The shape and width of observed PSFs varies slightly over time, due to the change in focus of the telescope. The focus variation consists of two terms: a secular change due to the ongoing shrinkage of the Metering Truss Assembly at an estimated rate of 0.25 ? ... See Figure 5.8 ). ... Systematic errors due to the secular focus drift can be corrected using aperture corrections as a function of focus change (see Figure 5.9 ). The aperture correction adjusted for focus change is hence: . ...

... The az/za plots show the errors in mm normal to the reflector surface. The measured points on the reflector surface go all the way to the edge of the dish so the zenith angle goes from 0 to 34 deg. ... The figures are: . ... Figure 3: Shows the reflector errors after the first adjustment. ... 120 degrees is too far by 2 times . ... You can see the large errors in the center (green, blue) that point at -60 degrees. ... The large errors at -120 degrees were turned the wrong direction. ...

Figure 4a. The defocus in arcseconds of blur on the image plane is shown as a function of time for the night of August 14. Arrows mark the times at which the telescope focus was manually changed. The labels show the magnitude of the changes made. The squares show measurements of the defocus just prior to and after manual focus changes. ... Below I will show clear indications of errors in the secondary motions which are probably contributing significantly to focus errrors in the telescope. ...

... With the ATCA beam at 3mm being comparatively small ( ), it is possible for tracking errors to be significant. ... In additional poor tuning of the antenna drive systems can sometimes cause poor tracking, particiularly soon after a change in source. ... Tracking errors are caused by flaws in the drive servo system, whereas pointing errors are a sum of tracking errors and errors in the antenna pointing model. ... The task uvflag can be used to flag based upon rms tracking error. ...

Next: Determine a background subtracted Up: Calibration Previous: Radial profile of an . It is possible to propagate statistical errors through an analysis procedure via the use of an error array. Error arrays can be used in such tasks as imcnts , imcontour and imsmooth . An error array contains the squares of the errors (it is the data file itself for Gaussian statistics). ... xs> errcreate ``xdata$snr.qp[bl=2]'' . ... Each array element will contain the square of the error. ...

... Tiny Tim has been used for generating Hubble Space Telescope ( HST ) point-spread functions (PSFs) for deconvolution, algorithm testing, proposal planning, and optical studies. ... Tiny Tim is a stand-alone program for simulating HST PSFs as viewed with the on-board imaging cameras (WF/PC-1, WFPC2, FOC, COSTAR/FOC). ... The measured aberrations for FOC f/96, WF/PC-1 PC6, WFPC2, and COSTAR/FOC are used by Tiny Tim . ... Figure: FOC f/96 observed and Tiny Tim model PSFs (pre-COSTAR) at 253 nm. ...

... B.1 New functionality . ... B.3 Semantic changes from CSS1 . ... CSS2 builds on CSS1 and all valid CSS1 style sheets are valid CSS2 style sheets. The changes between the CSS1 specification (see [CSS1] ) and this specification fall into three groups: new functionality, updated descriptions of CSS1 functionality, and changes to CSS1. ... Several internationalization features, including list numbering styles , support for bidirectional text , and support for language-sensitive quotation marks . ...

Tired light models invoke a gradual energy loss by photons as they travel through the cosmos to produce the redshift-distance law. ... The tired light model can not produce a blackbody spectrum for the Cosmic Microwave Background without some incredible coincidences. ... So the CMB must have come from a far away part of the Universe, and its photons will thus lose energy by the tired light effect. ... Assume that the CMB starts out as a T = (1+z)*T_o = 2.998 K blackbody, which is the blue curve. ...