J/A+A/671/A16 Carte du Ciel and Gaia. I. Astrometry. (Lehtinen+, 2023)
Carte du Ciel and Gaia. I. Astrometry.
Lehtinen K., Prusti T., de Bruijne J., Lammers U., Manara C.F., Ness J.-U.,
Siddiqui H., Poutanen M., Muinonen K., Morrison O.
<Astron. Astrophys. 671, A16 (2023)>
=2023A&A...671A..16L 2023A&A...671A..16L (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Positional data ; Photometry ; Optical
Keywords: astrometry - proper motions - binaries: general - surveys - catalogs -
techniques: image processing
Abstract:
The Carte du Ciel (CduC) archive at the University of Helsinki enables
us to see the sky as it was about 120 years ago. The archive consists
of single exposure and triple exposure plates between epochs 1896.8-
-1925.8. Our main aim is to find binary and multiple stars by
combining Carte du Ciel and Gaia data. The plates have been digitized
with a commercial digital camera. We use Gaia data to calculate
predicted coordinates of stars at the epoch of each plate. These stars
are used as reference stars to fit astrometry for each plate, giving
fitted coordinates for stars on the Carte du Ciel plates. If the
predicted and fitted coordinates differ at a significant level, we
classify the star as a non-single star, for which the proper motion
values given in the Gaia catalogue can be unreliable. We find that
several astrometric quality indicators of Gaia indicate that the
uncertainties of Gaia's single-star model fit are in general larger
for our non-single star candidates. The percentage of our non-single
star candidates which are in the catalogs of known binary stars is
relatively low, about 10% at maximum. The combination of the Carte du
Ciel and Gaia data can be used to identify candidates of non-single
stars. We propose that the sources with a significant difference
between the predicted and fitted coordinates are long-period binaries,
although astrophysical and/or instrumental effects as origin for the
coordinate difference cannot be excluded for individual cases.
Description:
tables 2 to 7:
tables differ from each other in the following ways: i) using either
Gaia DR2 or EDR3 sources, ii) using either a manual method (so called
visual method in the article) or an automatic method (so called
correlation method in the article) to identify sources with a
significant difference between the Carte du Ciel and Gaia coordinates
(at the epoch of the plates), and iii) having different ranges for the
distance between the Carte du Ciel and Gaia coordinates.
The catalogs have the following setups:
table2.dat; Gaia EDR3 sources, automatic method, distance >0.4"
table3.dat; Gaia EDR3 sources, automatic method, distance between 0.25"-0.4"
table4.dat; Gaia DR2 sources, automatic method, distance >0.4"
table5.dat; Gaia DR2 sources, automatic method, distance between 0.25"-0.4"
table6.dat; Gaia DR2 sources, manual method, distance >5 RMS_astr
(RMS_astr is the RMS value of an astrometric fit made to a plate)
table7.dat; Gaia DR2 sources, manual method, distance between
[2.5-3.5]RMS_astr
For each Carte du Ciel source, we give also the Gaia source
identification, distance, and magnitude of the second closest Gaia
source. This information can be used to identify those Carte du Ciel
sources for which the stellar profile on a plate is affected by two
close by Gaia sources, making the Carte du Ciel coordinates unreliable.
tables 8 to 11:
The tables include all the sources matched with either
Gaia DR2 or EDR3. The catalogs are given separately for single- and
triple-exposure plates.
The catalogs have the following setups:
table8.dat; single-exposure plates matched with DR2
table9.dat; single-exposure plates matched with EDR3
table10.dat; triple-exposure plates matched with DR2
table11.dat; triple-exposure plates matched with EDR3
We have taken four partly overlapping images of each plate, in such
a way that about 50% of the stars have been digitized once, and
about 50% have been digitized twice. A small percentage of the
sources have been digitized three or more times.
If a source has been digitized more than once, the following
parameters are mean values over individual digitizations;
RAdeg_CduC, DEdeg_CduC, FWHM_CduC, ellip_CduC, flux_CduC, mag,
dRACduCGaia, dDECduCGaia, distance, dRA_RMS, dDE_RMS, d_RMS,
SCAMPRARMS, SCAMPDERMS, SCAMP_RMS, SCAMP_chi2, SCAMP_nstar.
Note that for the single-exposure plates the catalogs give
instrumental flux, while for the triple-exposure plates the
catalogs give instrumental magnitude. Note that the Gaia source
identifier of a particular source may be different in Gaia DR2 and
EDR3 catalogs. Use the table gaiadr3.dr2_neighbourhood in the Gaia
archive to compare source records between different Data Releases
The digital images are hosted outside the CDS.
