Trifid Nebula

It’s another clear night sky as I write this – but the Moon is full and it’s not a good time to be taking images. However, only about three or four more days and dark evening skies will be back.

So let’s check the ten day weather forecast:

Oh, crap!  Cloudy skies predicted for the next ten nights in a row! By which time the  b@$#!&* Moon will be almost back again…   😶

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I took the above two hour exposure of M20 on 3rd September, it was the third and final image of a field night with Macarthur Astronomical Society,  when the Moon was a four day old crescent and less bothersome. I have already posted the other two images: Crescent Moon and Cat’s Paw Nebula.

This was a two hour exposure of one of the sky’s most charming nebulae. It’s three main lobes, separated by dark lanes radiating from the centre, contribute to its name.

I wondered what does Trifid mean? This is what dictionary.com revealed.

The Trifid is part of a much larger nebulous complex which also includes M8, the Lagoon Nebula. Some of the complex can be seen as a faint reddish background colour.

The nebula M20 is viewable in binoculars and can be picked out in small telescopes as a fuzzy patch about three quarters of the size of the Moon. 

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As I mentioned in my previous post, this image marks my return to image guiding after a period of relying on good polar alignment and shorter exposures. With this object, the guiding worked consistently, considering I was using a new guide camera and had forgotten much of what I had previously learned about PHD2 Guiding

2019-09-03 PHD on M20. The graph was consistent for two hours and doesn’t look too bad, even though the Y axis was at it’s greatest option and the exposure level was a bit fast. The main settings were default values.

 

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Object Details:

Designation:  Messier 20, NGC 6514.
Constellation:  Sagittarius.
Visual magnitude:  +6.3
Apparent size:  29′ x 27′
Diameter:  44 light years.
Distance:  5,200 light years.
Altitude during exposure:  31° above W. horizon.

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The following is just technical stuff:

Image: Exposure:  63 x 115.9 sec = 121 min. Gain: 136. Date:  2019-09-03. Location:  semi-dark rural. Conditions:  clear. Moon: NM+4 crescent in West.

Processing: Image acquisition:  SharpCap. Method: Live stacked. Darks: 10x. Image post-processing:  GIMP. Cropping:   no. Sky:   0.27 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:	Yes
Polar aligning:	QHYCCD PoleMaster	Polar Error:	00’ 28”

Geek Log:

[ZWO ASI071MC Pro] Debayer Preview=On 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=4 fps Gain=136 Exposure=115.92585 Timestamp Frames=Off White Bal (B)=50 White Bal (R)=53 Brightness=20 Temperature=-14.8 Cooler Power=41 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\118.4s\gain_220\dark_10_frames_-14.8C_2019-09-03T09_45_02.fits #Black Point Display Black Point=0 #MidTone Point Display MidTone Point=0.5 #White Point Display White Point=1 TimeStamp=2019-09-03T13:44:24.3181868Z SharpCapVersion=3.2.6086.0 TotalExposure(s)=7303.32854999999 StackedFrames=63

 

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Images © Roger Powell

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