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Silver sliver galaxy: NGC 4236

Mostly captured with just r,g,b filters, only used a little of the Ha data to bring out a small amount of red detail.

 

"The Silver Sliver Galaxy, officially known as NGC 4236, is a barred spiral galaxy located in the constellation Draco. It is a member of the M81 Group, a nearby galaxy group that includes well-known galaxies such as M81 and M82. Despite its proximity, NGC 4236 is often overlooked due to its low surface brightness and large angular size.

 

General Characteristics

 

Galaxy Type: Barred Spiral (SBdm)

 

Distance: Approximately 11 to 14 million light-years

Location: Constellation Draco

Apparent Magnitude: ~10.5

Size: ~25 arcminutes long (~100,000 light-years across)

Group: Member of the M81 Group

 

Key Features

 

Barred Spiral Structure

 

NGC 4236 displays a loosely wound spiral structure with a faint but extended central bar.

 

Its spiral arms are diffuse and lack the strong contrast seen in more active galaxies.

 

Due to its orientation, the galaxy appears as a thin, elongated sliver — giving rise to the nickname “Silver Sliver Galaxy.”

 

Star Formation Activity

 

Although overall low in surface brightness, the galaxy contains several H II regions, indicating localized pockets of star formation.

 

These regions are visible in hydrogen-alpha wavelengths and contribute to the galaxy’s subtle structure.

 

Low Surface Brightness

 

One of the defining traits of NGC 4236 is its very low surface brightness, which makes it challenging to detect visually or photograph under light-polluted skies.

 

This characteristic makes it a popular target for deep-sky astrophotography and studies of galaxy formation in less evolved systems.

 

Membership in the M81 Group

 

NGC 4236 resides on the outskirts of the M81 Group, a nearby cluster of galaxies in the northern sky.

 

Its relatively isolated position within the group may contribute to its low rate of interaction and slow evolutionary development compared to more centrally located members."

 

Askar 120APO: 840mm f/7

ZWO ASI533MM Mono Camera at -20C

Guided on ZWO AM5

28x5m with UV/IR cut filter @5m

20xHa, 21xR, 21xG, 26xB @5m

Captured with N.I.N.A. processed with PixInsight, Ps

 

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Uploaded on April 24, 2025