Globular Cluster 47 Tucanae

47 Tucanae is a spectacular globular cluster, one of the best in the sky – and easily seen with the naked eye in a dark sky. At a declination of 71° South, most observers in the Northern hemisphere cannot see it.

Object Details:
47 Tucanae, NGC 104, C 106.
Constellation: Tucana.
Visual magnitude: +3.95.
Apparent diameter: 50 arc-min. (about 1.6 Moon diameters).
Actual diameter: 213 light years.
Distance: 15,000 light years.
Altitude: 51°.

Exposure: 20 minutes.
Date: 2018-10-01.
Location: Leumeah, NSW.
Sky: outer suburban.
Cloud: no.
Moon: no.
Image acquisition software: SharpCap.
Image post-processing:  Deep Sky Stacker > GIMP.
Cropping: slight.

Imaging telescope: Skywatcher Esprit 120ED Super APO triplet refractor.
Focal length: 840 mm, focal ratio: f/7.
Telescope mount: SkyWatcher EQ6-R.
Field flattener: yes; filter: no.
Imaging camera: ZWO ASI 071 MC Pro.
Polar aligning method: QHYCCD PoleMaster.
Polar alignment error: 1′ 42″ (Synscan).
Guiding: none.

SharpCap Camera Settings:
[ZWO ASI071MC Pro]
Output Format=FITS files (*.fits)
Capture Area=4944×3284
Colour Space=RGB24
Hardware Binning=Off
Turbo USB=80(Auto)
Frame Rate Limit=Maximum
Timestamp Frames=On
White Bal (B)=1(Auto)
White Bal (R)=1(Auto)
Cooler Power=100
Target Temperature=-20
Auto Exp Max Gain=300
Auto Exp Max Exp M S=30000
Auto Exp Target Brightness=100
Mono Bin=Off
Anti Dew Heater=On
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

Observing Notes:
Test night for EQ6R following second return from service at Bintel and Tasco.

Image © R.Powell


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