Last night (this time much later) Part 2, with the best part near the beginning this time: So Amanda did not get back from Allentown with her family until after 2:30 am, which kept me outside looking at the late fall and winter sky display. This was cool, because I had already been out for three hours prior and seen the entire dome rotate a hugely significant amount. Counting everything, I saw parts or all of 9 of the 12 ecliptic constellations (or “zodiac” if you’re an astrologer). I’ll get to that a bit later. My main goal in the later part of the night was catching Neptune, which I have never before seen with knowledge. Culmination was about 2:35 EDT, which is only about 90 minutes after “true midnight” due to DST. Neptune is coming to opposition in just over 3 weeks, which doesn’t do a whole lot of anything for its size or brightness (now it’s 7.8, at conjunction it’s 8.0). It does, however, put the planet at its highest, above the haze, in the middle of the night. Neptune is currently in Aquarius, where it will be for the next seven years. I had to do a LOT of work in order to pin it down. Aquarius is a dim constellation in good conditions, with its brightest stars well above the ecliptic in its northern section. Neptune cannot be easily found using those stars; there is no way to traverse the distance without getting lost. I had to find a “guide star” closer to the planet, and all of them were above magnitude 4. Enter Coatesville. There is a significant light dome in the east that prevents viewing of objects too low to the horizon, but once the object rises above about 20 degrees and curves to the southern sky, the limiting magnitude increases to above 4.5. This allowed a jump to my first attempt, Iota Aquarii, which I found by extending the eastern stars of Capricornus (Delta and Gamma Capricorni) forward into Aquarius. Neptune is approximately that distance to the other side of Iota Aquarii, which I thought would make the second jump rather easy. Wrong. Neptune is simply not bright enough to stick out, and required more knowledge of the local area. I had to use a different, closer jumpoff point. My target was then changed to Sigma Aquarii, a 4.8 magnitude star to Neptune’s east. To get there, I had to make a rather long jump from Theta Aquarii (also known as Ancha), which sits below the bright line at the top of the constellation (and cannot be easily seen naked-eye from light-polluted West Chester except in perfect conditions). THEN, I had to continue running in and out of the house checking the area in Stellarium to make sure I had the correct local region of the sky (hooray, computers). In a “perfect” sky, I could have probably gotten Sigma without the “long jump,” but 4.8 is too faint to show up reliably with its low declination in the southeast. Had it been near the zenith, it *might* have been possible, but the telescope jump from Ancha was completed and absolved me of the need. It turned out Sigma Aquarii is actually totally obvious, though I did not know it at the time. Two fainter stars lie just adjacent to it, which makes it appear to have a little “train.” An arc of four “relatively” bright stars lies to the north, as well, which frames the region. After a little bit more crossreferencing, I confirmed a 9th-magnitude star just to the west, another red 7th-magnitude star above, and, in between, Neptune itself. The last classical planet on my list had been found. Neptune is certainly blue, but it does not show any kind of perceptible disk. The blue is not especially striking; it’s a pale, almost sea-blue color. It’s also very difficult to get color out of the point at all; the dot is a pinprick, similar to what I said about Chi Cygni in the previous note, except blue rather than red. Magnifying it does not change it much, though it does seem to make Neptune slightly more prominent in relation to the stars around it. I thought about this when I woke up this morning, and I think the reason why is that Neptune is actually perceptibly larger than the Airy disk of the stars, even in my telescope. Calculations say that the Airy disk should be 1.4-1.5 arcseconds; Neptune is 2.3. At higher magnifications, this should be very slightly perceptible, but only in a weak, telltale fashion. So Amanda got home, and I showed it to her and to her brother. That was that, though I will be tracking the area to confirm motion. It will be slow; Neptune circles the ecliptic once every 164 years (again, spending multiple years in each constellation). As the weeks go by, however, it should be obvious. I’m lucky the Sigma Aquarii region is as distinctive as it is; this should easily show Neptune’s movement within it. --- About ten minutes later, I was able to get the International Space Station as well, in a way I have never observed it before. I did not get it on SatTrack (which seems to be skewing the satellite passes a bit early), because the pass did not get above 20 degrees. Instead, I checked out the Heavens-Above website, which I had found when I was looking for the identity of the pass I saw in Gilbertsville two months ago. All passes brighter than 5.0 are shown, to any altitude (though in practice nothing will get above that magnitude unless it can climb above 10 degrees, except the ISS). The pass began at the Big Dipper, with the station exiting shadow at an altitude of just 11 degrees. I did not see this, as it was behind the ridgeline to my north. I ran along the road until I could see a gap, then watched the station seemingly running with me (though approximately 2000 times faster, give or take a bit of rounding). It passed almost directly through the body of the decidedly cold-weather constellation of Auriga, near the star Capella, before beginning to fall again toward the northeastern horizon. Its track was incredibly shallow, peaking at just 15 degrees, and it reached a magnitude of just -0.1. This seems bright (only three stars are brighter), but for the ISS it’s actually a very dim pass. This was, of course, due to the low altitude and the distance. Still, very interesting nonetheless. I think it’s a good time here to talk about those winter constellations. In addition