APOD: The Light, the Dark, and the Dusty (2022 Nov 30)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 5405
Joined: Fri Dec 04, 2009 3:27 am

APOD: The Light, the Dark, and the Dusty (2022 Nov 30)

Post by APOD Robot » Wed Nov 30, 2022 5:05 am

Image The Light, the Dark, and the Dusty

Explanation: This colorful skyscape spans about four full moons across nebula rich starfields along the plane of our Milky Way Galaxy in the royal northern constellation Cepheus. Near the edge of the region's massive molecular cloud some 2,400 light-years away, bright reddish emission region Sharpless (Sh) 155 is at the center of the frame, also known as the Cave Nebula. About 10 light-years across the cosmic cave's bright walls of gas are ionized by ultraviolet light from the hot young stars around it. Dusty reflection nebulae, like vdB 155 to the right, and dense obscuring clouds of dust also abound on the interstellar canvas. Astronomical explorations have revealed other dramatic signs of star formation, including the bright reddish fleck of Herbig-Haro (HH) 168. Below and right of center, the Herbig-Haro object emission is generated by energetic jets from a newborn star.

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

User avatar
Ann
4725 Å
Posts: 13490
Joined: Sat May 29, 2010 5:33 am

Re: APOD: The Light, the Dark, and the Dusty (2022 Nov 30)

Post by Ann » Wed Nov 30, 2022 11:28 am

Cave_Copyright_APOD1024[1].png
The Light, the Dark, and the Dusty
Image Credit & Copyright: Anthony Quintile
APOD 30 November 2022 annotated.png

What I like best about today's APOD is the way it shows us the huge slightly heart-shaped dusty cocoon from which all these stars have been born.

APOD 30 November 2022 detail.png

And I just love these two dust bunnies! :D

However, me being me, I wish that the reflection nebula, vdB 155, would have looked blue in the APOD. Here is a picture where it does look blue:

Velimir Popåov and Emil Ivanov wrote:

Sh2-155 (also catalogued BN 529, LBN 110.11+02.44, Caldwell 9, or Cave Nebula) is a diffuse nebula in the constellation Cepheus, within a larger nebula complex containing emission, reflection, and dark nebulosity. Sh2-155 is an ionized H II region with ongoing star formation activity. The estimated distance of Sh2-155 is about 725 parsecs (2400 light-years) from Earth. The Cave Nebula lies at the edge of the Cepheus B cloud (part of the Cepheus molecular cloud), and is ionized by very young stars (less than 100,000 years old) from the Cep OB3 association. It has been suggested that radiation from the hot O-type star HD 217086 is compressing the region, triggering the formation of a new generation of stars. This complex contains also LDN 1216 - a large dark nebula above Sh2-155 and VdB 155 - the blue reflection nebula just right of LDN 1216 (see mouseover). The illuminating star of VdB 155 is HD 216629 - a B2IV blue giant of mag. 9.37, which gives the bluish colour to the nebula.

Reflection nebulas are usually blue, because they typically scatter light from blue or blue-white stars of spectral classes A and B. But yellow reflection nebulas also exist, like the reflection nebula surrounding red supergiant star Antares.

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

User avatar
AVAO
Commander
Posts: 563
Joined: Tue May 28, 2019 12:24 pm
AKA: multiwavelength traveller
Location: Zurich, Switzerland

Re: APOD: The Light, the Dark, and the Dusty (2022 Nov 30)

Post by AVAO » Wed Nov 30, 2022 7:17 pm

.
Exciting area ...even in infrared

Click to view full size image 1 or image 2
https://live.staticflickr.com/65535/525 ... b60e_o.jpg
https://live.staticflickr.com/65535/525 ... 7427_o.jpg
jac berne (flickr)

heehaw

Re: APOD: The Light, the Dark, and the Dusty (2022 Nov 30)

Post by heehaw » Wed Nov 30, 2022 9:48 pm

I DON'T think I want to spend my holiday there.

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

Re: APOD: The Light, the Dark, and the Dusty (2022 Nov 30)

Post by orin stepanek » Thu Dec 01, 2022 4:36 am

Cave_Copyright_APOD1024.png
Ann said it! It kinda looks like a heart! Or maybe a valentine! 8-)
Sorry; no kitty or puppy today! 🥲
You do not have the required permissions to view the files attached to this post.
Orin

Smile today; tomorrow's another day!

Anthony Quintile

Re: APOD: The Light, the Dark, and the Dusty (2022 Nov 30)

Post by Anthony Quintile » Mon Dec 05, 2022 6:45 pm

@Ann

You are absolutely correct that LBN 524 should be more blue, and in fact this has been bugging me. Please read for my revision D description at Astrobin here: https://www.astrobin.com/y23yjl/F/, written before submitting to APOD.

Since I wrote that, Pixinsight has released it Spectrophotometric Color Calibration process based upon the newest Gaia DR3SP star catalogs.

Even when I apply that and no other color adjustments, however, that region is not nearly as blue as many folks show in their images. Even when I oversaturate, LBN 524 is just a bit pale blue even when the reds and yellows are overdone with the equal adjustment on saturation.

At some point I do need revisit the processing on this and capture that blue better. I am really on a learning mission to try to accurately capture color in my images.

I was kinda hoping no one would notice! ;-P

Thanks for your other kind comments!

