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View Full Version here: : My search for Terzan 10…


Dennis
22-06-2010, 09:40 AM
Introduction:
Inspired by Rolf’s images of faint globulars Terzan 5 & UKS-1, along with Justin’s herculean effort of HH-32, I thought that I’d attempt to take an image of Terzan 10 as a test of equipment and technique, as Gerald had kindly loaned me his SBIG ST2000 with CFW10 for a couple of nights.

Where the bl**dy hell are you???
I used The Sky 6 Pro to acquire the field and centred the view on where it plotted Terzan 10. Bad move! If I had been using my 765x510 pixel ST7, I would have completely missed the target as it wasn’t to be found at that location – something I didn’t discover until the next day.

However, the 1600x1200 pixel vista of the ST2000 managed to record Terzan 10 towards the top of the larger frame. I later used Sky Tools 3 Pro which plotted the position of Terzan 10 accurately and when prompted, downloaded a DSS image, verifying its established position.

I really should have read the Astronomy-Mall (http://astronomy-mall.com/Adventures.In.Deep.Space/obscure.htm)article for Terzan 10 which writes:
"One of the biggest problems in finding this globular is the incorrect positional data in several sources including Sky Catalog 2000"

Attached files:
1. Main image:
Full frame, Down sampled to 1280x960 (showing crop region)
Field centred on RA 18h 03m 27s, -26º 03’ 50”
Image scale 0.82 arcsec/pixel
FOV approx 22” x 16” (1600x1200)

2. Croped image:
800x600 crop from main image.

3. DSS Image:
STScI(US) Second Generation DSS Red, 10”x10” FOV downloaded via SkyTools

Imaging Details:
Brisbane, Qld, Australia
20th June 2010.
Tak Mewlon 180 F12 with x0.8 Reducer at an efl of 1728mm.
ST2000 and CFW10
Luminance: 2 x 15 minutes.
RGB 1 x 10 minute each.

Terzan 10 is listed as:
Apparent magnitude: 14.9
Brightest star: 19.7
Size: 0.3 arc minutes

Excuse the LRGB processing, I have much to learn and for this image, I just head-butted the data to beat it into submission – I know not yet how to do this stuff properly!:)

Terzan globulars:
Some background details on the Terzan globulars can be found here.
http://natkobajic.netfirms.com/listTERZAN.html

I also found and ESO paper which identifies Terzan 10 as ESO456-SC38.
http://aas.aanda.org/index.php?option=com_article&access=standard&Itemid=129&url=/articles/aas/abs/1997/17/ds6163/ds6163.html

A pdf article can be downloaded from the right hand Table of Contents under Abstract which shows images of Terzan 10 and UKS-1 taken with the European Southern Observatory 3.55 m New Technology Telescope (NTT) equipped with the SUSI camera and a 1024x1024 thinned Tektronix ESO CCD at the Nasmyth focus B.

Finally, this image would not have been possible without the generous sponsorship of Gerald and his ST2000! Thanks Gerald!:)

Cheers

Dennis

h0ughy
22-06-2010, 10:47 AM
Dennis you are the Indiana jones of the Australian Astro world - fair dinkum ;)

great result from excellent research and delivery

SkyViking
22-06-2010, 11:12 AM
Congratulations Dennis, that's a great result! It's nice to see all these obscure targets being imaged :D
I notice you got the deep red colour there, it looks beautiful and really gives a sense of the obscuring dust. Mine were not so red because I had to image without IR filter to catch as many photons as I could...
Yeah I remember reading the Astronomy-Mall article and noticing that several of the positions were off. I can confirm that at least Starry Night Pro 6 shows both Terzan 5 and UKS-1 in their correct positions.

Ric
22-06-2010, 12:45 PM
That's a capture and a half.

Top stuff Dennis

JD2439975
22-06-2010, 01:24 PM
Excellent capture of an obscure & very small wee beasty Dennis, well done indeed.
These things are hard enough to find sometimes even with true co-ordinates, just lucky it was still in frame.

Was just looking at it in WWT...WOW it is very small, at my native 1.2m FL it's just another star almost, lost in a wide field.

Thanks for the links to the other Terzan globulars, adds nicely to my list of future targets.

So are you thinking of hunting the complete set if conditions/time/interest allows?

Dennis
22-06-2010, 07:59 PM
Thanks for looking and commenting – I appreciate your comments.:)

The image looks a little too “dreamy” compared to what I think it “should” look like due to a combination of on-the-job learning and the use of noise reduction tools to offset the noisy background from not enough data.


Dave – I’m just following in the footsteps of Rolf and Justin; they do all the hard work in finding these esoteric faint objects!



Rolf – thanks for the heads up concerning the plotted position in SNP, I have SNP Pro Plus 6 although my field use Notebook only has 512Mb RAM so it really struggles with SNP.:sadeyes:



Ric – Thanks, your words give me confidence.:thumbsup:



Justin – I probably won’t go for the whole set although if Gerald loans me the ST2000 for a while longer I’ll definitely try to image a few others!

Cheers

Dennis

renormalised
22-06-2010, 08:13 PM
Nice shot, Dennis....good effort!!!:):)

RobF
22-06-2010, 08:28 PM
Fantastic work Dennis. Enjoyable and informative too, as always!

Moon
22-06-2010, 10:37 PM
Denis - thanks for posting this, I found it very interesting.
I've never visited the aanda website before - some amazing stuff there.
James

Dennis
23-06-2010, 01:51 PM
Thanks Carl, Rob and James for your comments – I appreciate them.

I’ve just completed an animation between the Mewlon 180 and the DSS Plate downloaded via SkyTools 3 Pro as follows:

Frame 1: LRGB with Mewlon 180 at F9.6 with ST2000/CFW10.
Frame 2: Downloaded STScI (US) Second Generation DSS Red Plate.

WARNING: File size is approx 170Kb.

Cheers

Dennis