Wersadix wrote:t00fri wrote:Wersadix wrote:Hey Fridger, will you add in next version of Celestia FT other dwarf galaxies near the our Milky Way? Dwarfs like: Sagittarius Dwarf, Ursa Minor Dwarf, Draco Dwarf, Sextans Dwarf, Carina Dwarf, Aquarius Dwarf, Cetus Dwarf, Phoenix Dwarf, Tucana Dwarf and Leo II.
I hope it`s not too big request.
Actually quite a few Dwarf galaxies are already in my deepsky.dsc data base. What catalog do you recommend for the remaining ones? I need also distances, magnitudes, minor/major half axes, PA, hubble types. J2000 coordinates!
Bye Fridger
So, Fridger, you need help? Well then here`s some link`s I found lately:
First I found this page http://www.anzwers.org/free/universe/galaxies.html which is ok, it have galactic coordinates, distances, hubble types and diameter.
On page http://www.seds.org/~spider/spider/LG/lg.html are some links that may be very useful, but coordinates are not too accurate, then I found following: http://www.astro.utu.fi/EGal/elg/ELGtable.html have very accurate
coordinates but i can`t find magnitudes, minor/major half axes and PA.
One thing i can`t comprehend is why is so hard to find these values?
And one more thing. How will you generate Axis line? I don`t see any way
to accomplish this reading the catalog! I`m confused, Fridger.
No, I don't really NEED help.
Notably since those data are INCOMPLETE (hence useless for celestia) and not "official" scientific publications. I will never use "semi-anonymous" WEB data for Celestia. Most importantly , the (absolute) magnitudes, min/max extensions and position angle (PA) are missing (as you already noted). Hence these data are completely useless for Celestia. The listed Dwarfs of the local group, where the available information is complete, are included in my catalog already. That's precisely why they are in and others (where the information is lacking) are NOT in.
I thought you have catalog sources or astronomical publications that I can use? Otherwise your suggestions are not very useful, unfortunately. I can easily exploit several /official/ catalogs jointly with PERL, but I need officially published results!
I will certainly NOT combine badly documented data BY HAND from a number of doubtful sources...
The axis-angle calculations are done with some simple subsequent quaternionic rotations, using the apparent min/max extensions to calculate the inclination angle relative to face-on view according to the standard formula (to be found in any major DSO catalog). The PA serves to calculating the rotation relative to north. Then there are additional quaternionic operations to transform into the celestia frame. This requires the RA,DEC coordinates and the ecliptic angle. After doing all these quaternionic operations in sequence and after standard decomposition of the resulting quaternion into [axis, angle], the data in my catalog follow straightforwardly.
That's just a few lines of PERL code altogether...What is /confusing/ here?
Bye Fridger
I dont want to hurt your ability to feel. 
