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Astronomy Picture of the Day 5-25-03
NASA ^ | 5-25-03 | Robert Nemiroff and Jerry Bonnell

Posted on 05/25/2003 12:51:41 AM PDT by petuniasevan

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2003 May 25
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

Spiral Galaxy NGC 253 Almost Sideways
Credit & Copyright: Jean-Charles Cuillandre (CFHT), Hawaiian Starlight, CFHT

Explanation: NGC 253 is a normal spiral galaxy seen here almost sideways. It is the largest member of the Sculptor Group of Galaxies, the nearest group to our own Local Group of Galaxies. NGC 253, pictured above, appears visually as one of the brightest spirals on the sky, and is easily visible in southern hemisphere with a good pair of binoculars. The type Sc galaxy is about 10 million light years distant. NGC 253 is considered a starburst galaxy because of high star formation rates and dense dust clouds in its nucleus. The energetic nuclear region is seen to glow in X-ray and gamma-ray light.

TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: edge; galaxy; southern; spiral
NGC 253

Right Ascension 00 : 47.6 (h:m)
Declination -25 : 17 (deg:m)
Distance 10000.0 (kly)
Visual Brightness 7.1 (mag)
Apparent Dimension 25 x 7 (arc min)

The 3-16-03 APOD had this beautiful Hubble image of the galaxy's central regions:

Locator chart for NGC 253:

This galaxy's midnight culmination (highest position - due south - in the sky at midnight) is about October 17th. It is only 21 degrees above the horizon (when due south) from my location at 44 degrees north latitude.

1 posted on 05/25/2003 12:51:41 AM PDT by petuniasevan
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To: MozartLover; Joan912; NovemberCharlie; snowfox; Dawgsquat; viligantcitizen; theDentist; ...

2 posted on 05/25/2003 12:52:51 AM PDT by petuniasevan (Wonders of the Universe)
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To: petuniasevan
There is a very peculiar solar eclipse coming May 31st.

RightWhale, you should see a partial eclipse from your locale. Note that for you it will be around 9 PM Alaska Daylight Time on May 30th.


A partial eclipse of the Sun surrounded by strange circumstances is on tap for Saturday, May 31 and will be visible in parts of North America, Europe and the Middle East. The event could be quite spectacular at sunrise in Europe, especially in the United Kingdom.

Looking directly at the Sun is dangerous, so proper viewing techniques are necessary.

The most impressive aspect of the event will be an annular, or ring eclipse, so named because the Moon’s disk will be too small to completely cover the Sun’s disk. The result is a ring of fire surrounding the black circle of the Moon. It's like a dull penny sitting atop a shiny nickel.

Annular eclipses can occur because the Moon's orbit around Earth is not quite a circle. When the Moon is closer to Earth than average, a total solar eclipse can occur. When it is farther than average, an annular eclipse can result. The annular eclipse will be visible across a sparsely populated swath of Earth from Scotland to the Canadian Arctic.

Strange track

The extreme northern track of the Moon's shadow will likely make this one of the most unusual solar eclipses that will occur in the 21st century.

The antumbra or negative shadow of the Moon – from where the annular phase of eclipse is visible – will strike the Earth at a very oblique angle. In fact, the shadow will actually pass above the North Pole and a bit beyond it before it finally makes contact with the Earth’s surface. As a result of this extraordinary geometry, the antumbra appears to graze the Earth’s surface resulting in a broad, semicircular region that will experience the "ring of fire" effect.

Also, because of this unusual circumstance, instead of moving in a typical west-to-east fashion, as is the case with most solar eclipses, the shadow’s movement will actually run in reverse – from east to west.

Where to see a partial eclipse

Outside of the zone of the annular eclipse, most of Europe, the Middle East, central and northern Asia and northwestern sections of North America will be underneath the Moon’s outer shadow, or penumbra, and will see a partial eclipse. The effect is that of the Moon taking a bite out of the Sun.

