The secondary mirror of the telescope “chops”Ī short distance (<= 180 arc-seconds) to either side.īeam switching produces better baselines than position switchingīut requires little or no emission close to the target due This can just be one point if you intend to perform a In this mode you should enter the number of map pointsĭirectly. The telescope moves to one or more individual points. Pattern, which controls the number of points being observed. If you select this option you will need to select a jiggle Making small maps which fit within the jiggle pattern The secondary mirror of the telescope moves in a pre-defined pattern. Raster mapping is often the most efficient method with only one off-sourceĮnter the size of your map. In the “Observation” section you define the type of observationĭata are recorded on-the-fly while the telescope scans an area. If you enter the declination then the zenith angle You can either enter the declination of the source or give It is helpful to include in your technical justificationĪn explanation of which transition lines you propose If you are saving the calculation to your proposal Will be computed as part of the calculation.) (If the radial velocity is not zero, the observed frequency Note that this is the rest frequency taking into account The frequency should be within the receiver’s tuning range, You will then be able to enter the frequency manually (the first box for the input labeled “transition line”). To do this, select “Other” from the top of the list of species If you wish to observe a transition line which is not listed, The set of enabled transition lines will also be updated Which is shown next to the rest frequency input box. Will be applied to the receiver’s tuning range, The redshift you select, or the velocity converted to a redshift, Therefore if your source has a significant radial velocity, Transitions which fall outside the receiver’s tuning This is done using two controls to select the
The transition line which you wish to observe.
In the source and conditions section, you should select You may select “Continuum mode” if it is required for your observations. You should select the “Separate polarizations” option. However if you wish to estimate the sensitivity which wouldīe obtained in each polarization individually, This is generally the best option, as the two polarization measurements Mixers together to reduce the integration time required. Have two mixers observing the same position in orthogonal polarizations.īy default the calculator will assume that you intend to use both So only one option will be available here.Ī single-sideband calculation should be used. Single, dual or sideband-separating (2SB), The current receivers each have only one sideband mode: Want the “best” sideband to be selected automatically. Similarly you can select a specific sideband if you do not You can select “Other” from the menu and then enter the desired frequency. The results will show the IF and LO frequencyįor example as part of a tuning for multiple simultaneous lines, Normally you can use the receiver default IF and the “best” sideband. (For other instruments this input line will be disabled.) Newer instruments where the calculator has receiver temperature dataĪs a function of local oscillator (LO) frequency. The “intermediate frequency” (IF) line will only be available for Then it is the frequency resolution as observed, If this is given as a frequency (in MHz), You can also enter a lower frequency resolution if you Page for information about available resolutions.
On the next line you should select the frequency resolution
First select the receiver you wish to use.
0 kommentar(er)