Before making an astrometric fit with SCAMP, each image has been
halved. The parameters xpos_CduC and ypos_CduC give the x and y pixel
coordinates of a source in a digital image, which can be identified
with the parameter plate_image, giving the number of the digital
image ([1,2,3,4]), and the parameter plate_sub, giving the number of
the half-image ([1,2]) used for astrometric fit.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 236 1997 Gaia EDR3 sources, automatic method,
distance >0.4"
table3.dat 236 3656 Gaia EDR3 sources, automatic method,
distance between 0.25"-0.4"
table4.dat 220 3048 Gaia DR2 sources, automatic method,
distance >0.4"
table5.dat 220 3755 Gaia DR2 sources, automatic method,
distance between 0.25"-0.4"
table6.dat 220 642 Gaia DR2 sources, manual method,
distance >5 RMS_astr (RMS_astr is the RMS value
of an astrometric fit made to a plate)
table7.dat 220 681 Gaia DR2 sources, manual method,
distance between [2.5-3.5]RMS_astr
table8.dat 356 825096 Single-exposure plates matched with DR2
table9.dat 356 830663 Single-exposure plates matched with EDR3
table10.dat 333 324189 triple-exposure plates matched with DR2
table11.dat 333 327456 triple-exposure plates matched with EDR3
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
Byte-by-byte Description of file: table2.dat table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
3- 21 I19 --- GaiaEDR3 Gaia EDR3 source_id (source_id)
23- 27 F5.2 arcsec dRA Coordinate difference CduC-Gaia along RA
at plate epoch (dRA)
29- 33 F5.2 arcsec dDE Coordinate difference CduC-Gaia along DE
at plate epoch (dDE)
35- 52 F18.14 deg RAdeg Right Ascension (ICRS) at Ep=2016.0
(Gaia EDR3) (RAdeg)
54- 70 F17.14 deg DEdeg Declination (ICRS) at Ep=2016.0
(Gaia EDR3) (DEdeg)
72- 80 F9.6 mag Bmag Integrated BP mean magnitude (Gaia EDR3)
(Bmag)
82- 91 F10.6 --- ruwe Renormalised Unit Weight Error (Gaia EDR3)
(ruwe)
93-102 F10.8 mas e_RAdeg RA error (Gaia EDR3) (e_RA)
104-113 F10.8 mas e_DEdeg DE error (Gaia EDR3) (e_DE)
115-124 F10.8 mas e_plx Parallax error (Gaia EDR3) (e_plx)
126-135 F10.8 mas/yr e_pmRA RA proper motion error (Gaia EDR3)
(e_pmRA)
137-146 F10.8 mas/yr e_pmDE DE proper motion error (Gaia EDR3)
(e_pmDE)
148-158 F11.8 mas epsi Excess noise of the source (Gaia EDR3)
(astrometricexcessnoise)
160-170 F11.4 --- sepsi Significance of excess noise (Gaia EDR3)
(astrometricexcessnoise_sig)
172-181 F10.8 mas amax The longest semi-major axis of the 5-d
error ellipsoid (Gaia EDR3)
(astrometricsigma5dmax)
183-193 F11.9 --- IPDgofha Amplitude of the IPD GoF versus position
angle of scan (Gaia EDR3)
(ipdgofharmonic_amplitude)
195-197 I3 % IPDfmp Percent of successful-IPD windows with
more than one peak (Gaia EDR3)
(ipdfracmulti_peak)
201-219 I19 --- 2ndNear source_id of the second closest Gaia EDR3
source (source_id2ndNear)
221-226 F6.2 arcsec Dist2ndNear Distance of the second closest Gaia EDR3
source (dist2ndNear)
228-236 F9.6 mag Bmag2ndNear Integrated BP mean magnitude of the second
closest Gaia EDR3 source (Bmag2ndNear)
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Byte-by-byte Description of file: table4.dat table5.dat table6.dat table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 21 I21 --- GaiaDR2 Gaia DR2 source_id (source_id)
23- 27 F5.2 arcsec dRA Coordinate difference CduC-Gaia along
RA at plate epoch (dRA)
29- 33 F5.2 arcsec dDE Coordinate difference CduC-Gaia along
DE at plate epoch (dDE)
35- 52 F18.14 deg RAdeg Right Ascension (ICRS) at Ep=2015.5
(Gaia DR2) (RAdeg)
54- 70 F17.14 deg DEdeg Declination (ICRS) at Ep=2015.5
(Gaia DR2) (DEdeg)
72- 80 F9.6 mag Bmag Integrated BP mean magnitude (Gaia DR2)
(Bmag)
