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Sunday, January 19, 2020

An animated Heart Nebula, IC1805 with and without stars

I have originally published this deep image of IC1805 at January 14 2020. This time I made a starless version of  the image. I'm usin the starless version of photo in my processing routine and sometimes they look kind of interesting. The actual nebula stands out very nicely without stars.

My "new" imaging system combines a Tokina AT-x 300mm f2.8 lens to a large CCD of Apogee Alta U16 astro camera with 4096x4096 9 micron pixels. This combination has a resolution of about 5 arc seconds/pixels. Undersampling imaging system is a great tool to bring out very dim and diffused nebulae very fast. This photo of Heart Nebula has only 2h of H-alpha light and just 30 min O-III light.

IC 1805 without stars
Please, click for a full size image

It's easier to see the actual nebula when stars are removed. Human brains has a tendency to form quasi logical shapes and forms from a random cloud of dots. Famous example of this phenomena is Percival Lowell and canals of Mars.

An animated image, IC 1805 with and without stars
Please, click for a full size image

Technical details

Processing workflow
Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack2.
Deconvolution with a CCDStack2 Positive Constraint, 33 iterations, added at 50% weight
Color combine in PS CS3
Levels and curves in PS CS3.

Imaging optics
Tokina AT-x 300mm f2.8 camera lens

10-micron 1000

Cameras and filters
Imaging camera Apogee Alta U16 and Apogee seven slot filter wheel
Guider camera, Lodestar x 2 and an old spotting scope of Meade LX200

Astrodon filters,
5nm H-alpha 3nm S-II and 3nm O-III

Total exposure time
H-alpha, 12 x 600 s, binned 1x1 = 2 h
O-III, 3x 600 s, binned 1x1 = 30 min..

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