Friday, January 31 - With plenty of dark sky tonight, let's head around a fingerwidth northeast of Zeta Orionis and right on the celestial equator for a delightful bright nebula known as M78 (Right Ascension: 5:46.7 - Declination: +00:03). This is both a binocular and small telescope Messier challenge object.
Often overlooked in favor of the Great Orion Nebula, this 8th magnitude diffuse area is easily captured under dark skies. Discovered by Pierre Mechain in 1789, M78 is part of the vast complex of nebulae and star birth that comprise the Orion region. Fueled by twin 10th magnitude stars, the nebula almost appears to resemble a "double comet" in binoculars. Upon close scrutiny with a telescope, observers will note two lobes separated by a dark band of dust. Each lobe bears its own designation - NGC 2067 to the north and NGC 2064 to the south.
While studying, you will notice the entire area is surrounded by a region of absorption, making the borders appear almost starless. Filled with T Tauri-type stars and residing 1,600 light-years away, this reflection nebula is a cloud of interstellar dust which reflects the light of these young stars, the brightest of which is HD 38563A. In 1919, Vesto Slipher was the first to discover its reflective nature. As of 1999, seventeen Herbig-Haro objects are also associated with M78, and are believed to be jets of matter being expelled from newly forming stars.
Saturday, February 1 - Are you ready for a challenge? Then take advantage of dark sky time to head to the eastern-most star in the belt - Zeta Orionis.
Alnitak resides at a distance of some 1600 light-years, but this 1.7 magnitude beauty contains many surprises - like being a triple system. Fine optics, high power and steady skies will be needed to reveal its members. About 15' east and you will see that Alnitak also resides in a fantastic field of nebulosity which is illuminated by our tripartite star. NGC 2024 (Right Ascension: 5:41.9 - Declination: -01:51) is an outstanding area of emission that holds a rough magnitude of 8 - viewable in small scopes but requiring a dark sky. So what's so exciting about a fuzzy patch? Look again, for this beauty is known as the Flame Nebula.
Larger telescopes will deeply appreciate this nebula's many dark lanes, bright filaments and unique shape. For the large scope, place Zeta out of the field of view to the north at high power and allow your eyes to re-adjust. When you look again, you will see a long, faded ribbon of nebulosity called IC 434 to the south of Zeta that stretches for over a degree. The eastern edge of the "ribbon" is very bright and mists away to the west, but look almost directly in the center for a small dark notch with two faint stars positioned to the south. You have now located one of the most famous of the Barnard dark nebulae - B33.
B33 is also known as the Horsehead Nebula. It's a very tough visual object - the classic chess piece shape is only seen in photographs - but those of you who have large aperture can see a dark "node" that is improved with a filter. B33 itself is nothing more than a small area cosmically (about 1 light-year in expanse) of obscuring dark dust, non-luminous gas, and dark matter - but what an incredible shape. If you do not succeed at first attempt? Do not give up. The "Horsehead" is one of the most challenging objects in the sky and has been observed with apertures as small as 150mm.
Sunday, February 2 - Tonight we're going in search of another Herschel 400 object. Wait until Orion has well risen and our lunar companion has ducked west. Our mark will triangulate with Xi and Nu Orionis and point back in the direction of Betelgeuse. It's name? Collinder 83...
It is believed that it may have been observed by Hodierna before 1654, but its discovery is credited to William Herschel in 1784 and cataloged by him as H VIII.24. It hangs out in space some 3600 light-years away and most catalogs refer to it as NGC 2169 (Right Ascension: 6:08.4 - Declination: +13:57). At a rough magnitude of 6, it is very well suited to even smaller binoculars. Although diffuse nebulosity accompanies this 50 million year old cluster, even a small telescope should be able to resolve out its 30 or so stellar members. But no matter which optics you chose to look at this cluster with, one bright asterism will stand out - the number '37' written in stars. Enjoy and write down your observations!
Until next week? Wishing you clear skies!
About Tammy Plotner - Tammy is a professional astronomy author, President Emeritus of Warren Rupp Observatory and retired Astronomical League Executive Secretary. She's received a vast number of astronomy achievement and observing awards, including the Great Lakes Astronomy Achievement Award, RG Wright Service Award and the first woman astronomer to achieve Comet Hunter's Gold Status.