- Use the button below the heading "uv Coverage" ("Beam Shape") to switch between the uv coverage and the beam shape
- For changes in parameters to take effect, you must press "calculate".
- This tool gives the theoretical sensitivity achievable in the absence of
calibration errors etc. The weak source approximation is assumed in all
calculations - observing strong sources will cause a degradation of
sensitivity, compared to the values displayed.
- The uv tracks and beam shape displayed are approximate (do not take into
account calibrator observations) and should be taken as a guide only.
- Observing time is assumed to be allocated such that the source will transit the midpoint of the two most widely separated antennas halfway through the observation.
- Telescopes are assumed to have the following elevations limits:
- Narrabri: 12 degrees
- Parkes: 30 degrees
- Mopra: 12 degrees
- Tid: 6 degrees
- Hobart: 16 degrees
- Ceduna: 10 degrees
- Hart: 10 degrees
- Kashima: 15 degrees
- VLBA antennas: 2 degrees
- Planned antennas (MIRANdA, 12mGEO): 10 degrees
- Planned antennas are shown in italics
- Correlator efficiency is assumed to be 0.88, appropriate for four-level sampling and floating point fringe rotation.
- Two density weighting options are supplied: Natural and Uniform. Natural weighting does not change the uv samples, and gives the best signal to noise ratio. Uniform weighting weights all points inversely proportional to the surrounding density of uv samples, which effectively upweights the long baselines and downweights the short baselines (since they are generally closer together).
- Two signal to noise weighting options are supplied: unweighted and 1/sigma^2. Normal does not weight the points by their signal to noise ratio. 1/sigma^2 weights points inversely proportional to the variance of their noise. This has the effect of downweighting points which have bad signal to noise and improving image sensitivity (although often at the expense of resolution as the longest baselines often have the worst signal to noise).
- For the Tid_70m antenna at 2.3 GHz, the quoted sensitivity is for single polarisation observations at a bandwidth <= 30 MHz. For dual polarisation observations or single polarisation observations with 32 MHz bandwidth or above, sensitivity on the Tid baselines will be degraded by a factor of 1.25, with a roughly similar impact on image sensitivity.