The beautiful face-on galaxy M33 in Triangulum is quite a challenge for the deep-sky imager. For one, it’s low surface brightness is deceiving and it requires a lot more, lot longer subs than you might think. Secondly – it is pretty big!
This image of M33 was taken with the original version Hyperstar lens and the small SXV-H9C one shot colour camera. The field of view with this setup was about 1 degree by 0.75 degree, and this meant a 2-frame mosaic for this combination.
I am now imaging with the new version III Hyperstar lens on the C11 with an SXVF-M25C one-shot colour camera, so I should be able to capture the whole of M33 in a single frame. However I will still need to think about how to grab the best data on this object.
M33 has a nice bunch of clearly visible HII regions which stick out like a sore thumb even in the above Hyperstar image. So if you are able to include an HII filter in your imaging of this object, it could be really worthwhile doing so. I shall simply stick with the IDAS LP filter and full-colour imaging with the Hyperstar. However, I shall take longer subs than I took back with the original image, probably including 3-minute and 5-minute subs. I want to do a really good job on M33 this year so I shall dedicate at least two imaging evenings to this object, hopefully each of 3 to 4-hours total exposure time.
As an incentive to you to go out and try this one yourself, there are surprisingly few good images of M33 out there!
Clear September Skies!!