How to photograph the Triangulum Galaxy (M33)
A face-on spiral studded with pink star-forming regions.
Photo byESO(CC BY 4.0)
When to shoot it from your location
About the Triangulum Galaxy
M33 is large and its light is spread thin, so it needs a darker sky than Andromeda. Its arms are dotted with hydrogen regions, the largest being NGC 604, which can be boosted by blending in a hydrogen-alpha layer.
Gear and framing
The Triangulum Galaxy spans about 70′ of sky. It frames best with:
- Telephoto (85-300mm lens)
- Small refractor (250-600mm)
You can see how other people have built their rigs on RigDesigner, including my Sony a6700 and 60mm refractor rig.
Filters
This is a broadband target, which means its light is mostly starlight across the whole spectrum. Shoot it with no filter or a UV/IR cut filter. A broadband light pollution filter can help a little in the suburbs. Dual-band and narrowband filters block most of its light, so leave them off. Plan it for a moonless night at a dark site.
Tips
- Low surface brightness means light pollution and moonlight hurt more than usual. Pick the darkest night available.
- At 400-600mm it fills the frame nicely.
Processing
Stack your light frames with darks and flats, then remove the background gradient before stretching. AstroBake does all of this for you. Point it at your folders of raw frames, then adjust the result with live sliders.