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‘The Headphones Nebula’ (Jones Emberson 1 / PK 164+31.1)


RobH
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‘The Headphones Nebula’ (Jones Emberson 1 / PK 164+31.1)

This very faint but quite large planetary nebula is in the constellation of Lynx, which lies between Ursa Major and Gemini.

It’s magnitude 14 and its angular size is 6’ x 7’.

It’s about 1600 light years away and 4 light years across, and is the outer layers of a star at the end of its life. What remains of the star now is the nebula and a very blue looking magnitude 16.8 white dwarf about the size of the earth. This white dwarf is giving off vast amounts of UV energy, which is ionising the gas cloud and heating it to about 10,000K, causing it to glow. It’s quite staggering when you think about it....something the size of the earth is producing enough energy to heat up a huge nebula to enormous temperatures. The nebula has a diameter the same as the distance from the sun to the nearest star and it takes light four years to cross the distance....fearsome power!

It is so faint that it really needs double the exposure, and I had nowhere near enough RGB to get good star colour, consequently I’ve had to use some noise reduction here and there, and did lots of star fixing to fix the worst of the astigmatism. Once the scope is fixed and properly collimated, it should give a brighter image and more detail, so this is on the list for Winter as I think it’s an interesting enough target to spend more time on, and when I got this data, it was getting low down over nearby roofs and into areas of light pollution.

Ha-20 x 1800

OIII-17 X 1800

R-6 X 160

G-6 X 150

B-11 X 180

All subs were binned 2x2.

Imaged April 2013

Imaged with an astigmatic 12 inch RC @ F5.3, Atik 460EX and Baader filters in April 2013 (the scope is now in scope hospital having a new mirror cell built)

gallery_1757_60_114699.jpg

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Thanks folks.......as I mentioned, it's a faint blighter. The 460EX binned 2x2 combined with a scope running at F5.3 gives a really fast system, but even with the amount of integration time, it was still a struggle to keep the noise levels down.

Incidentally, this scope/camera combination gives an imaging scale of 1.14 arcseconds per pixel, which is close to my seeing limit I suspect, so binning like this doesn't really lose any resolution.

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Thanks again folks......just looking at some more data I have from the scope now so more images to come soon I think.

BTW....Ha was red, OIII green and blue was a blend of 30%Ha and 70%OIII, the 30% Ha simulating the amount of H-beta emission you'd expect to get.

Star colour (what there is of it) was achieved by adding broadband stars into the NB mono masters as a 'lighten' layer in PS, so the red stars went into the Ha, Green into OIII and Blue into the Ha/OIII image.

You just have to make sure that your sky background is a fraction darker in the 'lighten' layer than in the NB layer or you'll wash out all the faint bits :smiley:

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