NRAO Home > CASA > CASA Toolkit Reference Manual
vpmanager.setpbairy - Function

2.3.2 Make an airy disk vp


Description

Information sufficient to create a portion of the Airy disk voltage pattern. The Airy disk pattern is formed by Fourier transforming a uniformly illuminated aperture and is given by

vpp(i) = (areaRatio*2.0*j1(x)∕x- 2.0*j1(x *lengthRatio)∕(x*lengthRatio))∕areaN orm,
(2.10)

where areaRatio is the dish area divided by the blockage area, lengthRatio is the dish diameter divided by the blockage diameter, and

x = i*maxrad-*-7.016*-dishdiam-∕24.5m-.
           Nsamples * 1.566* 60
(2.11)

Arguments





Inputs

telescope

Which telescope in the MS will use this vp/pb?

allowed:

string

Default:

VLA

othertelescope

If telescope==”OTHER”, specify name here

allowed:

string

Default:

dopb

Should we apply the vp/pb to this telescope’s data?

allowed:

bool

Default:

true

dishdiam

Effective diameter of dish

allowed:

any

Default:

variant 25.0m

blockagediam

Effective diameter of subreflector blockage

allowed:

any

Default:

variant 2.5m

maxrad

Maximum radial extent of the vp/pb (scales with 1/freq)

allowed:

any

Default:

variant 0.8deg

reffreq

Frequency at which maxrad is specified

allowed:

any

Default:

variant 1.0GHz

squintdir

Offset (Measure) of RR beam from pointing center, azel frame (scales with 1/freq)

allowed:

any

Default:

variant

squintreffreq

Frequency at which the squint is specified

allowed:

any

Default:

variant 1.0GHz

dosquint

Enable the natural beam squint found in the common vp model

allowed:

bool

Default:

false

paincrement

Increment in Parallactic Angle for asymmetric (ie, squinted) vp application

allowed:

any

Default:

variant 720deg

usesymmetricbeam

Not currently used

allowed:

bool

Default:

false

Returns
record
__________________________________________________________________


More information about CASA may be found at the CASA web page

Copyright 2016 Associated Universities Inc., Washington, D.C.

This code is available under the terms of the GNU General Public Lincense


Home | Contact Us | Directories | Site Map | Help | Privacy Policy | Search