Although you can transform an image/cube, the default only needs to know the distance (in AU, pc, kpc, mpc, z, ...) and unit size (in AU, pc, kpc, mpc, ....) of the object. This will give you the scaling factors for length and velocities.

When the distance is given in z, Wright’s (2006) cosmology calculator is used.

**in=**- Optional input image file. Must be in
*image(5NEMO)*format. **out=**- Output image
file, only required if an input image is given. Will be in
*image(5NEMO)*format, with optionally scaled image values and axes coordinates. **d=#,[unit]**- Distance to your object, and optionally a unit. AU, pc, Kpc, Mpc, and Gpc are allowed. You can also specify a dimensionless number ’z’, in which case the special cosmology calculator is used. Or if you know the recession speed and assume a Hubble constant, d=4500/69,Mpc [default: 1,pc]
**r=#,[unit]**- Length scale of object, and optionally a unit. km, AU, pc, Kpc, Mpc, and
Gpc are allowed. Together with a distance
**d=**, this will convert the length scale in your maps to degrees, required for FITS. [default: 1,AU] **v=#,[unit]**- Velocity scale of object, and optionally a unit. The output units will be the one that FITS uses, m/s. [Default: 1,km/s]
**sdv=#**- Total flux, in Jy.km/s, of the source. Based on the distance, it will the compute the HI and H2 (given some reasonable X factor) masses, in units of solar masses. Default: 1
**scale=#**- Scale the intensity values in the data itself. Default: 1.
**H=**- Specify
the cosmology model, with up to 3 parameters. Only used when units in
**d=**are ’z’ were specified. The first parameter is the Hubble Constant. Optionally followed by the WM (Omega(matter)) and WV (Omega(vacuum)), for different cosmologies. If only H0 and WM are given, a flat universe (WV=0) is used. See also Wright(2006). WMAP-9 values: H=71,0.27,0.73 (2011?), Planck-1 values: H=67.15,0.317,0.683 (2013) [Default: 71,0.27,0.73]

WMAP-9 (2011)710.270.73 Planck (2013)67.150.3170.683 Planck (2018)67.660.31110.6889

% ccdsky d=1,pc r=1,AU v=1,km/s d=1 pc r=1 AU v=1 km/s rscale=0.000277785 (1.00003 arcsec) vscale=1000

To find out the radius of 2 pc at the distance of the galactic center:

ccdsky r=2,pc d=8.5,kpc rscale=0.0134814 (48.5329 arcsec)

Here is an example of creating a small bar, at position angle 30, and
observed at RA=6h and DEC=30d:

% ccdgen "" map4 bar 1,10,0.5,30 size=512,512,1 % ccdsky map4 map4b % ccdfits in=map4b out=map4b.fits radecvel=t crval=90,30 crpix=256.5,256.5 % # now switch to MIRIAD % fits in=map4b.fits out=map4b.mir op=xyin % cgdisp in=map4b.mir device=/xs labtyp=arcminand you should see a bar (possibly with a sign error position angle) of about 1 arcmin in length, in an 8 arcmin field. Notice that

Here is a cosmological example:

% ccdsky H=67.7,0.307,0.693 d=2.19,z ------------------------------------------------------------- For H_o = 67.7 Omega_M = 0.31 Omega_vac = 0.69 z = 2.190 It is now 13.830 Gyr since the Big Bang. The age at redshift z was 3.012 Gyr. The light travel time was 10.818 Gyr. The comoving radial distance, which goes into Hubbles law, is 5592.2 Mpc or 18.239 Gly The comoving volume within redshift z is 732.530 Gpc^3. The angular size distance D_A is 1753.026 Mpc or 5.718 Gly. This gives a scale of 8.499 kpc/arcsec The luminosity distance D_L is 17839.0 Mpc or 58.183 Gly. The distance modulus, m-M, is 46.26 ------------------------------------------------------------- d=2.19 z [3635.8 Mpc] r=1 AU v=1 km/s SdV=1 Jy.km/s rscale=1.5846e-13 [ 5.70457e-10 arcsec 5.70457e-07 mas] vscale=1000 iscale=1 Mass(HI) = 7.25098e+11 Mass(H2) = 3.22675e+10 (alpha=4.3; includes 1.36 He contribution)compare this with the (selected) output for

% astcosmiccal --H0=67.7 --olambda=0.693 --omatter=0.307 -z2.19 CosmicCalculator (GNU Astronomy Utilities) 0.11 Universe now ------------ - Age of Universe now (Ga*): 13.844296 - Critical density now (g/cm^3): 8.610662e-30 - Proper distance to z (Mpc): 5592.995113 - Angular diameter distance to z (Mpc): 1753.290004 - Tangential distance covered by 1 arcsec at z (Kpc): 8.500190 - Luminosity distance to z (Mpc): 17841.654411 - Distance modulus at z (no unit): 46.257176 - Conversion to absolute magnitude (no unit): 44.997699 Universe at desired redshift z ------------------------------ - Age of Universe at z (Ga*): 3.017860 - Look-back time to z (Ga*): 10.826436 - Critical density at z (g/cm^3): 9.177897e-29

http://arxiv.org/abs/astro-ph/0609593
*A Cosmology Calculator for the Web*
(E.Wright)

http://www.astro.ucla.edu/~wright/CosmoCalc.html
* The CosmoCalc website*

17-Aug-2012V1.0 CreatedPJT 23-aug-2012V1.1 added sdv=PJT 28-aug-2012V1.2 implemented scale=PJT 28-feb-2013V2.2 more verbose, added H=PJT 16-mar-2013V3.0 added Wright’s cosmology calculatorPJT