UNDER A DOG DAY (NIGHT) SKYby Mike Allen |
I know my life would not be as pleasant without a telescope to wander the night sky. But sometimes a hazy summer night can ruin any motivation for observing. Think again though because there is still a lot to see. Hazy skies usually mean steady skies, and steady air is just what the doctor ordered for observing planets and double stars. Mars is well past opposition and becoming less an item of interest as it shrinks in size, but Jupiter and Saturn are well placed in the early morning August sky. This month the rings of Saturn will reach their maximum tilt of 21 degrees. I like to look at double stars that display color differences. One such star is 70 Ophiuchi located on the eastern side of Ophiuchus in an easily seen "V" shaped asterism called the "Bull of Poniatowski". The double is composed of two dwarf stars about 16.5 light years away. Their magnitudes are 4.2 and 6.0. They are currently separated by 3.8 arcseconds, which makes them an easy target for small telescopes. The colors I see are reddish-orange for one star and yellow for the other. This will be an interesting double to follow during the next couple of decades because they are separating at a rapid rate. By 2024 they will move an additional 3 arcseconds farther apart. Almost directly overhead in August is the constellation Cygnus. On the northwestern side of the constellation you a find a very interesting planetary nebula that stands out nicely in hazy skies. NGC 6826, also called "The Blinking Planetary", is magnitude 8.8. It has an easily observed 10.6 magnitude central star. If you stare at the central star for a few seconds, the nebulosity of the planetary seems to fade to practically nothing. Move your eyes to an averted position and the light-blue nebulosity snaps back into view. It’s fun to compare the view between large and small telescopes. In my 10 inch Newtonian the central star is very bright, and the blinking affect is very evident. In my 3.5 inch Questar the central star is not as bright. This causes the nebulosity to fade at a slower rate, but interestingly it blinks back just as fast as in the 10 inch when I move my eyes. Compare this with a planetary of similar brightness and size on the other side of Cygnus, just east of Deneb, called NGC 7027. It doesn’t have a bright central star like 6826, so you can stare all night long without it doing a disappearing act. Cygnus is also host to a lot of small open star clusters that stand up to inspection under hazy skies. M29 and NGC 6910 for example, are within a small telescope bump of the central star of the "cross". So get out there and observe even if it is hazy. In our busy lives observing time is very precious. Don’t waste a bit of it. “Sehr Gut Fernglas!”On a recent trip to Mainz, Germany, I happened to be walking by a camera store that had a lot of used equipment in a display window. As I am always somewhat intrigued by optical equipment, I stopped to take a look at what they had to offer. Tucked away in a corner of the display was a used pair of binoculars. The price on the tag was 29 Euros, which is about 30 American dollars. A cursory inspection through the window indicated they might be of fairly good quality, so I decided to walk inside and see if they would let me take a closer look. The salesperson was very friendly and promptly took the binocs out of the window and handed them to me. The finely engraved logo on the eyepiece plate stated that they were 10 power with 50 mm objectives, manufactured by Weltblick. The salesperson told me they were older binoculars of West German origin. As I hefted them in my hand I noticed they seemed light weight despite the fact that they were all metal construction, which indicated they might have a magnesium frame. There were a few wear marks here and there on the metal parts, but the heavy duty black pebble covering on the body was in excellent shape. The eyepieces didn’t seem to have much of a coating, but the objectives were nicely coated on both the front and back surfaces. All optics were crystal clear and exquisitely polished. There was one tiny scuff mark on the left objective coating which I guessed would not make any detectible difference in the view. I next held them to my eyes and checked the field and collimation. Looking out over the town plaza while focusing and adjusting the right diopter, it became instantly apparent to me that the optics had high quality. The view was bright and with stunning detail. As I alternately opened one eye and closed the other I could see that the collimation was as near to perfect as it could be. The apparent field of view was about 50 degrees, which produced about a 5 degree true field. Everything indicated they would make excellent astronomical binoculars, so I plunked down 29 Euros. There wasn’t any case for them, so I walked out of the store with my purchase in a plastic bag. On the way back to the hotel I decided to celebrate my good luck with a beer at a small worker pub that I also like to take dinner at. Inside, the pub is quite smoky, but they sell Beck beer on tap. While sipping my brew I pulled out the binocs to admire again. An older