View Full Version : Hole in Orion (M-42 nebula)

2005-Mar-14, 10:12 PM
Hi does anyone know the exact loaction of William Herchels Hole in the opening of Orion? I am told that the trapezium stars marks it entrance. Does the hole exist within the boundries of the trapezium or is it off to one side? Is it also possable to view it in a 36 inch telescope?

2005-Mar-14, 10:55 PM
This is an animation of a flight through the centre of the nebula around the Trapezium;
There is a kind of hole in this model; I wonder if that is what you mean. It is of course an 'artists impression' produced by the American Museum of Natural History.

The brilliant stars of the Trapesium have cleared a massive hole in the nebula, and in the animation you fly right into it...

2005-Mar-14, 11:50 PM
That animation is really cool!

2005-Mar-15, 03:30 AM
Really, really cool!

2005-Mar-15, 04:05 AM
I 3rd that!

Hope someone can answer your question. This is the first I've heard of a hole in the orion nebula.

Welcome to the board ashley. :D

2005-Mar-15, 02:18 PM
I will see if I can get William Herchels exact quote in the next few days and post it. I believe he said that it was a hole and that their was nothing (no stars within it boundries).
The animation was cool and I can see where hole he might have been talking about. Thanks. Somebody did state that the orion nebula looked like an ear turned toward us.

2005-Mar-15, 02:28 PM
I liked the animation for the jets and how as the disk lost matter, the jets turned off.

2005-Mar-16, 07:27 PM

Brady Yoon
2005-Mar-16, 11:42 PM
Anyone know how bright the Trapezium stars are? Compared to Rigel and the other stars of Orion...? All the books say "bright stars", but don't say how bright.

2005-Mar-17, 02:41 AM
This (http://www.astropix.com/HTML/B_WINTER/TRAPEZ.HTM) should help.

Brady Yoon
2005-Mar-17, 04:02 AM
This (http://www.astropix.com/HTML/B_WINTER/TRAPEZ.HTM) should help.

Thanks Archer. Awesome link, but I didn't really see the luminosities of the stars. But judging from an 06 and 07 spectral type, it's probably in the hundred thousand solar luminosities (bolometric).

2005-Mar-17, 05:33 AM
This (http://www.astro.uiuc.edu/~kaler/sow/theta1ori.html) should help also.

2005-Mar-17, 12:52 PM
This is an animation of a flight through the centre of the nebula around the Trapezium;
Whoa, what a ride! 8)

2005-Mar-17, 01:54 PM
Celestia puts Theta1 Orionis at 54700 solar luminosites; but that is just the visual brightness, and assumes that the Hipparchos derived distance is accurate (unlikely at that distance). These stars will be much brighter in the UV range.

2005-Mar-17, 05:30 PM
Hi Everyone
Thanks for all the information and the great welcome! :D
I found this sight as a link from one of the Willam Herschel sites http://vis.sdsc.edu/
It has a longer narrated version the flyaround plus the page has more information about the hole/fishmouth.
I was always looking for a hole through (Blackness)the nebula :oops:
Thanks once again to everyone.

2005-Mar-18, 07:04 PM
Hi everyone
Here is sites and info. referencing the hole in orion. I have not been able to find the exact quote. I guess I will have to read through my books to find it.
You can see where I was led to believe that the hole was a blacken spot
It seems that Hercshel refered to the black absorption nebulas as holes in the sky


William Herschel observed it in 1784 with his newly completed 18.7-inch f/13 speculum telescope. He wrote of "the beautiful Nebula of Orion. Its extent is much above one degree; the eastern branch passes between two very small stars, and runs on till it meets a very bright one. Close to the four small stars, which can have no connection with the nebula, is a total blackness; and within the open part, towards the north-east, is a distinct small faint nebula, of an extended shape, at a distance from the border of the great one, to which it runs in a parallel direction,

In the bright center area, (rectangular) surrounding the Trapezium, that is so often seen "burnt-in" to photographs, there were included intricate lacy threads of gas, and a nearly complete "canal" or dark lane cutting almost all the way through it, (bisecting it , but offset) opposite from M43, and opp. from the dark wedge that pokes into it. This was not at all like any photos, much better resolution. The outer arms were lacy, and delicate, very clearly seen, similar to photos,but nearly colorless the further out you go. The Trapezium stars, at the core of the brightest part of the nebula were a bit bloated, due to seeing . 4-5 stars were clearly noted. More on the Trapezium stars (6) was reported on in a separate observation report. M43 looks like it is included in M42, a roundish piece cut off from the main body.

The area around the Trapezium in very, very mottled, like storm clouds. The dark marking called the "fish mouth" appears three dimensional. The dark area is obviously in front of the nebulosity. The dark lane extends beyond the nebula to the NE. Raising the power to 220X will hold 10 of the faint stars in the nebula steady. The central region around the Trapezium has "rays" of nebulosity that extend into the darker region to the south. The Trapezium stars are contained within a "hole" in the nebula, it appears that these stars lit off and blew away the material nearby.


Stars are created from nebulas - a thin expanse of material. If the nebula is near a star or group of stars, it can be seen as emitted light (caused by re-emitting energy absorbed from the star light) or as reflected light (bounced off the nebula material). The Great Nebula of Orion displays both types. A nebula far from any stars is not directly visible and can only be detected as it blots out stars behind it, forming a "hole in the heavens" as one astronomer (William Herschel) once described them. There's no good example of such a "hole" in the Northern Celestial Hemisphere,

Brady Yoon
2005-Mar-22, 01:37 AM
This (http://www.astro.uiuc.edu/~kaler/sow/theta1ori.html) should help also.

That's awesome... So this is almost an Eta Carinae. Is the brightness being lowered as a result of the nebula, and what will hapen to the Orion Nebula when the supernova hits?

I thought it was interesting how much more luminous some stars in Orion are. Betelgeuse and Rigel are nothing compared to stars like Alnilam, with a luminosity of 375,000 solar.