An open cluster in Cancer
|Magnitude: +3.1||Diameter: 12 light years.|
|Apparent size: 70 arc min||Distance: 610 light years.|
I started getting serious about amateur astronomy when I bought my second telescope in 2008 and began going regularly to field nights with other members of Macarthur Astronomical Society. Like many new visual observers, I began with the Messier List of 110 bright objects and raced to see how many of them I could tick off. I recall reaching a hundred, with the inclusion of two northerly objects spotted in Cassiopeia, M52 and M103 when I was in the UK.
The Society handed out achievement certificates to members who had spotted 30/60/90/100 Messiers through the eyepiece – but I didn’t qualify because I used a ‘goto’ telescope. 🥴
When a globular cluster hunt was proposed, to see who could spy the most globs throughout the course of the evening, I was banned again of course, which I was ok with – but it amused me and I drew this stickman cartoon for our monthly magazine:
Since I bought my latest telescope – specifically for the purpose of astro-imaging – I’ve kept track of the objects I’ve imaged and started, once again to tally how many Messiers I’ve imaged.
Capturing long-exposure astro-images is a somewhat longer process than quickly observing them though an eyepiece – and I’ve complicated it even further by including the Caldwell List as well.
It’s a long haul and because there aren’t too many nebulae in these two lists I need to choose objects to image from other lists as well. This is because Messier created his list of fuzzy objects to help astronomers distinguish between permanent fuzzies like globular clusters and transient fuzzies like comets.
So how am doing, I hear you ask? Well, so far I’ve imaged 38 of the 110 Messiers and 45 of the 109 Caldwell objects. One globular cluster arguably looks much like all the others, so I might give it a break and go look for some nebulae for a while – and I don’t expect a certificate if I reach fifty!
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The Beehive Cluster (above) is one of those permanent fuzzy naked eye objects that resolve into stars with binoculars and is a favourite at public nights. It’s estimated to include over a thousand stars, two thirds of which are tiny Class M dwarfs and too dim to show up in my twenty-two minute image.
Just don’t ask me why it’s called The Beehive……
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|Feature image date:||2021-04-02|
|Exposure:||22.5 minutes (6 x 225 sec)|
|Field of View:||1.59° x 1.06° (up is 50.3 degrees E of N)|
If the Astrometry images do not appear it is because the Astrometry website is sometimes off line.
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Telescope & Imaging Details
|SkyWatcher Esprit 120 mm apochromatic 3-element refractor; 840 mm f/l @ f/7.|
|Field flattener; ZWO Duo-band Hα (656nm) and [OIII] (500nm) filter.|
|SkyWatcher EQ6-R Pro mount; ZWO ASI120 guide camera.|
|Imaging camera: ZWO ASI 071 MC Pro (CMOS 28.4mm 16 Mpx).|
|Software: Telescope control: Cartes du Ciel, EQMOD, PHD2, Imaging: SharpCap, Gimp.|
|Observatory location: 34° South.|
Images © Roger Powell
I’m one of the founder members of Macarthur Astronomical Society and its current webmaster.