-Anthony Quintile

User avatar
Ann
4725 Å
Posts: 13490
Joined: Sat May 29, 2010 5:33 am

Re: APOD: The Light, the Dark, and the Dusty (2022 Nov 30)

Post by Ann » Mon Dec 05, 2022 8:42 pm

Anthony Quintile wrote: Mon Dec 05, 2022 6:45 pm @Ann

You are absolutely correct that LBN 524 should be more blue, and in fact this has been bugging me. Please read for my revision D description at Astrobin here: https://www.astrobin.com/y23yjl/F/, written before submitting to APOD.

Since I wrote that, Pixinsight has released it Spectrophotometric Color Calibration process based upon the newest Gaia DR3SP star catalogs.

Even when I apply that and no other color adjustments, however, that region is not nearly as blue as many folks show in their images. Even when I oversaturate, LBN 524 is just a bit pale blue even when the reds and yellows are overdone with the equal adjustment on saturation.

At some point I do need revisit the processing on this and capture that blue better. I am really on a learning mission to try to accurately capture color in my images.

I was kinda hoping no one would notice! ;-P

Thanks for your other kind comments!

-Anthony Quintile
APOD 30 November 2022 original version.png
The Light, the Dark and the Dusty. Original version by Anthony Quintile.

@Anthony,

I checked your website, and I like the original version of your image better than the one that became an APOD.

In your original version, the reflection nebula does look blue. It doesn't look very blue, but believe me: As a self-appointed Color Commentator I am acutely aware that the color of reflection nebulas is always moderated by the presence of dust. That means, for example, that reflection nebulas surrounding A- and B-type stars can indeed be reddened by dust to a whitish blue, grayish blue, greenish blue or even "beige blue" hue.

Check out this page to compare the blue hue of the Rho Ophiuchi nebula with the washed-out dust-reddened color of IC 4603.

It is clear to me that vdB 155 is a blue reflection nebula whose blue hue is relatively strongly reddened by dust. Still, it is not so reddened that its blue color has been lost completely. I believe that your original image did a great job at bringing out the "true" color of vdB 155.

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

Anthony Quintile

Re: APOD: The Light, the Dark, and the Dusty (2022 Nov 30)

Post by Anthony Quintile » Tue Dec 06, 2022 12:48 am

@Anthony,

I checked your website, and I like the original version of your image better than the one that became an APOD.

In your original version, the reflection nebula does look blue. It doesn't look very blue, but believe me: As a self-appointed Color Commentator I am acutely aware that the color of reflection nebulas is always moderated by the presence of dust. That means, for example, that reflection nebulas surrounding A- and B-type stars can indeed be reddened by dust to a whitish blue, grayish blue, greenish blue or even "beige blue" hue.

Check out this page to compare the blue hue of the Rho Ophiuchi nebula with the washed-out dust-reddened color of IC 4603.

It is clear to me that vdB 155 is a blue reflection nebula whose blue hue is relatively strongly reddened by dust. Still, it is not so reddened that its blue color has been lost completely. I believe that your original image did a great job at bringing out the "true" color of vdB 155.

Ann
Hey Ann-

There were some other issues with those first iterations, but I wanted to try to get that blue in LBN 524 closer to the correct blue.

How about this-

https://www.astrobin.com/full/y23yjl/H/

Image

User avatar
Ann
4725 Å
Posts: 13490
Joined: Sat May 29, 2010 5:33 am

Re: APOD: The Light, the Dark, and the Dusty (2022 Nov 30)

Post by Ann » Tue Dec 06, 2022 5:35 am

Anthony Quintile wrote: Tue Dec 06, 2022 12:48 am
@Anthony,

I checked your website, and I like the original version of your image better than the one that became an APOD.

In your original version, the reflection nebula does look blue. It doesn't look very blue, but believe me: As a self-appointed Color Commentator I am acutely aware that the color of reflection nebulas is always moderated by the presence of dust. That means, for example, that reflection nebulas surrounding A- and B-type stars can indeed be reddened by dust to a whitish blue, grayish blue, greenish blue or even "beige blue" hue.

Check out this page to compare the blue hue of the Rho Ophiuchi nebula with the washed-out dust-reddened color of IC 4603.

It is clear to me that vdB 155 is a blue reflection nebula whose blue hue is relatively strongly reddened by dust. Still, it is not so reddened that its blue color has been lost completely. I believe that your original image did a great job at bringing out the "true" color of vdB 155.

Ann
Hey Ann-

There were some other issues with those first iterations, but I wanted to try to get that blue in LBN 524 closer to the correct blue.

How about this-

https://www.astrobin.com/full/y23yjl/H/

Image
Yes, that's much better. :ssmile:

Your image made me go hunting for other pictures of the Cave Nebula, to see what other photographers have made of this part of the sky. My hands-down favorite portrait of this nebula is the one by Bart Delsaert. I find it so utterly beautiful.

But I realize, of course, that you could argue that other pictures do a better job of showing us the "true" (whatever that is) nature of this nebula.

Ann
Color Commentator

Anthony Quintile
Asternaut
Posts: 1
Joined: Tue Dec 06, 2022 1:19 am

Re: APOD: The Light, the Dark, and the Dusty (2022 Nov 30)

Post by Anthony Quintile » Tue Dec 06, 2022 6:38 am

Ann wrote: Tue Dec 06, 2022 5:35 am
Yes, that's much better. :ssmile:

Your image made me go hunting for other pictures of the Cave Nebula, to see what other photographers have made of this part of the sky. My hands-down favorite portrait of this nebula is the one by Bart Delsaert. I find it so utterly beautiful.

But I realize, of course, that you could argue that other pictures do a better job of showing us the "true" (whatever that is) nature of this nebula.

Ann
Bart Delsaert is one of my favorite astrophotographers! I follow him on Astrobin.