Hindsley R., Harrington R., Urban S.

See Astron. J. 107, 280 (1994) for more detailed description of the original compilation.



The U.S. Naval Observatory Catalog of Positions of Infrared Stellar Sources (CPIRSS) was originally compiled in 1994 to provide astrometry at the sub-arcsecond level for many of the point sources in the 1987 version of the IRAS Point Source Catalog (NASA RP-1190). This was accomplished by the identification of IRAS sources with bright optical stars, checked by requiring the color V-[12] (with [12] being a magnitude derived by the IRAS flux) to be consistent with the optical colors or spectral type. Additionally, the K magnitude (2.2 microns) has been estimated. The latest version, completed in 2001, contains 37,700 stars and includes the Hipparcos and Tycho-2 astrometry and photometry which was unavailable at the time of the original compilation.

The data are available at NASA's Astronomical Data Center by clicking HERE.

For a description of the 1994 compilation, click here HERE.


The Infrared Astronomical Satellite (IRAS) carried out an all-sky survey at 12, 25, 60 and 100 microns. Approximately 250 000 point sources were identified. However, by the standards of optical astrometry, the positions of these sources are poorly determined, with errors of tens of arc-seconds. Optical astrometric catalogs such as Hipparcos (ESA 1997) and Tycho-2 (Hoeg et al. 2000) have errors in position under 0.1 arc-seconds, some two to three orders of magnitude less than the IRAS positions.

Many of the sources in the IRAS Point Source Catalog (1987, hereafter referred to as PSC) have been identified as stars. Thus it is possible to construct a higher quality astrometric catalog of infrared sources by combining these positions with the IRAS identifications. However, because the IRAS positions have such large errors, the identifications provided in the PSC are suspect. The V-[12] color, with [12] being a magnitude determined from the 12 micron flux, is very sensitive to temperature. If the optical identification of an IRAS source is correct, the V-[12] color should be consistent with optical colors or spectral type. Once a cross-correlation is established, an estimation of the Johnson system K magnitudes is made. Hindsley and Harrington (1994) describe the details on the confirmation identification based on color and the K magnitude determination.

The CPIRSS has had two upgrades following the 1994 release; one in 1996 and one in 2001. In 1996, 4022 new sources were added, bringing the total to 37,700. As with the 33,678 stars in the original CPIRSS, the positional matches were checked by using the optical colors and visual magnitudes to estimate the 12 micron magnitudes, which were compared to the actual IRAS 12 micron measurement. Stars with an estimate that do not match the observations are included in the catalog but flagged so that the user is aware of the questionable identification. Also in 1996, the record number in the IRAS Point Source Catalog was added to each record. The 1996 version also had various errata corrected.

In 2001, better astrometry was substituted. Of the 37,700 stars, all but 105 were found in either the Hipparcos or Tycho-2 catalogs (Cat. , ). Since these surpass the accuracies found in the astrometric catalogs used in earlier versions, their values were added. Given the availability of both for a star, the Hipparcos data take precedence. Both Hipparcos and Tycho-2 numbers are provided, along with several flags that can give users warning of possible multiplicity or non-linear proper motions. At the same time, the V magnitudes from Hipparcos or Tycho-2 were substituted for the poorer values found in the previously used astrometric catalogs. Since much of the original work was performed using those older values, differences between them and the current values are provided for the user.

Earlier versions of this work not put into the Astronomical Data Centers, but were made available through the U.S. Naval Observatory.

File Summary:
 FileName     Lrecl    Records    Explanations
ReadMe           80          .    This file   
cpirss01.dat    288      37000    The CPIRSS (2001) catalog 

