APOD: M16 Cose Up (2021 Sep 09)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 5360
Joined: Fri Dec 04, 2009 3:27 am

APOD: M16 Cose Up (2021 Sep 09)

Post by APOD Robot » Thu Sep 09, 2021 4:05 am

Image M16 Cose Up

Explanation: A star cluster around 2 million years young surrounded by natal clouds of dust and glowing gas, M16 is also known as The Eagle Nebula. This beautifully detailed image of the region adopts the colorful Hubble palette and includes cosmic sculptures made famous in Hubble Space Telescope close-ups of the starforming complex. Described as elephant trunks or Pillars of Creation, dense, dusty columns rising near the center are light-years in length but are gravitationally contracting to form stars. Energetic radiation from the cluster stars erodes material near the tips, eventually exposing the embedded new stars. Extending from the ridge of bright emission left of center is another dusty starforming column known as the Fairy of Eagle Nebula. M16 lies about 7,000 light-years away, an easy target for binoculars or small telescopes in a nebula rich part of the sky toward the split constellation Serpens Cauda (the tail of the snake).

<< Previous APOD This Day in APOD Next APOD >>


Re: APOD: M16 Cose Up (2021 Sep 09)

Post by Guest » Thu Sep 09, 2021 5:54 am

"M16 Cose Up" ??

User avatar
4725 Å
Posts: 13402
Joined: Sat May 29, 2010 5:33 am

Re: APOD: M16 Cose Up (2021 Sep 09)

Post by Ann » Thu Sep 09, 2021 7:17 am

Guest wrote: Thu Sep 09, 2021 5:54 am"M16 Cose Up" ??
Cose up? No. Close up? Sure!

M16 with arrow and M17 eBear Foto.png
M16 (arrow) widefield. Credit: eBear Foto.

In the picture at right, you can see what M16 looks like when it is not close up. Note that in any sort of RGB photography, M16 will not look blue like it does in the APOD. The blue color in the APOD represents doubly ionized oxygen, OIII, whose wavelength is 501 nm, making its true color look like this: . Green color in the APOD represents Hα, hydrogen alpha, whose wavelength is 656nm, which makes it all red: . Red in the APOD either represents ionized sulfur, SII, which at 673 nm is also all red , or ionized nitrogen, which at 658 nm is also all red .

In RGB photography, like in the picture at right, a nebula like M16 will look reddish-pink. Red Hα completely dominates the light of the nebula, but the color is diluted by Hβ, hydrogen beta, at 486 nm, whose color is bluish cyan: . OIII also dilutes the color of the nebula close to the hottest stars.

The ESO image above gives you a good idea of what the Eagle Nebula would look like to our eyes, if our eyes were many times more sensitive to faint colored light than they are. The bluish hue in parts of the nebula is due partly to the emission of OIII, but more to the fact that light from many hot blue stars is being scattered in the nebula.

You do not have the required permissions to view the files attached to this post.
Color Commentator

User avatar
orin stepanek
Posts: 8200
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: M16 Cose Up (2021 Sep 09)

Post by orin stepanek » Thu Sep 09, 2021 12:04 pm

You do not have the required permissions to view the files attached to this post.

Smile today; tomorrow's another day!


Re: APOD: M16 Cose Up (2021 Sep 09)

Post by Avalon » Fri Sep 10, 2021 6:07 pm

In the base of a pillar just about 4 o'clock from the image center there is a hot red spot that looks as if it might be a jet of some sort. Is it?