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Re: Short Term Proper Motion
From: Bill Bertrand
Date: 2019 Mar 11, 08:54 -0700
#-c.eq=J2000
#-c.r= 2
#-c.u=arcmin
#-c.geom=r
#-source=I/311/hip2
#-order=I
#-out=HIP
#-out=n_HIP
#-out=Sn
#-out=So
#-out=RArad
#-out=DErad
#-out=Plx
#-out=e_Plx
#-out=pmRA
#-out=pmDE
#-out=Hpmag
#Hpmag=<7
#-out=B-V
#-out=HIP1
#HIP1=HIP1
#Phot=Phot
#
#RESOURCE=yCat_1311
#Name: I/311
#Title: Hipparcos, the New Reduction (van Leeuwen, 2007)
#Coosys J2000_1991.250: eq_FK5 J2000
#Table I_311_hip2:
#Name: I/311/hip2
#Title: The Astrometric Catalogue
#Column _RAJ2000 (F14.10) Right ascension (FK5, Equinox=J2000.0) at Epoch=J2000, proper motions taken into account [ucd=pos.eq.ra]
#Column _DEJ2000 (F14.10) Declination (FK5, Equinox=J2000.0) at Epoch=J2000, proper motions taken into account [ucd=pos.eq.dec]
#Column HIP (I6) Hipparcos identifier [ucd=meta.id;meta.main]
#Column n_HIP (A1) Simbad column added by the CDS [ucd=meta.note]
#Column Sn (I3) [0,159] Solution type new reduction (1) [ucd=meta.id;stat.fit]
#Column So (I1) [0,5] Solution type old reduction (2) [ucd=meta.id;stat.fit]
#Column RArad (F12.8) Right Ascension in ICRS, Ep=1991.25 [ucd=pos.eq.ra;meta.main]
#Column DErad (F12.8) Declination in ICRS, Ep=1991.25 [ucd=pos.eq.dec;meta.main]
#Column Plx (F7.2) Parallax [ucd=pos.parallax]
#Column e_Plx (F6.2) Formal error on Plx [ucd=stat.error;pos.parallax]
#Column pmRA (F8.2) Proper motion in Right Ascension [ucd=pos.pm;pos.eq.ra]
#Column pmDE (F8.2) Proper motion in Declination [ucd=pos.pm;pos.eq.dec]
#Column Hpmag (F7.4) Hipparcos magnitude [ucd=phot.mag;em.opt.V]
#Column B-V (F6.3) Colour index [ucd=phot.color;em.opt.B;em.
#Column HIP1 (A4) Data from the first edition of the Hipparcos Catalog (1997, Cat. I/239) [ucd=meta.ref.url]
_RAJ2000 |_DEJ2000 |HIP |n_HIP|Sn|So|RArad |DErad |Plx |e_Plx |pmRA |pmDE |Hpmag|B-V |HIP1
deg |deg | | | | |deg |deg |mas |mas |mas/yr|mas/yr |mag |mag |
----------------------|-------
081.2827635599|+06.3497032659| 25336| | 7|0 |081.28278339|+06.34973457| 12.92| 0.52| -8.11| -12.88| 1.5493|-0.224|HIP1
#Table: IV/27A/catalog.dat (cdsarc.u-strasbg.fr)
------------------------------
| | | | | R R D D | | | |
HD|DM | GC| HR| HIP|Ah Am RAs Ed Em DEs| Vmag| Fl|Bayer|Cst
------|------------|-----|----
35468|BD+06 919 | 6668|1790| 25336|05 25 07.87 +06 20 59.0| 1.64| 24|gam |Ori
#Table: IV/27A/table3.dat (cdsarc.u-strasbg.fr)
------------------------------
HD|BFD |Name
------|-------------|---------
35468| 24 gam Ori|Bellatrix
γ Ori - 24 Ori - HIP 25336 - SAO 112740 - HD 35468 - HR 1790 - WDS J05251+0621AB
Type: double star
Magnitude: 1.60 (extincted to: 2.06)
Absolute Magnitude: -2.84
Color Index (B-V): -0.22
RA/Dec (J2000.0): 5h25m07.86s/+6°20'58.7"
RA/Dec (on date): 5h26m03.06s/+6°21'41.0"
HA/Dec: 18h59m30.86s/+6°23'10.8" (apparent)
Az./Alt.: +90°59'13.0"/+16°08'00.3" (apparent)
Gal. long./lat.: -163°04'19.7"/-15°57'11.8"
Supergal. long./lat.: -20°28'43.1"/-58°39'59.6"
Ecl. long./lat. (J2000.0): +80°56'47.1"/-16°48'57.9"
