Tag Archives: M13

M13 – Hercules Cluster

I have a guilty pleasure: I like globular clusters. I should put more effort into more challenging classes of objects – diffuse nebulae and galaxies, but I’ve always loved GCs, even though they are easy to see. M13 is my favourite.

This was a test image last night, after a couple of days of maintenance, collimating the scope and then re-doing the mount polar alignment and pointing model.

Exposure Luminance: 60 minutes (20 x 3 minutes)
Colour: 15 minutes (5 x 1) of each of Red, Green, Blue
Camera QSI583wsg, with Astrodon LRGB filters, running at -15°C
Image scale 0.69 arceconds/pixel (luminance), 1.38 (colour)
Telescope AT8RC
Mount Paramount MX+
Guiding Autoguided with Starlight XPress Lodestar
Processing 32 dark frames per sequence
32 flat frames per filter
Sigma-clip mean combination on the darks and flats
Sum-combination on the light frames
Aligned, combined, and deconvolved with CCDStack2

Start capturing colour for M13.

It was a pleasant evening last night – very clear, and unseasonably warm (+17 degrees at midnight, after frost the night before).

M13-Mean-Red-ScaledI was able to capture an hour of Red data for M13 under good steady skies. I thought it might be interesting to share the colour channels data for such projects as they are collected, in case others might like to use them to experiment with processing, colour combination, etc. (I found few such examples to play with when doing my own searching some years ago.)

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Starting M13 project

M13-Mean-Luminance-ScaledNow, in mid-autumn, the sky has rotated to the point where M13 is well-located from my observing spot – and it’s dark earlier too.  So I started an M13 data collection project tonight with 2 hours of luminance data, in 5-minute subs.  Colour will follow over the next few available nights.


Very clear night, and a quick M13

M13-LRGB-2010-05-17I finished the mount and scope tuning, re-did the PEC training, and feel generally ready to start trying the new configuration. I took a quick image of M13 to test. It wasn’t supposed to be a quick image, but I almost immediately ran into a guiding problem, so only got about 25 minutes of data. The problem was just my very limited horizon – my guide star drifted behind an obstacle. I still have to get used to planning where the clear path is for objects I’m trying to image.

It’s supposed to be clear again tonight, so I hope to have a chance for another go.