When to photograph NGC 7662 (Blue Snowball Nebula)
NGC 7662, the Blue Snowball Nebula, is a planetary nebula in Andromeda, 0′ across at magnitude 8.3. Also listed as C 22.
When to photograph it
From 45° N the best months are September to November, with up to 8.8 hours of astronomical darkness above 30° in October. It reaches 88° at its highest.
From 35° S it never climbs above 30°. It peaks at 12° 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
At 0′ 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 7662's altitude through tonight, its transit time and its distance from the moon. For sub length, use the exposure calculator.
Nearby targets
Gear that suits NGC 7662
NGC 7662 is only 0.3′ 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 1% 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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