▴ NORTHERN CONVERGENCE Juan Ignacio Jimenez Straddling the Cassiopeia-Cepheus border is the aptly named Lobster Claw Nebula (Sh2-157). Bright, compact NGC 7538 is at far left and dimmer Sh2-159 at center. NGC 7635, along the bottom, is better known for the Bubble Nebula at its center. Details: APM-TMB 105/650 Triplet Apo refractor and QHY9M CCD camera with Baader Hα, O III, and S II narrowband filters. Total exposure: 7½ hours. ◀ BUBBLE NEBUL A CLOSE-UP David Mittelman Although it looks delicate, the Bubble Nebula has been blown into the surrounding nebula by fierce winds and radiation from a massive O star near its center. Details: PlaneWave CDK20 astrograph and SBIG STX-16803 CCD camera with Astrodon filters. Total exposure: 32 hours. ✦ Sk yandTelescope.com August 2015 77http://www.SkyandTelescope.com