IC 434 and NGC2024

The place to discuss creating, porting and modifying Celestia's source code.
Guest

Post #41by Guest » 23.04.2003, 17:25

thank you...

:D

Avatar
selden
Developer
Posts: 10138
Joined: 04.09.2002
With us: 18 years 4 months
Location: NY, USA

Post #42by selden » 23.04.2003, 17:36

With Celestia v1.3.0 when you put a subdirectory within the extras directory, you do *not* have to make any changes to celestia.cfg. Celestia automatically looks through all the subdirectories that it finds in its extras directory. The change to celestia.cfg is only needed if you want to use a directory that is *not* within the extras directory.

added slightly later:
I've updated http://www.lns.cornell.edu/~seb/celestia/addon-intro.html to include several examples of this procedure.
Selden

Darkmiss
Posts: 1059
Joined: 20.08.2002
With us: 18 years 5 months
Location: London, England

Post #43by Darkmiss » 23.04.2003, 21:56

Looks amazing praesepe, thank you
CPU- Intel Pentium Core 2 Quad ,2.40GHz
RAM- 2Gb 1066MHz DDR2
Motherboard- Gigabyte P35 DQ6
Video Card- Nvidia GeForce 8800 GTS + 640Mb
Hard Drives- 2 SATA Raptor 10000rpm 150GB
OS- Windows Vista Home Premium 32

Guest

Post #44by Guest » 23.04.2003, 23:14

Oh, I didn't realize that you didn't have to modify the celestia.cfg file for folders in the extras folder. I misread your response in this thread:

http://www.shatters.net/forum/viewtopic.php?t=2062

Thanks for clearing that up Selden.

Anyway, adding those names to the celestia.cfg file did *not* hurt anything! :wink:

Guest

Post #45by Guest » 23.04.2003, 23:44

Many thanks for your nebula praesepe... I've also found NGC 1999 which is nearby?!

Fantastic...bh(not logged in again!).

Avatar
selden
Developer
Posts: 10138
Joined: 04.09.2002
With us: 18 years 4 months
Location: NY, USA

Post #46by selden » 23.04.2003, 23:57

bh,

yup: they're really part of a single gigantic star-forming region. The Rosette nebula is just a little to the north-west, for example.
Selden

bh
Posts: 1509
Joined: 17.12.2002
With us: 18 years 1 month
Location: Oxford, England

Post #47by bh » 24.04.2003, 23:44

I'd really like to use the star cluster generator to populate this nebula.
Im having trouble getting the cluster in the right place. 'RA' 'Dec' and the other variables just fox me...I'm no astronomer.

Any help would be great.

Regards...bh.

Avatar
selden
Developer
Posts: 10138
Joined: 04.09.2002
With us: 18 years 4 months
Location: NY, USA

Post #48by selden » 25.04.2003, 00:56

bh,

Right Ascension (RA) is measured in Hours, Minutes and Seconds of time:
it corresponds to the Earth turning under the sky, similar to longitude. 0 hours is measured from the position of the sun at the Vernal (spring) Equinox. RA Hours increase toward the East (not West, as I had here before!) on the sky.

Declination is measured in Degrees, Minutes and Seconds of angle: it corresponds to latitude on the Earth's surface: 0 at the equator and 90 at the poles, the North Pole being positive and the Sough Pole negative.

The stars should be put in about the right place if you use the same coordinates as for the Nebula -- although you didn't say which Nebula you want to do this for.

A quibble: bear in mind that Rassilon's Cluster Generator is supposed to be for simulating Globular Clusters. Open Clusters (also known as Galactic Clusters) tend to be much more irregular.
Last edited by selden on 25.04.2003, 14:18, edited 1 time in total.
Selden

Guest

Post #49by Guest » 25.04.2003, 13:49

Selden, sorry, yes I want to put a star cluster in IC434.

bh...(not logged in).

Guest

Post #50by Guest » 01.05.2003, 22:10

Does anyone have any accurate settings for star clusters around the NGC2023 and 2024 nebulas for use in the cluster generator?

I have made up my own using the following settings;

NGC2023
Distance 1614 LY : Radius 3 LY : MAG 15 :CORE 2 : 100 STARS
RA 5(hr!?) 42' 7.2"
DEC -2(hr) 19' 48"
HIP 180000

NGC2024
Distance 1605 LY : Radius 15 LY : MAG 12 : CORE 4 : 300 STARS
RA 5(hr) 42' 0"
DEC -1(hr) 42' 0"
HIP 180100

You get some pretty spectacular views by visiting some of the stars inside the nebula!

But as I say they are made up and I would like to be more accurate if possible.

TERRIER
Posts: 717
Joined: 29.04.2003
With us: 17 years 8 months
Location: West Yorkshire, England

Post #51by TERRIER » 01.05.2003, 22:19

Does anyone have any accurate settings for star clusters around the NGC2023 and 2024 nebulas for use in the cluster generator?


OOOPS!
The above post was from me but I forgot to log in.

chris
Site Admin
Posts: 4211
Joined: 28.01.2002
With us: 18 years 11 months
Location: Seattle, Washington, USA

Post #52by chris » 01.05.2003, 22:23

The units required in STC files are fractional degrees, both for RA and Dec. (I think this was a serious mistake, but it's probably too late now.)

Yes, I agree that this was a mistake. RA for stars should be in fractional hours, just as for objects in DSC files. The hours/minutes/seconds representation I find very cumbersome, however, and I've deliberately avoided using it.

--Chris

Avatar
selden
Developer
Posts: 10138
Joined: 04.09.2002
With us: 18 years 4 months
Location: NY, USA

Post #53by selden » 01.05.2003, 23:04

Chris,

Although cumbersome, I think it would be greatly appreciated by many if the RA and Dec fields could be persuaded to accept h/m/s and d/m/s, presumably in quoted strings, similar to the way the Epoch can be specified. Many astronomical information sites use that notation and it's all too easy to make mistakes when manually converting from one format to another. After all, that's what computers are for, right? to eliminate some of the numerical drudgery :)

This certainly isn't a critical problem, just a minor annoyance.
Selden


Return to “Development”

Who is online