APOD: A September Morning Sky (2017 Sep 21)

Comments and questions about the APOD on the main view screen.
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APOD: A September Morning Sky (2017 Sep 21)

Post by APOD Robot » Thu Sep 21, 2017 4:15 am

Image A September Morning Sky

Explanation: The Moon, three planets, and a bright star gathered near the ecliptic plane in the September 18 morning sky over Veszprem Castle, Hungary. In this twilight skyscape, Mercury and Mars still shine close to the eastern horizon, soon to disappear in the glare of the Sun. Regulus, alpha star of the constellation Leo, is the bright point next to a waning crescent Moon, with brilliant Venus near the top of the frame. The beautiful morning conjunction of Moon, planets, and bright star could generally be followed by early morning risers all around planet Earth. But remarkably, the Moon also occulted, or passed directly in front of, Regulus and each of the three planets within 24 hours, all on September 18 UT. Visible from different locations, timing and watching the lunar occultations was much more difficult though, and mostly required viewing in daytime skies.

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ta152h0
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Re: APOD: A September Morning Sky (2017 Sep 21)

Post by ta152h0 » Thu Sep 21, 2017 5:54 am

I need to buy an astromnomy program cd
Wolf Kotenberg

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Re: APOD: A September Morning Sky (2017 Sep 21)

Post by Boomer12k » Thu Sep 21, 2017 6:05 am

Wonderful...Romantic even... Fairy tale like...

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Re: APOD: A September Morning Sky (2017 Sep 21)

Post by Boomer12k » Thu Sep 21, 2017 6:06 am

ta152h0 wrote:I need to buy an astromnomy program cd
No... STELLARIUM.... free.... pretty good too...
or ... Star Chart... if you have Android... also free....

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orin stepanek
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Re: APOD: A September Morning Sky (2017 Sep 21)

Post by orin stepanek » Thu Sep 21, 2017 11:47 am

I noticed that Luna looked a little hexagonal while I was sizing it for a wallpaper for my desktop! Beautiful picture though! 8-)
Orin

Smile today; tomorrow's another day!

heehaw

Re: APOD: A September Morning Sky (2017 Sep 21)

Post by heehaw » Thu Sep 21, 2017 2:26 pm

Astronomy is looking up!

othermoons

Re: APOD: A September Morning Sky (2017 Sep 21)

Post by othermoons » Thu Sep 21, 2017 2:53 pm

Best Monday morning drive to work. Right there in front of me, beautifully still.

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Re: APOD: A September Morning Sky (2017 Sep 21)

Post by Bird_Man » Thu Sep 21, 2017 3:14 pm

ta152h0 wrote:I need to buy an astromnomy program cd
Take a look at Stellarium, a free open source astronomy program available for download for Mac, Windows, and Linux machines. Their web site is http://www.stellarium.org.

wstchr

Re: APOD: A September Morning Sky (2017 Sep 21)

Post by wstchr » Thu Sep 21, 2017 3:53 pm

Is there another star showing in this picture up near Mars?

wstchr

Re: APOD: A September Morning Sky (2017 Sep 21)

Post by wstchr » Thu Sep 21, 2017 3:58 pm

wstchr wrote:Is there another star showing in this picture up near Mars?
Sorry, I see three stars in the upper left of the picture NOT near the planets or the moon.

badmoonbilly
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APOD today 09/21/2017

Post by badmoonbilly » Thu Sep 21, 2017 8:12 pm

In today's piccture I see another object grouped with Mars and Mercury that is not named. It is above and to the right of Mars about 1 1/2 times as far from Mars as Mars is from Mercury. --- what is it? It doesn't appear to be an image artifact...

De58te
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Re: APOD: A September Morning Sky (2017 Sep 21)

Post by De58te » Thu Sep 21, 2017 8:24 pm

If that is Regulus, then the three stars in the top left are probably Leo's head. Gamma Leo and Zeta Leo probably, not sure which name the faint star is.

