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Дата изменения: Mon Sep 17 19:47:52 2007 Дата индексирования: Mon Oct 1 19:28:28 2012 Кодировка: Поисковые слова: южная атлантическая аномалия |
Solution of problems at identification of star field.
If the field is not identified, the following reasons are possible:
1) The coordinates of the centre of the frame are not correct.
2) Scale is not correct. Generally this problem arises at first use of the
program, or if a changes in equipment were made. Scale set in "Properties/Telescope".
Possible actions:
a) Set "Properties/Telescope/New instrument". In this case algorithm of identification will revise all values of scale from twice smaller up to twice greater. For example if you have sited scale 1 second per pixel; the algorithm will work correctly, if the real value of scale is made from 0.5 up to 2.
b) Try to pick up scale, taking into account the range of operation of algorithm.
3) Not there are enough of stars for identification in the frame. For identification it is necessary not less 4 stars.
4) Not there are enough of stars for identification in the catalogue. Try to choose the catalogue with the large number of stars. The catalogues by way of increase of number of stars are TYCO, UCAC, USNO.
5) For this field the algorithm of identification does not work. Possible ways of a solution of the problem:
a) Try to change the configuration of stars used for identification. (Red circles mark stars of the old configuration.) For this purpose:
I) Open the image anew.II) On the "Calculations"menu, click "Measure".III) Measure stars of a new configuration by click.IV) Try again to identify the field.b) Reduce the field from the catalogue.c) Try to change parameters of algorithm of identification. These parameters are set on the tab "Properties/Identification".
Significance of parameters is the following:
I) "Number of stars in frame" A configuration from such number of stars is used for identification.II) "Number of stars from catalogue" Such number brightest is used from a catalogue. There should be more than value of the field "Number of stars in frame".III) "Maximal residual in coordinates" If the stars residual between coordinates in a frame and coordinates in the catalogue is more than the specified value, the star is excluded from consideration.IV) "Min. number of stars for ident." The star field is considered identified if number of the identified stars more or equally to this value. It is necessary to set value from 4 up to value of field "Number of stars in frame".