82- 91 F10.8 mas e_RAdeg RA error (Gaia DR2) (e_RA)
93-102 F10.8 mas e_DEdeg DE error (Gaia DR2) (e_DE)
104-113 F10.8 mas e_plx Parallax error (Gaia DR2) (e_plx)
115-124 F10.8 mas/yr e_pmRA RA proper motion error (Gaia DR2) (e_pmRA)
126-135 F10.8 mas/yr e_pmDE DE proper motion error (Gaia DR2) (e_pmDE)
137-147 F11.8 mas epsi Excess noise of the source (Gaia DR2)
(astrometricexcessnoise)
149-159 F11.4 --- sepsi Significance of excess noise (Gaia DR2)
(astrometricexcessnoise_sig)
161-170 F10.8 mas amax The longest semi-major axis of the 5-d
error ellipsoid (Gaia DR2)
(astrometricsigma5dmax)
172-181 F10.6 --- ruwe Renormalised Unit Weight Error (Gaia DR2)
(ruwe)
185-203 I19 --- 2ndNear source_id of the second closest Gaia DR2
source (source_id2ndNear)
205-210 F6.2 arcsec Dist2ndNear Distance of the second closest Gaia DR2
source (dist2ndNear)
212-220 F9.6 mag Bmag2ndNear Integrated BP mean magnitude of the second
closest Gaia DR2 source (Bmag2ndNear)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table8.dat table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- Gaia Gaia source_id (DR2 for table8,
EDR3 for table9) (source_id)
21- 29 F9.4 pix xposCduC x-axis pixel position of the CduC source
(xpos_CduC)
31- 39 F9.4 pix yposCduC y-axis pixel position of the CduC source
(ypos_CduC)
41- 52 F12.8 deg RAdegCduC RA coordinate of the CduC source at the
plate epoch (RAdeg_CduC)
54- 65 F12.8 deg DEdegCduC Dec coordinate of the CduC source at the
plate epoch (DEdeg_CduC)
67- 76 F10.8 deg e_RAdegCduC uncertainty of RAdeg_CduC (eRACduC)
78- 87 F10.8 deg e_DEdegCduC uncertainty of DEdeg_CduC (eDECduC)
89- 99 F11.9 deg FWHMCduC Full Width at Half Maximum size of the
CduC source (FWHM_CduC)
101-105 F5.3 --- ellipCduC ellipticity of the CduC source (ellip_CduC)
107-114 F8.4 arcsec dRA RA coordinate difference between CduC and
Gaia, at the epoch of the plate
(dRACduCGaia)
116-123 F8.4 arcsec dDE Dec. coordinate difference between CduC and
Gaia, at the epoch of the plate
(dDECduCGaia)
125-136 E12.6 arcsec Dist total coordinate difference between CduC and
Gaia (distance)
138-149 E12.6 --- dRARMS RA coordinate difference between CduC and
Gaia in units of astrometric RMS (dRA_RMS)
151-162 E12.6 --- dDERMS Dec. coordinate difference between CduC and
Gaia in units of astrometric RMS (dDE_RMS)
164-175 E12.6 --- dRMS total coordinate difference between CduC and
Gaia in units of astrometric RMS (d_RMS)
177-183 F7.4 deg oRA RA offset of the cduC source from the
plate center (oRA)
185-191 F7.4 deg oDE Dec. offset of the cduC source from the
plate center (oDE)
193-196 I4 --- CduC-plate CdUC plate number (CduC_plate)
198 I1 --- plate-image [1/4] Number of the digital image of the
plate (plate_image)
200 I1 --- plate-sub [1/2] Number of the sub-image used for
astrometric fit (plate_sub)
203-209 F7.2 yr Epoch Epoch of the plate (epoch)
211-216 F6.4 arcsec SCAMP-RARMS astrometric RMS along RA as derived by
SCAMP (SCAMPRARMS)
218-223 F6.4 arcsec SCAMP-DERMS astrometric RMS along Dec. as derived by
SCAMP (SCAMPDERMS)
225-230 F6.4 arcsec SCAMP-RMS sqrt(SCAMPRARMS^2 + SCAMPDERMS^2)
(SCAMP_RMS)
232-238 F7.3 --- SCAMP-chi2 chi-squared value of the astrometric fit
made by SCAMP (SCAMP_chi2)
240-242 I3 --- SCAMP-nstar number of stars used in the astrometric fit
made by SCAMP (SCAMP_nstar)
244-255 E12.6 ct FluxCduC instrumental flux of the CduC source
(flux_CduC)
257-268 E12.6 ct e_FluxCduC uncertainty of flux_CduC (efluxCduC)
270 I1 --- Ndigit [1/7] number of times a CduC source has been
digitised (N_digitised)
272-279 F8.4 arcsec stdRA standard deviation of RA when a CduC source
has been digitised more than once (std_RA)
