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IC410, Tadpoles

Contains: NGC 1893, IC 410

Technical card

Resolution: 4594x3282

Dates: Oct. 16, 2014Nov. 14, 2014

Frames:
Baader Planetarium Ha 7nm: 4x1200" ISO1600
Baader Planetarium Ha 7nm: 10x900" ISO1600

Integration: 3.8 hours

Darks: ~16

Flats: ~21

Bias: ~50

Avg. Moon age: 21.95 days

Avg. Moon phase: 52.13%

Astrometry.net job: 415403

RA center: 80.669 degrees

DEC center: 33.384 degrees

Orientation: 15.935 degrees

Field radius: 0.726 degrees

Locations: Backyard, Hampton, VA, Hampton, VA, United States

Description

IC 410 is an emission nebula 12,000 light years away in the constellation Auriga. Swimming among the clouds of gas and dust are two tadpoles, formed by the energetic solar wind and radiation pressure of a nearby star cluster.

This image was captured over two nights using an H-alpha filter. It really needs some more time to get the noise under control. I intended to acquire 6 hours of exposure time on the second night, but entire evening ended up a total calamity where my subpar polar alignment caused field rotation in the 20 minute subs which became progressively worse over the night. It was a bitterly cold night so rather than battle with gear to diagnose the problems, I opted to pack it up early. Four frames were salvageable which helped (the first two versions of this image are prior to adding the second night). Still, I plan to revisit this object next year and add a pile of more time.

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Processing Workflow (PixInsight)
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Pre-processing
1. Calibrate light frames using darks, bias, flats
2. Superpixel Debayer, extract red channel.
3. Drizzle Integration using sigma clipping rejection.

Post-processing
1. Noise reduction (MultiscaleLinearTransform w/luminance mask).
2. Non-linear stretch: set midtones to median image value (HistogramTransformation).
3. Non-linear stretch: set midtones to 0.8 (HistogramTransformation).
4. Non-linear stretch: lower black point (HistogramTransformation).
5. Non-linear stretch: increase midtones by lowering slider (HistogramTransformation).
6. Non-linear stretch: set midtones to 0.8 (HistogramTransformation).
7. Clean up dark pixels (Pixel Math [Shwartz script])
8. Compress dynamic range (HDRMultiscaleTransform, scale: 8).
9. Increase small scale contrast (LocalHistogramEqualization w/ luminance mask selecting nebula, but no stars).
10. Contrast curve (CurvesTransformation).
11. Noise reduction (GREYCstoration w/ inverted luminance mask).
12. Reduce star sizes (MorphologicalTransformation w/contour star mask).
13. Sharpen (MultiscaleMedianTransform w/luminance mask selecting nebula, but no stars).
14. Lower median background value to 0.12 using a contast curve (CurvesTransformation).
15. Lower background brightness (HistogramTransformation)
16. Final Crop (DynamicCrop)
17. Set ICC profile to sRGB for web publishing (ICCProfileTransformation).

References:
Manfred Schwarz’ galaxy tutorial:
http://www.astrophoto.at/PixInsight/

Comments

Author

Jason Tackett
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IC410, Tadpoles, Jason Tackett

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