N.V. Kharchenko All-sky Compiled Catalogue of 2.5 million stars (ASCC-2.5, 2nd version)

The catalogue ASCC-2.5 is available at

Description: The All-Sky Compiled Catalogue of 2501304 stars (ASCC-2.5) with the limiting magnitude V=12-14 is a result of a merging of star lists from present day large high-precision catalogues from space ( Hipparcos- Tycho family catalogues: Hipparcos main catalogue including Multiple System Annex (I/239), Tycho-1 (I/239), Tycho-2 (I/259), ACT-RC (I/246), TRC(I/250)) and ground-based (PPM-N (I/146), PPM-S (I/193), PPM-add (I/208), CMC11 (I/256)) observations and reduction to standard systems of corresponding stellar data.

Main stellar data presented in the ASCC-2.5 are the equatorial coordinates (J2000, epoch 1991.25), proper motions in the Hipparcos system, B and/or V stellar magnitudes in the Johnson system. Additionally for some stars are given trigonometric parallaxes, spectral classes in the MK or HD system, multiplicity and variability flags, Hipparcos, Tycho-2, HD, DM designations. Equatorial coordinates and their standard errors were taken from the source catalogues in accordance with the priority: Hipparcos (I/239/hip_main), Tycho-2 (I/259), Tycho-1 (I/239/tyc_main), CMC11 (I/256), PPM (I/146, I/193, I/208).

Proper motions from the source catalogues were compared with Hipparcos data. The compiled proper motions in the Hipparcos system and their standard errors were computed as the weighted means. The weights were set in accordance with the proper motion errors listed for individual stars in the source catalogues. Trigonometric parallaxes are taken from Hipparcos and Tycho-1 catalogues. Stellar B, V magnitudes were determined on the basis of the ground-based photometric data taken from CMC11, Hipparcos, and space B_T_, V_T_ from Tycho-1, Tycho-2.

Magnitudes from PPM catalogue were used if no other photometric data were available. Tycho data were transformed to the Johnson system with:

V = V_T_ - 0.09 (B-V)_T_ + d_V_,
(B-V) = 0.850 (B-V)_T_ + d_(B-V)_,

i.e. using recommendations from the Introduction to the Tycho catalogue and including additional corrections d_V_ and d_(B-V)_. These additional corrections were determined by comparison with ground-based data in the Johnson system. These corrections depend non-linearly on colour and reach 0.02 and 0.04 mag, respectively. Spectral classes in MK or HD systems were taken from Hipparcos, CMC11, and PPM catalogues. Multiplicity and variability flags were taken from Tycho-1, Tycho-2, Hipparcos, CMC11, and PPM catalogues.

The 1st version of the ASCC-2.5 contained some errors in the zones -1 to +1 degree which have been corrected (see details in the "History" section below); 2 files (ccp00.dat and ccm00.dat) have consequently been modified, and a new file (ccadd.dat) contains the previously missing stars (including components of multiple systems). Notice that the ASCC numbers did not change between the two versions, but additional numbers (2600001 to 2603318) were assigned. Stars in the ASCC-2.5 are divided into 31 files: 30 files are ordered by declination (North and South polar caps and 28 bands with a width of 5 degrees), then sorted in right ascension order within each file; the 31st file "ccadd.dat" contains additional stars that were not present in the 1st version.

File Summary:


