NGC 3532

Image of NGC 3532, an open star cluster containing 120 stars, on the outskirts of the Carina nebula. It was taken from my home location with a total exposure of 32 minutes.

I’ve had ongoing problems with intermittent frame dropping and on this night I had to cut short my imaging, as no more of the 29 second still frame exposures were being received by SharpCap, amid warning dings from my laptop.

Subsequent to this I have spent a lot of time testing all my USB3 cables and found a 2m cable which transmitted frames consistently, while most did not. However,  I really would like to use a longer cable and my suspicion is that the USB system in my laptop is not up to scratch. 😕

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Object Details:

NGC 3532, Caldwell 91
Constellation: Carina
Visual magnitude: +3.0
Apparent size: 50′
Diameter: 23.3 light years.
Distance: 1600  light years.
Altitude: 55° above SW horizon.


Exposure: 32m 37s (67 frames 29.2s).
Gain: 128.
Date: 6th May 2019.
Location: Outer suburban.
Conditions: Mostly clear.
Sky: 1.80 e/pixel/s
Moon: no


Image acquisition software: SharpCap, live stacked.
Image post-processing:  GIMP.
Cropping: no.
Diffraction spikes: added.


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: N Guiding: No
Polar aligning: QHYCCD PoleMaster Polar Error: 04’ 05”

Also relevant:  
Star Cluster Portfolio

Image © Roger Powell

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