The closer one is positioned to the region of visibility of the annular eclipse, the larger the eclipse. Those living in northern and eastern sections of Europe will be in position to see more than 80 percent of the Sun’s diameter eclipsed at, or soon after sunrise. Across parts of central Europe, which includes Ireland, much of England and France, Switzerland and Italy, the peak of the eclipse will have already occurred when the Sun finally comes up above the horizon – nonetheless still making for a most unusual sunrise!

Interestingly, the partial eclipse will also be visible across all of Alaska as well as a swath of northern and western Canada. Depending on where you are located, you might expect to see anywhere from about 40 to 80 percent coverage.

However, adding to the oddities associated with this eclipse, for these "Al-Can localities," since the Moon’s penumbral shadow falls to the east of the International Date Line, local clocks will be set to the previous day: Friday, May 30. Moreover, for these particular locations the eclipse will be occurring not at sunrise, but around the time of sunset.

Where to see the annular eclipse

The region from where the annular phase will be visible takes on an outline resembling a peculiar "D" shape that spans nearly 750 miles (1,200 kilometers), broader than any eclipse path in this century. The antumbra itself, thanks to the grazing angle it makes from the low Sun, projects onto the Earth’s surface as an extremely elongated ellipse. The broad area of visibility includes northern Scotland, encompasses all of Iceland before crossing into central Greenland, before ending in Baffin Bay, Canada.

3 posted on 05/25/2003 1:18:13 AM PDT by petuniasevan (Wonders of the Universe)
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To: petuniasevan
If I understand this, those in the southern hemisphere, south Pacific area won't see this at all. Is that right?

I'm thinking Aussie-land.
4 posted on 05/25/2003 1:37:30 AM PDT by Jemian
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To: RightWhale
The May 30/31 event will be on the evening of May 30th for you. First contact will be at about 8:35 PM local. Maximum partial will occur about 9:20 PM with about 30% coverage. Last contact will be around 10:20 PM.

The partial eclipse of October 13, 2004 (think ahead! :-) will be as follows: 6 PM local time first contact, and sunset at 6:32 PM with about 40% coverage. That would make a nice photo if you have the equipment and filters needed.

5 posted on 05/25/2003 1:42:15 AM PDT by petuniasevan (Wonders of the Universe)
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To: Jemian
You got it. But the next one will be more favorable for Down Under.

The November 23 2003 event will be total in Antarctica and partial in Australia/New Zealand.

6 posted on 05/25/2003 1:45:51 AM PDT by petuniasevan (Wonders of the Universe)
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To: All
Planning ahead? North America will be host to more solar eclipses in the next 50 years. Here is a chart showing TOTAL eclipse paths for the time period 2001-2050:

And here is a map of ANNULAR eclipse paths for the same time period:

7 posted on 05/25/2003 1:55:51 AM PDT by petuniasevan (Wonders of the Universe)
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8 posted on 05/25/2003 2:01:24 AM PDT by petuniasevan (Wonders of the Universe)
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To: petuniasevan
The sun might still be high enough May 30 to see something. Don't know about the one in Oct. Thanks for the heads-up. We get few astronomical events during decent viewing conditions here.
9 posted on 05/25/2003 11:58:42 AM PDT by RightWhale (Theorems link concepts; proofs establish links)
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To: petuniasevan
Thanks for the nice compilation on solar eclipses over the next few years!

The centerline of the April 2024 eclipse pretty much goes right over my house -- God willing that I'm still around and decide to stay in this godforsaken state to see it.

The August 2017 event would be a good reason to make a field trip down south to view...
10 posted on 05/25/2003 12:34:10 PM PDT by mikrofon
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To: petuniasevan
11 posted on 05/25/2003 3:01:41 PM PDT by firewalk
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To: petuniasevan
Oh my, that's beautiful!
12 posted on 05/25/2003 7:23:07 PM PDT by Soaring Feather
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