The Tulip in Hydrogen-alpha

August 3, 2025

The Tulip in Hydrogen-alpha: Tulip Nebula Sh2-101 and the surrounding HII region in Cygnus, centered on the open star cluster NGC 6871. Most of this is around six or seven thousand lightyears away from us, and to give you a sense of the size of this region: that bright tulip shape is over 600 trillion kilometers wide (top to bottom in this rotation).

Gear details: William Optics SpaceCat 51 Apochromatic refractor (250mm fl, f/4.9), ZWO ASI2600MM-Pro cooled monochrome camera, ZWO AM5 Harmonic Drive EQ mount, Antlia 3nm Ha filter, 60x300-second subs, 5 hours total integration time. Location: my backyard, coastal New Hampshire, US.