Starship Asterisk*

So, what does the aqua (blue-green) circle that covers the left half of the APOD represent?
If the entire nebula is 450 LY wide, and the scale in the upper right of the image shows 10 LY, the aqua circle is too small to be the nebula.

[quote="Chris Peterson" post_id=293181 time=1561339463 user_id=117706]
[quote=BillBixby post_id=293176 time=1561316794 user_id=139344]

Today I particularly like the scale added to the top right as it helps to clarify an area(s) I keep trying to understand better. Parsecs.

Is the lower line showing the length of 4 parsecs plus three arcminutes? Or is the line showing the length of 4 parsecs, in this view, being equal to three arcminutes. I’m not sure my mind is willing to grasp the astronomical concept of a parsec, yet.
[/quote]

A parsec is a simple unit of length. It is based on parallax angles, from the amount we see nearby stars shift against a distant background as the Earth moves around the Sun over a half year. You can read the article and see a diagram on the [url=https://en.wikipedia.org/wiki/Parsec]Wikipedia page[/url] about it.

The 3 arcmin annotation is showing the angular scale of the image; it is unrelated to distance. What that bar is telling you is that at the distance of this nebula, a 3 arcmin wide object spans 4 parsecs. A parsec is about 3.3 light years.
[/quote]

Thank you Chris. A huge help to me on this. At this distance 4 parsecs in a 3 arcmin view. At other distances more, or less, parsecs will be in the same 3 arcmin. Much appreciated.

[float=right][youtube]https://www.youtube.com/watch?v=fjYuw6zWk_Y[/youtube][/float][quote=BillBixby post_id=293176 time=1561316794 user_id=139344]Still confused by parsecs …[/quote]
So was [url=https://www.imdb.com/name/nm0000184/]George Lucas[/url]. :wink: [i]“It’s the ship that made the Kessel Run in less than 12 parsecs.”[/i] Although the filmmaker later tried to justify his error with an alternate explanation (finding a dangerous shortcut route, making it about distance again).

[quote=BillBixby post_id=293176 time=1561316794 user_id=139344]
I enjoy the pictures, comments and appreciate all the work going into the APODs. Recall being overwhelmed previously by the scope of this APOD. The information is terrific, today, with the annotation. I don’t recall if it was annotated previously.

Today I particularly like the scale added to the top right as it helps to clarify an area(s) I keep trying to understand better. Parsecs.

As I understand the terms, light years is a measure of distance, arcminutes a measure of angle. Still confused by parsecs as applied to things outside our solar system. It seems to be a term combining both distance and angle. Is the lower line showing the length of 4 parsecs plus three arcminutes? Or is the line showing the length of 4 parsecs, in this view, being equal to three arcminutes. I’m not sure my mind is willing to grasp the astronomical concept of a parsec, yet.
[/quote]

A parsec is a simple unit of length. It is based on parallax angles, from the amount we see nearby stars shift against a distant background as the Earth moves around the Sun over a half year. You can read the article and see a diagram on the [url=https://en.wikipedia.org/wiki/Parsec]Wikipedia page[/url] about it.

The 3 arcmin annotation is showing the angular scale of the image; it is unrelated to distance. What that bar is telling you is that at the distance of this nebula, a 3 arcmin wide object spans 4 parsecs. A parsec is about 3.3 light years.

[quote=dlw post_id=293175 time=1561306965 user_id=100770]
What is the "bubble" near the left edge of the Carina image?
[/quote]

I wish I knew. As you can see, though, Eta Carina is right next to this bubble (to the lower right of it in your picture), so mighty Eta Carina might have something to do with it.

There is something vaguely bubble-like some distance "above" powerful star cluster Trumpler 14, too. At least a large bright rim can be seen.

I too appreciate the annotation.

Ann

I enjoy the pictures, comments and appreciate all the work going into the APODs. Recall being overwhelmed previously by the scope of this APOD. The information is terrific, today, with the annotation. I don’t recall if it was annotated previously.

Today I particularly like the scale added to the top right as it helps to clarify an area(s) I keep trying to understand better. Parsecs.

As I understand the terms, light years is a measure of distance, arcminutes a measure of angle. Still confused by parsecs as applied to things outside our solar system. It seems to be a term combining both distance and angle. Is the lower line showing the length of 4 parsecs plus three arcminutes? Or is the line showing the length of 4 parsecs, in this view, being equal to three arcminutes. I’m not sure my mind is willing to grasp the astronomical concept of a parsec, yet.

What is the "bubble" near the left edge of the Carina image?

When you're on your cosmic exploration trip; :rocketship: keep a safe distance from this area! :mrgreen:

Awesomely Annotated...:-)
And a great image, of course.
:---[===] *

[url=https://apod.nasa.gov/apod/ap190623.html] [img]https://apod.nasa.gov/apod/calendar/S_190623.jpg[/img] [size=150]Carina Nebula Panorama from Hubble[/size][/url]

[b] Explanation: [/b] How do violent stars affect their surroundings? To help find out, astronomers created a 48-frame high-resolution, controlled-color panorama of the center of the [url=https://apod.nasa.gov/apod/ap040517.html]Carina Nebula[/url], one of the largest star forming regions on the night sky. The [url=http://hubblesite.org/image/2099/news_release/2007-16]featured image[/url], taken in 2007, was the most detailed image of the Carina Nebula yet taken. Cataloged as NGC 3372, the [url=https://en.wikipedia.org/wiki/Carina_Nebula]Carina Nebula[/url] is home to streams of hot gas, pools of cool gas, knots of dark globules, and pillars of dense dusty interstellar matter. The [url=https://apod.nasa.gov/apod/ap160814.html]Keyhole Nebula[/url], visible left of center, houses several of the most [url=https://apod.nasa.gov/apod/ap190220.html]massive star[/url]s known. These large and [url=https://apod.nasa.gov/apod/ap170815.html]violent stars[/url] likely formed in dark globules and continually reshape the nebula with their [url=https://science.nasa.gov/ems/10_ultravioletwaves]energetic light[/url], outflowing [url=https://apod.nasa.gov/apod/ap000318.html]stellar winds[/url], and ultimately by ending their lives in [url=https://www.youtube.com/watch?v=sTyMffjKTTo]supernova explosion[/url]s. Visible to the unaided eye, the [url=https://apod.nasa.gov/apod/ap160323.html]entire Carina Nebula[/url] spans over 450 [url=https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html]light years[/url] and lies about 8,500 light-years away toward the constellation of Ship's Keel ([url=https://en.wikipedia.org/wiki/Carina_(constellation)]Carina[/url]).


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