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Contains:  NGC 3521
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NGC 3521, 


            Gary Imm
NGC 3521

NGC 3521

Technical card

Resolution: 2216x1350

Dates:May 16, 2018May 19, 2018May 20, 2018May 4, 2019May 5, 2019

Astrodon Blue 31mm Gen2 I-Series: 120x60" (gain: 139.00) -20C bin 1x1
Astrodon Green 31mm Gen2 I-Series: 120x60" (gain: 139.00) -20C bin 1x1
Astrodon Lum 31mm Gen2 I-Series: 240x60" (gain: 139.00) -20C bin 1x1
Astrodon Red 31mm Gen2 I-Series: 120x60" (gain: 139.00) -20C bin 1x1

Integration: 10.0 hours

Avg. Moon age: 8.17 days

Avg. Moon phase: 10.94% job: 2700440

RA center: 166.453 degrees

DEC center: -0.033 degrees

Pixel scale: 0.782 arcsec/pixel

Orientation: 269.953 degrees

Field radius: 0.282 degrees

Locations: Backyard (Mag 20.8 - New Moon), Onalaska, Texas, United States

Data source: Backyard


This object is a spiral galaxy located 30 million light-years away in the constellation of Leo. It is about half the diameter of our Milky Way and spans 11 arc-minutes in our apparent view. The galaxy is 30 degrees from edge-on, which allows us to see characteristics which are typical for both edge-on and face-on galaxies. This is one of my favorite "unsung" galaxies.

The galaxy has a number of interesting qualities - the flocculent nature of the multiple arms, the purplish tint along the edges, the detailed dust lanes (including one at the bottom which appears to veer out of plane), and the bright central barred core.

But there are two things which make this galaxy really special. The first is the galaxy's spherical shell of stars which encompasses the disk. Once your eyes adjust to it a bit, the "bubble" gives the galaxy a very 3-D type of appearance. It looks to me like the whole galaxy is steaming. Scientists believe that this tidal stream of stars is the result from one or more galaxies which have merged with NGC 3521 long ago.

The second thing, even more interesting to me, is difficult to see at first, but then obvious once you are aware of it. There are two hexagonal disk structures - the brighter whitish disk which extends about halfway across the diameter, and the dimmer gray one which extends about 75% across the diameter. They may not be true hexagons - it is tough to see since the disk is only 30 degrees from edge-on. But both of those structures look like straight sided hexagons to me.

Numerous faint galaxies are visible in the image background.



Gary Imm
License: None (All rights reserved)

Sky plot

Sky plot


NGC 3521, 


            Gary Imm