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Friday, November 30, 2018

The Giant Cosmic Squid in Mapped colors

I started this imaging project at this autumn season and after a several months I got it ready!
I have published a natural color version few days ago, the result can be seen HERE.

This is a dimmest target I have shot so far! (At end of the post, there is a single 20 min subframe od O-II light.) 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 (Giant indeed, it's 50 light years across)
Please, click for a large image

Image is in mapped colours, from the emission of ionized elements, R=Sulphur, G=Hydrogen and B=Oxygen. The Squid Nebula is visible only at light of an ionized oxygen, O-III

Ou4 in light of an ionized oxygen only
Please, click for a large image

Also stars has been removed to show the actual formation better. Only the central star shines there.

Wider field of views, Ou4 inside the Sharpless 129
Please, click for a large image

The location  in the sky as a relation to the IC 1396

NOTE, a relative size of the full Moon is shown as a white circle at lower right corner.


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 
Please, click for a large image

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.

Please, click for a large image

This animated GIF shows the Giant Squid Nebula with all three channels, H-alpha, S-II and O-III versus just the light from an ionized oxygen, O-III

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