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IC 434 and NGC2024
Posted: 08.04.2003, 02:36
by praesepe
Well, this is my new experiment, the IC434 reflection nebula, and NGC2024 emission nebula, just a test to try to implement to Celestia.
The 3d mesh still needs LOTS of work in order to have it a decent look (the horsehead looks distorted for example) and of course, the object its not properly oriented in space (Zeta Orionis should be in the left, just on top of NGC2024), so RA and DEC parameters for the dsc file would be very apreciated.
Celestia
Hubble
![Image](http://www.la-guarida.com/Celestia/Image/horsehead2.jpg)
Posted: 08.04.2003, 03:21
by billybob884
can't see either pic
Posted: 08.04.2003, 03:53
by praesepe
Damn Netfirms server...
![Mad :x](./images/smilies/icon_mad.gif)
I've moved the pics to another one and edited the previous post.
![Smile :)](./images/smilies/icon_smile.gif)
Posted: 08.04.2003, 04:18
by marc
That looks fantastic, are the stars in the celestia image part of the nebula texture, or are they rendered by celestia?
In other words (did you filter the stars out of the nebula texture?)
Re: IC 434 and NGC2024
Posted: 08.04.2003, 04:33
by selden
praesepe wrote:the object its not properly oriented in space (Zeta Orionis should be in the left, just on top of NGC2024), so RA and DEC parameters for the dsc file would be very apreciated.
http://www.astropix.com/HTML/B_WINTER/B33_O.HTM has coordinates for most of the components of the Orion Nebula, including IC 434 (RA 5h 41m Dec 2 23' 59" ), NGC 2024 ( RA 5h 41m 54s Dec -1 50' 07") and B33, the Horsehead itself ( RA 5h 40m 49s Dec -2 28' 19")
Does this help?
Posted: 08.04.2003, 05:08
by praesepe
marc wrote:That looks fantastic, are the stars in the celestia image part of the nebula texture, or are they rendered by celestia?
In other words (did you filter the stars out of the nebula texture?)
Yes, all stars there are rendered by Celestia, I've carefully edited the original Hubble photograph and removed all stars using Photoshop.
![Image](http://www.la-guarida.com/Celestia/Image/h1.jpg)
selden wrote:http://www.astropix.com/HTML/B_WINTER/B33_O.HTM has coordinates for most of the components of the Orion Nebula, including IC 434 (RA 5h 41m Dec 2 23' 59" ), NGC 2024 ( RA 5h 41m 54s Dec -1 50' 07") and B33, the Horsehead itself ( RA 5h 40m 49s Dec -2 28' 19")
Does this help?
Sure! lots of thanks!
![Wink :wink:](./images/smilies/icon_wink.gif)
Posted: 08.04.2003, 05:25
by Rassilon
beautiful work....wishing I had more time to work with some of you in making the models I would help to decorate Celestia but the billboards should do for now...
Posted: 08.04.2003, 11:36
by billybob884
(referring to first set of pics) It looks like the milkey way is too visible. in hte hubble shot its not visible at all
Posted: 08.04.2003, 21:32
by jgrillo2002
Posted: 08.04.2003, 22:08
by selden
praesepe,
A minor quibble: the blue "star" just below and to the left of Barnard 33 is actually the emission nebula NGC 2023. It's much more extended in some wavelengths. You might want to include it. As best I can tell the other bright blue stars are just overexposed.
Posted: 09.04.2003, 01:33
by praesepe
Here's an update. I've reworked the texture again in photoshop and improved a little more the 3d mesh. I've also arranged the dsc file so the nebula is now placed in the correctly in Orion (thanks to selden for the data).
Here are some screenshots:
selden wrote:praesepe,
A minor quibble: the blue "star" just below and to the left of Barnard 33 is actually the emission nebula NGC 2023. It's much more extended in some wavelengths. You might want to include it. As best I can tell the other bright blue stars are just overexposed.
Oops! I just thought it was a star. I'll add it in the next update, thanks!
Horsehead
Posted: 09.04.2003, 05:13
by ogg
I seem to remember my old copy of sky3d rendering the horsehead as a dark 'dust nebula' object many light years in front of the bright nebula: the horsehead effect being an artifact of the line-up of the dark and bright nebulas as seen from earth. It looked kinda hokey... but what's the truth of that matter here? are all the features we see in this nebula from earth part of the same object, or is it two objects? anyone know?
