Explanation: Interstellar dust clouds and glowing nebulae abound in the fertile constellation of Orion. One of the brightest, M78, is centered in this colorful, wide field view, covering an area north of Orion's belt. At a distance of about 1,500 light-years, the bluish reflection nebula is around 5 light-years across. Its tint is due to dust preferentially reflecting the blue light of hot, young stars. Reflection nebula NGC 2071 is just to the left of M78. Flecks of emission from Herbig-Haro objects, energetic jets from stars in the process of formation, stand out against the dark dust lanes. The exposure also brings out the region's fainter, pervasive reddish glow of atomic hydrogen gas.
The reflection nebula looks great, and the dark dust associated with it looks downright menacing!
The stars at upper right look diffuse, as if they were car lights seen through a fog. Is it possible that the "smoke" that seems to rise from the darkest part of the dark dust associated with M78 is actually diluting the light from these stars? Or maybe there's just a "wall" there of slightly polluted gas?
APOD Robot wrote:
Flecks of emission from Herbig-Haro objects, energetic jets from stars in the process of formation, stand out against the dark dust lanes.
Yes. The middle of the darkest dust cloud is lit up, and tiny reddish flecks are seen there. These are jets from tiny fledgling stars. I think we are seeing the birth of little red dwarfs in there.
Notice that in today's APOD picture, there is a black cloud to the right of M78 and it extends into a thin arm cupping beneath M78
If you look at other photos of M78, the black cloud is to the right, but that thin arm arches above M78. I think the APOD image is flipped horizontally. Right?
Re: APOD: M78 Wide Field (2021 Jan 21)
Posted: Thu Jan 21, 2021 9:36 am
by Ann
SuperStargazerScott wrote: ↑Thu Jan 21, 2021 6:59 am
Notice that in today's APOD picture, there is a black cloud to the right of M78 and it extends into a thin arm cupping beneath M78
If you look at other photos of M78, the black cloud is to the right, but that thin arm arches above M78. I think the APOD image is flipped horizontally. Right?
SuperStargazerScott wrote: ↑Thu Jan 21, 2021 5:46 am
Isn't that image upside down?
There is no such thing as upside down in astrophotography.
But chirality is a thing,
and this photo appears to be mirror-reversed.
And now, if e'er by chance I put
My fingers into glue,
Or madly squeeze a right-hand foot
Into a left-hand shoe,
Or if I drop upon my toe
A very heavy weight,
I weep, for it reminds me so
Of that old man I used to know--
Whose look was mild, whose speech was slow
Whose hair was whiter than the snow,
Whose face was very like a crow,
With eyes, like cinders, all aglow,
Who seemed distracted with his woe,
Who rocked his body to and fro,
And muttered mumblingly and low,
As if his mouth were full of dough,
Who snorted like a buffalo--
That summer evening long ago,
A-sitting on a gate.
SuperStargazerScott wrote: ↑Thu Jan 21, 2021 5:46 am
Isn't that image upside down?
There is no such thing as upside down in astrophotography. But chirality is a thing, and this photo appears to be mirror-reversed.
The photo’s orientation can be found in the copyright link to the photographer.
Cousin Ricky:
You're right, I misstated my observation, and thanks for the correction. It's not upside down, and it's not flipped horizontally.
That photo's an error of chirality, and it's flipped vertically on a horizontal axis.
SuperStargazerScott wrote: ↑Thu Jan 21, 2021 5:46 am
Isn't that image upside down?
There is no such thing as upside down in astrophotography. But chirality is a thing, and this photo appears to be mirror-reversed.
The photo’s orientation can be found in the copyright link to the photographer.
Cousin Ricky:
You're right, I misstated my observation, and thanks for the correction. It's not upside down, and it's not flipped horizontally.
That photo's an error of chirality, and it's flipped vertically on a horizontal axis.
There is a convention in astroimages that north is up and east is to the left. It's usually observed in professional images, but is commonly ignored in the case of images (especially amateur images) with primarily aesthetic intent. Whether an image is reversed or not depends on how many reflections (if any) the light undergoes in the imaging equipment. That is, the type of telescope. This was more of an issue with film. With digital images it's common to simply correct back to north up/east left.
M78 Wide Field
