\begin{table}%t1 \caption{\label{tab1_lrdata} Summary of the AMBER low-spectral resolution observations of \object{IRC+10420} and the calibrator star HD~190327.} \small%\centerline { \begin{tabular}{cccccc} \hline \hline ${\rm date}$& ${\rm UTC}$& ${\rm AT}$ & $B_{\rm p}$ & $PA$ & {\rm seeing}\\ & & ${\rm configuration}$& [${\rm m}$] & $[\degr]$ & $[\arcsec]$ \\ \hline \multicolumn{6}{c}{${\rm \irc}$}\\ 2007-05-17 & 08:11:53 & {\rm A0-D0-H0} &31--93 & 75 & 1.0\\ 2007-05-17 & 09:18:51 & {\rm A0-D0-H0} &32--96 & 72 & 1.4\\ 2007-06-18 & 08:09:22 & {\rm E0-G0-H0} &15--48$^{a}$& 69 & 0.7\\ 2008-05-21 & 08:12:14 & {\rm A0-D0-H0} &31--94 & 74 & 0.8\\ \hline \multicolumn{6}{c}{${\rm HD~190327}$}\\ 2007-05-17 & 08:48:23 & {\rm A0-D0-H0} &31--93 & 74 & 1.2 \\ 2007-06-18 & 08:39:13 & {\rm E0-G0-H0} &16--47 & 70 & 0.6 \\ 2008-05-21 & 08:48:41 & {\rm A0-D0-H0} &32--95 & 74 & 0.7 \\ \hline \end{tabular}} \medskip $^a$ Due to technical problems during the observations, visibilities could only be obtained for the intermediate baseline ($B_{\rm p}=31$~m). \par UTC is the time stamp (Universal Time) corresponding to the start of fringe tracking, $B_{\rm p}$ is the projected baseline, and PA denotes the position angle of the observation. The seeing value given in the last column corresponds to the DIMM seeing at the time of the corresponding observation. Each measurement consists of 5000~frames with an exposure time of 50~ms. The calibrator HD~190327 has spectral type K0III, $K=3.2^{\rm m}$ \citep{2mass}, and a uniform-disk diameter $d=1.10 \pm 0.01$~mas \citep{charm2}. \end{table}