FileName   Lrecl Records   Explanations

ReadM      80 .                    This file


ccp70.dat   169 66363   Declination from +70.0 to +90.0

ccp65.dat   169 33983   Declination from +65.0 to +69.99999999

ccp60.dat   169 53771   Declination from +60.0 to +64.99999999

ccp55.dat   169 71394   Declination from +55.0 to +59.99999999

ccp50.dat   169 70957   Declination from +50.0 to +54.99999999

ccp45.dat   169 75767   Declination from +45.0 to +49.99999999

ccp40.dat   169 80743   Declination from +40.0 to +44.99999999

ccp35.dat   169 95077   Declination from +35.0 to +39.99999999

ccp30.dat   169 99016   Declination from +30.0 to +34.99999999

ccp25.dat   169 92121   Declination from +25.0 to +29.99999999

ccp20.dat   169 89789   Declination from +20.0 to +24.99999999

ccp15.dat   169 83858   Declination from +15.0 to +19.99999999

ccp10.dat   169 87180   Declination from +10.0 to +14.99999999

ccp05.dat   169 92853   Declination from +05.0 to +09.99999999

ccp00.dat   169 88230   *Declination from +00.0 to +04.99999999

ccm00.dat   169 78912   *Declination from -00.0 to -04.99999999

ccm05.dat   169 80109   Declination from -05.0 to -09.99999999

ccm10.dat   169 84142   Declination from -10.0 to -14.99999999

ccm15.dat   169 92036   Declination from -15.0 to -19.99999999

ccm20.dat   169 96430   Declination from -20.0 to -24.99999999

ccm25.dat   169 97134   Declination from -25.0 to -29.99999999

ccm30.dat   169 97264   Declination from -30.0 to -34.99999999

ccm35.dat   169 94151   Declination from -35.0 to -39.99999999

ccm40.dat   169 97810   Declination from -40.0 to -44.99999999

ccm45.dat   169 98216   Declination from -45.0 to -49.99999999

ccm50.dat   169 95662   Declination from -50.0 to -54.99999999

ccm55.dat   169 94846   Declination from -55.0 to -59.99999999

ccm60.dat   169 80669   Declination from -60.0 to -64.99999999

ccm65.dat   169 57295   Declination from -65.0 to -69.99999999

ccm70.dat   169 72217   Declination from -70.0 to -90.0

ccadd.dat     169 3318   *Additional stars

fals.dat            333982   *False stars removed from 1st version

corr.dat           333948   *List of stars corrected from 1st to 2nd version




Note on ccp00.dat, ccm00.dat, cadd.dat, fals.dat, corr.dat: files added or modified in 2nd version


I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)

I/259 : The Tycho-2 Catalogue (Hog+ 2000)

I/246 : The ACT Reference Catalog (Urban+ 1997)

I/250 : The Tycho Reference Catalogue (Hog+ 1998)

I/146 : Positions and Proper Motions - North (Roeser+, 1988)

I/193 : Positions and Proper Motions - South (Bastian+ 1993)

I/208 : The 90000 stars Supplement to the PPM Catalogue (Roeser+, 1994)

I/256 : Carlsberg Meridian Catalogs (CMC, 1999)


Author's Address: Nina V. Kharchenko Main Astronomical Observatory NAS of Ukraine

27 Academica Zabolotnogo Str.

03680 Kiev Ukraine

Voice: +(380)44-266-4768 Fax: +(380)44-266-2147 e-mail:

Byte-by-byte Description of files: cc*.dat

Bytes    Format      Units        Label       Explanations


1-12         F12.9         h         RAhour     Right Ascension J2000.0, epoch 1991.25

14- 25      F12.8       deg         DEdeg      Declination J2000.0, epoch 1991.25

27- 30      I4        0.1mas       e_RAhour      Standard error in RA*cos(DEdeg)

32- 35      I4        0.1mas       e_DEdeg      Standard error in DEdeg

37- 42      I6        0.01mas         Plx      *?=999999 Trigonometric parallax

44- 48      I5        0.01mas       e_Plx      *?=99999 Standard error in Plx

50- 56      I7        0.01mas/yr   pmRA    Proper Motion in RA*cos(DE)

58- 64      I7        0.01mas/yr   pmDE    Proper Motion in Declination

66- 70      I5        0.01mas/yr   e_pmRA    Standard error in pmRA

72- 76      I5        0.01mas/yr    e_pmDE    Standard error in pmDE

78- 82      I5        0.001mag    Bmag   *?=99999 B magnitude in Johnson system

84- 88      I5        0.001mag    Vmag    *?=99999 V magnitude in Johnson system

90- 93      I4        0.001mag    e_Bmag    *?=9999 Standard error on Bmag

95- 98      I4        0.001mag    e_Vmag    *?=9999 Standard error on Vmag

100-103    I4        0.001mag    Scat    *?=9999 Scatter on V_T_ or Hp mag

105          A1        ---             v1       *[GN ] Known variability from GCVS/NSV

106          A1        ---             v2       *[UVW ] Variability from Tycho-1

107          A1        ---             v3       *[CDMPRU ] Variability type

108          A1        ---             v4       *[VYIXR ] Variability from CMC11

109-110   A2        ---           d12             *[A-S ] CCDM component identifier