Ecl. long./lat. (on date): +81°11'08.7"/-16°48'50.0"
Ecliptic obliquity (on date): +23°26'04.3"
Mean Sidereal Time: 0h25m22.1s
Apparent Sidereal Time: 0h25m21.7s
IAU Constellation: Ori
Distance: 252.44 ly
Spectral Type: B2III
Parallax: 0.01292"
Position angle (2009): 144.00°
Separation (2009): 178.000" (+0°02'58")
Proper motions by axes: -9.1 -13.6 (mas/yr)
Position angle of the proper motion: 213.8°
Angular speed of the proper motion: 16.4 (mas/yr)
From: Bill Bertrand
Date: 2019 Mar 11, 08:54 -0700
Thanks Paul. I negelected to include the Hipparcos fragments at the bottom of my firs post. I am including the complete post to avoid neeing to jump between them. In answer to your comments
- The header notes indicate that the j2000 values are extrapolated. (In BOLD)
- The j1991.25 Dec value is listed (it differs ~3x10^-5) degrees for the 9 year difference
- I used BOLD font for important parts
- I assumed that I could multiply mas/year * years to get the delta declination (mas) for this simple short term declination change. (Is that incorrect?)
- As you noted, I fear I am using the catalog data incorrectly.
I am having a problem calculating simple short term proper motion. Since I am off by orders of magnitude, it's certain I missed a point obvious to others.
To use the simplest case, I am confining my example on proper motion in declination, to avoid RA's need to be a function of the cos(declination).
The example: Bellatrix on Date: 2016/12/28 T 23:14:15 UTC
- (Stellarium output for the date is listed below and the Bellatrix fragment of Hipparcos below that)
- Dec J2000 (Stellarium & Hipparcos): 6°20'58.7" or 6°20.98'
- Declination on that date (USNO, Stellarium): 6°21'41.0" or 6°21.68'
- The Declination on the 2 dates differ by 0.7 minutes of arc!
- I calculate 16.99 Julian years between J2000 and the date above at 365.25 JDays/JYear
- Stellarium pmDec =-13.6 (mas/yr), Hipparcos pmDec = -12.88 (mas/yr) milliarcseconds/year
- @-12.88 mas/yr I get -218.86 mas in 16.99 years or -0.218 arcseconds
Where did I go wrong?
Thank you in advance,
Bill Bertrand
What follows is the Hipparcos catalog fragment (supplied by VizieR) for Belletrix that I used:
#
# VizieR Astronomical Server vizier.u-strasbg.fr
# Date: 2018-07-31T21:42:33 [V1.99+ (14-Oct-2013)]
# In case of problem, please report to: cds-question@unistra.fr
#
#
#Coosys J2000: eq_FK5 J2000
#INFO votable-version=1.99+ (14-Oct-2013)
#INFO -ref=VIZ5b60d1c7543c
#INFO -out.max=99999
#INFO queryParameters=26
#-oc.form=dec
#-out.max=99999
#-out.add=_RAJ,_DEJ
#-nav=cat:I/311&tab:{I/311/
#-c.eq=J2000
#-c.r= 2
#-c.u=arcmin
#-c.geom=r
#-source=I/311/hip2
#-order=I
#-out=HIP
#-out=n_HIP
#-out=Sn
#-out=So
#-out=RArad
#-out=DErad
#-out=Plx
#-out=e_Plx
#-out=pmRA
#-out=pmDE
#-out=Hpmag
#Hpmag=<7
#-out=B-V
#-out=HIP1
#HIP1=HIP1
#Phot=Phot
#
#RESOURCE=yCat_1311
#Name: I/311
#Title: Hipparcos, the New Reduction (van Leeuwen, 2007)
#Coosys J2000_1991.250: eq_FK5 J2000
#Table I_311_hip2:
#Name: I/311/hip2
