Sunday, 4 May 2014

First Shot Through the SM90ii - 4th May

Far from a perfect image when you consider the conditions this was taken in as the picture below shows.  The sky was covered in at best a very thick haze with passing clouds, and at it's worst completely overcast.  Still, this is the first image with my newly purchased external sm90ii etalon.  This is actually a double stack unit for the sm90ii scope, and as such gives quite a wide passband on it's own accord, and being a double stack etalon naturally sits on the red side of the Ha band, as a result the disk views reflect this.  However for proms it works very well, certainly much better than the PST mod does.  I've very briefly tried it with the PST mod in the back of the focuser, and this gives a clearly double stacked view, albeit working at only 85mm effective aperture because of a small amount of vignetting in the system.  The unit is a lovely piece of kit and quite clearly has some real potential.  It is quite clearly designed to perform at it's best on the SM90ii scope, and this is something that may have to be considered longer term to exploit the true performance of this great piece of kit.  I'm sure as the clouds allow there will be plenty more images and updates!
Here's the full disk proms taken with the sm90 with 0.5x focal reducer with the DMK31