OU4 is a very faint nebula, so I have to change exposure time three times during the acquisition period with 4 reasonable good seeing nights. It is my first time using PI's normalized scale gradient (NSG) products with much better image quality at contrast and gradient. I just used 8 sample points of DynamicBackgroundExtractor on my OIII integrated image. See https://www.youtube.com/watch?v=9b957C6NQiA. Highly recommend it.

This is an SHO color mapping image and blending with an RGB image.

Hope you like it and C & C are welcome!

Jian Yuan Peng

-- facts -----

The red/golden color (Ha/SII Signal) is sh2-129, the flying bat nebula. The blue squid nebula (OIII signal) in this image (OU4) was discovered by the French Amateur Astrophotographer Nicolas Outters in 2011. The Giant Squid Nebula is cataloged as Ou4, and Sh2-129 also known as the Flying Bat Nebula is located in the constellation Cepheus.

OU4 is a bipolar outflow emitting in the OIII spectrum about 50 light-years across at 2,300light-years away and physically lies within Sh2-129. The blue grow is possibly emanating from a triple star system((HR8119) located in the center of Ou4.

The size of Sh2-129 is 4 degrees field of view or 8 Full Moons across and its arch-shape is sometimes nicknamed Flying Bat Nebula.

Technical details:

Telescope: Takahashi FSQ-106EDX4

Reducer: None

Telescope Mount: Ioptorn CEM40EC

Image Camera: ZWO ASI6200MM

Software: PHD2, PixInsight, Lightroom 6.4, Sequence Generator Pro, Photoshop CS6, StarNet++

Location: Palo Alto, California, USA

PhotometricColorCalibration data (preCorp):

Resolution ............... 1.461 arcsec/px

Rotation ................. -0.205 deg

Reference system ......... ICRS

Observation start time ... 2021-05-02 09:24:14 UTC

Observation end time ..... 2021-06-10 11:19:47 UTC

Focal distance ........... 531.02 mm

Pixel size ............... 3.76 um

Field of view ............ 3d 46' 46.0" x 2d 32' 5.2"

Image center ............. RA: 21 09 45.709 Dec: +59 52 33.75

Image bounds:

top-left .............. RA: 21 25 21.743 Dec: +61 05 38.11

top-right ............. RA: 20 54 05.633 Dec: +61 04 46.54

bottom-left ........... RA: 21 24 17.297 Dec: +58 33 52.48

bottom-right .......... RA: 20 55 18.591 Dec: +58 33 04.57

Astrodon 50mm Unmounted 3nm Narrowband Ha, SII, OIII filters

Blue 36x60" 36 Minutes Bin1x1

Green 36x60" 36 Minutes Bin1x1

Red 36x60" 36 Minutes Bin1x1

Ha 22x1200" 23x1500" 16.9 Hours Bin1x1

OIII 38x1200" 12x1500" 24*1800" 29.6 Hours Bin1x1

SII 18x1200" 23x1500" 15.5 Hours Bin1x1