ING La Palma Technical Note no. 85

  Standard Star lists available at the ING

This note provides a brief description of the sets of standard stars available for use with the Isaac Newton Group telescopes at the Roque de Los Muchachos Observatory on the island of La Palma. Lists of all the tables of standards are also given. This version refers to CMS generation 3 of SYSTEM.CAT.


Star Positions:    All star positions given in these tables are either extracted from astrometric catalogues or have been derived from measurements of POSS glass plates. The equinox and epoch for each position are identical unless otherwise stated.

Proper Motions:    Catalogues were searched to provide proper motions where available. For any of the spectrophotometric standards which might have a measurable proper motion, but were not in any catalogue, plates were taken with the 13-inch telescope at Herstmonceux in 1987, a position measured, and compared with the position on the POSS plates.

Names:    The name given to stars in the column LP name in the tables can be entered directly at the control console of any one of the WHT, INT or JKT and the telescope will automatically set at the required position. On the WHT the catalogues do not have to be read in explicitly, but are accessed automatically by typing GOCAT followed by the object name (eg SP2311-068) given that an object of the same name does not exist in the user's own catalogue. On the INT and JKT, however, it is necessary to input the catalogue, then request the object (eg INPUT FK5 followed by NEXT N04+45 and then GO). On the INT and JKT no more than 500 sources can be held in memory, so only the catalogues required should be read in. The catalogues available are:

  Catalogue Name Table No. of entries
  PTGRID.CAT (Table I) 229
  FK5.CAT (Table II and Table IX) 276
  UBVRI.CAT (Table III) 216
  SPECPHOT.CAT (Table IV) 59
  GEOM.CAT (Table V and Table VI) 200
  BLANK.CAT (Table VIII) 6

Faint Pointing Grid:    Table I is a selection of AGK3, Perth70 and CPC2 stars forming a grid over that part of the sky visible from La Palma. CPC2 refers to the Cape Photographic Catalogue. The plates for this were taken at SAAO, and measured using the GALAXY automatic measuring machine at the RGO. The accuracy of the catalogue is comparable with the AGK3. All AGK3 stars have both equinox and epoch of 1950.0, Perth70 and the CPC2 stars have equinox 1950.0 and epoch of date of the second epoch plates. The stars were selected to form a grid at approximately one hour intervals in Right Ascension and 15o in Declination, with alternate hour zones offset in Declination. Stars of approximately 9th magnitude and G0 to K0 spectral type range were chosen. The positions in the files held in the computers on the INT and JKT have been corrected to both equinox and epoch 1950.

Bright Pointing Grid:    Table II is a list of stars selected from the FK5 catalogue on a grid similar to the faint pointing grid. A diagrammatic version of this grid is given in Table IX. These stars are all 6th magnitude or brighter. For the +30o zone, two stars were selected at each Right Ascension position, one north and the other south of the La Palma zenith. All the star names are given an N or S to indicate whether the star is north or south of the zenith. Stars which pass close to the zenith are useful for improving the pointing coefficients of the Altazimuth WHT, and extra ones are given at the end of this list.

Photometric Standards:    Table III lists the photoelectric standard stars measured by Landolt on the 16-inch and 36-inch telescopes at Kitt Peak (1973) and the 0.4m and 0.9m telescopes at the Cerro Tololo Observatory (1983). Magnitudes as well as colours are given to help the observer determine a suitable exposure. The UBV photometry is based on the Landolt (1973) sytem which was derived from Johnson and Morgan (1953). The RI photometry is on the Cousins (1976) system, which was derived from the Kron et al. (1953) data.

Cousins, A.W.J. 1976, Mem. R. Astron. Soc., 81, 25.

Johnson, H.L. & Morgan, W.W. 1953, Astrophys. J., 117, 313.

Kron, G.E., White, H.S. & Gascoigne, S.C.B. 1953 Astrophys. J, 118, 502.

Landolt, A.U., 1973, Astron. J., 78, 959.

Landolt, A.U., 1983, Astron. J., 88, 439.

Spectrophotometric Standards:    Table IV is the list of Spectrophotometric standards of Oke, Stone and Fillipenko & Greenstein. A complete set of these data, with flux plots and finding charts, is given in La Palma Technical Note 65 and Technical Note 100.

Fillipenko, A.V. & Greenstein, J.L., 1984, Publ. astron. Soc. Pacif., 96, 530.

Oke, J.B., 1974, Astrophys. J. Suppl., 27, 21.

Oke, J.B. and Gunn, J.E., 1983, Astrophys. J., 266, 713.

Stone, R.P.S., 1977, Astrophys. J., 218, 767.

Geometry Fields:    Tables V and VI are lists of stars measured to arcsecond accuracy to test the detector and focal plane geometry. Table V has two fields (2 arcmin square) which are useful for the acquisition TVs on all three telescopes and the Cassegrain autoguider on the WHT. Table VI has two fields (approximately 15 arcmin square) which are suitable for the full focal planes. Centres for these fields are given in the first line of each list (eg F1), followed by positions for all the stars in the field (eg F1-1).

Photometric sequences in compact fields:    Table VII is a list of photometric sequences for CCD fields. The positions given are the field centres. Vmax gives the magnitude of the brightest star and Vmin give the magnitude of the faintest star measured in the field. The final column gives the passbands for which photometry is available.

Christian, C.A., Adams, M., Barnes, J.V., Butcher, H., Hayes, D.S., Mould, J.R., & Siegel, M., 1985, Publ. astron. Soc. Pacif., 97, 363.

Schild, R.E., 1983, Publ. astron. Soc. Pacif., 95, 1021.

Stobie, R.S., Sagar, R. & Gilmore, G. 1985, Astron. Astrophys. Suppl. Ser., 60, 503.

Empty Fields:    Table VIII is a list of areas of sky in which there are few stars. These are useful for flat fields and fringe frames.

Christian, C.A., Adams, M., Barnes, J.V., Butcher, H., Hayes, D.S., Mould, J.R., & Siegel, M., 1985, Publ. astron. Soc. Pacif., 97, 363. Users' Manual for the CCD Camera on the 0.9m telescope. K.P.N.O.

Janet Sinclair