## Appendix EFCFs by reduction date

Ongoing development of the SCUBA-2 analysis has resulted in ongoing changes to the tau relationship and the FCFs. Depending on when your data were reduced you will need to apply different calibration values.

 Date FCF - 450$\mu$m FCF - 850$\mu$m Jy/pW/beam Jy/pW/arcsec${}^{2}$ Jy/pW/beam Jy/pW/arcsec${}^{2}$ until January 2012 383 4.9 1080 5.0 January 2012 - July 2012 606 6.06 556 2.42 July 2012 onwards 491 4.71 537 2.34

 Date Tau Relation 450$\mu$m 850$\mu$m until January 2012 32 $×$ (${\tau }_{225}$ - 0.02) 5.2 $×$ (${\tau }_{225}$ - 0.013) January 2012 - July 2012 26 $×$ (${\tau }_{225}$- 0.01923) 4.6 $×$ (${\tau }_{225}$ - 0.00435) July 2012 onwards 26 $×$ (${\tau }_{225}$ - 0.01196) 4.6 $×$ (${\tau }_{225}$ - 0.00435)

• Peak FCF (Jy/pW/beam)—multiply your map by this when you wish to measure absolute peak fluxes of discrete sources.
• Arcsec FCF (Jy/pW/arcsec${}^{2}$)—multiply your map by this if you wish to use the calibrated map to do aperture photometry.

You can find out when your data was reduced and hence what tau relation was applied by using the Kappa command hislist.

%  hislist file | grep EXT.TAURELATION

This will return something like the following,

EXT.TAURELATION.450=(26.0,-0.012),
EXT.TAURELATION.850=(4.6,-0.0043), EXT.TAUSRC=auto, FAKESCALE=1,