yes, it was a seemingly small issue that kept me quite busy, recently: the precise alignment of the MilkyWay using my standard quaternionic rotations and the "new" IAU MilkyWay coordinates of 1959.
The origin of the problam came from a small 1.5 degree sideways discrepancy with Selden's (semi-empirical) graticule alignment of the galactic plane...Since my procedure really went back to the basics, I wanted to clear this up before committing my galaxy upgrade to CVS.
The reason for the discrepancy was tricky, as usual...Now that I solved it, let me show you how beautifully consistent everything comes out. As an independent check on the alignment, I followed and expanded Selden's method of directly generating & marking accurate points in the galactic plane and above by using this professional-level coordinate calculator:
http://cxc.harvard.edu/toolkit/precess.jsp
of the Chandra X-ray Center.
In the following top and sideways views you see the generated points in form of yellow crosses and one green cross that sits above the galactic plane just over the sun's position. You also see the MilkyWay as aligned via quaternion rotations from the IAU data ONLY. Moreover, I have added the pulsar data from Selden as a crosscheck on the MilkyWay position angle of 122.932 degrees. The matching of the pulsar locations with the MW arms has now even been considerable improved!
Have a click for kingsize (important!)!
The green cross marks the sun's position in Orion's arm of the MW. The line from there to the center of the MW corresponds to zero galactic longitude.
The second image shows sideways views of the alignment quality where the top and bottom images differ by a 90 degree rotation within the galactic plane. Look for the sun's position...
So all in all the alignment is PERFECT now!
This is also an important crosscheck on my PERL orientation routines that are used to align 10000+ galaxies!
My galaxy database upgrade was a lot of work...
I have almost completely rewritten the ~1300 line PERL extraction script, since now many more professional catalogs have been merged to determine distances and other crucial galaxy data. Notably, I have now implemented the complete LOCAL GROUP of galaxies from a new catalog on "Galaxies in Local Group Volume (d < 10 Mpc)" and from the new "NED-1D Distance Data Base". Also the complete zcat redshift catalog and the NED batch service has been exploited...
So here is the final account:
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Catalog Input:
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333 Galaxies in Local Group Volume (d < 10 Mpc)
717 Averaged distances from NED-1D Distance Data Base
289 Surface Brightness Fluctuation (SBF) distance data
544 Tully-Fisher elliptical galaxy distance data
469 Tully-Fisher spiral galaxy distance data
7302 ZCAT redshift data
16588 RC3 galaxy distance data
2416 NED redshift data (batch)
While previously, only about 60% of my galaxies in deepsky.dsc involved reliable distance measurements now I am VERY close to 100%. Trara! Trara!
Summary Output:
-----------------------
10937 Galaxies in Total
10032 with good distance data
Code: Select all
333 with distances from 'catalog of neighboring galaxies'
718 with NED-1D averaged distances
1 with Surface Brightness Fluctuation (SBF) distances
515 with Tully-Fisher distances
37 with B200 distances
4672 with distances from Hubble Law (v_CMB, RC3)
1330 with distances from Hubble Law (ZCAT).
2426 with distances from Hubble Law (NED, batch).
