When to photograph M 108
M 108 is a galaxy in Ursa Major, 4′ x 2′ across at magnitude 10.1. Also listed as NGC 3556.
When to photograph it
From 45° N the best months are January to March, with up to 10.3 hours of astronomical darkness above 30° in February. It reaches 79° at its highest. It never sets from this latitude, so some imaging is possible all year.
From 35° S it never rises.
Framing
At 4′ x 2′ it is small. Even 4000 mm of focal length leaves it filling less than a third of an APS-C frame, so it suits long focal lengths, small pixels and good seeing.
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 108's altitude through tonight, its transit time and its distance from the moon. For sub length, use the exposure calculator.
Nearby targets
- M 97 Owl Nebula 0.8° away
- M 109 7.1° away
- NGC 4088 9.6° away
- M 40 Winnecke 4 9.9° away
- M 106 13.4° away
- IC 2574 Coddington's Nebula 13.7° away
Gear that suits M 108
M 108 is only 4.0′ across, so it stays small in any amateur telescope. The longest focal length gives it the most pixels.
- Celestron C8 OTA 2032 mm f/10: fills 15% of an APS-C frame's short side View at High Point Scientific
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