V. K. Verma

Uttar Pradesh State Observatory, Naini Tal - 263 129, India

The Ha emission line (6563 Å) provide spatial information very accurately to study electron time of flight information which is crucial for determining the energy release processes in solar flare. Kampher and Magun (1983) and other have shown that there is a component of the Ha emission that shows impulsive variation that are coincident with microwave spikes. The expected rapid onset of Ha during flares will be compared with microwave and hard X-ray emission to understand the physical processes in solar flares during flare triggering. Keeping above problem in mind we have developed and tested a CCD camera (100x100 pixels) system for observing Ha images of the solar flares with time resolution >25 msec. This CCD camera system employ CCD chip EEV37 (512 x 512 pixels), pixel sizes 15m ². The camera controller of the system has variable read out rate 0.5 - 4.0 Mega pixels/sec with 12 bit (4096 grey levels) resolution. At present the CCD system has maximum read out rate of 2M pixels/sec. The 4.0 Mpixels/sec readout card will be installed and tested by mid 1997. The software, which controls the working of camera controller is installed on Sun Sparc Station 20, 50 Hz computer having 7.3GB disk capacity and 14 GB Cartridge drive. A GPS (Global position system) clock is connected to Sun Sparc 20 computer to record time with accuracy of 1 ms in header of the each flare image. The CCD chip of the CCD camera is cooled to -25^o C by liquid circulator unit connected to head of the camera system. The CCD camera system is installed at the focus of 15 cm F/15 Coude's refractor telescope after Daystar Ha filter having 0.5 Å passband. The 512x512 pixels image of CCD camera at 2 Mpixels/sec record more than 5 frame/sec while 100x100 pixels record more than 40 frames/sec. The 100x100 pixels image of CCD camera corresponds to 130x130 arc second of the solar disk. In the light of above we are of view that our CCD camera system is fastest flare monitoring system and about four times faster than the flare monitoring system of Kiplinger et al (1988) which is 8 bit (256 grey level) CID camera system. The observing cost of this system is about 1 Gigabyte. The flare time profile and flare including kernal's contours of solar Ha flare observed with this instrument will also be presented and discussed to show the performance of the above said instrument.

References

Kampher, N. and Magun, A. : 1983, Ap. J., 274, 910.

Kiplinger, A. L et al : 1988, Flare Research at the Next Solar Maximum (Eds. R. C. Canfield and B. R. Dennis) p. 214.