Hemisphere:  Northern  ·  Constellation: Cassiopeia (Cas)
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CTB1 - Abell 85, 



    
        

            Luca Marinelli
CTB1 - Abell 85
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CTB1 - Abell 85

Imaging telescopes or lenses: Teleskop Service ONTC 10" f4 Newton

Imaging cameras: ZWO ASI1600MM Pro

Mounts: Astro-Physics 1100GTO

Guiding telescopes or lenses: Teleskop Service ONTC 10" f4 Newton

Guiding cameras: Starlight Xpress Ultrastar Mono

Software: Topaz Labs Denoise AI  ·  Main Sequence Software Sequence Generator Pro Sequence Generator Pro  ·  Starnet ++  ·  Astro-Physics Command Center (APCC) Pro Software  ·  Photoshop CC  ·  PIXINSIGHT 1.8  ·  PHD2 Guiding PHD2 v2.6.5

Filters: Astrodon Narrowband 3nm Ha  ·  Astrodon Tru-Balance Gen2 E-Series - B 36mm  ·  Astrodon Tru-Balance Gen2 E-Series - G 36mm  ·  Astrodon Tru-Balance Gen2 E-Series - R 36mm  ·  Astrodon Narrowband 3nm OIII

Accessory: QHYCCD OAG-M  ·  Tele Vue Paracorr Type 2  ·  Pegasus Astro Ultimate Power Box  ·  QHYCCD QHYCFW3-M


Dates:Oct. 1, 2020Oct. 5, 2020Oct. 10, 2020Oct. 20, 2020Oct. 31, 2020

Frames:
Astrodon Tru-Balance Gen2 E-Series - B 36mm: 30x60" (gain: 50.00) -15C bin 1x1
Astrodon Tru-Balance Gen2 E-Series - G 36mm: 30x60" (gain: 50.00) bin 1x1
Astrodon Tru-Balance Gen2 E-Series - R 36mm: 30x60" (gain: 50.00) bin 1x1
Astrodon Narrowband 3nm Ha: 260x360" (gain: 139.00) -15C bin 1x1
Astrodon Narrowband 3nm OIII: 245x360" (gain: 139.00) -15C bin 1x1

Integration: 52.0 hours

Darks: ~50

Flats: ~20

Flat darks: ~50

Bias: ~100

Avg. Moon age: 14.78 days

Avg. Moon phase: 70.46%

Bortle Dark-Sky Scale: 5.00


Astrometry.net job: 4061371

RA center: 23h 59' 48"

DEC center: +62° 27' 7"

Pixel scale: 0.685 arcsec/pixel

Orientation: 180.985 degrees

Field radius: 0.535 degrees


Resolution: 4526x3342

Locations: Home Observatory, Schenectady, New York, United States

Data source: Backyard

Description

CTB 1 (Abell 85, SNR G116.9+0.1) is a faint supernova remnant in the constellation Cassiopeia. It was originally cataloged by George Abell as a planetary nebula as Abell 85 but was identified by van der Bergh, Marscher and Terzian in 1972 as a supernova remnant based on its appearance in the optical as an almost perfect half-circle of radiative filaments. CTB 1 is approximately 10,000 light years away and physically spans roughly 100 light years in diameter. It is dated to be ~7,500-11,000 years old. (Hailey and Craig, Astrophys. J. 434:635, 1994).

The brightest arcs of the hydrogen shell can barely be seen in a single exposure with my optical train, while the OIII signal is significantly fainter. This image was the result of one of the first datasets collected in my brand new backyard roll-off roof observatory. The ability to squeeze every minute of clear sky was crucial to generate quality data for this faint deep-sky object.

The acquisition is primarily bi-color narrowband (Ha and OIII) and star color is replaced from RGB data. Calibration, stacking, and linear processing of the data in Pixinsight, star separation with Starnet (PI plugin). Non-linear processing in Photoshop CC with denoising using Topaz Denoise AI.

Comments

Revisions

    CTB1 - Abell 85, 



    
        

            Luca Marinelli
    Original
    CTB1 - Abell 85, 



    
        

            Luca Marinelli
    B
  • Final
    CTB1 - Abell 85, 



    
        

            Luca Marinelli
    C
    CTB1 - Abell 85, 



    
        

            Luca Marinelli
    D
    CTB1 - Abell 85, 



    
        

            Luca Marinelli
    E

B

Description: Slight curves adjustment.

Uploaded: ...

C

Description: Shrunk stars slightly to emphasize nebula.

Uploaded: ...

D

Description: Progressive buildup of signal to noise ratio as a function of number of subs used in the image integration process, from 1 to 292 subs in a small crop of the Ha channel.

Uploaded: ...

E

Description: Noise measured as the standard deviation of the signal in a small window of pure background sky as a function of number of subs in image integration. The square root dependence on number of subs is apparent.

Uploaded: ...

Sky plot

Sky plot

Histogram

CTB1 - Abell 85, 



    
        

            Luca Marinelli