The Medulla nebula, also called Abell 85, LBN 576 and CTB-1, is a supernova remnant. 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.

This deep sky object it’s pretty faint and needs some deep integrations to show some detail. I struggled to get as much data as I could with my dual Takahashi FSQ setup during several full moon January 2022 nights. For the nebula structure I used a 3nm Ha filter in front of my ASI2600M and FSQ106 EDX4. On the other side, the FSQ85 was gathering lots of data in [OIII] with the smaller ASI294MM sensor. RGB images were also captured to create the starfield image in natural color.

Processing technique to increase the details:

Details on this target are extremely faint. That implies a difficult task trying to show some detail… To sharpen the details I used a technique that consists of creating 2 images: the first one with all the Ha original data (carefully selected) and a Luminance image composed by the best Ha frames. This new image was used to enhance the detail on the supernova “shell”. You can see the result in one of the gallery images.

Thanks for taking your time on this site.

Image Details


Ha 128×600″ (21h20′)

RGB: (18,18,18) x 300″ (4h30′)


[OIII]: 298×300″ (24h05′)


Calibrated with darks, flats and dark-flats.


Total exposure: 50h40′


Moon at 85% (on average)

Image resolution: 1.46”/pixel

FOV (full image): 2º11′ x 1º38′


FSQ106 EDX4 + ASI2600MM + LRGB Astrodon filters + Ha3nm Antlia – with ZWO EFW 7 pos

FSQ85 + ASI294MM + SHO LRGB Baader filters – with ZWO EFW 8 pos

Mesu200 mount

Guiding with ASI120MM and ZWO Mini Guide Scope



Aleix Roig, January 2022
Prades (Tarragona, Catalonia – Spain).


Full HD view on Astrobin:

TOP PIC on Astrobin

TOP PIC Nomination on Astrobin:


error: Image protected by copyright.