Sent: Tuesday, March 20, 2007 1:39 PM
Subject: Observing at Beresford, SD 2007 March 20 U.T.
Hi Guys,
James Hoefelmeyer joined me here in rural
Beresford, SD, (Hodgson Observatory) before sunset and set up his fine 12.5 inch Dobsonian telescope in a dark spot SW of the observatory tower. The sky was quite clear (transparency ~ 6), although a little dust was evident near the horizon, and the atmosphere steady (seeing ~ 8/10 most of the evening.) There was no wind. (I observed with James rather than opening my Observatory since I am still recovering from a hernia surgery, and have not been cleared yet by
my surgeon to lift more than 10 pounds.)
In the early evening we looked at gibbous Venus in the western sky. At (01h 09m UT) James spied the very very thin crescent Moon, and we were impressed by the view in the telescope. The image was razor-thin indeed. A very few small craters were seen “engraved” on a thin line. I do think this was the youngest Moon I have ever seen!
Later in the evening we observed Saturn, getting good to very good views, but only three satellites were seen clearly: Titan, Rhea, and Dione, all approaching eastern elongation. I believe I also saw
IapetusNE of Saturn, but I was not sure until I checked the Astronomical Almanac later in the evening. Cassini’s Division, and the three major rings were well seen. We enjoyed fine views of a variety of Messier objects: M45, M42 (looking for but not seeing the Horsehead Nebula), M41, M46 (including the Planetary Nebula within it), and M1. It was a cold night, but a delightful one. We ceased observing about (CDT).
I very much appreciate a report from John Johnson of observing last evening with Brook Moyer and Leon Lewis at
LakeAlvin. It seems John may have seen the Horsehead Nebula. Let’s try it again if we can at the gatherings (for the intrepid observers) on Friday April 13 and / or at the New Moon Saturday gathering on Saturday, April 14. Let’s hope for clear skies both nights!
Sent: Tuesday, March 20, 2007 11:34 AM
Subject: Impromptu Observing Session 3/19/07Last night 3/19/07 Leon Lewis, Brook Moyer, and Myself agreed upon meeting at lake Alvin for a short observing session. I had one target in mind, and that was the Horse Head Nebula. After initial alignment, I targeted M42 to verify that I had an exacting alignment. M42 appeared almost dead center in the 12.5 mm eyepiece (200 X). Knowing the telescope knew where it was, I entered B 33 as target. The telescope slewed to position. I then green lasered the position to visually compare to printed star charts. We then used a low power eyepiece to locate pointer stars and confirm proper telescope location. According to star charts and telescope readout we were located on the Horse Head Nebula. Now to find it. First attempt was with Leon’s 26mm Plossel 50 deg AFOV with 1.25″ H-Beta filter giving us a .5 deg TFOV at 100X. Slight nebulosity could be discerned crossing the eyepiece from an 11 o’clock to 4 o’clock region. Averted vision only hinted at a slight dark area. Three different observers could not confirm sighting.
Next I tried a 27 mm Panoptic 68 deg AFOV with a 2″ H- Beta filter giving us a .72 deg TFOV at 95 x. This helped a little with the nebulosity and contrast improving. Using averted vision I could just make out the outline of the Horse Head. Leon tried to confirm but was unsuccessful, as was Brook. Without others confirmation I must say that I imagined the Horse Head, as to really having observed it. However I now know the guide stars to location and the orientation of the object in the eyepiece and what eyepiece and filter combination to use.
Other interesting events were seeing the Orion Nebula through Leon‘s 80 mm ED Celestron refractor. I honestly did not expect much but I was astounded by the tack sharp Trapezium and the complete circle of nebulosity surrounding it. The view was most unexpected. Also a visit to Saturn with the 80 ED revealed a high contrast orb with a hint of the Cassini division. Also was a surprising wide field view of M81 / 82. M82 revealed the dark dust lane that crosses its edge on view. Most impressive for a 3″ telescope. Brook had an excellent view of the Bee hive cluster and also of Saturn at 500x. I was very impressed with the detail he was getting at the telescopes theoretical limit of magnification. Five moons could be discerned and I made an attachment as to what we saw.
The temperature had fallen very fast and we were not prepared for much more observing so we packed up at abut 10 pm and called it a night. All in all a good time.
JJ
Subject: Loose Globular Cluster NGC 5053
Date: Sun, 11 Mar 2007 18:47:55 -0600
Hi JJ! Thanks again for the many beautiful views of so many deep sky objects you showed us last night! That 20-inch Obsession telescope of yours continues to impress us all! Remember after you showed us the magnificent M53 globular star cluster in Coma in the late evening, I suggested we find the a fainter globular, NGC 5053 located just one degree away? We didn’t find it, and now I knowwhy. The answer is clear in the write-up in Kepple & Sanner’s “The Night Sky Observer’s Guide” volume 2, pages 103 and 104. Pull your copy off the shelf and look at Figure 37-43 on page 103. NGC 5053 WAS HIDDEN IN PLAIN SIGHT. It is an EXTREMELY LOOSE globular cluster, Class XI. Most globular clusters in our Galaxy have 50,000 to 100,000 stars; some have 500,000 (M13); the best of them, Omega Centauri in the southern hemisphere, has over a million stars. In contrast NGC 5053 is a very poor relation. According to Kepple & Sanner has only about 3,400 stars. It is 49,500 light years away and has a diameter of ~ 150 light years. It looks more like a faint open star cluster, not a globular. We should have checked the field more carefully! Sir William Herschel did when he discovered it in 1783, and no one was directing him where to look.
Why is NGC 5053 a globular cluster when it has so few stars and looks like an open cluster? The answer is the presence of RR Lyrae type variable stars it has, and the nature of its Hertzsprung-Russell diagram (also called its Color-Magnitude diagram). I recommend that we look again for NGC 5053 this coming New Moon Saturday Night, or on the next clear night.
Also, taking some observing advice from Stephen James O’Meara, we need to take darkness adaptation more seriously. There is a time for red lights when setting up and taking down, but very faint red light and that only then when absolutely needed is even better. That is what Herschel had going for him.O’Meara says that the human eye’s ability to adjust to very, very low light levels is astonishing if you give it half an hour or more of complete darkness to allow true darkness adaption to develop. (I have just been checking my two O’Meara volumes on Caldwell and Messier objects and can’t give you a supporting page reference on this, but trust me, I am sure I read it a few days ago.) So we all have to try to do better I guess. In part that is what NGC 5053 is teaching us.Have a great week! And thanks again! Dick
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