2 JHK photometry

JHK photometry of V723 Cas was obtained by using a LN₂-cooled InSb photometer at the cassegrain focus of the 1.2 m telescope of PRL's Mt. Abu Infrared Observatory. The details of the experimental setup are given in Ashok et al. (1994). A chopping frequency of 10 Hz, a throw of 30$\hbox{$^{\prime\prime}$}$ and a 26$\hbox{$^{\prime\prime}$}$ aperture was generally used for the observations.

  

Table 1: JHK photometry of V723 Cas

A 39$^{\prime\prime}$aperture was used on some occasions and the chopper throw was adjusted to 40$^{\prime\prime}$. $\psi$ Cas (J=3.01, H=2.48, K=2.41, Varricatt et al. 1998) was used as the standard star for obtaining the nova magnitudes. Two different dewars were used for the observations - dewar 1 was used from Nov. 1996 onwards, and dewar 2 was used for the earlier ones. Our experience with both the systems shows that they are essentially identical. The photometry is accurate to $\pm 0.05$ mag. The observations, presented in Table 1, cover a period of fifteen months starting from two months since outburst.