Eric David commented on August 12:
“Talking about the total length of time and inflation makes my head spin, but back here on Earth I was treated to a nice view of all five naked-eye planets this evening, including what seemed to be a perfectly symmetrical diamond of the Moon, Mars, Antares, and Saturn at almost the exact south point. In the west, what was (a week or so ago) a straight line between Venus, Mercury, and Jupiter has become bent as Mercury slides south of the ecliptic.”
I thought I’d illustrate this, but had to wait till today to learn Eric’s location (Fredericksburg, Virginia) and the time after sunset (he estimates “about 45 minutes to an hour”).
I would say it could not have been much more than 45 minutes; by an hour, Mercury would be on the horizon and Venus below it.
Eric had some more to say about this, which I hope he will put into another comment here.
The item is copywrited.
I will send you my personal copy of the issue to the Raynham, MA post office address or to such other as you may suggest.
KH
Change of Topic:
Is there intelligent life out there? The SETI program has thus far failed to find definitive proof. Perhaps they’ve been looking for the wrong kind of signal. In light of recent political events in this country (and Guy would probably add his own to the list), as well as nuclear weapons/power and global warming, I think I may have identified a sign that someone out there towards Carina has written us off or is telling us to stay out of their neck of the galaxy. Please see the Astronomical Picture of the Day for Aug 14, 2016 for the evidence (http://apod.nasa.gov/apod/astropix.html). If you don’t see it, feel free to consult my flickr page (link below) where I have helpfully annotated the apod image. Warning: with this thread, I have slightly lowered the otherwise impeccable standards of propriety and intellectual discourse maintained by Guy and the other correspondents on this blog. OK, maybe considerably lowered.
It’s always exciting to see Venus for the first time in the evening. Have you seen Venus yet since its superior conjunction?
The cloud cover in England probably limits your celestial viewing.
A vague high gave us enough sunshine yesterday for the London-region Amnesty International picnic in Lincoln’s Inn, a pleasant park; today we’re under enough of a low to give continuous cloud. Don’t know whethere you can see this satellite movie: http://en.sat24.com/en/eu/visual
I very much appreciate Guy taking the time to diagram the scene. The shape of the diamond and its (mirror-imaged) orientation reminded me of the dolphin’s body in the constellation Delphinus, with the Moon symbolizing the beautiful double star Gamma Delphini. Seeing the Moon as part of this almost perfect diamond shape made it easy to detect the Moon’s motion, because an hour later the shape had become noticeably distorted.
My wife, after I introduced her to astronomy, quickly picked out Delphinus as one of her favorite constellations because it’s so cute and represents an animal she loves, so she would always point out the little diamond if it was visible in the sky. Her affinity for the diamond shape reminded me of a story I read somewhere (I cannot remember if Guy wrote it or if Fred Schaaf wrote the piece) that the ancient Persians held some sort of festival centered around the constellation Crux, but when precession gradually made it no longer visible from their latitude, they “switched gears” to Delphinus because of the shape. A bit of a come down, I would say! A couple of nights ago they would have had a temporary but spectacular substitute to enjoy.
By the way, I found several websites describing the Persian association with Crux and Delphinus, and both cited Richard Allen’s book “Star Names, the Lore and Meaning” as a source, so although I have not read that book, perhaps some of you have.
Best of luck to all in seeing the Venus – Jupiter conjunction on the 27th!
Delphinus the Dolphin is one of my favorite constellations too – perhaps equal first favorite small constellation with Lacerta the Lizard.
Richard Hinckley Allen says in “Star Names” (I have the Dover republication, 1963), under Crux, that “It was last seen on the horizon of Jerusalem – 31°36’45” – about the time that Christ was crucified. But 2000 years previously all its stars were 7° above the horizon of the savages along the shores of the Baltic Sea, in latitude 52°30′.”
If I understand the way precession works and its effect on the visibility of the stars, it seems like we are living in the “worst” possible epoch for viewing the Sagittarius – Scorpius region of the sky from the northern hemisphere. We are somewhat compensated, however, by living in the “best” possible one for viewing Orion and Canis Major.
So, based on what Allen writes, it seems that 4,000 years ago the peoples of Earth saw the Milky Way circling the sky at a much lesser inclination compared to the galactic equator, so the entire Milky Way would have been visible from almost all inhabited locations. Those lucky savages!
I think this is made fairly clear by the large “Precession” sphere picture in my Astronomical Companion. What moves are the celestial poles and the celestial equator, so there are many circles for that equator at different epochs. It now passes through the middle of Orion, and earlier passed north of it. The galactic equator (Milky Way) is now at a fairly steep angle to the celestial equator, and earlier was at a shallower angle to it.
Hello Mr. Ottewell
In view of the imminent roll out of the new edition of “The Under-Standing of Eclipses”, see if you can pull up this unusual photo that appeared in “The New England Journal of Medicine” two weeks ago:
“Sky Shadow”
Ho-Cheol Kang, M.D.
N ENGL J MED 375;5 p479
NEJM.ORG
The New England Journal of Medicine
Volume 375 No.5 p.479
AUGUST 4, 2016
Thank you. When I clicked on the link, it led to the website of the journal, but I didn’t see how to find the photo. Could you give me guidance, or could you perhaps give the direct link? I’m curious to know about this unusual photo.
When I saw your comment as an email, waiting for “approval”, the line “NEJM.ORG” had a hyperlink, but it no longer seems to have that in the approved comment. These technical problems…
Each week the Journal publishes, from submissions that come in from doctors around the world, two photos in each issue to fill “white space” at the end of one or another learned article.
I tried my subscriber website but these photos are evidently not considered “editorial material” and are nowhere to be found there.
I think the simplest thing would be just to mail you the physical page with the photo out of my issue.
The photo is of the sun, quite low with respect to the horizon, but unseen because it is eclipsed by a higher nubbin of cumulus cloud beyond which a compact cone of shadow projects towards the zenith upon an even higher layer of altostratus.
Could you scan the photo and post it here for us to see?