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Observation by Graeme Coates: Sh2-129 + OU4 - The Flying Bat and Squid

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Graeme Coates


Graeme Coates


2020 Aug 31 - 23:00


2020 Oct 12 - 12:54


Sharpless 129

Planetarium overlay



Field centre

RA: 21h13m
Dec: +60°04'
Position angle: -93°43'

Field size

2°27' × 1°49'

  • Skywatcher Esprit ED80
  • SBIG STF8300
  • MI-250

73.7hrs combined LRGB, HA, [OIII]



Target name

Sh2-129, OU4


Sh2-129 + OU4 - The Flying Bat and Squid

About this image

This is an Ha+OIII+LRGB image showing the diffuse nebula Sh2-129 (The Flying Bat) and the enigmatic, bipolar planetary nebula OU4 (The Squid Nebula).

In addition to the 12.7hrs of LRGB data (Baader), there is another 16hrs of HA data (Chroma 3nm) added into the R channel, using a "lighten" method (MAX() function) in PixelMath, and on top of this, 45 hrs (!) of [OIII] (Chroma 3nm) (made starless using Starnet++) blended in using a lighten function in Photoshop. The [OIII] with a selective mask to bring forth the Squid itself and leaving the noisier background out. Data was captured throughout Summer 2020. 

The scope used is only 80mm in aperture, and I think throwing more aperture at this one is really the only way to improve the [OIII] signal, which was not very strong (understatement!) - OU4 is extremely faint, and I've reached the end I think in what can be pulled out from here, and I feel time to move on (to something brighter!).

There is some(...) [OIII] emission corresponding to the main Ha emission regions in SH2-129, but it's so very faint it's barely above the noise floor. (2x2 bin may well have been better here...ho hum)

This data was captured from EEYE on our shared rig.

Acquisition: Graeme Coates & Paul Tribe

Processing: Paul Tribe

Files associated with this observation
Like this image
Nick Atkinson
Nick Atkinson, 2021 Sep 09 - 18:27 UTC

I am having a go at this with my TAK150B and a Nikon 810A I think you have a great image for such a faint target. Looks like I will need 20+ hours to pull the details out.

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