111          A1        ---             d3       *[A-S ] Component identifier

112          A1        ---             d4       *[DRSYZ ] Duplicity from Tycho-1

113          A1        ---             d5       *[CGOVX ] Double/Multiple Systems flag

114          A1        ---             d6       *[D ] Duplicity flag from PPM

116-127    A12       ---         SpType          *Spectral type in MK or HD system

129-132    I4          ---          TYC1          *?=0 TYC1 number from Tycho-2

133-137    I5          ---          TYC2          *?=0 TYC2 number from Tycho-2

138          I1        ---             TYC3       *?=0 TYC3 number from Tycho-2

140-145    I6          ---          HIP                *?=0 Hipparcos number

147-152    I6          ---          HD                *?=0 HD number

154-161    I8          ---          DM                *?=0 DM number

163-169    I7          ---          ASCC                *[1,2603318] ASCC-2.5 number


Note on Plx:    Substituted with 999999 if no data

Note on e_Plx:    Substituted with 99999 if no data

Note on Bmag and Vmag:    Substituted with 99999 if no data

Note on e_Bmag, e_Vmag, and Scat:    Substituted with 9999 if no data

Note on v1:    Byte 292 from Tycho-1 file tyc_main.dat This flag is set when the variability is known: G : variable known in General Catalog of Variable Stars N : variable known in New Suspected Variables catalog Substituted with blank if no data

Note on v2:    Byte 294 from Tycho-1 file tyc_main.dat This flag has the following meaning: U : apparent variability in the Tycho data; may be due to duplicity V : strong evidence of intrinsic variability W : suspected intrinsic variability Substituted with blank if no data

Note on v3:    Byte 322 from Hipparcos file hip_main.dat Hipparcos-defined type of variability (a blank entry signifies that the entry could not be classified as variable or constant): C : no variability detected ("constant") D : duplicity-induced variability M : possibly micro-variable (amplitude <0.03mag) P : periodic variable R : V-I colour index was revised due to variability analysis U : unsolved variable which does not fall in the other categories Substituted with blank if no data

Note on v4:    Flag from CMC11 catalogue V : variable star Y or I : if the CAMC did not measure the mag, an approximate value from other sources is given to a precision of 0.1 mag X or R : star fainter than 12 with unknown mag is given as 12. Substituted with blank if no data

Note on d12:    Bytes 149, 150 from Tycho-2 file catalog.dat. The CCDM component identifiers for double or multiple Hipparcos stars contributing to this Tycho-2 entry. Substituted with blank if no data Tycho-2 byte 151 with the third component is not included. This byte contains data (equal to "C") for two stars of the ASCC-2.5 No 244181 (ccp50.dat) and No 339869 (ccp45.dat) only.

Note on d3:    Byte 41 from Hipparcos file hip_dm_com.dat Substituted with blank if no data

Note on d4:    Byte 296 from Tycho-1 file tyc_main.dat Unresolved duplicity status from Tycho data analysis: D : duplicity clearly indicated (B_Tmag and V_Tmag refer to combined light) R : duplicity weakly indicated, combined with indication of variability S : duplicity suspected Y : investigation for duplicity carried out on Tycho data, no indication of duplicity was found Z : investigation for duplicity not carried out blank : Hipparcos star not observed by Tycho Substituted with blank if no data

Note on d5:    Byte 347 from Hipparcos file hip_main.dat Indicates that further details are given in the Hipparcos Double and Multiple Systems Annex: C : solutions for the components G : acceleration or higher order terms O : orbital solutions V : variability-induced movers (apparent motion arises from variability) X : stochastic solution (probably astrometric binaries with short period) Substituted with blank if no data

Note on d6:    Substituted with blank if no data

Note on SpType:    Substituted with blank if no data

Note on TYC1, TYC2, TYC3, HIP, HD:    Substituted with 0 if no data

Note on DM:    DM = Zone sign and abs(Zone)*100000 + running number within this Zone Substituted with 0 if no data Note on ASCC: Stars are numbered from 1 to 2501977 (as in the first version, in agreement with the file order indicated in the File Summary) and from 2600001 to 2603318 (new stars in file ccadd.dat).