Byte-by-byte Description of file: cpirss01.dat
 Bytes   Format   Units       Label     Explanations
001-010  A10      ---         DM_ID     Primary Durchmusterung identifier
012-022  A12      ---         PSC_ID1   IRAS PSC identifier
024-029  I6       ---         PSC_ID2   IRAS PSC record number
031-032  I2       h           RAh       R.A. (hours), epoch=2000.0, HCRS
033-034  I2       min         RAmin     R.A. (minutes), epoch=2000.0, HCRS
035-040  F6.3     s           RAs       R.A. (seconds), epoch=2000.0, HCRS
042-048  F7.3     s/cy        pmRA      Prop. mot. in RA, seconds/century
050-050  A1       ---                   Decl. (sign), epoch=2000.0, HCRS
051-052  I2       deg         DEd       Decl. (degree), epoch=2000.0, HCRS 
053-054  I2       arcmin      DEm       Decl. (minutes), epoch=2000.0, HCRS
055-059  F5.2     arcsec      DEs       Decl. (seconds), epoch=2000.0, HCRS
061-067  F7.3     arcsec/cy   pmDE      Prop. mot. in Decl., arcsec/century
069-070  I2       ---       r_Pos      *Source of position
072-080  E9.7     Jy          Fnu_12    IRAS flux density, 12 micron
081-089  E9.7     Jy          Fnu_25    IRAS flux density, 25 micron
090-098  E9.7     Jy          Fnu_60    IRAS flux density, 60 micron
099-107  E9.7     Jy          Fnu_100   IRAS flux density, 100 micron
108-114  F7.3     mag         Vmag     *Observed V magnitude
115-121  F7.3     mag         Vdiff    *Vmag(previous) - Vmag(cpirss2001)
123-123  I1       ---       r_Vmag     *Source of V magnitude
125-139  A15      ---         SpType   *Spectral type 
140-141  I2       ---       r_SpType   *Source of Spectral Type
143-148  F6.3     mag         Color     Color
150-150  A1       ---         Fcolor   *Flag for color
152-157  F6.3     mag         Excess   *B-V color excess
159-159  I1       ---         Method   *Method used in color confirmation
161-166  F6.2     mag         Deviat   *Color deviation
168-168  I1       ---         Confrm   *Result of color confirmation
170-175  F6.3     mag         Kmag      Estimated K magnitude
177-177  I1       ---         Qual_12  *IRAS Flux quality indicator; 12 microns
178-178  I1       ---         Qual_25  *IRAS Flux quality indicator; 25 microns
179-179  I1       ---         Qual_60  *IRAS Flux quality indicator; 60 microns
180-180  I1       ---         Qual_100 *IRAS Flux quality indicator; 100 microns
182-182  A1       ---         Corr_12  *IRAS correlation coeff.; 12 microns
183-183  A1       ---         Corr_25  *IRAS correlation coeff.; 25 microns
184-184  A1       ---         Corr_60  *IRAS correlation coeff.; 60 microns
185-185  A1       ---         Corr_100 *IRAS correlation coeff.; 100 microns
187-188  I2       ---         Vari     *Probability (0%-99%) of variability
190-196  A7       ---         WDS      *WDS id code (discoverer & number)
197-201  A5       ---         WDS_comp *WDS components
203-206  I4       yr          WDS_yr    Year of last observation in WDS
208-210  I3       deg         WDS_theta Position angle at last obs. in WDS
212-216  F5.1     arcsec      WDS_rho   Separation at last obs. in WDS
218-222  F5.2     mag         WDS_mag1  V magnitude of primary in WDS
224-228  F5.2     mag         WDS_mag2  V magnitude of secondary in WDS
230-230  A1       ---         WDS_orb  *Orbit flag
231-236  I6       ---         HIP       Hipparcos number
237-237  A1       ---         H10      *HIP field 10; double and mult. system
238-238  A1       ---         H59      *HIP field 59; annex flag
239-250  I12      ---         Tyc2     *Tycho-2 number
251-251  A1       ---         T10      *Tycho-1 field 10; Ref. for astrometry
252-252  A1       ---         T40      *Tycho-1 field 40; Astrometric Quality
253-253  A1       ---         T49      *Tycho-1 field 49; Duplicity from Tycho-1
254-254  A1                   Tpflag   *Tycho-2 position flag
255-255  A1       ---         Tposflg  *Tycho-2 posflg, astrometric treatment
256-256  A1       ---         dupflg   *CPIRSS duplicity flag

