Posts by Fafers_br

by Fafers_br
24.03.2020, 16:57
Forum: Development
Topic: Visual Extinction in Celestia?
Replies: 4
Views: 97

Re: Visual Extinction in Celestia?

As an exercise of pure imagination, if we could abandon the scientific rigour for a while... We could fix the value of Rv=3.1. Then, for the same Schulte 16 given as example above. From Earth: d'=d=1514.6pc The declared value for Av would be 4.5. Then: Avpc=Av/d'=0.02971mag/pc. So: E(B-V)=d'*Avpc/Rv...
by Fafers_br
24.03.2020, 04:24
Forum: Development
Topic: Visual Extinction in Celestia?
Replies: 4
Views: 97

Re: Visual Extinction in Celestia?

Have you thought of a good way to add interstellar reddening as well? As we know, stars appear not just dimmer, but redder when obscured by dust because the dust preferentially scatters blue light. I think reddening is more complicated. Well, even my suggestion for extinction is already naively con...
by Fafers_br
24.03.2020, 02:41
Forum: Development
Topic: Visual Extinction in Celestia?
Replies: 4
Views: 97

Visual Extinction in Celestia?

Hello there! As everybody knows, Celestia does not take visual extinction (Av) in consideration in its calculations. This has some consequences, and one of them is the underestimation of the AbsMag and, hence, the calculation of the stars' radius when using the black body aproximation. I'd like to p...
by Fafers_br
08.03.2020, 14:56
Forum: Add-on development
Topic: Poll: Exoplanet Catalogue planet ordering
Replies: 14
Views: 315

Re: Poll: Exoplanet Catalogue planet ordering

The tree displayed in the solar system browser, with the star on the top and the planets below, also gives the "feeling" of increasing distance from the star as you go down the planet list. So, it's one more reason in favor of the distance order. As long as the order of discovery date is r...
by Fafers_br
19.02.2020, 20:59
Forum: Add-on releases
Topic: Updated stars.dat including Gaia DR2 data (update 2020-02-15)
Replies: 49
Views: 1572

Re: Updated stars.dat including Gaia DR2 data (update 2020-02-15)

It is a great work indeed, ajtribick.
Congratulations and thank you for that!
by Fafers_br
17.12.2019, 15:16
Forum: Help Central
Topic: Inclination for a barycenter ?
Replies: 6
Views: 257

Re: Inclination for a barycenter ?

Hi Jujuapapa! Try this: Barycenter "Star_A" { RA 180.0000 Dec 20.0000 Distance 200.0 #Inclination -20.0000 } # # Star B # "Star B" { OrbitBarycenter "Star_A" SpectralType "G1V" AbsMag 4.67 EllipticalOrbit { Period 1000 SemiMajorAxis 100 Eccentricity 0.01 Incli...
by Fafers_br
16.12.2019, 16:36
Forum: Help Central
Topic: Inclination for a barycenter ?
Replies: 6
Views: 257

Re: Inclination for a barycenter ?

Hi Jujuapapa. This is strange. In my Celestia the code I sent resulted in the figure bellow when viewing from the Sun: celestia_Inclination for a barycenter.jpg The orbits are aligned and it's an eclipsing system. Of course, you'd have to change the orbital parameters of the rest of the system to ma...
by Fafers_br
15.12.2019, 15:52
Forum: Help Central
Topic: Inclination for a barycenter ?
Replies: 6
Views: 257

Re: Inclination for a barycenter ?

Hi jujuapapa. I think what you want is basically a system inclined 90º relative to the plane-of-sky. I recommend you use Grant Hutchison's starorbs spreadsheet for Celestia. Here's the code using your data in Grant Hutchison's spreadsheet, supposing that the AscendingNode you provided is relative to...
by Fafers_br
11.12.2019, 01:47
Forum: Development
Topic: Proposed cool stars temperatures update
Replies: 8
Views: 321

Re: Proposed cool stars temperatures update

No objections. I see you are propposing the temperatures from E. Mamajek's table. I think it's a good source.
by Fafers_br
08.11.2019, 03:13
Forum: Add-on releases
Topic: Extrasolar Planets (updated catalogue)
Replies: 63
Views: 57118

