We present a color-magnitude (CM) diagram of M35, an open cluster. A DSLR camera was used for measuring the color index with the RGB channels. It is cost-effective and has relatively easy controls compared to astronomical CCDs for educational environments. The 8-inch refracting telescope was used at the Korea Science Academy of KAIST in Busan. The B-G color index was obtained from observations and the magnitudes from publications in order to draw CM diagram. The linear correlation of B-G to B-V is found. The RGB channel of the DSLR camera can be easily represented on the CM diagram for astronomical education with aid of easy controls.

In the region of the intermediate open cluster M35 (NGC 2168), the time-series of V CCD images was taken for 12 nights from December 18, 2007 to September 25, 2010. From this observation, we detected 22 variable stars including 15 new ones. They are 6 δ Scuti, a Cepheid, an RR Lyrae, 9 eclipsing binaries and 5 semi-long periodic and/or slow irregular type variable stars. For the V photometry of the δ2 Scuti stars, the multi-frequency analysis was performed using the Discrete Fourier Transform and the linear least-square fitting.

New photoelectric UBV Photometry of 112 stars in open cluster M35 field was obtained. The distance modulus and age of the cluster are 9. m 3 (725pc) and 8.5 × 10 7 y r s , respectively. The internal differential reddening within the cluster is apparent.