gentleman sitting next to me took an interest and tried to strike up a conversation in German. As I speak little German, I asked the bartender to translate. She said that he was a retired worker who used to work at the Schott glass factory, and that he wanted to take a look at the binoculars. I placed them in his hands and his face lit up with a smile. He turned them over and over as I did in the photo shop. “My glass.” He said with his smile still intact. As he handed them back to me he said, “Sehr gut fernglas!” with an even bigger grin. The bartender explained that he made the glass for the lenses and that they were very good binoculars. Although they are of an older manufacture, the company still makes the same model. Later that night at the hotel, I walked outside to use my new binoculars under a clear, but somewhat light polluted German sky. Jupiter appeared as a perfectly round tiny yellow-white disk. Ganymede and Callisto flanked the left and right side, and either Io or Europa was just coming out from behind the planet’s disk. It was very nice view. M42 in Orion gave a good performance, as did M35 in Gemini. The Pleiades appeared as a cluster of tiny sparkling diamonds. Stars appeared pinpoint even as they approached the edge. Saturn was overhead and displayed a hint of ring structure. Overall I was very satisfied. The next day as I passed through customs in Chicago, I was somewhat concerned that they might not believe the 30 dollar cost I listed on the declaration form. To my relief, I was waved on through anyhow. Back at home in Ohio I was able to compare the German binoculars to my Chinese made 11 X 56 Oberwerks. The Oberwerks have a very apparent advantage in light gathering ability and a wider, 60 degree apparent field. The German binocs seem to have a better color correction, and perhaps a crisper image, although this is very close. The view through the Oberwerks was more dramatic and satisfying. I think my German “fernglas” will make a great companion to stuff in my suitcase on trips in the future without worrying about accidentally breaking an expensive pair of binoculars. Clear skies to my observing friends, Mike Allen Within Ten Degrees of PolarisThe circumpolar region of the sky is an area that is often overlooked by amateur astronomers. Most people looking for a decent observing site consider a southern view of the sky a priority. An equatorial mount can even make observing the polar region difficult. Anyone who has tried to observe the northern regions with a fork-mounted equatorial scope, understands the gymnastics required when pointing it in that direction. A German equatorial mount becomes maddening when pointing north. The mechanical difficulty involved in observing far northern objects can be avoided by using a Dobsonian, or other type of alt-azimuth mounting. Equatorial mounts can also be turned around so that the polar axis points south, producing a modified alt-azimuth configuration. A clock drive won’t work in this fashion, but you really don’t need it when observing close to Polaris. The movement of objects across the sky in this region is very slow compared to areas closer to the celestial equator. Manual tracking is sufficient, and star hopping is more leisurely. Having solved the engineering of how to get there, I’ll describe what I saw during a recent night of discovery. I chose an area within a ten-degree radius of the celestial pole because everything in this region stays at least thirty degrees above the horizon. All objects located here will be above the thickest part of the atmosphere, and hopefully, most light pollution. Of course the added bonus is that observing this area can be accomplished at any time during the year. My search was conducted on a night in early February when the sky was very dark, transparent and steady. The instrument I chose to use in this search was an 8-inch Celestron Schmidt-cassegrain, because this is the type or size of scope that many amateurs use. Light pollution towards the north at my location was less than moderate. The corrector plate on my SCT was fairly dirty, and dew was a persistent problem. The outside temperature was 20 degrees F. I began with planetary nebula IC 3568, located in Camelopardalis. This is one of the brightest deep sky objects within the ten-degree radius, shinning at magnitude 10.6. It displayed a bright central core with nebulosity near the edges. 