[APML] Horsehead and Pleiades testshots with 6x9 camera/OAG and BRC

["tan@home.com" <tan@home.com>]

Just got the chance to try out the Mitsuboshi 6x9 camera with OAG on a 
Tak BRC250. Here are shots of the Horsehead and Pleiades Nebulas which 
are cropped from a full 6x9 frame:

Horsehead:
http://www.starryscapes.com/nebula/horsehead.html

Pleiades:
http://www.starryscapes.com/clusters/pleiades.html

These were processed rather hastily and should be considered work in 
progress.

A single full frame of the Horsehead (1 hour exposure) can be seen here 
for those interested. The large version is really large so beware of 
long downloads. The small version suffices if you want to check out 
illumination. The larger version is better for seeing stellar spot sizes.

Small 178kB version:
http://www.starryscapes.com/tmp/hh2_small.jpg

Large 903kB version:
http://www.starryscapes.com/tmp/hh2.jpg

As can be seen, there is vignetting at the very edge of the corners. 
This could be attributable to some form of obstruction, but this is only 
a guess. Since it is rather small, I do not think this to be critical. 
Also noticeable is some gradual light dropoff.

I have not empirically measured the stellar spot sizes of this 
combination but I can tell they are small. Please judge for yourself. 
Also noticeable is the fact that there is somewhat of a degradation of 
spot sizes towards the edge of the 6x9 field.

Anyway, I thought this information might be of interest to someone.

Loke



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