Every once in a while you get one of those special nights, that revitalizes your love of astronomy, or maybe it’s just a “me thing.” Monday, March 22, 2004, I had one of those nights and I think I’d like to share as much of it as I can. I knew early in the day that it was going to be clear this night and that I was going to be out at sunset. If only to see the planets lined up from the western horizon to the eastern sky, with a two-day old moon mixed in there just for good esthetics.
At 18:45 EST I was at one of my favorite places to observe from in Ann Arbor, Leslie Park (south off Dhu Varren, between Nixon Rd. and Pontiac Trail). This is another one of Ann Arbor’s wonderfully maintained City Parks that have proved to be, great observing areas for me, with low horizons and an absence of lights inside the park area. Leslie Park is particularly good for its horizons all the way around because it’s located on a hill north and east of downtown Ann Arbor I have seen many “ground scraping” sights from this location and whenever I need a low horizon this is the place I go.
Well, let me get on to the observing session that inspired this article. As I was setting up my 12.5” f/5.6 Truss Type Newtonian telescope, I could tell its was going to be a good night when I noticed a thin “Cheshire Cat Grin” smiling at me from about 20 degrees above the western horizon. The two-day old moon was easily visible even as the ground began to swallow the sun. Bring on the Night! I thought and almost spoke aloud. By 19:05 EST the day’s light source had left only its bright twilight glow in the west and now Mercury shining at -1.0 magnitude 5 degrees below and to the right of the “Cheshire Smile” poked its way into view. By now my telescope was put together and I quickly collimated the mirrors and waited for it to cool down. About 22 degrees above the Moon and almost out shining it was brilliant Venus at -4.3 magnitude and about 55% illuminated. As I followed the ecliptic eastward I could see that familiar orange glow of the 1.3 magnitude Mars had camped out just to the south of the Pleiades, some 12 degrees away from Venus. Moving another 35 degrees eastward along the ecliptic and almost directly overhead was the “Ringed Jewel of the Night” Saturn, with its multitude of moons. Now roll a third of the sky further east and the “King of Planets” Jupiter rules that part of the night’s firmament.
By now the telescope’s optics had cool sufficiently to afford a magnified view of these sparkling gems of the night, but which one do I start with? Mercury was racing to hide itself below my horizon so let’s start there. Even as low as it was, Mercury at 145x was simply, “beautiful!” 67% illuminated this tiny planet is always a treat to see. I could tell by the steady image I was getting that something wonderful was happening, beside have some incredibly clear and transparent skies, they were also steady! I watched Mercury until my neck got sore and then moved up the ecliptic to the Moon. With only just a little over 4% of its face illuminated most of the features visible were highlands, but four small Maria which include Smythii and Humboldtianum (impact basins), and Marginis and Australe (old flooded basins). Every time I look at the Moon’s surface I ask myself, when will we return? When will man walk upon that monochromatic surface again?
Now, it was time to put the telescope on Venus, and I like to use a lunar filter when observing this bright planet, it cuts down the glare just right. Venus was just a little over half lit, and if you examine it closely you may notice very subtle differences in the brightness of the clouds that shroud the planet. I was able to see a little difference in the northern third near the terminator, it was very subtle but it was there, Gary Perrine’s photo confirms this.
Mars was calling me and despite its miniscule size of just less than 5 arc seconds, it can still show wonderful detail given enough power and steadiness of the seeing. The southern polar ice cap has grown considerably since last summer and showed as a bright white spot on the right limb in my view at almost 300x.
I don’t want you to think that I wanted to keep all these views to myself. I wanted desperately to share this evening with anyone who was willing to come out. I was calling all of my “peeps” (or at least those who were programmed into my cell phone), but I either got no answer or an excuse. Oh well, I tried! John Causland had set up a scope before his class and hosted an impromptu mini star party somewhere in Detroit; for about 20 people and Doug Scobel had taken up temporary residence in Clayton Kessler’s Driveway in attempt to pick off a few more of the Herschel 400. I learned later that Gary Perrine and Doug Nelle were also out gathering photons from their favorite haunts, so at least a few of Lowbrows were out observing.
Next stop Saturn .... I love the views of Saturn that my scope has given me in the past, but on this night I had the collimation of the optics “dialed in” and the views at 400x were breathtaking! The Cassini division, Crepe ring, Encke division, and 6 of its moons, Titan, Rhea, Tethys, on Saturn’s left and to its right, Mimas, Enceladus, and Dione were all part of my incredible evening. With its bands slightly shadowed by the planet itself, I could have spent all night just staring in total awe!
But I had done a little pre-session homework before coming out, and I knew that Jupiter was the object to observe this night. Two of the Galilean moons, Io and Europa would be transiting this evening at the same time and owing to the fact the Jupiter has just past opposition of March 4th, the shadows of these two moons would follow closely behind and would be easy to see crossing the face of Jupiter. By 19:50 EST my scope was aimed directly at the face of Jove and what I saw was very special. At 400x I could just make out the two moons just a little past half way thru the transit. But their shadows were perfect little black spots just to the east of center. After only 15 minutes of watching I could already see that the trailing shadow was catching up its partner. Would it pass before leaving the face ... only time would tell? By 20:35 EST, Europa was protruding from the western limb of Jupiter’s face like an angry pimple about to burst, and 1/3 in from the eastern limb the GRS was moving across the face now! While the moons and their shadows race each other along the Northern Equatorial belt, the GRS was sliding along its centuries old path on the Southern Equatorial belt. By 20:50 EST the two shadows were neck and neck with a 1/3 of the face to go, it looks like Io’s Shadow wins by two lengths. Mean while back to the moons ... Europa has left the building! and is free to move about the planet (within reason, of course!) I must admit that although the GRS has lost a lot of its “R” and is now more like the GPH (Great Pale Hollow) I am still fascinated by this multiple world size storm that has been raging centuries and almost certainly millennia. Whenever I see the GRS I think of Galileo pointing his crude telescope at Jupiter and discovering the 4 moons which are grouped and referred to, with his moniker attached. There is no record of Galileo seeing the GRS but Cassini did and made some wonderful drawings of the feature in 1665, while he was the first director of the Paris Observatory. After another few minutes Io poked itself out from Jupiter’s western limb and in few more minutes Io will have left the building, too! By 21:20 EST, Io’s shadow had left its partner in the dust and was now, just a hole on the edge of Jupiter. The GRS was nearing the meridian by now and I was going to have to start packing up soon, I still need to be up and off to work by 04:00 EST, so weekday observing sessions are usually short ones. By 21:30 EST the moons and their shadows were done transiting and only the GRS and those magnificent bands were left. I took one more look at Jupiter and then Saturn before I packed my gear away.
But the sights
Of this night,
Tend to excite
And makes it
Hard to sleep
Either sound or light.
Sorry about the lousy poetry but as you can tell, I was inspired, until next time I wish for all of you, Clear Skies and Dark Nights. Carpe Nocturne!