Well, I did it yesterday, Saturday, June 25! I'm not sure I've ever observed all the planets in a single session before. Plus the thin crescent Moon and asteroid Vesta. It required a fair bit of planning, plus a trial run the previous morning.
Mercury, of course, is the problem child, since it's still very low at sunrise. By the time Mercury is well up, the sky is already too bright to locate Neptune easily, so I was resigned to viewing the planets sequentially rather than all at once. Ironically, this would have been trivial if I were at my city home, because my local park (atop the old town garbage dump) has almost unobstructed views to the east. But since I'm at my hilly country home, I did the first half of the observing from my backyard, with a decent view to the south, and finished at my neighbor's yard, which has a pretty low view to the east-northeast. Good thing it's the solstice, when everything rises as far north as possible. Nowhere near me has a decent view to the east-southeast, or even due east.
I tried to observe them all in distance order, starting with Neptune and ending with Mercury and the Moon, but that wasn't really feasible, since Uranus was still below the treetops when I started observing Saturn. Also, I used the Moon to start my star-hop to Uranus, since nothing else in the vicinity was visible in the morning twilight. Curiously, Vesta, Venus, and Mars are currently all almost exactly the same distance from Earth; I had to look them up to find the correct order.
I considered starting the session with Pluto, which would have been logistically possible. But I was using my 7-inch Dob, and although I have spotted Pluto once through that scope, that was decades ago when Pluto was quite a bit brighter and my eyes were better. At this point it requires my 12.5-incher, which is far too clunky to transport to my neighbor's yard in the wee hours of the morning. Besides, Pluto is always hard work, and I (correctly) anticipated that everything else would be easy.
I also considered observing Vesta twice, early and late, to see its motion through the stars. Normally I don't count an asteroid as well-observed unless I do that. But again, it's pretty hard work, especially considering that the sky started to get light almost as soon as I was outside.
The session did have some surprises. I ended up observing Uranus when the sky was too bright to see any but the very brightest stars; I was surprised that it was so easy to star-hop to it in a sky so bright. And the view was actually half-decent; quite likely the bright sky helped defined the disk's edge and bring out the blue color. In any case Uranus was a very substantial blue circle at 184X.
As luck would have it, I was barely able to see Mercury naked-eye when it cleared the treetops 5 degrees above the theoretical horizon. I kept wondering where it was until I tried binoculars, which located it in a few seconds. And after that, knowing exactly where to look, I could just barely see it without optical aid. The telescopic view was not very good, even though I followed it almost to sunrise. It was obvious that Mercury wasn't round, but I would have guessed it was fat gibbous when it was in fact 57% lit.
I did in fact track Venus past theoretical sunrise, at which point it was still quite obvious to the unaided eye, and fairly high in the sky. Its gibbous phase was quite obvious at 120X, helped by its decent 19-degree altitude and the very bright sky background.
If I had my solar filter, I would likely have waited for the Sun to clear the treetops, too. But as it was, I went home and took a nap in the vain attempt to make up for rising before 3 a.m.
. But still, a very cool sight to see.
