Unguided M22

[Geoff45]

Just another globular cluster, but with a difference. My guide camera bit the dust, so I had to go unguided. At 2500mm focal length long unguided exposures of galaxies and nebulae were out of the question, so it had to be stars. The sweet spot for subs was about 80-120sec. I still had to cull ruthlessly.
Telescope: 12.5" Plane Wave
Mount: AP900
Camera: FLI Proline16803
Exposure: About 40min through R, G and B. Some at 120s, most at 80s.
FOV:49' x 49'

M22 is one of the nearer globular clusters to Earth at a distance of about 10,600 light-years away. Its angular size of 32' translates to a spatial diameter of about 100 light years.
M22 is very unusual in that it is one of only four globular clusters that are known to contain a planetary nebula, the others being M15, NGC 6441 and Palomar 6.
Small version here http://www.astrobin.com/205919/
Higher Res here http://www.astrobin.com/full/205919/0/


Geoff

[Placidus]

The AP900 is obviously rock steady. The stars are all pinpoint. Nice exposure (great core detail while showing faint periphery) and beautiful colour contrast. It could be an interesting test shot for discussing whether and how to set absolute colour.

[Geoff45]

Thanks Mike. Colour calibration was done in PixInsight by using the entire star field as the white reference.

[Ryderscope]

Certainly came out quite well Geoff. Nice colours. Good to see that you didn't have to waste the trip to Wiruna.

[Geoff45]

Thanks Rod. I was also lucky in that on the previous night Ian P arrived too late to set up his portable gear, so I borrowed his Lodestar and got this image http://www.iceinspace.com.au/forum/showthread.php?t=138010. Also got some NB on M16.

I also did stuff I've been putting off--tweak collimation, try to get PEC going, etc

Geoff

[strongmanmike]

Ok, ok, once is a coincidence but twice?.. it's definite, you are image stalking me :scared2:

Pretty good for unguided Geoff particularly at 2500mm too :thumbsup:

Mike

[Geoff45]

Thanks Mike. Actually, it happens with me and Joe Cauchi as well. We have neighbouring observatories at Wiruna and one of us will wander across and ask the other "What are you imaging?" Snap!
Geoff

[strongmanmike]

He, he yeah, Marcus Davies and I seemed to be playing tag a couple of years ago too...then we started to hesitantly ask what each was imaging so we didn't double up :)

...soooo, errr? what are youuu imaging next then..? :whistle:

Mike

[Geoff45]

More data on the Pavo cluster, more NB data on start I made on M16, some dust in Octans, IC5148 and maybe NGC7252.

[strongmanmike]

Right! duly noted....:computer: :thumbsup: just as well too, I was definitely considering IC5148 too for over this full moon period (if it clears) and to a lesser extent (it's a bit small) the Atoms for Peace galaxy next new moon :lol:

Mike

[multiweb]

Sweet shot for an unguided gig. Great colors too. :thumbsup: Bummer about the guider. Hope you get back in soon.

[Rod771]

Looks good, Geoff! Nice colour in the stars!

[Rex]

Aewsome guiding and nice colour Geoff. I struggle getting stars this round with guiding and 1/3 the FL. Great job.

[Geoff45]

Thanks Marc. I had to send the guide camera (Lodestar) back to Starlight Xpress in the UK. I don't think there is going to be a rapid turnaround. In the meantime I'm getting a cheap backup guider from Bintel.



Thanks Rod

Thanks Rex. It's all down to the AP mount--no skill needed.

[multiweb]

Lodestar? Ouch! Did you kneecap that little USB socket at the back?

[Geoff45]

When I sent Terry Platt some of the "pictures" it was producing he thought it might be a cracked component somewhere.

[RickS]

Lovely colours, Geoff. My condolences on the guide camera. My main camera is finally on the way back after several months away...