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Usage of wildcards

The wildcards,`' and `%', may be used in alphanumeric values to replace part of the character string by any character. The difference between `' and `%' is that `' can indicate a character string of any length, including zero length, while `%' stands for one character only. For example, `%% A' indicates all three-character strings with an A as last character, while ` *A' may have any length, and includes ` A' itself.

The use of wildcard(s) is particularly useful when searching on object_name: Most catalogue entries contain, apart from the, possibly abbreviated, object title, additional information, ranging from a filter name to a run number or seeing information. The wildcard can replace such additional information, and the user only needs to concentrate on the object name. For example, if you want to find observations of the object NGC205 you may try:


However, better is this:

SEL OBJECT = (N*205 *,N*205)

The second formulation will also uncover N205..., but not, for instance, NGC2051. Further, the blank specified in this form is significant, and a curiosity of the software is that N*205 * will not uncover the plain name `NGC205', because the blank after the 5 is not treated as part of the name in the catalogue object name field.

Wildcards can not be used in the values of coded catalogue items, such as Telescope or Waveband; see table .

Fri Aug 12 10:24:53 BST 1994