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Wednesday, November 28, 2018

A Giant Squid, Ou4, imaging project finalized

I started this imaging project at this autumn season and after a several months I got it ready!
This is a dimmest target I have shot so far! Total exposure time for the light from an ionized oxygen (O-III) alone was around 35h. Most of the data was shot at binned down to 4x4! For some details I shot about ten hours of 2x2 binned data. H-a is brighter but not bright either. There is about ten hours of H-alpha light exposed. There is very little light from an ionized sulfur, I shot bin 4x4 data about three hours for S-II. Total exposure time used is around 48h

The Celestron Edge 11" telescope with a 0.7 focal reducer has a perfect field of view for this object. This combo delivers a very high quality image from edge to edge. The Apogee U16 can be very challenging to have a good orthogonality and collimation due to very large CCD-shell. 
Ou4, the Giant Squid
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Natural color scheme from the emission of an ionized elements, H-a, S-II and O-III. This is a very large nebula, this image spans horizontally about 1.5 degrees = three full Moons side by side in a sky.

Ou4 in light of an ionized oxygen only
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35h of O-III exposures, the Apogee U16 astro camera and Astrodon 3nm O-III filter.
Telescope, Celestron Edge 11"

Wider field of view, Ou4 inside the Sharpless 129
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Natural color scheme from the emission of an ionized elements, H-a, S-II and O-III
I have shot the Sharpless 129 nebula, surrounding the Ou4, back at 2013. I combined the new data with the old one and here is the results.

A panoramic view shows the IC 1396, Sh2-129 and Ou4 in same field of view.


Animated frames, All channels, O-III only  and O-III with no stars.


The giant Squid Nebula cataloged as Ou4. Nebula was discovered in 2011 by French astro-imager Nicolas Outters, the Squid Nebula's alluring bipolar shape is distinguished here by the telltale blue-green emission from doubly ionized oxygen atoms. The true distance and nature of the Squid Nebula have been difficult to determine. Still, a recent investigation suggests Ou4 really does lie within Sh2-129 some 2,300 light-years away. Consistent with that scenario, Ou4 would represent a spectacular outflow driven by HR8119, a triple system of hot, massive stars seen near the center of the nebula. The truly giant Squid Nebula would physically be nearly 50 light-years across.

A single 20 min. calibrated and stretched 4x4 binned O-III exposure 
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Image is divided with a bias corrected flat frame and subtracted with master dark. Even after a heavy nonlinear stretching, very little can be seen in this single 20 min. 4x4 binned  light frame.

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