (open cluster, mag=4.2, size=28.0’)
Immediately north of the “Running Man” nebula complex, one can find this cluster. It is dominated by nine stars of 6th to 8th magnitude scattered around its large field with many of dimmer magnitudes filling in between. It may be visible with the naked eye as a small hazy patch, depending on your sky quality, and definitely improves as aperture increases.
NGC 2169 (open cluster, mag=5.9, size=5.0’x5.0’):
Over 7° NNE of brilliant Betelgeuse, the famous “37” cluster forms a triangle with mag 4.5 Xi Orionis and mag 4.2 Nu Orionis. This most curious object truly does look like its nickname, both visually and in images. Two clumps of stars dominate this cluster’s field, one to the southeast and one to the northwest, with a nearly starless void between. This highlights the respective subgroups that indeed vaguely look like a 3 and a 7. Give it a look; do you see what I see?
(Image Credit: Rick Johnson)
Collinder 70 (open cluster, mag=0.6, size~3.0°):
This object is the epitome of a binocular object. The Orion belt star cluster is huge as it encompasses the three belt stars with myriad around them. It is bright and scattered, just perfect for binoculars or low power wide filed telescopes. While its enormity can be appreciated with the naked eye, it truly is best enjoyed with some level of optical enhancement.
Collinder 69 (open cluster, mag=2.8, size=70.0’):
We now move to the head of our great hunter. This cluster is also known as the Lambda Orionis Cluster, It contains a wide scatter of about 15 stars in the range of 4th to 9th magnitude predominantly in a south to north line starting at Lambda and trickling north, and scattered to the eastern half of the cluster’s field. As aperture and magnification are increased, more and more dimmer stars come into view. While not a particularly showing cluster, it nonetheless is still another facet of the beauty of Orion.
NGC 1924 (barred spiral galaxy, mag=12.5, size=1.6’x1.2’, SBr=12.9):
We now turn our collective focus to the subject of galaxies. While Orion is rarely considered a fertile galaxy hunting ground, it is not devoid of these distant star islands either. The distinctive thing about this particular galaxy is that it is located not quite 2° due west of the great Orion Nebula complex. Of course, being so close to such a stalwart of the night sky and not particularly bright goes a long way toward ensuring the object’s relative anonymity.
NGC 1684 (elliptical galaxy, mag=12.0, size=2.2’x1.7’, SBr=13.5):
This elliptical galaxy is located in the far southwestern corner of Orion near the border with Eridanus, about 1.75° east of mag 4.0 Mu Eridani. It contains a small bright core that may appear stellar. Be sure to look out for dimmer NGC 1682 less than 3’ to its west.
NGC 1691 barred lenticular galaxy, mag=12.0, size=1.7’x1.5’, SBr=12.9):
Located in the lower part of Orion’s shield, this lenticular is found about 50’ north of mag 3.7 Pi 5 Orionis. A bit of a thick oval in appearance, its core can appear a little brighter than the surround halo of its galactic disk. One may even glimpse an intermittent stellar core buried within.
NGC 1819 barred lenticular galaxy, mag=12.4, size=1.7’x1.2’, SBr=13.0):
Located about 3.5° WSW of brilliant mag 1.6 Gamma Orionis (Bellatrix), this lenticular lay about 44’ due west of the mag 5.4 star HD 34043. While overall a little dim, this galaxy does display some brightness within its small core, typical of this type of galaxy. With enough aperture and magnification one may discern a fleeting stellar core.
So there you have it my friends. A small sampling of the various treats awaiting you in the amazing constellation Orion. It sports objects for all aperture and experience levels, from easy to challenging; from bright and showy to dim and underwhelming visually. It has something for everyone, so spend some time in the great hunter’s stomping grounds and reward yourself with some of his visual treats! Good luck and I encourage all to post your personal experiences with Orion so that we may all enjoy and learn from your personal experiences in one of the most sought after parts of the sky.