The Grandeur of Orion
Some of my early attempts at astrophotography. Below is a photograph of Bait Saih al Maleh, the new head office of Petroleum Development Oman, taken early one evening in December, 1998. The constellation Orion (the Hunter) is rising behind it. Look towards the East on a winter evening and you should be able to recognize it. By midnight it should be overhead. It rises and sets, just like the sun. It is one of the first constellations that any beginner in astronomy learns to recognize. The photo was a bit of a challenge; how to show the stars and not over-expose the building. The stars were given sufficient exposure (30 sec, 28mm lens at f2.8, camera on ordinary photo tripod) by holding and jiggling a black-covered book in front of the camera to block out the building. At the end of the exposure the book was removed for about a second to record the building. All photos below were taken on ISO 800 Fuji colour print film. For long exposures, because of reciprocity failure, it seems to be actually faster than Kodacolor Gold 1000 (something to note if you want to try out this type of photography).
Next below is a close-up of Orion, 60 sec exposure, 50 mm lens at f2.8, camera mounted piggy-back on a telescope tracking in alt azimuth mode, to better "freeze" the drift of the stars. Orion is supposed to be a hunter, here with his head towards the left-top corner (the small cluster of 3 stars), belt made of 3 stars in a straight line in the middle (almost vertical line in the picture below, sword made up of the 3 stars that are at about 45 degrees and then legs below.
Sky map of Orion follows below, note that the map shows Orion standing up (i.e. rotated compared to the photo above). It is interesting that the formal astronomical names of the brightest stars are Arabic from centuries ago (perhaps it's all those Ramadhan nights in the desert?). The imagination has wavered over the centuries and while Rigel (=foot in Arabic) is still a foot in modern sketches, Saiph (=sword in Arabic. Not sure whether it refers to Saif Hinai or Saif al Harthy!) is often taken as the other leg in Western sketches. Some of the other names are readily identifiable with modern Arabic (Alnitak=Belt, Mintaka=Region, Betelgeuse=Beit al Ghuss?) but what is Alnilam or Bellatrix?! Deciphering Bellatrix looks as much of a challenge as realising that Gibraltar started out as Jebel Tariq or that the River Guadalkivir in Spain started off as Wadi al Kabir! Would be most interesting to see a modern Arabic star atlas, if anyone out there has one...Later I found out that Betelgeuse = Yad al-Jauza = Hand of Orion, and Alnilam = Al Nidham = String of Pearls
It is interesting that many people, like myself, do not really see the colours of stars, they all seem bright yellow, but to prove that they are coloured, strongly, the photo below was taken for a minute with the lens set at infinity, then defocused for 30 seconds. The colours of Betelgeuse and Rigel are now obvious. Betelgeuse is a red giant star. If we could see infrared it would be the brightest star in the sky. Rigel is a much hotter, younger star, blue hot. Please also note the blue hot stars of the belt of Orion. Let us now zero in on the 3 "stars" that constitute the modern "sword" of Orion. In particular note the tiny, fuzzy, red region of M42 and M43.
Below is a close-up of this region. It is the magnificent Orion Nebula. In fact we note that the 3 stars are not 3 at all, more like 3 clusters. The longer the photo exposure, the more stars we see. This photo was taken using an 8" SCT at f/6.3 for one minute. The telescope was unguided but was tracking in alt azimuth mode. The 3 "stars" from the above photo (Orion's sword) are rotated to vertical (as in the map) and span the picture below. The nebula is a gas cloud 1500 light years from us (some 14000 trillion kilometers!) but still just next door in astronomical terms. It is still in our galaxy (the Milky Way), just a tiny fraction of the diameter of our galaxy away from us, and stars are still being formed by the gas condensing under gravitational pull. The nebula itself is trillions of km across and is illuminated by the stars in the bright, central region.
Below is an even closer view of the bright, central region, image rotated somewhat. I cut the exposure way down so that you are now able to see the Trapezium Star System, right at the heart of the nebula. Image is an RGB combination of 3 I took with a CCD (an astronomical digital camera suited to very low light levels). Same telescope as above, at f10, but the tiny CCD yields a 7 times enlarged view compared to 35mm film. Notice how softly and delicately the light falls on the nebula. Actually the light from the stars causes the nebula to fluoresce and emit a red (hydrogen alpha) light. I rather like the way the Trapezium Stars are hanging in the foreground, i.e. we can clearly tell what is in front of, or behind what. And the light left these stars 1500 years ago to reach us today!
Hopefully the next time you look up and recognize Orion, you will recall a bit of what you see here. It's all right there before your eyes!
God's work is truly humbling! Season's Greetings!
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