Tarantula Nebula

Designation:  NGC 2070, Caldwell 103, in constellation of Dorado.

Visual magnitude: +5.0

Apparent size: 40 x 25 arc-minutes.

Diameter: 1833 light years.

Distance: 160,000 light years.

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One thing you learn in astronomy is to always keep watching the latest weather forecasts. A few nights ago I was expecting an astronomy session but got a surprise electrical storm instead. The next night I was expecting more poor conditions but ended up with a surprise astronomy session.

I decided on the Tarantula Nebula, a fabulous object 31° from the South Celestial Pole and in a part of the sky which is accessible from my observing spot at home. I had not yet imaged this object with my current setup.

The glorious thing about the Tarantula is not just that it is so prominent in our southern sky but also that it is so far away ——> in another galaxy!

It is part of the Large Magellanic Cloud (LMC), 160,000 light years away – yet incredibly it is one of the finest sights in our sky.

Wikipedia states that “this is an extremely luminous non-stellar object. Its luminosity is so great that if it were as close to Earth as the Orion Nebula, the Tarantula Nebula would cast visible shadows. In fact it is the most active starburst region known in the Local Group of galaxies.”

The Night Sky Observers Guide describes it as “A very bright, large nebulous mass with wisps, loops and hazy tufts…….the central region is very bright and contains the bright star 30 Doradus and another ten stars gathered around it…..one of the sky’s top highlights.”

The ill-fated Robert Burnham Jr. described it as an “object which stands forth without an equal”.

Here is a cropped version of the same image, showing more detail of the Nebula:

Tarantula regional crop.

There are a number of other interesting objects in the LMC itself but – because it extends well beyond the field of view of most telescopes – imaging the entire galaxy requires either using a stitched mosaic approach or reverting to a DSLR camera without a telescope, something I intend having another go at soon.

I was aiming for two and a half hours exposure but only got 106 minutes because later in the session SharpCap began rejecting frames, most likely because the object was moving towards the blinding new street light installed last year by my local council. @#!&!B@*#!! 🤐

The Tarantula is not an easy image to process, because it is such a congested region. Add to that my impression that WordPress may not be presenting the colours of the image exactly as it was submitted; and the obvious (to me) fact that I have not yet got the hang of producing flat frames which completely eliminate the effect of dust particles located in the optical train.

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Other objects in the above image – See my image with:
 Astrometry.net annotated overlay.

They include: NGC 2009, NGC 2015, NGC 2018, NGC 2042, NGC 2044, NGC 2048, NGC 2052, NGC 2055, NGC 2069, NGC 2074, NGC 2077, NGC 2078, NGC 2079, NGC 2080, NGC 2081, NGC 2083, NGC 2084, NGC 2085, NGC 2086, NGC 2091, NGC 2092, NGC 2093, NGC 2100, NGC 2102, NGC 2108, NGC 2113 and more.

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Image Details

Date:  2020-02-19.	Sky brightness (e/px/sec): 0.66.
Frame exposure: 45 x 142 sec.	Total exposure: 106 min.
Gain setting:  10.	Location:  outer suburban.
Moon:  no.	Conditions: < 5% cloud, calm.
Camera: ZWO ASI 071 MC Pro.	Type: CMOS 28.4mm 16 Mpx.
Imaging software: SharpCap Pro.	Post process software: GIMP.
Guiding software: PHD2.	Polar alignment: 00′ 03″
Cropping: (main image) no.

Equipment Details

SkyWatcher Esprit 120 mm apochromatic 3-element refractor.

840 mm focal length @ f/7 with field flattener.

Baader L-Booster UHC-S light pollution filter 2458276.

SkyWatcher EQ6-R Pro mount.

ZWO ASI120 guide camera.

QHYCCD PoleMaster polar aligning camera.

Images © Roger Powell

I’m one of the founder members of Macarthur Astronomical Society, Australia. 🙃

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=80(Auto) Flip=None Frame Rate Limit=Maximum Gain=10 Exposure=142.142432 Timestamp Frames=Off White Bal (B)=99 White Bal (R)=60 Brightness=16 Temperature=-10 Cooler Power=92 Target Temperature=-10 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=On Banding Threshold=35 Banding Suppression=0 Apply Flat=C:\Users\powel\Desktop\SharpCap Captures\2020-02-19\Capture\flats\20_20_37.png Subtract Dark=C:\Users\powel\Desktop\SharpCap Captures\darks\ZWO ASI071MC Pro\RAW16@4944×3284\142.1s\gain_10\dark_6_frames_-9.4C_2020-02-19T10_23_28.png Black Point Display Black Point=0 MidTone Point Display MidTone Point=0.5 White Point Display White Point=1 TimeStamp=2020-02-19T12:35:05.1682269Z SharpCapVersion=3.2.6173.0 TotalExposure(s)=6396.40944 StackedFrames=45

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