My new PERL extraction script now can also list all galaxies of the local group for people to check. The output should look like this:
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Milky Way ; 17 45 37.2; -28 56 10; SBc; 8.499; -20.60
WLM DDO 221; 00 01 58.1; -15 27 40; Irr; 920.000; -13.95
Cetus Dwarf KKSG 1; 00 26 11.0; -11 02 40; E4; 780.000; -10.18
And III KK 5; 00 35 33.8; +36 29 52; E6; 760.000; -9.30
And I KK 8; 00 45 40.0; +38 02 14; E0; 810.000; -10.87
SMC ; 00 52 38.0; -72 48 01; Irr; 60.000; -16.35
Sculptor dSph ESO 351-30; 01 00 09.4; -33 42 33; E0; 90.000; -9.77
LGS 3 ; 01 03 56.6; +21 53 41; Irr; 620.000; -7.96
And V ; 01 10 17.1; +47 37 41; E0; 810.000; -8.41
And II KK 12; 01 16 29.8; +33 25 09; E3; 680.000; -9.33
Phoenix Dwarf PGC 6830; 01 51 06.3; -44 26 41; Irr; 440.000; -10.22
Fornax dSph ; 02 39 54.7; -34 31 33; E4; 140.000; -11.50
LMC ; 05 23 34.6; -69 45 22; Irr; 50.000; -17.93
Carina Dwarf ; 06 41 36.7; -50 57 58; E3; 100.000; -8.97
Leo A DDO 69; 09 59 26.4; +30 44 47; Irr; 690.000; -11.36
Sextans B DDO 70; 10 00 00.1; +05 19 56; Irr; 1360.000; -13.96
Antlia Dwarf PGC 29194; 10 04 04.0; -27 19 55; E3; 1320.000; -9.75
Leo I DDO 74; 10 08 26.9; +12 18 29; E3; 250.000; -10.97
Sextans A DDO 75; 10 11 00.8; -04 41 34; Irr; 1320.000; -13.95
Sextans dSph ; 10 13 03.0; -01 36 52; E4; 90.000; -7.98
Leo II DDO 93; 11 13 29.2; +22 09 17; E0; 210.000; -9.23
UrsaMinor Dwarf ; 15 09 11.3; +67 12 52; E5; 60.000; -7.13
Draco Dwarf ; 17 20 01.4; +57 54 34; E3; 80.000; -8.74
Sagittarius dSph ; 18 55 03.1; -30 28 42; E6; 20.000; -12.67
Sagittarius DIG ESO 594-4; 19 29 59.0; -17 40 41; Irr; 1040.000; -11.49
Aquarius Dwarf DDO 210; 20 46 51.8; -12 50 53; Irr; 940.000; -11.09
Tucana Dwarf PGC 69519; 22 41 49.0; -64 25 12; E5; 880.000; -9.16
And VII Cassiopeia dSph; 23 26 31.8; +50 40 32; E3; 790.000; -11.67
Pegasus DIG DDO 216; 23 28 34.1; +14 44 48; Irr; 760.000; -11.47
And VI Pegasus dSph; 23 51 46.4; +24 35 10; E3; 820.000; -10.80
NGC 147 UGC 326; 00 33 11.7; +48 30 26; E5; 700.667; -13.82
NGC 185 UGC 396; 00 38 57.6; +48 20 14; E3; 610.800; -13.63
M 110 NGC 205; 00 40 22.1; +41 41 07; E5; 760.500; -15.50
M 32 NGC 221; 00 42 41.8; +40 51 57; E2; 847.111; -15.54
M 31 NGC 224; 00 42 44.3; +41 16 08; Sb; 788.767; -20.12
M 33 NGC 598; 01 33 51.9; +30 39 29; Sc; 862.892; -18.46
NGC 2363 UGC 3847; 07 28 29.9; +69 11 34; Irr; 956.239; -9.40
NGC 3109 ESO 499-36; 10 03 06.6; -26 09 30; Irr; 1241.111; -15.06
NGC 6822 IC 4895; 19 44 56.6; -14 48 23; Irr; 549.722; -14.40
IC 10 UGC 192; 00 20 24.5; +59 17 33; Irr; 796.375; -12.70
IC 1613 UGC 668; 01 04 47.5; +02 07 07; Irr; 752.156; -14.48
IC 3658 ZWG 99.110; 12 41 20.6; +14 42 04; E0; 614.310; -9.04
So now it's all up to you! We need to test the many new galaxies and I hope you will help...Finally myself and other people have written useful .celx scripts, that one may use for displaying the local group and other useful features.
Here are mine
http://www.celestiaproject.net/~t00fri/images/z-dist.celx
http://www.celestiaproject.net/~t00fri/images/mark-lg.celx
The first z-dist.celx script marks ALL galaxies in my new catalog and looks at them from a large distance.
The galaxy dots get increasingly read the higher their redshift! You may use the command-line to select any galaxy in the lot. It will then be marked as a green dot. Initially the MilkyWay is selected. There may be some recent changes or adaptations necessary, since Vincent has been industrious making all sorts of celx changes in CVS. But basically I checked that the scripts work fine.
The second script, mark-lg.celx marks ALL members of the local group of galaxies. By turning on the labels and increasing the sensitivity (] key) you get a nice overview of what is new as to the local group of galaxies.
Probably tonight, I shall commit the whole lot to CVS so you can download and test everything (=> DONE!)!
Enjoy,
Bye Fridger