G STC Parameters recognized by Celestia v1.4.0 prerelease 1 (and later)

STC Parameters recognized by Celestia v1.4.0 prerelease 1 (and later)


Contents


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0.0 Introduction.

This is a brief description of the STC parameters recognized by Celestia v1.4.0 pre1. STC functionality has undergone a substantial improvement when compared to the previous versions of Celestia, v1.3.2 and earlier.

Some of these may change before the final release of v1.4.0.


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1.0 List of Parameters.


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2.0 Description.

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3.0: Example STC definition.

This example is taken from Grant Hutchison's star catalog file Celetia/data/nearstars.stc. It's one of the catalogs which are included with Celestia v1.4.0pre5 and later.


Barycenter "Rigel Kentaurus:Toliman:ALF Cen:Gliese 559" { RA 219.917516 # mass ratio 1.09:0.92 Dec -60.837128 # Distance 4.365 } 71683 # ALF Cen A { OrbitBarycenter "ALF Cen" SpectralType "G2V" AppMag 0.01 EllipticalOrbit { Period 79.914 SemiMajorAxis 10.765 # mass ratio 1.09:0.92 Eccentricity 0.5179 Inclination 82.980 AscendingNode 67.708 ArgOfPericenter 3.774 MeanAnomaly 200.119 } } 71681 # ALF cen B { OrbitBarycenter "ALF Cen" SpectralType "K0V" AppMag 1.34 EllipticalOrbit { Period 79.914 SemiMajorAxis 12.755 # mass ratio 1.09:0.92 Eccentricity 0.5179 Inclination 82.980 AscendingNode 67.708 ArgOfPericenter 183.774 MeanAnomaly 200.119 } }


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Contents]

4.0: Renaming Stars.

The following procedure can be used to change the names associated with a Star or Barycenter in Celestia.

For example, this STC file (betel.stc) renames Betelgeuse:


27989 "Betelgeuse:Al Mankib:Almerzamo nnagied:Gula:Besn:ALF Ori:58 Ori" { RA 88.792958 Dec 7.407064 Distance 419.13 AppMag 0.58 SpectralType "M1Iab" }

The alternative names above are from "Star Names, Their Lore and Meaning" by Richard Allen, Dover, 1963. The location and spectral information are from the Simbad catalog server.


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5.0: Visual Magnitudes in Celestia

by Fridger Schrempp.

In view of various different standards used to characterize (apparent) magnitudes, it might be worth specifying what Celestia actually wants:

In Celestia, AppMag corresponds to the so-called V-magnitude in the Johnson UBV photometric system!

Confusion may arise, since Celestia uses data from the Hipparcos catalog and that has introduced its own visual filter profile. The Hipparcos "visual" magnitude is called Hp.

This profile is much wider in wavelength than the "standard" Johnson one.

Moreover, Tycho data again use different photometry, designated with V_T and B_T for the visual and blue magnitudes, respectively.

There exist detailed mutual transformation algorithms and|or lookup tables. The relations are quite non-trivial in general and thus it is useful to be informed here...

For interested people, here is a good summary of transformations etc. http://www.tass-survey.org/tass/catalogs/tycho.html


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6.0: Hipparcos and Tycho Catalog Numbers.


Contents


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A.0 Appendices.