Note on r_Pos:
   This field is the source of astrometry.
    4 = Astrographic Catalogue Reference Stars (ACRS)
    6 = Positions and Proper Motions Catalog (PPM)
    7 = Smithsonian Astrophysical Observatory Star Catalog (SAO)
   10 = Hipparcos
   11 = Tycho-2
Note on Vmag and Vdiff:
   These fields give the current, best values for Vmag, as well as
   information regarding these parameters in previous releases of 
   the CPIRSS.  It was decided to provide the best V magnitude available,
   so many values have been replaced from earlier releases.  When the 
   Vmag data are from Hipparcos, the values from Hipparcos H5
   field were used.  Where the Vmag data are from Tycho-2, the values
   from VT were used with no converversion to the Johnson system attempted.
   Since the color confirmation and K magnitude estimates were made using
   older data, it was decided to provide users a way to compute these older
   values.  The field Vdiff is the value of the older Vmag - current Vmag.
Note on r_Vmag:
   This field it the source of the observed V magnitude
   1   = Mermilliod 1991
   2   = Lanz 1986
   8   = From Astrographic Catalogue Reference Stars
   9   = From the same catalog as the positional information
   Data NOT from Mermilliod 1991,  Lanz 1986, Hipparcos or Tycho-2 is 
   deemed somewhat unreliable.
Note on SpType and r_SpType:
   These fields are for the spectral type and its source
   For r_SpType,
   1 = MK Extension catalog (Morris-Kennedy 1983)
   2 = Michigan HD catalog  (Houk & Cowley 1975)
   3 = Henry Draper catalog (Cannon & Pickering 1918-24)
   4 = Average of MK Ext. data(1) and Michigan HD data(2)
   Positive values of the source mean the raw entries have been
   "interpreted" (eg, a spectral subtype of 3+ in the MK Exten-
   sion catalog has been converted into 3.5).  A negative source
   value means that the data are directly from the catalog. 
   Note that the result of averaging (source = 4) is occasionally
   a subclass not represented in either catalog.  For example,
   K5 & M0 are averaged to produce K7.5, although neither the
   MK Extension catalog nor the Michigan HD catalog have any
   spectral subtypes between K5 and M0.  The spectral types are
   used for determining intrinsic colors, and the fictitious
   subtype K7.5 is useful for interpolating.  Also note that the
   result of averaging luminosity classes can be intermediate
   between two classes.  This is indicated by a value in
   bytes 166:168 (eg, .5, .75).  Such a value as 'IV   .25'
   should be interpreted as being 0.25 of the way from luminosity
   class IV toward V.  Again the point is to allow interpolation,
   in this case for calculating absolute magnitudes.
Note on Fcolor:
   This field is the flag for the color field.
   '1'= Intrinsic (not reddened) B-V
   '2'= Observed (reddened) B-V
   '3'= Observed (reddened) R-I
Note on Excess:
   This field is the B-V color excess.  Its interpretation depends on
   field 'Confrm' (byte 190).  If byte 190 is 1, this
   was calculated as the difference (observed color - intrinsic color).
   Otherwise this was calculated from the coordinates and the relationships
   of Arenou, Grenon, and Gomez (1992).  Blank means assumed zero if byte 190
   is 1,2,3,4, or 5; otherwise, blank means it cannot be estimated.
Note on Method:
   This field indicates the method used in color confirmation
   0 = insufficient data available, no color confirmation attempted
   1 = both B-V and spectral type available
   2 = only spectral type (with luminosity class) available
   3 = only spectral type (without luminosity class) available
   4 = B-V only available (no spectral type)
   5 = R-I used; either no B-V data at all, or not both B-V and spectral type
       data (case 1 above).  R-I used in this case if available because
       it is less sensitive to reddening.
Note on Deviat:
   If this value is lower than 20.0, then then this is the deviation
   ([calculated from color confirmation] - [observed from IRAS])
   in magnitudes.  For values greater than 20.0, the color confirmation
   could not be attempted and the value indicates what data are lacking,
   with the following meaning. 
   21.0 = IRAS 12 micron flux is a lower limit
   22.0 = IRAS variability probability > 50%
   23.0 = Color data indicates multiplicity
   24.0 = Color data indicates variability
   25.0 = Spectral type data indicates multiplicity
   26.0 = Spectral type data indicates variability
   27.0 = Spectral type data indicates peculiarity
          (eg, Carbon star, Am star, emission or peculiar)
   28.0 = No observed V magnitude
   29.0 = No observed color or spectral type data
   30.0 = Color too red: (B-V) > 1.60, cannot analyze
   31.0 = Reddening < -0.15; indicates spectral type data
          or photometry is in error (probably one data set does not apply
          to this star or is contaminated by a double).
Note on Confrm:
   This field shows the results of the color confirmation.
   1 = Optical and IRAS match confirmed
   2 = Optical and IRAS match questionable
   0 = No color confirmation attempted
Note on Qual_12, Qual_25, Qual_60, Qual_100:
   These fields are the IRAS Flux quality indicators.
   1 = Upper limit
   2 = Moderate quality
   3 = High quality
Note on Corr_12, Corr_25, Corr_60, Corr_100:
   These fields are the IRAS point source correlation coefficents.
   A =100%, B =99%, etc.  See IRAS Point Source Catalog, col. 14.
Note on Vari:
   This field indicates the percent probability of variability. 
   A value of -1 means the source was not examined for variability.
Note on WDS:
   These fields give data from the Washington Double Stars (WDS) catalog.
   (Worley and Douglass 1984)
Note on WDS_comp
   This filed gives data on the components. AB means data for components
   A and B.  A-BC means secondary component consists of a double. Etc.
Note on WDS_orb:
   This field indicates an orbit is available in the WDS catalog.
   'O' = Orbit available
   ' ' = No orbit available
Note on H10:
   This field is the Hipparcos field 10, reference flag for astrometry
   A,B,... = The specified component of multiple system.
   @ = Photocenter of multiple system. See HIP-C annex.
   + = Center of mass.  See HIP-O annex.
Note on H59:
   This field is the Hipparcos field 59, double/multiple system flag.
   C = Component solutions available from Hipparcos
   G = acceleration terms available from Hipparcos
   O = Orbital solutions available from Hipparcos
   V = variability induced mover from Hipparcos
Note on Tyc2:
   This field gives the Tycho-2 identification number.  Note that if the
   star was in Tycho-1 but not Tycho-2, the Tycho-1 ID is given.  
   Blanks are replaced with zeros.
Note on T10
   This field is the Tycho-1 field 10, reference flag for Tycho-1 astrometry
   'X' = Indication of a dubious astrometric reference star.
Note on T40:
   This field is the Tycho-1 field 40, astrometric quality flag
   ' ' = HIP star not observed by Tycho.
   1 to 4 = very high to high quality.
   5 = medium quality.
   6 = perhaps non-single.
   7 = low quality.
   8 = perhaps non-stellar.
   9 = low quality; position derived from TICR.
Note on T49:
   This field is the Tycho-1 filed 49, duplicity flag.
   ' ' = HIP star not observed by Tycho.
   'D' = Duplicity clearly indicated.
   'R' = duplicity weakly indicated.
   'S' = duplicity suspected.
   'Y' = investigation made; no indication of duplicity found.
   'Z' = investigation for duplicity not made.
Note on Tpflag:
   This field is the Tycho-2 pflag, it has the following meaning.
   ' ' = normal mean position and proper motion
   'P' = astrometry from photocenter of two Tycho-2 stars
   'X' = no mean position, proper motion in Tycho-2
Note on Tposflag:
   This field is the Tycho-2 posflg, and describes what treatment method the 
   Tycho-2 data utilized to get position.
   ' ' = normal treatment in Tycho-2
   'D' = double star treatment
   'P' = photocenter treatment
Note on dupflg:
   This field is an attempt to summarize many of the WDS, Hipparcos,
   Tycho-1 and Tycho-2 flags found above into one flag.
   ' ' = astrometry does not indicate duplicity
   '1' = astrometry does indicate duplicity


