Horsehead Nebula among February night sky features
February is here, like it or not! I say this because February is supposed to be the cruelest month, hinting at the end of winter, but capable of some of the worst weather of the season. Let us see if this February can bring us some clear night skies.
Venus rules the beginning of the evening and is quite bright in the southwest. As the month goes on, this inner planet will rise higher in the sky and it will be easier to see. I haven’t gotten a good image of Venus ever, so perhaps this month I will make another try. Any good image will likely appear in this column.
Mercury, the innermost planet, will be visible as of Feb. 10. It will be about 10 degrees above the west-southwestern horizon. At 10 degrees, it will be rather low and will appear star-like. A moderate-sized telescope will show that it is a tiny ball, not a star.
As far as constellations go, Orion the Hunter still is most prominent. It will be almost directly south in the night sky after 9 p.m., and it will be well above the horizon for easy viewing. On a clear, dark night, just scanning it with the family binoculars can be very rewarding. The constellation itself lies almost square on with the winter Milky Way. This means Orion presents beautiful star fields within its borders and some of the prettiest nebula to be seen. These include the Horsehead Nebula, so named for its shape, the wonderful nebula in Orion’s sword, and M42, a somewhat Christmas-tree shaped red nebula, visible in long-exposure photographs.
The Horsehead Nebula has always been very intriguing to me. The horsehead shape is caused by an enormous cloud of nearly opaque black dust lying in front of a large cloud of excited hydrogen. So, the horsehead shape is “backlit” by the fluorescing hydrogen. It really cannot be seen, even in large binoculars because it is very faint. I once could just see it visually in a 17-inch telescope deep in the California desert. It was so faint, it appeared to dodge in and out of my sight, being right at the limits of what the color receptors in my retina could detect. It is interesting to note that if we were looking at this nebula from a position, say, 50 light-years to the left or right of the nebula, it most likely would not appear as the horsehead shape at all. What shape might it appear to be?
Long-exposure photographs can reveal its beauty. Some years ago, as a faculty member at John Brown University, I could use the school’s 16-inch reflector, and, with a new digital camera my brother had just given me, I set about trying to record this very faint object. I usually sit on a little stool when making images — even now, I still sit on that little stool. When I saw my shot of the Horsehead in the tiny display screen, I nearly fell off that little stool! It was so hard to photograph but I did it! I have included my image here, made up of a stack of ten individual images, stacked with a computer program I have that allows me to combine the ten shots into one shot, better than any individual shot by itself.
I expect that February will present some winter weather, with the night sky obscured by clouds and rain — even snow. If there are a few good nights of good seeing, I will be in my backyard, observing and perhaps photographing what the February sky presents. You could be in your backyard too, doing the same thing and appreciating the sheer awe of it all. •••