Starship Asterisk*

Super Moon vs. Micro Moon

Explanation: What is so super about tomorrow's supermoon? Tomorrow, a full moon will occur that appears slightly larger and brighter than usual. The reason is that the Moon's fully illuminated phase occurs within a short time from perigee - when the Moon is its closest to the Earth in its elliptical orbit. Although the precise conditions that define a supermoon vary, given one definition, tomorrow's will be the third supermoon of the year -- and the third consecutive month that a supermoon occurs. One reason supermoons are popular is because they are so easy to see -- just go outside and sunset and watch an impressive full moon rise! Since perigee actually occurs today, tonight's sunset moonrise should also be impressive. Pictured above, a supermoon from 2012 is compared to a micromoon -- when a full Moon occurs near the furthest part of the Moon's orbit -- so that it appears smaller and dimmer than usual. Given many definitions, at least one supermoon occurs each year, with the next being 2015 August 30.

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Oh, dear, the dates embedded in the photo are not ISO 8601 compliant, unlike everything else on the APOD site, which is scrupulous about it.

RichardSRussell wrote:Oh, dear, the dates embedded in the photo are not ISO 8601 compliant, unlike everything else on the APOD site, which is scrupulous about it.

Information in the images is the responsibility of the contributor, and there are few guidelines.

RichardSRussell wrote:Oh, dear, the dates embedded in the photo are not ISO 8601 compliant, unlike everything else on the APOD site, which is scrupulous about it.

I just searched this entire forum for "8601" and only got four results (now five). Two of them (now three) were in this topic.

ISO 8601 is an all-numeric date/time format with digits ordered from most to least significant. The fact that the date shown immediately above each APOD (not in the URL) shows a non-numeric month, kinda sorta disproves your point about APOD being so scrupulous about dates.

I think you'll find that APOD adopts ISO 8601 most scrupulously, when it is most convenient for the administrators to do so, like when sorting dated lists of URLs in chronological order. But adopting a "most to least significant" date format also has the advantage of avoiding confusion between the common American (MMDDYYYY) and non-American (DDMMYYYY) formats, as it matches neither.

Interesting discussion.

And nice picture, too. I saw the Moon rise last Saturday and it seemed bigger than usual. Well, since the Moon's orbit around the Earth is elliptical, it has to look bigger at times and smaller on other occasions.

But I have to admit that to me, the highlight of today's APOD was the clue about what we will be served tomorrow. Galaxy topping, indeed. I have to wonder what this banana split would taste like with a galaxy rather than a cherry on top.

Ann

My impression is the illustration is "faked" for demonstration's purpose,
in the sense that both moon photos are one and the same, just
differently rescaled : no visible differential libration longitudinal or
latitudinal, which if the photos were truly of the alleged full moon
occurrences would be an almost impossible coincidence. Admittedly I did not
fetch and consult the epehmerids. Am I just being paranoïd ?

Czerno o wrote:My impression is the illustration is "faked" for demonstration's purpose,
in the sense that both moon photos are one and the same, just
differently rescaled : no visible differential libration longitudinal or
latitudinal, which if the photos were truly of the alleged full moon
occurrences would be an almost impossible coincidence. Admittedly I did not
fetch and consult the epehmerids. Am I just being paranoïd ?

They are definitely different images. I haven't checked the dates, but the differential libration is quite apparent to me near Grimaldi in the West (bottom left limb of both discs) and Mare Smythii in the East (top right limb of both discs).

Nitpicker wrote:
They are definitely different images. I haven't checked the dates, but the differential libration is quite apparent to me near Grimaldi in the West (bottom left limb of both discs) and Mare Smythii in the East (top right limb of both discs).

OK ! My bad ! I hadn't checked the larger versions of the pics,
they are definitely different pictures. Apologies to the author
and everybody ! Happy viewing !

Nitpicker wrote:

RichardSRussell wrote: But adopting a "most to least significant" date format also has the advantage of avoiding confusion between the common American (MMDDYYYY) and non-American (DDMMYYYY) formats, as it matches neither.

And that is very good! My own non-standard scheme, which I use on a daily basis, is, say for today, 2014 Sep 08 Mon. The day of the week is the most important practical bit of information, which for some reason seems never to be included in any of the common dating schemes!

Just for scale and using a tape measure on the monitor screen(very unscientific,yes), the supermoon measures 29% larger than the micromoon. Very significant indeed. Also, "spellchecker" rejects both.

lefthip wrote:Just for scale and using a tape measure on the monitor screen(very unscientific,yes), the supermoon measures 29% larger than the micromoon. Very significant indeed. Also, "spellchecker" rejects both.

That's okay. My spell checker rejects "spellchecker"!

I immediately looked for the libration. Seeing so many impossible sky images in TV, movies, and photographs (especially involving the moon) makes me do an immediate reality check with every such image I see.

I realized it was good for generating a stereo pair: https://farm4.staticflickr.com/3926/149 ... cfa9_o.jpg
Here is the cross eyed version, which works better for me: https://farm6.staticflickr.com/5578/151 ... e9ba_o.jpg

The supermoon is 13% bigger, so I resized the micromoon at 113%. The resizing wasn't really necessary, as anyone who's nearsighted in only one eye can attest, but it helps a little.

Ann, nice one masted banana boat to sail under any sized moon! Myself, i prefer a 3-masted banana boat, with extra mast support and lots of chopped walnuts roaming the decks.