LBN 576 / CTB-1 – The Popped Balloon Nebula

LBN 576 / CTB-1

The Popped Balloon Nebula Supernova Remnant

What powers this unusual nebula?


CTB-1 is the expanding gas shell that was left when a massive star toward the constellation of Cassiopeia exploded about 10,000 years ago. The star likely detonated when it ran out of elements, near its core, that could create stabilizing pressure with nuclear fusion. The resulting supernova remnant, nicknamed the Popped Balloon / Medulla Nebula for its brain-like shape, still glows in visible light by the heat generated by its collision with confining interstellar gas. Why the nebula also glows in X-ray light, though, remains a mystery. One hypothesis holds that an energetic pulsar was co-created that powers the nebula with a fast outwardly moving wind. Following this lead, a pulsar has recently been found in radio waves that appears to have been expelled by the supernova explosion at over 1000 kilometers per second. Although the Medulla Nebula appears as large as a full moon, it is so faint that it took over 60-hours of exposure with the Celestron RASA at f/2.2, to create the featured image.

A supernova remnant in Cassiopeia


Technical card


ObjectLBN 576 / CTB-1 / Abell 85
Imaging telescopesCelestron Rowe-Ackermann Schmidt Astrograph 8″ and 11″
Imaging cameraZWO ASI 1600MM PRO
Mount iOptron CEM60
GuidingGuidescope 130mm, ZWO ASI 120MM
FilterBaader 3.5 / 4nm f/2 Ultra-Highspeed-Filter-Set 50mm² (H-alpha / O-III / S-II), Baader R, G, B (50mm²)
AccessoriesBaader UFC, Baader UFC-Tilter,  Celestron Focus Motor for SCT
Integration61.08 hours, H-Alpha: 302×180″, 156×120″OIII: 280×180″, 130×120″SII: 287×180″, 153×120″, RGB each: 120×30″
Dates of recording13 nights between November 2020 and November 2021


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