When to photograph M 31 (Andromeda Galaxy)
M 31, the Andromeda Galaxy, is a galaxy in Andromeda, 178′ x 70′ across at magnitude 3.4. Also listed as NGC 224.
When to photograph it
From 45° N the best months are September to November, with up to 9.8 hours of astronomical darkness above 30° in October. It reaches 86° at its highest.
From 35° S it never climbs above 30°. It peaks at 14° when it crosses the meridian, low enough that haze and light pollution soften it. It is possible with a clear northern horizon, but hard.
Framing
Its long axis is 178′. It fills 35 to 80% of the short side of an APS-C sensor at about 110 to 240 mm, and of a full-frame sensor at about 160 to 370 mm.
Filters and the moon
Galaxies are broadband targets. Filters cannot separate their light from light pollution, so dark skies and moon-free nights matter most. The dark sky calendar shows which nights this month are moon-free where you are.
Plan it for tonight
Dates and times depend on your exact location. The imaging planner shows M 31's altitude through tonight, its transit time and its distance from the moon. For sub length, use the exposure calculator.
Nearby targets
- M 32 0.4° away
- M 110 0.6° away
- NGC 185 7.1° away
- NGC 147 7.4° away
- NGC 7662 Blue Snowball Nebula 14.3° away
- M 76 Barbell Nebula 14.5° away
Gear that suits M 31
M 31 is 178′ along its long axis. These frame it on an APS-C sensor with room to crop.
- Samyang 135mm f/2 135 mm f/2: fills 45% of an APS-C frame's short side View at High Point Scientific
- William Optics RedCat 51 250 mm f/4.9: fills 83% of an APS-C frame's short side View at High Point Scientific
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