3568 is small and spherical, and can easily be mistaken for a star when using low magnification. Its color was white with a hint of powder blue. If you stare directly at this planetary, it will very slowly fade from view. Return to averted vision and it instantly brightens. Next, I easily located the open cluster NGC 188 in Cepheus. The magnitude of this cluster is listed at 8.5. This figure is misleading because I estimate that most of its 120 stars are much fainter. I could see at least 20 faint stars enclosed by a trapezoid of four brighter stars. Almost beyond the limit of detection I could see many other stars occasionally twinkling. They formed an eerie nebulous glow across the face of the cluster. NGC 188 is of particular interest to astronomers because it is composed mostly of yellow giants. This indicates it must be very old. NGC 2300 and NGC 2276, also in Cepheus, are a pair of galaxies that are close enough to appear in the same low power field of view, however I could only see NGC 2300. It appeared as a fairly bright round patch of nebulosity, with a bright central core. Even though it is listed at 11.0 magnitude, I found it to be an easy target for my 8-inch scope. Up until now I had been using Sky Atlas 2000. The next targets on my list required the horsepower of my Uranometria atlas. NGC 2268, in Camelopardalis, is a very faint galaxy. To make a point, I underlined “easy to miss” in my notes. Although it shines at only magnitude 11.5, it displays an elongated shape that gradually brightens towards the center. The next object in Camelopardalis was the most frustrating of all. NGC 2336 is listed in my Sky Catalog 2000 as magnitude 10.4. It most certainly is nowhere nearly that bright. I searched for over 30 minutes without success before I took a break. My problem was I believed the 10.4 figure, and was looking for something that bright. After returning to the eyepiece I was finally able to locate it using averted vision while slowly sweeping the charted position. It was incredibly faint, and on the absolute edge of visibility. This left me confused enough to search my Night Sky Observer’s Guide for any additional information. I found a photo of the galaxy and from the position of the surrounding stars was able to confirm my observation. The solution to the problem was found when I consulted my old dog-eared Burnhams guide. It listed the magnitude of 2336 as a more believable 12.4. After my exhausting search for 2336, I was ready pick off a few double stars. Of course you can’t talk about double stars near the celestial pole without mentioning Polaris. Polaris is actually quite a beautiful double when viewed through a telescope. The primary is a 2.0 magnitude star with yellow-white color. It is also a Cepheid variable that varies only slightly in a period of about four days. The 8.2 magnitude companion lies about 18 arc-seconds away. It has a color described as white by some, but appears almost pale blue to me. The Polaris system is 820 light years away. I often use the de-focused image of Polaris to collimate my telescopes because of its negligible apparent motion across the field of view. W. Struve 1694 is a fairly wide double with components nearly identical in brightness. This gives the appearance through the telescope of a pair of golden yellow car headlights approaching from the distance. 1694 is located in Camelopardis. The 5.5 magnitude twin components are separated by over 21 arc-seconds. I could discern this star by naked eye, which indicates how dark the sky was that night. W. Struve 2034 is a more difficult target. The nearly identical 8th magnitude companions lay only 1.4 arc-seconds apart. Both are white in color. In my C-8 at 400X they appear as two tiny Airy disks separated by a small gap of dark sky. You can locate this double on page 11 of Uranometria 2000 Vol. 1, near the top of the chart. Its coordinates are 15h 48.7m, +83 deg 37 min. I should mention that I previously observed most of the above objects in December with my 15 inch Obsession Dobsonian. Many exhibit impressive detail in this scope. It seems that almost every object plotted on the Sky Atlas 2000 is an easy target for the Obsession. NGC 2276, although undetected in my 8-inch, was seen in enough detail to allow me to make a pencil sketch. Uranometria shows many fainter deep sky objects that were not part of this search, and these will certainly be worthy of a future observing session with the 15-inch. By now I was ready for some fireworks in the southern sky, so I placed the crosshairs of my 10 inch Newtonian on V Hydrae near the border of Crater and Hydra. This is a carbon star with shimmering blood red color. I hadn’t seen V Hydrae in many months, and was happy to find it near its maximum magnitude of 6.6. What a show! It is second in beauty only to the great R Leporis. This variable star has a period of over 500 days, so now is the time to see it at its very best. It was now past 3AM, and I had been observing for six hours. The noise of distant civilization had faded away, leaving only the whisper of a faint breeze. New star patterns appeared in the east, but fatigue and frozen feet were draining my enthusiasm. Both my telescopes had a thick coating of frost on their tubes. After closing the roof on my observatory, I carefully walked across the pasture towards the house. I smiled as I thought about what comment my wife Marilyn would have as I slid my frozen body under the blankets of our bed. Glancing up I noticed the familiar shapes of Lyra and Cygnus. Bootes was nearing the meridian. “Good night old friends”, I said to the stars above, “We will meet again”. Clear skies, Mike Allen THE 2002 BLACK FOREST STAR PARTY "I can feel it coming in the air tonight, Oh Lord.
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"Sometimes, when I am watching through my
telescopes, the question comes to me – what would life be like without a
telescope?" - Leslie C. Peltier