Byte-by-byte Description of files: fals.dat and corr.dat


Bytes   Format   Units   Label    Explanations


7    I7      ---    ASCC      ASCC-2.5 number

9- 20    F12.9    h    RAhour    Right Ascension J2000.0, epoch 1991.25

22- 33    F12.8    deg    DEdeg    Declination J2000.0, epoch 1991.25


History:   * 21-Aug-2002 (date of the first release) * 18-Jun-2003: Version 'A' The 1st version of the ASCC-2.5 (21-Aug-2002) contains some errors: - 3982 false stars were detected at Dec = 0 ... +1 degrees. In the 2nd version of the ASCC-2.5 these stars were excluded from the file ccp00.dat. The corrected file ccp00.dat supersedes the previous file ccp00.dat and contains 88230 stars. - for 3948 stars at Dec = 0 ... -1 degrees the PPM data were missed during the catalogue compilation. In the 2nd version the missed data were added and corresponding stellar data were recompiled. The corrected file ccm00.dat supersedes the previous file ccm00.dat and contains the same number of stars. - 34 stars with PPM-only data were missed in zone Dec = 0 ... -1. They were included in a new file of additional catalogue objects ccadd.dat. Besides, 3284 components of multiple systems from over the sky were included in the catalogue. These stars and their compiled stellar data are placed in the file ccadd.dat. The false and corrected stars are listed in files fals.dat and corr.dat, respectively. Within each new file stars are sorted in right ascension order. ASCC-2.5 numbers of stars in files ccp00.dat and ccm00.dat were kept as in the 1st version. New stars in file ccadd.dat received numbers from 2600001 to 2603318.


Bastian U., Roeser S., 1993, "PPM Star Catalogue, 3, 4", Spectrum Akademischer Verlag, Heidelberg (PPM-S) (Cat. I/193)

Carlsberg Meridian Catalogue La Palma Numbers 1 to 11, "Observations of positions of stars and planets: May 1984 to May 1998", 1999, Copenhagen University Observatory, Royal Greenwich Observatory and Real Instituto y Observatorio de la Armada en San Fernando, CD-ROM distribution (CMC11) (Cat. I/256)

ESA, 1997, "The Hipparcos and Tycho Catalogues", ESA SP-1200, 17 (Hipparcos: files hip_main.dat and hip_dm_com.dat), (Tycho-1: file tyc_main.dat) (Cat. I/239)

Hog E., Kuzmin A., Bastian U., et al., 1998, "The Tycho Reference Catalogue", AA, 335, N 3, L65-L68 (TRC) (Cat. I/250)

Hog E., Fabricius C., Makarov V.V., Urban S.E., Corbin T.E., Wycoff G.L., Bastian U., Schwekendiek P., Wicenec A, 2000, "The Tycho-2 Catalogue: Positions, proper motions and two-color photometry of the 2.5 million brightest stars", Copenhagen, CD-ROM distribution (Tycho-2) (Cat. I/259)

Kharchenko N.V., 2001, "All-sky Compiled Catalogue of 2.5 million stars", Kinematics and Physics of Celestial Bodies, 17, N 5, 409 - 423, (ASCC)

Roeser S., Bastian U., 1991, "PPM Star Catalogue, 1, 2", Spectrum Akademischer Verlag, Heidelberg, Berlin, New York (PPM-N) (Cat. I/146)

Roeser S., Bastian U., Kuzmin A., 1994, "The 90000 stars supplement to PPM", AApSS, 105, N 2, 301-303 (PPM-add) (Cat. I/208)

Urban S.E., Corbin T.E., Wycoff G.L., 1998, "The ACT Reference Catalog", AJ, 115, N 5, 2161-2166 (ACT RC) (Cat. I/246)

Photographic Survey of the Northern Sky (Фотографічний огляд Північного неба - ФОН)

Catalogues of Astrometric Positions and Photometric Stellar Magnitudes of SS Bodies (Каталоги астрометричних положень та фотометричних зоряних величин тіл Сонячної системи)

Astrometric and Photometric Catalogues for research in stellar kinematics (Астрометричні та фотометричні каталоги для зоряно-кінематичних досліджень)

Catalogues of Positions and Orbital Elements of Geosynchronous Space Objects (Каталоги положень та орбітальних елементів геосинхронних небесних об'єктів)

L.Pakuliak. Questions, remarks and propositions are welcome.