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Gina

Heart and Soul Nebulae - Bi-Colour

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Heart and Soul Nebulae in Ha and OIII.

135mm f2.5 Asahi Super Takumar lens, 3nm Astrodon filters in ZWO EFW, ASI 1600MM-Cool camera.   FoV 10° x 7.5°.  EQ8 mount, no guiding. 

50 Ha and 172 OIII subs of 180s (3m) exposures with gain of 300 and temperature of -25°C.  Processed in PixInsight.  Calibrated with darks and flats.  Colour combination HOO mapped to RGB.  Rotated to put north at the to[p and cropped.

1454940765_Screenshotfrom2020-01-2417-51-43.png.e9ee53170a9e6df4428ee776cb7d248b.png

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That's come out great Gina, that must be a good lens as the only time I tried lens imaging my stars were horrible and it wasn't down to trailing.

Only comment would be to try to lose the cyan stars.  No idea how to do it on Pixinsight.

Carole 

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Than you Carole.  Yes, these vintage ex film SLR lenses are brilliant.

Guess I can use a star mask.  The colour seems to originate from the OIII subs though I don't know why the Ha isn't contributing much to the stars - could be the Curves.

Edited by Gina

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I've examined the Ha and OIII stacked images and the stars are smaller in the Ha.  Maybe the focus was a bit out in the OIII.  Here's the Ha image.

1987692089_Screenshotfrom2020-01-2420-39-22.png.89def2d698698d98bc11e17d3e5e7e42.png

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Nice one Gina.

Edited by simmo39
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3 hours ago, Gina said:

Maybe the focus was a bit out in the OIII

I have a very similar problem with my Samyang 135 and my Canon 200. Try as I may I cannot achieve the same focus I achieve with Ha. The resulting FWHM figures are always higher with OIII and coincidently with G and especially B. I’ve taken to reducing star size in OIII before combining. Any residual halos I lose with noise filtering in PS. 
Adrian

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Nicely framed Gina and looks great.  I think you are probably right about the OIII focus, F2.5 is a mega challenge for focusing!

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