|M103, open cluster in Cassiopeia. Total exposure 90 minutes (18 x 300 sec) at ISO800. IDAS-D1 filter.|
I always prefer diffraction spikes on star cluster images, so I used braided fishing line taped to my dew shield to produce those seen here. I have experimented in the past with different thickness mono filament fishing line and I have yet to find one that I really like. In all cases, and including here, the diffraction spikes broaden with distance from the star and produce rainbow colors. It's kind of a neat effect, but I'm not sold on it. In the future I will try metal guitar string instead.
It took time to figure out the best framing for this cluster because a wide view makes it difficult to figure out what you are supposed to be looking at (i.e., the subject) and too close of a view makes it hard to recognize that this is a cluster rather than just a picture of a bunch of stars. I think I found a good balance here. Just for kicks I tried off-setting the cluster to the lower left or upper right following the rule of thirds, but no orientation had other bright stars that would lead the eye to the cluster and again the subject was lost. In the end, it just made sense to position M103 dead center. Sure, that's a lot of thought for a simple star cluster, but it is good practice for any image.
Full resolution image here: