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.


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


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


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


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
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=100
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=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

Image © Roger Powell


  1. As a resident of the Northern Hemisphere it’s always strange to hear accounts of freezing temperatures in August. I’m just under +42 latitude and July and August are the main “hot” months here.


  2. I lived at +52 before I moved to -34 and I can still get confused myself.
    I think Spring and Autumn are best – less cool but still early enough sunset to get a good session.

    Liked by 1 person

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