the region around M 16 and M17 - 28x120seconds, iso 1600, Hap Griffin mod 350d

this image is a test of the Canon 70-300 DO-IS zoom with deffractive optics.
I set the zoom at 200 mm, the known sweet spot and taped it in position, set the apature at f5.6 (wide open)
and mounted it piggyback on the classic LX 200 in the observatory...

the sub frames were acquired using DSLR shutter from Stark Labs and the DSUSB from Shoestring. Raw sub-frames
were accumulated in Canon DPP, scaled and stacked in Nebulosity and stretched and balanced in PS CS3.

the zoom, while pretty sharp in much of the field shows a large amount of coma on the edges. Interestingly, there is
more coma and distortion on the right edge than on the left, possibly due to the loosness of the front element...