When to photograph NGC 40 (Bow-Tie nebula)
NGC 40, the Bow-Tie nebula, is a planetary nebula in Cepheus, 1′ across at magnitude 11.9. Also listed as C 2.
When to photograph it
From 45° N the best months are October to December, with up to 11.0 hours of astronomical darkness above 30° in November. It reaches 62° at its highest. It never sets from this latitude, so some imaging is possible all year.
From 35° S it never rises.
Framing
At 1′ 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
Planetary nebulae are bright in OIII and H-alpha and small, so narrowband works and the moon matters less. Short subs help with the bright core. 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 NGC 40's altitude through tonight, its transit time and its distance from the moon. For sub length, use the exposure calculator.
Nearby targets
- NGC 7822 5.4° away
- NGC 559 11.6° away
- M 52 11.8° away
- IC 59 12.1° away
- C 9 Cave Nebula 12.2° away
- NGC 7635 Bubble Nebula 12.4° away
Gear that suits NGC 40
NGC 40 is only 0.8′ across, so it stays small in any amateur telescope. The longest focal length gives it the most pixels. It shines in H-alpha and OIII, so a dual-band filter on a color camera cuts through light pollution and moonlight.
- Celestron C8 OTA 2032 mm f/10: fills 3% of an APS-C frame's short side View at High Point Scientific
- Optolong L-Ultimate 3 nm 3 nm dual-band, Ha, OIII, for color cameras View at High Point Scientific
- Antlia ALP-T 5 nm 5 nm dual-band, Ha, OIII, for color cameras View at High Point Scientific
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