281-288 F8.4 arcsec stdDE standard deviation of Dec. when a CduC
source has been digitised more than once
(std_DE)
290-304 F15.11 deg RAdegGaia RA of a Gaia source (ICRS) at the plate
epoch Epoch (RAdeg_Gaia)
306-320 F15.11 deg DEdegGaia Dec. of a Gaia source (ICRS) at the plate
epoch Epoch (DEdeg_Gaia)
322-333 E12.6 deg e_RAdegGaia error of RAdeg_Gaia (eRAdegGaia)
335-346 E12.6 deg e_DEdegGaia error of DEdeg_Gaia (eDEdegGaia)
348-356 F9.6 mag BPmag BP magnitude of the Gaia source (BPmag)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table10.dat table11.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- Gaia Gaia source_id (DR2 for table10,
EDR3 for table11) (source_id)
21- 29 F9.4 pix xposCduC x-axis pixel position of the CduC source
(xpos_CduC)
31- 39 F9.4 pix yposCduC y-axis pixel position of the CduC source
(ypos_CduC)
41- 52 F12.8 deg RAdegCduC RA coordinate of the CduC source at the
plate epoch (RAdeg_CduC)
54- 65 F12.8 deg DEdegCduC Dec coordinate of the CduC source at the
plate epoch (DEdeg_CduC)
67- 76 F10.8 deg e_RAdegCduC uncertainty of RAdeg_CduC (eRACduC)
78- 87 F10.8 deg e_DEdegCduC uncertainty of DEdeg_CduC (eDECduC)
89- 96 F8.4 arcsec dRA RA coordinate difference between CduC and
Gaia, at the epoch of the plate
(dRACduCGaia)
98-105 F8.4 arcsec dDE Dec. coordinate difference between CduC and
Gaia, at the epoch of the plate
(dDECduCGaia)
107-118 E12.6 arcsec Dist total coordinate difference between CduC and
Gaia (distance)
120-131 E12.6 --- dRARMS RA coordinate difference between CduC and
Gaia in units of astrometric RMS (dRA_RMS)
133-144 E12.6 --- dDERMS Dec. coordinate difference between CduC and
Gaia in units of astrometric RMS (dDE_RMS)
146-157 E12.6 --- dRMS total coordinate difference between CduC and
Gaia in units of astrometric RMS (d_RMS)
159-165 F7.4 deg oRA RA offset of the cduC source from the
plate center (oRA)
167-173 F7.4 deg oDE Dec. offset of the cduC source from the
plate center (oDE)
175-178 I4 --- CduC-plate CdUC plate number (CduC_plate)
180 I1 --- plate-image [1/4] Number of the digital image of the
plate (plate_image)
182 I1 --- plate-sub [1/2] Number of the sub-image used for
astrometric fit (plate_sub)
185-191 F7.2 yr Epoch Epoch of the plate (epoch)
193-198 F6.4 arcsec SCAMP-RARMS astrometric RMS along RA as derived by
SCAMP (SCAMPRARMS)
200-205 F6.4 arcsec SCAMP-DERMS astrometric RMS along Dec. as derived by
SCAMP (SCAMPDERMS)
207-212 F6.4 arcsec SCAMP-RMS sqrt(SCAMPRARMS^2 + SCAMPDERMS^2)
(SCAMP_RMS)
214-220 F7.3 --- SCAMP-chi2 chi-squared value of the astrometric fit
made by SCAMP (SCAMP_chi2)
222-224 I3 --- SCAMP-nstar number of stars used in the astrometric fit
made by SCAMP (SCAMP_nstar)
226-235 F10.6 mag mag Instrumental magnitude of the CduC source
(mag)
237-245 F9.6 mag e_mag rms uncertainty of mag (e_mag)
247 I1 --- Ndigit [1/8] number of times a CduC source has been
digitised (N_digitised)
249-256 F8.4 arcsec stdRA standard deviation of RA when a CduC source
has been digitised more than once (std_RA)
258-265 F8.4 arcsec stdDE standard deviation of Dec. when a CduC
source has been digitised more than once
(std_DE)
267-281 F15.11 deg RAdegGaia RA of a Gaia source (ICRS) at the plate
epoch Epoch (RAdeg_Gaia)
283-297 F15.11 deg DEdegGaia Dec. of a Gaia source (ICRS) at the plate
epoch Epoch (DEdeg_Gaia)
299-310 E12.6 deg e_RAdegGaia error of RAdeg_Gaia (eRAdegGaia)
312-323 E12.6 deg e_DEdegGaia error of DEdeg_Gaia (eDEdegGaia)
325-333 F9.6 mag BPmag BP magnitude of the Gaia source (BPmag)
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Acknowledgements:
Kimmo Lehtinen, carteduciel120(at)gmail.com
(End) Patricia Vannier [CDS] 12-Jan-2023