I might be mistaken about this... I'll see if I can dig it up again. Not that this really matters; the thing looks fantastic!!!
Posted: 09.04.2003, 08:29
by marc
Again very nice work, cant wait to get the addon.
Posted: 09.04.2003, 17:11
by selden
Ogg,
Yes, they're at different distances, although the distances aren't known very accurately. The only precise measurement that I've found so far is for the star that's illuminating NGC 2023. That star is already in Celestia as HD 37903 / HIP 26816 at a distance of 1538 ly. It's "obviously" either in front of, or in the closest fringes of, the absorption nebula that includes the Horsehead Nebula. 1600 ly seems to be a reasonable estimate for the distance to the nebular complex.
Re: IC 434 and NGC2024
Posted: 10.04.2003, 17:59
by selden
praesepe,
Where did you get your "Hubble" picture of the nebula?
Can you provide a URL? I haven't been able to find it.
The Hubble telescope itself can't take pictures that are so wide; they had a lot of trouble getting a mosaic of just the Horsehead. See
http://heritage.stsci.edu/2001/12/supplemental.html
Posted: 10.04.2003, 21:12
by praesepe
selden wrote:praesepe,
Where did you get your "Hubble" picture of the nebula?
Can you provide a URL? I haven't been able to find it.
The Hubble telescope itself can't take pictures that are so wide; they had a lot of trouble getting a mosaic of just the Horsehead. See
http://heritage.stsci.edu/2001/12/supplemental.html
selden,
i've got all the information from
http://www.seds.org/billa/twn/b33x.html and also the original pic wich I modified in order to use for Celestia.
Here's also a new update, with some work on the east region (the original picture had a cut off) and with the emission nebula NGC2023 added.
![Image](http://www.la-guarida.com/Celestia/Image/ic434.jpg)
Posted: 10.04.2003, 21:29
by selden
Thanks!
(I'm guessing that you haven't put the nebula in exactly the right place yet. There are a few strange stars in the image
![Smile :)](./images/smilies/icon_smile.gif)
)
But it's looking quite good!
Posted: 11.04.2003, 01:15
by praesepe
selden wrote:(I'm guessing that you haven't put the nebula in exactly the right place yet. There are a few strange stars in the image )
Ummm may be I've done something wrong in the conversion of dec and ra coordinates, for now, the dsc setting I'm using are these:
Code: Select all
Nebula "IC434"
{
Mesh "IC434neb.3ds"
Radius 5
RA 5.673
Dec -1.95
Distance 1500
}
And here's a pic of the current orientation:
![Image](http://www.la-guarida.com/Celestia/Image/position.jpg)
Posted: 11.04.2003, 02:09
by selden
Praesepe,
The problem is its orientation: the long dimension should be north-south, not east-west.
I've created a billboard of the Horshead Nebula region which can be seen at
http://www.lns.cornell.edu/~seb/celestia/billboard.html#5.0
I think you can get the orientation and size right if you can use the original picture with stars. Then you can turn up the limiting magnitude in Celestia and align its stars with those in the texture. That's what I did for the "billboard" picture.
Another minor quibble: the distance to the lower part of the absorption nebula is probably slightly more than 1500 ly. The distance to the star in the middle of the emission nebula was measured by Hipparcos. It is in Celestia's database as HD 37903 / HIP 26816 at a distance of 1538 ly. Since we can see it, the emission nebula must be in front of the absorption nebula that forms the Horsehead. Of course, B33 could be closer to us than the eastern parts of the nebula.
(added later)
Here's the DSC that I used:
Code: Select all
#Horsehead Nebula in Orion
#
# the "billboard" picture used with this definition is derived from
#a photograph of the Horsehead Nebula Region taken by Walter Koprolin,
# Austria, Europe: http://www.astro.univie.ac.at/~koprolin/
#
Nebula "Barnard 33" {
Mesh "b33.3ds"
Axis [ -0.625476 0.339879 -0.702326 ]
Angle 128.818
Distance 1600
RA 5.69
Dec -2.35
Radius 40.3
(added still later)
here's a picture of the billboard with constellation lines
As usual, this links to a much larger picture.
Posted: 11.04.2003, 04:34
by praesepe
selden,
Looks like I got strongly confused when orientating the model
I've done the appropiate corrections and checked some data that was wrong (i.e. radius).
Now it looks like this:
![Image](http://www.la-guarida.com/Celestia/Image/ic434b.jpg)