Query : 1999A&AS..135....1E

1999A&AS..135....1E - Astron. Astrophys., Suppl. Ser., 135, 1-3 (1999/February-2)

Variable stars: which Nyquist frequency?


Abstract (from CDS):

In the analysis of variable stars, the problem of sampling is central. This article focusses on the determination of the Nyquist frequency. It is well defined in the case of regular sampling. However, the time series of variable stars observations are generally unevenly sampled. Fourier analysis using the spectral window furnishes some clues about the equivalent Nyquist frequency in the irregular case. Often it is pushed very high, and thus very short periods can be detected. A specific example is shown, drawn from MACHO databases.

Abstract Copyright:

Journal keyword(s): stars: variable - methods: analytical - methods: data analysis

Simbad objects: 1

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Number of rows : 1
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 MACHO 162.25348.3066 * ~ ~           ~ 1 0

Query : 1999A&AS..135....1E

Basic data :
MACHO 162.25348.3066 -- Star
Origin of the objects types :

(Ref) Object type as listed in the reference "Ref"
(acronym) Object type linked to the acronym according to the original reference
() Anterior to 2007, before we can link the objet type to a reference, or given by the CDS team in some particular cases

Other object types:
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
ICRS coord. (ep=J2000) :
No Coord.

The link on the acronym of the identifiers give access to the information for this acronym in the dictionary of nomenclature.
Identifiers (1) :
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MACHO 162.25348.3066

References (1 between 1850 and 2023) (Total 1)
Simbad bibliographic survey began in 1850 for stars (at least bright stars) and in 1983 for all other objects (outside the solar system).
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MACHO 162.25348.3066

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