Terzan 11 – Faint Globular in Sgr

[Dennis]

Hello,

My observation planning software, SkyTools 3 Professional, listed Terzan 11 as the faintest of the 11 Terzan objects, at magnitude 16.4, with a size: 1.5 arc minutes. Then, for Terzan 11, The Astronomy-Mall article (http://astronomy-mall.com/Adventures.In.Deep.Space/obscure.htm)writes the following …

“This is a brutally tough object. It was a weak glow in the 36" near two fairly faint stars visible on the Palomar Sky Survey Prints”

So I knew that I had a challenge on hand, under the suburban skies of Brisbane.

Images:
Main image: Full frame, down sampled from 1600x1200 to 1280x960
Image scale of 0.82 arcsec/pixel with FOV approx. 22’ x 16’

DSS Image: STScI(US) Second Generation DSS Red, downloaded via SkyTools

Imaging Details:
Brisbane, Qld, Australia, 3rd July 2010.
Tak Mewlon 180 F12 with x0.8 Reducer at an efl of 1728mm.
SBIG ST2000 and CFW10
L= 4x15 mins, R:G:B = 1x10 min each filter.

Notes:
This particular session revealed a few problems with my set up, attributable mainly to the sheer weight of the ST2000+CFW10. The combined weight of this camera and filter wheel causes flexure in my Crayford Focuser as well as slippage of the focuser tube. The slippage resulted in “fatter” stars as the evening progressed. I only noticed this at the end of the session where the colour images were noticeably out of focus compared to the initial luminance frame. Next time I’ll use some strong rubber bands to take up some of the weight of the camera/filter wheel assembly.

Terzan globulars:
Some background details on the Terzan globulars can be found here.
http://astronomy-mall.com/Adventures.In.Deep.Space/obscure.htm
http://natkobajic.netfirms.com/listTERZAN.html

This image would not have been possible without the generous sponsorship of Gerald via the loan of his ST2000 & CFW10! Thanks Gerald!

Cheers

Dennis

[multiweb]

Very nice shot Dennis and interesting read. Well done. :thumbsup:

[SkyViking]

You've done it again Dennis :) Congratulations on yet another faint obscure fuzzy - those that we treasure so much! That's a spectacular catch, must have left your camera gasping for photons :D
It even looks like it's hiding behind a dark nebula, it must be fairly bright in absolute magnitude to be able to penetrate all that interstellar dust.

Did you have any trouble locating its position or were the coordinates right from the start? I recall some of the Terzan coordinates were a bit off.

[DavidU]

Very cool capture.
You fellas are nut's with the Mag limit's you are reaching.

[strongmanmike]

That's Terzaniffic :P

Interesting blurb too.

I remember tracking a few Terzans down visually with my 12"LX200 back in 2002/3.

Mike

[JD2439975]

Nicely done Dennis, the hard targets though not spectacular to behold bring a satisfaction of thier own. :thumbsup:

[Dennis]

Thanks Marc – I always appreciate your comments.



Hi Rolf
Thanks! This one was much easier to find that Terzan 10 as the position was accurate in all my planetarium programs. The luxury of Gerald’s 1600x1220 ST2000 and the ability to expose for 15 minutes certainly makes these objects much less challenging!



Thanks Dave – I have the engineers at Takahashi and SBIG to thank for this one.



Hi Mike

Thanks! Hmm, let me see…I can see an article in next months Aussie Sky & Tel…Tarzan in search of Terzans!:lol:



Thanks Justin – you and Rolf have ignited the fire in my belly for this faint stuff; I’ll never forgive you both!;)

Cheers

Dennis