APOD: Trifid, Lagoon, and Mars (2016 Oct 06)

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APOD Robot
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APOD: Trifid, Lagoon, and Mars (2016 Oct 06)

Post by APOD Robot » Thu Oct 06, 2016 4:10 am

Image Trifid, Lagoon, and Mars

Explanation: Bright nebulae and star clusters along this 5 degree wide field of view are popular stops on telescopic tours of the constellation Sagittarius and the crowded starfields of the central Milky Way. Cataloged by 18th century French astronomer Charles Messier, M20, the colorful Trifid Nebula, and M8, the expansive Lagoon Nebula, are at upper left and center. Both are well-known star forming regions about 5,000 light-years distant. Just passing through the same field of view on September 29, the yellowish star lined up with M8 and M20 at the lower right is actually Mars, close to 8.8 light-minutes from Earth on that date. That distance is nearly equivalent to 1 astronomical unit or the distance from Earth to Sun. Mars is overexposed in the image, with visible diffraction spikes created by the telescope mirror supports. Of course, Mars has long been known to wander through planet Earth's night skies.

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Ann
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Re: APOD: Trifid, Lagoon, and Mars (2016 Oct 06)

Post by Ann » Thu Oct 06, 2016 4:11 am

Okay - M-20, M-8 and M-ars.

Nice picture!

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Re: APOD: Trifid, Lagoon, and Mars (2016 Oct 06)

Post by atnastr » Thu Oct 06, 2016 4:02 pm

Why Mas is close to 8.8 light-minutes from Earth? Mars's distance to Sun is more than Earth's distance to Sun, and distance from Earth to Sun is 8 light-minutes.

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Re: APOD: Trifid, Lagoon, and Mars (2016 Oct 06)

Post by Chris Peterson » Thu Oct 06, 2016 4:14 pm

atnastr wrote:Why Mas is close to 8.8 light-minutes from Earth? Mars's distance to Sun is more than Earth's distance to Sun, and distance from Earth to Sun is 8 light-minutes.
Because right now, Earth is roughly between the Sun and Mars, such that we're about the same distance from both.
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Re: APOD: Trifid, Lagoon, and Mars (2016 Oct 06)

Post by Fred the Cat » Thu Oct 06, 2016 4:35 pm

The Trifid nebula is often displayed with its distinctive red-blue colors. But what is a Trifid? I thought it was a popular episode of Star Trek.
Oh – that was a Tribble. :bang:

Trifid was in The Alternate Factor. "Forgettable" it was said. But back to the Trifid - it looks like four lobes to me :?:
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Re: APOD: Trifid, Lagoon, and Mars (2016 Oct 06)

Post by Visual_Astronomer » Thu Oct 06, 2016 4:59 pm

Fred the Cat wrote:The Trifid nebula is often displayed with its distinctive red-blue colors. But what is a Trifid? I thought it was a popular episode of Star Trek.
Oh – that was a Tribble. :bang:

Trifid was in The Alternate Factor. "Forgettable" it was said. But back to the Trifid - it looks like four lobes to me :?:
The traditional names for most objects were based on visual appearance, not photographs, so unless you are using a large scope, it is difficult to see the fourth dark lane dividing the nebula. I can plainly see four segments through a 20" with a narrow-band filter, but only three are obvious through a 4" refractor.

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Re: APOD: Trifid, Lagoon, and Mars (2016 Oct 06)

Post by Fred the Cat » Thu Oct 06, 2016 7:13 pm

Visual_Astronomer wrote:
Fred the Cat wrote:The Trifid nebula is often displayed with its distinctive red-blue colors. But what is a Trifid? I thought it was a popular episode of Star Trek.
Oh – that was a Tribble. :bang:

Trifid was in The Alternate Factor. "Forgettable" it was said. But back to the Trifid - it looks like four lobes to me :?:
The traditional names for most objects were based on visual appearance, not photographs, so unless you are using a large scope, it is difficult to see the fourth dark lane dividing the nebula. I can plainly see four segments through a 20" with a narrow-band filter, but only three are obvious through a 4" refractor.
As Spock might have said, "That's logical" Thanks!
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Re: APOD: Trifid, Lagoon, and Mars (2016 Oct 06)

Post by Boomer12k » Thu Oct 06, 2016 7:56 pm

Awesome shot...

My M20....through my 10" Meade LX 200...with DSI II color camera....
I don't have the Lagoon Neb....yet....

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