A tridimensional model of the galactic interstellar extinction, 1992, Arenou, F., Grenon, M., and Gomez, A., Astron & Astrophys., 258, 104. =1992A&A...258..104A

The Henry Draper Catalog, 1918-1924, Cannon, A.J., & Pickering, E.C., Ann. Astron. Obs. Harvard College, 91-99 (from CDROM).

University of Michigan Catalogue of Two-Dimensional Spectral Types for the HD Stars, vol. 1, 1975, Houk, N. and Cowley, A.P., (this and vol. 2, 3, and 4 from CDROM).

IRAS Catalogues and Atlases: The Explanatory Supplement, 1987, eds. C.A. Bechman, G. Neugebauer, H.J. Habing, P.E. Clegg, T.J. Chester, NASA RP-1190, vol. 1.

IRAS Catalogues and Atlases: The Point Source Catalog, 1987, eds. C.A. Bechman, G. Neugebauer, H.J. Habing, P.E. Clegg, T.J. Chester, NASA RP-1190, vol. 2-6 (from CDROM).

Photoelectric Photometric Catalogue in the Johnson UBVRI System, 1986 Lanz, T., A&A Suppl., 6, 195 (from CDROM) =1986A&AS...65..195L

Homogeneous Means in the UBV System, 1991, Mermilliod, J.-C., unpublished (from CDROM)

MK Classification System, 1983, Morris-Kennedy, P., unpublished (from CDROM).

Selected Astronomical Catalogs, 1991, vol. 1, No. 1 (USA_NASA_ADC_CAT_0011), Astronomical Data Center, Goddard Space Flight Center, NASA (CDROM).

Superseded Washington Double Star Catalog, 1984, Worley, C.E., and Douglass, G.G., unpublished (from CDROM).

The U.S. Naval Observatory Catalog of Positions of Infrared Stellar Sources, 1994, Hindsley R. and Harrington R., Astron. Journal 107 280 =1994AJ....107..280H

The Hipparcos and Tycho Catalogues, 1997, ESA SP-1200, =1997HIP...C......0E

The Tycho-2 Catalogue of the 2.5 Million Brightest Stars Hog E., Fabricius C., Makarov V.V., Urban S., Corbin T., Wycoff G., Bastian U., Schwekendiek P., Wicenec A. Astron. Astrophys. 355, 27 (2000), =2000A&A...355L..27H


Last update: September 20, 2001

This page developed and maintained by Sean Urban.