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Re: APOD: A September Morning Sky (2017 Sep 21)

Post by Joe Stieber » Thu Sep 21, 2017 8:52 pm

wstchr wrote:Is there another star showing in this picture up near Mars?
Above-right of Mars, approximately at the 1 o'clock position from Mars and about 50% greater than the Mars to Mercury spacing, is magnitude 3.9 Rho Leonis. You have to look carefully to see it.

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Re: APOD: A September Morning Sky (2017 Sep 21)

Post by Joe Stieber » Thu Sep 21, 2017 9:23 pm

De58te wrote:If that is Regulus, then the three stars in the top left are probably Leo's head. Gamma Leo and Zeta Leo probably, not sure which name the faint star is.
Actually, at the upper-left edge of the frame, Algieba (Gamma Leonis, the fine double star) is on the left, while dimmer 40 Leonis is just below-right of it (they're just above a wisp of a cloud). Farther right, roughly halfway to Venus from Algeiba (but not quite on a straight line), is Eta Leonis. Gamma and Eta are both part of Leo's Sickle, which frames the Lion's head.

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Joe Stieber
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Re: APOD: A September Morning Sky (2017 Sep 21)

Post by Joe Stieber » Thu Sep 21, 2017 9:52 pm

Perhaps this labeled version of today's image will be more clear than my written descriptions of the locations of the additional stars that have been discussed.

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Re: APOD today 09/21/2017

Post by bystander » Thu Sep 21, 2017 10:47 pm

badmoonbilly wrote:In today's piccture I see another object grouped with Mars and Mercury that is not named. It is above and to the right of Mars about 1 1/2 times as far from Mars as Mars is from Mercury. --- what is it? It doesn't appear to be an image artifact...
wstchr wrote:Is there another star showing in this picture up near Mars?
Joe Stieber wrote:Above-right of Mars, approximately at the 1 o'clock position from Mars and about 50% greater than the Mars to Mercury spacing, is magnitude 3.9 Rho Leonis. You have to look carefully to see it.
Joe Stieber wrote:Perhaps this labeled version of today's image will be more clear than my written descriptions of the locations of the additional stars that have been discussed.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
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tomatoherd

Re: APOD: A September Morning Sky (2017 Sep 21)

Post by tomatoherd » Fri Sep 22, 2017 5:29 pm

I don't see how, from the geometry of this skyscape, the moon occulted Regulus and the 3 planets the day of the photograph. From Venus at the top to Mercury at the bottom I estimate about 19 full moons, or a little over 9 degrees, which is fine, distance and time-wise. BUT, drawing a line from Venus to Mercury, the Moon is NOT ON IT, and is to the side of Regulus. Even if it already occulted Venus and is heading towards Mars and Mercrury, it is NOT occulting Regulus here, and is not on the line. Venus, Regulus and the Moon are forming a right angle. No trajectory sense here.
What's up???

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Chris Peterson
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Re: APOD: A September Morning Sky (2017 Sep 21)

Post by Chris Peterson » Fri Sep 22, 2017 5:52 pm

tomatoherd wrote:I don't see how, from the geometry of this skyscape, the moon occulted Regulus and the 3 planets the day of the photograph. From Venus at the top to Mercury at the bottom I estimate about 19 full moons, or a little over 9 degrees, which is fine, distance and time-wise. BUT, drawing a line from Venus to Mercury, the Moon is NOT ON IT, and is to the side of Regulus. Even if it already occulted Venus and is heading towards Mars and Mercrury, it is NOT occulting Regulus here, and is not on the line. Venus, Regulus and the Moon are forming a right angle. No trajectory sense here.
What's up???
You're overlooking just how close the Moon is to the Earth compared with the other planets and with the stars. Whether you see an occultation or not depends on where you are on Earth. From the location this image was made, no occultations occurred. In order, they were (1) Venus, seen from SE Asia, Australia, and NZ; (2) Regulus, seen from NE Africa to N Australia; (3) Mars, seen from Micronesia to NW South America; (4) Mercury, seen from E Asia to N Polynesia. I don't think there was any one location where you could witness all of them.
Chris

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tomatoherd

Re: APOD: A September Morning Sky (2017 Sep 21)

Post by tomatoherd » Fri Sep 22, 2017 6:30 pm

Ah! thanks! just like an eclipse....