to Auriga, the 2-3 am sky projected well eastward from the culminating Aquarius. Pegasus was visible to its east, as was the next ecliptic constellation of Pisces. The light dome of Coatesville made it tough, but I was able to see the Circlet, made up almost entirely of 4+ magnitude stars. Pisces currently contains Uranus, which I did not attempt to go after tonight. I will be doing so later in the summer, but the Neptune Operation was so obnoxious, and I was so tired, that I didn’t want to engage in another one (though Uranus, being much brighter at 5.9, would have been easier). Next up, farther north, was Aries. The main stars are actually above the ecliptic, which passes through a rather empty area of the constellation. Hamal and Sheratan, the brightest, are actually of higher declination than Aldebaran, despite Taurus being a “higher” ecliptic constellation. Finally, as I stood there, I noticed Aldebaran itself low in the east, between some houses. The V of the Hyades was also visible, though very difficult. The line-of-sight to Taurus’ rise point is northerly enough on the eastern horizon as to pass *above* Coatesville; from my house through Aldebaran’s rise point you’re looking more toward the Route 30 Freeway than you are toward the city, which is southeast of where I live by about 2 miles. Anywhere below the celestial equator is going to have a bad time until it clears 20-25 degrees (if it ever does), but above the celestial equator, I think the track will take it clear of the dome. I’m analyzing as I write, here; I didn’t think of this one at the time. To the west, the band of the Milky Way was quite obviously moving across to the west (at least the main portion). Instead of simply being an overhead band, it was taking an oblique angle (note: this proves a magnitude 5 zenithal sky, and it also showed me exactly where the light pollution domes were, namely Coatesville City and Chester County Airport). Before, the band “ended” at Cassiopeia, which was near the horizon, preventing one from seeing the continuation of the circle. As Cassiopeia rises, though, it exposes Perseus below it, then Auriga below that, all of them obviously covered by the band. Below that would be Orion, Canis Major, and then a forever-invisible ride through the southern sky (including the great ship Argo Navis, now split into three constellations, then Crux, the Southern Cross, and Centaurus, home to the nearest stars). Finally, the band reaches Scorpius. The galactic center is between Scorpius and Sagittarius, the “anticenter” (the look outward) in southern Auriga near the star Al Nath. We, the Sun and all her planets, are right in the middle of one of the spiral arms. One thing I noticed about the half of Taurus I could weakly see was the absence of Jupiter. Jupiter has progressed past the area in its orbit, and has moved on into Gemini. It rose at about 3:25, before Mars 20 minutes later, and I was not going to stay outside for another two hours to catch the assembly (though I would have loved to, and may have done so before I had to wake up on weekdays at 6:30). That entire unseen area of the sky is quite rich, containing Mars, Jupiter, Mercury, and the waning crescent Moon, and I’m somewhat regretting not having the endurance to have stayed up to see them (though that may have required staying up until at least 5:30). Among the other things visible at that time were the fall and winter clusters and galaxies, though I did not attempt more than the obvious. In the last ten minutes, I looked at Andromeda (M31), which probably was the greatest view of that body I have ever had in my telescope. It approached the view seen through Josh’s 8” telescope, and in some ways surpassed it when I relaxed and let myself study it for a while. It had a bright white core, and I could see the gas lanes spreading out a small amount from either side of the core. In a larger telescope, I would certainly have been able to see a greater amount of it; in sky terms it is actually four times wider than the Full Moon, though not all of that can usually be seen except in the best telescopes. I probably saw only a tenth of that, maybe, which would be enhanced with a better telescope, a darker sky, and more experience. The Pleiades were also a very interesting sight. This is not the first summer in which I saw them; last year I caught them at 5 am when I was observing Jupiter and Venus in early July. However, it was certainly a weird sight seeing them over the eastern horizon at about 2:30 am. Of course I had to put the telescope on them, and again, the best view I have ever had of the cluster sat in my eyepiece. I likened it to hundreds of perfect diamonds on the water; a few stars I had never seen before popped into view, and the brighter ones were crisper and clearer than ever. My mind wandered to the thought of a civilization on one of the stars, or even an empire; what would they see from that vantage point, and what resources would there be on the countless planets that must be orbiting many of the stars? Perhaps they have not had time to evolve (the B-class stars will not survive as long as the Sun has already lived). Anyway, it was awe-inspiring nonetheless, and beautiful. Finally, I want to mention one other thing. I confirmed three meteors, one out of the south and two definitive early Perseids. A fourth most likely streaked through my peripheral vision earlier in the night, but I can’t *prove* that it wasn’t a bit of “glasses aberration” from the airport searchlight (though I’m 90% sure it was a meteor). The best was a Perseid, streaking obviously, cleanly to the south over Aquarius as I was looking for Neptune. It wasn’t a fireball, and it was brief (as almost all meteors are), but it’s only making me look forward to next weekend even more, when the Perseids hit their peak. I highly recommend a look if the sky is clear, by the way. So that was that. Went to bed at 3 am, ruined my biological clock, and tomorrow’s going to be a horrible day when I wake up at 6:30 and my body says “what.” Entirely worth it, though.
Posted on: Mon, 05 Aug 2013 00:42:06 +0000
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