We present photometry on 23 Jupiter Family Comets ( JFCs ) observed at large heliocentric distance , primarily using the 2.5m Isaac Newton Telescope ( INT ) .
Snap-shot images were taken of 17 comets , of which 5 were not detected , 3 were active and 9 were unresolved and apparently inactive .
These include 103P/Hartley 2 , the target of the NASA Deep Impact extended mission , EPOXI .
For 6 comets we obtained time-series photometry and use this to constrain the shape and rotation period of these nuclei .
The data are not of sufficient quantity or quality to measure precise rotation periods , but the time-series do allow us to measure accurate effective radii and surface colours .
Of the comets observed over an extended period , 40P/Väisälä 1 , 47P/Ashbrook-Jackson and P/2004 H2 ( Larsen ) showed faint activity which limited the study of the nucleus .
Light-curves for 94P/Russell 4 and 121P/Shoemaker-Holt 2 reveal rotation periods of around 33 and 10 hours respectively , although in both cases these are not unique solutions .
94P was observed to have a large range in magnitudes implying that it is one of the most elongated nuclei known , with an axial ratio a / b \geq 3 .
36P/Whipple was observed at 5 different epochs , with the INT and ESO ’ s 3.6m NTT , primarily in an attempt to confirm the preliminary short rotation period apparent in the first data set .
The combined data set shows that the rotation period is actually longer than 24 hours .
A measurement of the phase function of 36P ’ s nucleus gives a relatively steep \beta = 0.060 \pm 0.019 .
Finally , we discuss the distribution of surface colours observed in JFC nuclei , and show that it is possible to trace the evolution of colours from the Kuiper Belt Object ( KBO ) population to the JFC population by applying a ‘ de-reddening ’ function to the KBO colour distribution .