NGC 6188 & 6193

A one hour image of this star cluster and huge emission nebula in the southern Milky Way.

I didn’t do my homework properly on this.  The nebula was listed as 20′ x 12′, fitting easily into my 1.5° x 1.0° field of view. It seems the cluster may be that size but the nebula is very much bigger, forming part of a much wider region of complex nebulosity which stretched well outside this image.

It was my second target of the evening and unfortunately I failed to recheck the focus, which had become slightly off due to the temperature dropping to sub-zero and ice forming everywhere.    😨

So, not one of my best images but an interesting region.

Object Details:

Designation: NGC6188 (emission nebula); NGC 6193 (open star cluster).
Constellation: Ara
Visual magnitude:  +5.2
Apparent size:  20′ x 12′
Diameter:  21.9 light years.
Distance:  3,800  light years.
Altitude during exposure:  53° above SW horizon.

 

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Technical stuff.
Please feel free to jump to the end and like or comment.

Image: Exposure:  41 x 89.4 sec = 61 min. Gain: 270 Date:  2019-08-06 Location:  semi-dark rural. Conditions:  clear Moon: 5 days old, set 11.00 pm

Processing: Image acquisition:  SharpCap. Method: Live stacked. Darks: 10x Image post-processing:  GIMP. Cropping:   No Sky:  0.29 e/pixel/s .

Gear:

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: LP	Guiding:	No
Polar aligning:	QHYCCD PoleMaster	Polar Error:	00’ 22”

Geek Log:

[ZWO ASI071MC Pro] Debayer Preview=On Pan=0 Tilt=0 Output Format=FITS files (*.fits) Binning=1 Capture Area=4944×3284 Colour Space=RAW16 Hardware Binning=Off Turbo USB=40 Flip=None Frame Rate Limit=1 every 4 seconds Gain=270 Exposure=89.375778 Timestamp Frames=Off White Bal (B)=50 White Bal (R)=53 Brightness=40 Temperature=-4.9 Cooler Power=100 Target Temperature=-15 Cooler=On 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=C:\Users\Roger\Desktop\SharpCap Captures\darks\ZWO ASI071MC Pro\RAW16@4944×3284\89.4s\gain_270\dark_10_frames_-0.8C_2019-08-06T09_39_54.fits #Black Point Display Black Point=0.01953125 #MidTone Point Display MidTone Point=0.340754725333788 #White Point Display White Point=0.998046875 TimeStamp=2019-08-06T12:40:14.8720991Z SharpCapVersion=3.2.6062.0 TotalExposure(s)=3664.406898 StackedFrames=41

Image © Roger Powell

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