Tuesday, November 20, 2018
A Giant Squid, Ou4, a start of the new imaging project
I have planned to shoot this very dim nebua for a long time. So far I have collected ~20h of light emitted by an ionized oxygen (O-III). I'll shoot more exposures for this object in near future, if the weather gives any support.
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 with it, due to very large CCD-shell.
Here is some optical analysis to see, https://astroanarchy.blogspot.com/2014/10/a-start-of-new-project-tulip-nebula.html
Ou4 in light of an ionized oxygen only
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Telescope, Celestron Edge 11"
An experimental starless version
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This object is dim to extreme
I shit this object at several night between 1. and 18. November. Total 60 frames of 20 min. exposures,
all binned down 4x4. (Total 20h of O-III signal) By this way I can have 16 times more signal than by using 1x1 binned exposures. I will shoot 1x1 binned high resolution exposures later for stars and some high signal to noise features and details in the area.
A single 20 min. calibrated and stretched O-III exposure
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INFO
Very faint but also very large on planet Earth's sky, a giant Squid Nebula cataloged as Ou4 is composed out of 20 hours of narrowband O-III image data. The telescopic field of view is 1 degrees or 2 Full Moons across. 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.
Source, Nasa APOD
The scale in the sky and the orientation in a constellation Cepheus
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2 comments:
Superb! You are an inspiration, J-P.
Val
Superb! You are an inspiration, J-P.
Val
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