IC 4628

A bright emission nebula, located in Scorpius.

Probably a bit too close to the Moon that night. I also had a strange artifact on the image which looked like tree or shrub leaves, which may possibly have been my television antenna. I managed to conceal most of it but it is still visible as slight bluish markings at the bottom of the image. 😨

I must admit I have seen better images of this object……..

Once again I was forced to pack up early, this time due to getting condensation on my objective lens, which proved once and for all that I needed a new dew manager which I have been putting off – and I have since bought a replacement one.

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Object Details:

Designation:  IC 4628, the Prawn Nebula.
Constellation:  Scorpius.
Visual magnitude:  +10.0
Apparent size:  90′ x 60′
Diameter:  71 light years.
Distance:  2700  light years.
Altitude:  50° above SE horizon.
Also in image:  Clusters: Collinder 316 (3rd mag , 100’) & Trumpler 24 (8th mag, 60’).


Exposure:  7356. sec (196 frames x37.5 sec)
Gain:  0
Date:  2019-05-14
Location:  Outer suburban.
Conditions:  Mostly clear.
Moon:   Bright FQ+2, about 90° from target.
Sky:   1.80 e/pixel/s  


Image acquisition software:  SharpCap, live stacked.
Image post-processing:  GIMP.
Cropping:   edges only.


Telescope: SkyWatcher Esprit  Type: 120ED triplet refractor
Focal: 840 mm F/7 Mount: SkyWatcher EQ6-R Pro
Camera: ZWO ASI 071 MC Pro Type: CMOS 28.4mm 16 Mpx
Optical aids: Flattener: Y; filter: N Guiding: No
Polar aligning: QHYCCD PoleMaster Polar Error: 04’ 51”

Geek Log:

Debayer Preview=On
Output Format=FITS files (*.fits)
Capture Area=4944×3284
Colour Space=RAW16
Hardware Binning=Off
Turbo USB=40
Frame Rate Limit=1 every 4 seconds
Timestamp Frames=Off
White Bal (B)=50
White Bal (R)=53
Cooler Power=67
Target Temperature=-15
Auto Exp Max Gain=300
Auto Exp Max Exp M S=30000
Auto Exp Target Brightness=100
Mono Bin=Off
Anti Dew Heater=Off
Banding Threshold=35
Banding Suppression=0
Apply Flat=None
Subtract Dark=None
#Black Point
Display Black Point=0
#MidTone Point
Display MidTone Point=0.5
#White Point
Display White Point=1


Image © Roger Powell



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