#Title: The Astrometric Catalogue
#Column _RAJ2000 (F14.10) Right ascension (FK5, Equinox=J2000.0) at Epoch=J2000, proper motions taken into account [ucd=pos.eq.ra]
#Column _DEJ2000 (F14.10) Declination (FK5, Equinox=J2000.0) at Epoch=J2000, proper motions taken into account [ucd=pos.eq.dec]
#Column HIP (I6) Hipparcos identifier [ucd=meta.id;meta.main]
#Column n_HIP (A1) Simbad column added by the CDS [ucd=meta.note]
#Column Sn (I3) [0,159] Solution type new reduction (1) [ucd=meta.id;stat.fit]
#Column So (I1) [0,5] Solution type old reduction (2) [ucd=meta.id;stat.fit]
#Column RArad (F12.8) Right Ascension in ICRS, Ep=1991.25 [ucd=pos.eq.ra;meta.main]
#Column DErad (F12.8) Declination in ICRS, Ep=1991.25 [ucd=pos.eq.dec;meta.main]
#Column Plx (F7.2) Parallax [ucd=pos.parallax]
#Column e_Plx (F6.2) Formal error on Plx [ucd=stat.error;pos.parallax]
#Column pmRA (F8.2) Proper motion in Right Ascension [ucd=pos.pm;pos.eq.ra]
#Column pmDE (F8.2) Proper motion in Declination [ucd=pos.pm;pos.eq.dec]
#Column Hpmag (F7.4) Hipparcos magnitude [ucd=phot.mag;em.opt.V]
#Column B-V (F6.3) Colour index [ucd=phot.color;em.opt.B;em.
#Column HIP1 (A4) Data from the first edition of the Hipparcos Catalog (1997, Cat. I/239) [ucd=meta.ref.url]
_RAJ2000 |_DEJ2000 |HIP |n_HIP|Sn|So|RArad |DErad |Plx |e_Plx |pmRA |pmDE |Hpmag|B-V |HIP1
deg |deg | | | | |deg |deg |mas |mas |mas/yr|mas/yr |mag |mag |
----------------------|-------
081.2827635599|+06.3497032659| 25336| | 7|0 |081.28278339|+06.34973457| 12.92| 0.52| -8.11| -12.88| 1.5493|-0.224|HIP1
#Table: IV/27A/catalog.dat (cdsarc.u-strasbg.fr)
------------------------------
| | | | | R R D D | | | |
HD|DM | GC| HR| HIP|Ah Am RAs Ed Em DEs| Vmag| Fl|Bayer|Cst
------|------------|-----|----
35468|BD+06 919 | 6668|1790| 25336|05 25 07.87 +06 20 59.0| 1.64| 24|gam |Ori
#Table: IV/27A/table3.dat (cdsarc.u-strasbg.fr)
------------------------------
HD|BFD |Name
------|-------------|---------
35468| 24 gam Ori|Bellatrix
Stellarium Output Bellatrix 2016/12/28 T 23:14:15 UTC:
Bellatrixγ Ori - 24 Ori - HIP 25336 - SAO 112740 - HD 35468 - HR 1790 - WDS J05251+0621AB
Type: double star
Magnitude: 1.60 (extincted to: 2.06)
Absolute Magnitude: -2.84
Color Index (B-V): -0.22
RA/Dec (J2000.0): 5h25m07.86s/+6°20'58.7"
RA/Dec (on date): 5h26m03.06s/+6°21'41.0"
HA/Dec: 18h59m30.86s/+6°23'10.8" (apparent)
Az./Alt.: +90°59'13.0"/+16°08'00.3" (apparent)
Gal. long./lat.: -163°04'19.7"/-15°57'11.8"
Supergal. long./lat.: -20°28'43.1"/-58°39'59.6"
Ecl. long./lat. (J2000.0): +80°56'47.1"/-16°48'57.9"
Ecl. long./lat. (on date): +81°11'08.7"/-16°48'50.0"
Ecliptic obliquity (on date): +23°26'04.3"
Mean Sidereal Time: 0h25m22.1s
Apparent Sidereal Time: 0h25m21.7s
IAU Constellation: Ori
Distance: 252.44 ly
Spectral Type: B2III
Parallax: 0.01292"
Position angle (2009): 144.00°
Separation (2009): 178.000" (+0°02'58")
Proper motions by axes: -9.1 -13.6 (mas/yr)
Position angle of the proper motion: 213.8°
Angular speed of the proper motion: 16.4 (mas/yr)
