The M7 Open Star Cluster in Scorpius

[Mike Salway]

Hi all

This image of M7 (Ptolemy's Cluster) was taken at IISAC2009, early on the Saturday night before it clouded over. The Milky Way was setting in the West, and I captured 50 minutes of data on this object before it set behind the mountain.

This image is my first real deep space (prime focus) image in some time (since January this year!!), so while it’s not in the league of Louie’s beautiful version of M7 that appeared on APOD last week (congrats Louie!), I’m reasonably happy with the image given the lack of data, no flats calibration and the guiding problems I was having at IISAC2009. It really needs to be much deeper and longer to get the golden star field of the Milky Way.

The image was captured with my normal Deep Space Imaging equipment – the unmodded Canon 350D with the ED80, riding on the EQ6 and guided with an 80mm refractor using my DMK21AU04 and PHD guiding.

Exposures were 5 minutes each, with dark frame subtraction in camera. 10 exposures @ ISO800, FL ~ 480mm, F/6.

Larger version here:
The M7 Open Cluster in Scorpius

Thanks for looking.

[Chip]

Impressive work and a beautiful photo, Mike. It makes my efforts to capture star trails look quite feeble.

I'm curious about what you mean when you say that "the Milky Way was setting in the West." To ask a dumb question, would you mind explaining that to me if you have the time?

[Aegea]

Super photo. Congratulations!

[leonaashlee]

Pretty impressive work.

[Mike Salway]

Thanks for your comments.

Originally Posted by Chip

Impressive work and a beautiful photo, Mike. It makes my efforts to capture star trails look quite feeble.

I'm curious about what you mean when you say that "the Milky Way was setting in the West." To ask a dumb question, would you mind explaining that to me if you have the time?

The stars rise in the East and set in the West. The heart of the Milky Way, from our vantage point, was setting in the West at that time.

Check this video and you'll see what I mean:

The Milky Way Setting at IISAC2009

Cheers and thanks.