Cookie consent

AstroBin saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing AstroBin without changing the browser settings, you grant us permission to store that information on your device.

I agree
Contains:  Sculptor galaxy, NGC 253
Getting plate-solving status, please wait...
NGC 253 'Silver Coin' galaxy in Sculptor (20.7 hours), 


            Barry Brook
NGC 253 'Silver Coin' galaxy in Sculptor (20.7 hours)

NGC 253 'Silver Coin' galaxy in Sculptor (20.7 hours)

Technical card

Resolution: 1475x1339

Dates:Sept. 2, 2014

Astronomik Ha 12nm 1.25'': 15x600" bin 1x1
ZWO optical ZWO RGBL Filters: 218x300" 3C bin 1x1

Integration: 20.7 hours

Darks: ~70

Flats: ~100

Bias: ~100

Avg. Moon age: 7.43 days

Avg. Moon phase: 50.53%

Bortle Dark-Sky Scale: 6.00

Mean FWHM: 2.80

Temperature: 8.00 job: 359350

RA center: 11.891 degrees

DEC center: -25.291 degrees

Pixel scale: 1.550 arcsec/pixel

Orientation: -175.740 degrees

Field radius: 0.429 degrees


A deep integration of the famous galaxy (brightest member of the Sculptor group). With a visual magnitude of 8.0, it is appears as a long, oval bulge and mottled disk, some 25' x 7' min size (true size of some 70,000 light years across), with complex dust lanes north of the core.

It is part of a group of galaxies located 11.4 million light years from the Milky Way, and is viewed by us almost side on spiral (Sc type), giving it the shape of a coin. There is intense starburst activity in its outer arms, and some prominent HII regions, whereas the core is older and redder with a 5 million solar mass black hole at its centre.

The image was captured from my Adelaide surburban backyard, using an Orion ED80T CT apo astrograph (at f/4.8), mounted on an AZ-EQ6. The CCD camera was an Orion StarShoot G3 mono, guided with PHD2 using a think OAG and an ASI120MM-S guide camera.

The image is composed of the following:
Lum = 62 x 5 min
Ha = 15 x 10 min
R, G & B = 52 x 5 min for each channel

After rejections, this led to a total integration time of 20.7 hours.

I used a synthetic luminance channel by blending an exposure-based weighting of the L, Ha, R, G and B luminances. All subs were unbinned.

Captured over the period 24 Aug to 2 Sept 2014, as weather permitted. Pre-processed with flats (light box), bad pixel map (based on 70 darks) and bias in Nebulosity. Aligned and Drizzled in DSS. Post-processed in StarTools.



Barry Brook
License: Attribution Creative Commons

Sky plot

Sky plot


NGC 253 'Silver Coin' galaxy in Sculptor (20.7 hours), 


            Barry Brook