Radio Eyes Help
Topic: Main Window â A guide to the primary interface of Radio Eyes.
Overview of the Main Window
There are many things to learn about the main window of the program. Of primary importance is the menu bar across the top of the window. This is your primary access point to the many features of the program. The menu items File, View, Observer, etc are treated separately in the help pages. Here we will concentrate on other aspects of the main window.
The Sky Map
Most obvious is the sky map. When the program loads this equatorial-rectangular map shows the full sky. At the top of the map is the north celestial pole. Because of the projection used this single point is stretched all of the way across the top of the image. The same is true for the southern celestial pole at the bottom of the map.
This projection may not appear ânaturalâ to optical observers; however, it is quite useful for our purposes. A secondary âDome Viewâ is available to help you see how the sky would appear to the eye. The full-view map has declination +90° at the top and â90° at the bottom. 24 hours of Right Ascension (RA) are displayed horizontally.
The default background is a colour representation of the 408 MHz sky. The bright regions on the background are primarily emission from our own galaxy. Other backgrounds may be loaded (see Backgrounds & Catalogs help). By default the image is centred on your local meridian, a line running from North to South at your location.
The meridian line is optionally displayed. Because many radio-astronomy observations are done along the meridian, it is a useful reference. With time the background and objects will move from left to right.
In the picture above you will see a yellow dotted line that dips to the centre of the image. This is the horizon line and represents the local horizon of the observer. For an observer in the southern hemisphere this line would be highest at the top of the map. With a little practice you will quickly identify which part of the map is above your local horizon and which part is below.
If in doubt, move the mouse cursor to a point on the map. What does the Altitude box at the bottom of the screen say? If the altitude is negative, the mouse cursor is in a region of the map that lies below your local horizon. By default the horizon is simply 0° of elevation; however, you can define a custom horizon that takes hills, buildings, etc. into account.
Time Modes
At the upper left youâll see a clock/calendar and buttons labeled Real Time and UT. These are your primary time controls and displays. Click the UT button to switch between Universal Time and Local Time. You can display the sky for times other than the present or freeze the automatic screen updates by pressing the Real Time button. When pressed, the Real Time button changes to Fixed Time.
In Fixed Time mode you can type in new times/dates or select new dates from the drop-down calendar. After making a change in Fixed Time mode youâll see an Update button (with a clock icon) just to the right of the date/time display bar. You must click it to apply your new time and date.
In addition to Local or UT time, you may read the Local Mean Sidereal Time (LMST) in the box at the bottom of the main window. LMST changes at a rate about 4 minutes per day faster than UT and is keyed to the RA value on your meridian.
Status Displays & Controls
The bottom of the window also includes boxes showing RA (Right Ascension), Declination, Altitude, Azimuth, and the âTransits In / Atâ box. In normal mode the values displayed refer to the last pointer position; in other modes they may refer to specific points. A label above the boxes indicates what the boxes reference.
The âTransits In / Atâ box supports two display modes. In Transits In mode, the box tells you how much time will elapse before the referenced point crosses your meridian. In Transits At mode, the box shows at what time the referenced point will next cross the meridian. Switch between these modes under the Options menu. These are important when performing meridian drift scans.
If the loaded background fileâs FITS table supplies values, the box labeled T (Kelvins) displays those values, such as for the 408 MHz background where values are in equivalent temperature in °K. Other backgrounds may measure different things (see Backgrounds help).
A general-purpose status display appears at the bottom right of the main window. Above it are quick labels indicating files currently being used.
Menus & Navigation
Learn about the specific drop-down menu items via the following links:
Also: