Sky Charts |
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Configuring the appearance of objects
Label of the objects It is possible to assign a label to the type of object that has been selected. If the option "Display" is checked, then a label is given for all selected objects. The option "Options" lets you choose the information you want to display (name, magnitude, coordinates), where the information is displayed (left or right), the label text color and size, and the type of object that has to be displayed.
Date and Time ![]() Define the date and time used to calculate the position of the planets, comets, asteroids as well as the azimuth position and the proper motion. It is possible to use the system date and time or you can enter any valid date and time between year -3000 and +3000. If the option "Auto Refresh" has been selected, then the time is updated every minute, otherwise the default time is when the program was started and will be used throughout the session ( unless you manually refresh it with the button "Actual time"). The time zone has to be given relative to UTC. Give the difference in hours to obtain your local time: this number is positive if you are located east of Greenwich and negative if you are located west of it. The difference between the dynamic time used by the program and the standard time is given. Simulation : It is possible to calculate an objects position for several dates. Give the number of dates you would like and the interval between them. Observatory ![]() Define the location of the observation site to be used when calculating the parallax and the azimuth position. Enter the latitude, the longitude and the altitude (in metres) of your observatory. You can assign a name to a location. Press "Save" to keep it for next session. It will appear in the list of the available locations. Projection types
This panel lets you choose the projection you want to be used when displaying
a chart according to the selected field width. Not all the projections
can be used in any case. I.e. the tangent projection has a great distortion
for fields larger than 45° and diverge for 90°. The sinus projection
overlaps at more than 90°.
![]() by E. Griessen, AIPS memo 27 The selected projection described up to here can be modified according
to the header of the file in FITS format containing WCS when you load such
an image.
Displaying images
This panel lets you select the image that will be displayed together with the chart. The image is loaded in a preview window. You can modify the display
tresholds (min and max), the color palette (composite colors LUT and intensity
tables ITT) and zoom a portion of the image.
In the case of FITS format files, which contain the coordinates RA, DE or GLAT, GLON (i.e. the images provided from DSS-ESO or IRAS) the program uses the coordinates and the projection from the header of the FITS format to automatically positioned to the current chart. Please notice that it is only possible to zoom a section of the image from the preview window and not on the main screen, otherwise the automatic positioning does not work. In the case of other image formats it is necessary to place the image on the chart manually. You can of course use the function "Online Resources "to download an image directly from the Internet. It is possible to derive the initial thresholds from the information
contained in the file header, from the lowest and highest values or from
the average plus one or two standard deviation values.
The right mouse button on a file name displays the header of the file in the format FITS or PIC.
In the case of bitmap formats its is possible to check the option "Bitmap Palette" from the selection box "Image Color". In this case all the other functions are disabled. Otherwise and if the image is a 24 bit format, the program generates a gray level from the average of all the RGB planes (plane=0) or each color independently (plane=1,2,3). In both cases the image can be modify as for the files in format FITS or PIC. You can save the current image in a file in BMP format and reuse it later with the same appearance. The following formats are supported:
With the OK button you load the image into the current chart.
Note regarding the coordinates of the FITS files:
Bulk calculation of asteroids
This function computes the position of all asteroids for a given date.
Online Resources This menu gets you directly to the Internet resources.
The following resources are available: Images corresponding to displayed chart: - SkyView : Images in all wave lengths - ESO Skycat Digitized Sky Survey : Palomar atlas for the whole sky. The image dimension is limited to 1600 square minutes. The size of the corresponding file is 2.5 KB multiplied by the square size in minutes. - ESO Skycat Digitized Sky Survey 2 : The same survey but with a 15 micron scan ratter than 25 micron. The pixel resolution is 1 arcsec instead of 1.7 arcsec. The files are three time bigger. Extraction of large star catalogs: The data requested from these catalogs corresponding to the current chart is stored in a temporary file and automatically defined as catalog according to the magnitude, the disabling is done in this panel. HST Guide Star Catalog (20,000,000 stars) - CDS VizieR : Stars up to the magnitude 15. The field is limited to 5 degrees or 5000 stars. - ESO Skycat : Stars up to magnitude
15. The field is limited to 2 degrees or 1000 stars.
USNO-A (526,000,000 stars) - CDS Vizier : USNO-A2.0 Stars up to magnitude 20. The field is limited to 2 degrees or 5000 stars. - ESO Skycat : USNO-A1.0 Stars up to magnitude 20. The field is limited to 2 degrees or 5000 stars. Comets and asteroids
You can carefully modify some default options in the file EXTRES.INI.
HEASARC SkyView This panel gives you the possibility to directly obtain a sky image
corresponding to the current chart.
Do not modify the default value of "Coord" and "Field" if you want an
image for the current chart.
Pixel X et Pixel Y represent the number of pixel of the image. If these
two fields are empty, then the resolution of the catalog will be used.
If you plan to keep the file for later utilization, give a name to it in the corresponding field but do not modify the extension ".fit". Estimation of the file size:
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