FCFs at 120" & 180" chops

I found a few matching pairs of jiggle maps on Uranus, and have analyzed the most recent three :

UT date
Obs.No.
taucso
Chop
(")
peak flux
(V)
Integrated flux
30" aperture
(*)
ratios 180/120
20001122
15
0.060
180
0.253
5.329
0.91 (peak)

16

120
0.279
5.911
0.90 (int.)
20000618
43

120
0.287
6.018
0.96 (peak)

51
0.085
180
0.276
5.835
0.97 (int)
20000612
49

120
0.329
6.860
0.92 (peak)

50
0.112
180
0.302
6.258
0.91 (int)

(*) s.d.'s usually ~0.1% of total.

So there is a definite 5-10% increase in FCF when using 180" chop cf 120".

There are other pairs for Uranus were earlier than 2000 :

19990921_0031 & _0037
19990409_0077 & _0078
19990316_0079 & _0080
19990316_0085 & _0086
19980904_0022 & _0029
19980725_0013 & _0014 (180) & _0015 (120 again)

but I can't imagine they'll change the picture much.

Iain M. Coulson
Latest Update: 28 Oct 2003