The pitch, roll, and focus errors of the telescope (measured and computed in AO9 survey and tilt sensor pitch,roll ) can be corrected by using the tiedowns. ... Tiedown positions to correct the pitch,roll, focus errors versus azimuth for za 2 through 20 degrees. ... The pitch, roll, and focus errors are plotted versus azimuth for za 1 to 20 degrees (the color changes every two degrees) . ... The pitch error is on the top and the roll error is on the bottom. ... The pitch and roll errors versus za. ...
... 2.3 Data acquisition Spectra generated by the Multibeam correlator contain the usual structure seen in spectra from other H i instruments: a bandpass spectrum which is the sum of the sky , ground and receiver temperatures multiplied by the product of the filters in the receiver chain; superimposed on this is a noise ... Note also that sources extended much beyond ,40 arcmin can be imaged poorly in HIPASS images because of the bandpass sidelobe effect described in Section 3.3. ...