Re: Extrasolar Planets (updated catalogue)

If I can find some rotation rate relations for planet's mass vs age, that's what I'd like to do. I've considered just extrapolating downward from the brown dwarf regime -- something that should be somewhat well characterized, but I haven't managed to find some decent research on it since I haven't ...
by Fafers_br
31.08.2019, 01:11
Forum: Add-on releases
Topic: Object Comparison
Replies: 20
Views: 4577

Re: Object Comparison

The issue arises in the way Celestia calculates the "distance." For a planet, the distance is between the observer and the surface, whereas for a star, it is defined with respect to the centre of the star. If you "land" on the star's surface, you'll note you will have quite some...
by Fafers_br
29.08.2019, 20:56
Forum: Add-on releases
Topic: Object Comparison
Replies: 20
Views: 4577

Re: Object Comparison

Talking about object comparison, and apologizing for drifting a little offtopic, this topic reminded me of an issue I observed in my Celestia 1.6.0 (Yes, I know...). Once upon a time, in a not so far away galaxy, I had the idea of making a comparison of object sizes putting them side by side in a ve...
by Fafers_br
24.08.2019, 19:55
Forum: Celestia Users
Topic: Celestia Location Distribution
Replies: 13
Views: 3086

Re: Celestia Location Distribution

City included in my profile. :wink:
by Fafers_br
12.08.2019, 21:36
Forum: Bugs
Topic: Circumbinary Planet Issues
Replies: 8
Views: 3096

Re: Circumbinary Planet Issues

(...)the barycenters do not show up in the Stars List when set to "planets with stars." Apparently it was the developers' choice not to show barycenters in the Star Browser (if you mark the option "nearest", they will not show up too). But their planetary companions are correctl...
by Fafers_br
06.08.2019, 22:12
Forum: Add-on releases
Topic: Extrasolar Planets (updated catalogue)
Replies: 63
Views: 57118

Re: Extrasolar Planets (updated catalogue)

Very good, Sirius!
:clap: :clap:
by Fafers_br
16.05.2019, 03:46
Forum: Add-on releases
Topic: Extrasolar Planets (updated catalogue)
Replies: 63
Views: 57118

Re: Extrasolar Planets (updated catalogue)

Great question! Basically, I determined the planetary system's ecliptic plane (if there were transiting planets, it was set as coplanar to the innermost transiting planet, otherwise as might be the case for multi-planet systems from direct imaging or astrometry, it was set as the average orbit plan...
by Fafers_br
15.05.2019, 01:39
Forum: Add-on releases
Topic: Extrasolar Planets (updated catalogue)
Replies: 63
Views: 57118

Re: Extrasolar Planets (updated catalogue)

Good job, Sirius. I line myself up with LukeCEL in the team of the "bit jealous people", because I was also working in my exoplanet catalog. :clap: We did somethings in common like, for example, using Eric Mamajek's table to estimate the spectral types from effective temperatures (at least...
by Fafers_br
02.12.2018, 16:19
Forum: Add-on releases
Topic: Updated stars.dat for Celestria using Gaia data
Replies: 14
Views: 4338

Re: Updated stars.dat for Celestria using Gaia data

simbad-hipparcos_v114 is now available. This Addon for Celestia v1.6.1 or later provides an updated binary catalog of 114357 stars from the Hipparcos Catalog. It provides star distances, coordinates, spectral types and visual magnitudes obtained from Simbad, as provided by Gaia DR2 and other recent...
by Fafers_br
01.12.2018, 19:51
Forum: Add-on releases
Topic: Populating WLM (and other galaxies) with REAL stars
Replies: 96
Views: 9788

Re: Populating WLM (and other galaxies) with REAL stars

gironde wrote: It seems that we can add TYC numbers: TYC format 4027-803-1 becomes 18034027 Yes, we can add TYC numbers, but the format demands 10 digits. The green set of number must have 5 of them (using "zeros" at the left in order to achieve this). Then, 4027 - 803 - 1 becomes 1 00803...

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