Starship Asterisk*

Hi Steve,

Thanks for the kind words and for your additional image with text.

No question this is one difficult target requiring dark skies. I have typical suburban skies which can be quite poor at times and the two weeks invested in early September/2010 for CTB 1 could have been better. My master O-III was rich in light pollution gradients whereas the master S-II fared slightly better. I was fortunate to do a decent job in mitigating their undesireable presence in the final result.

On one hand we have the bad weather doing its dirty work and on the other light pollution doing its thing as well. It is very sad how hard one must battle to get a half-decent image and which becomes even more difficult with objects requiring extended total exposure data. :(

Anthony.

Hello Anthony,

Nice write up and photo. I imaged this object over 2 years ago at an image scale of 3.5"/pixel using the STL11K and the FSQ-106N:
[img]http://www.starrywonders.com/ctb1cropped.jpg[/img]

More details can be found here:
[url]http://www.starrywonders.com/ctb1.html[/url]

It's an interesting object that benefits from fairly dark skies and long exposure.

Regards,

Steve Cannistra
http://www.starrywonders.com

The image below is the stunning, dim and difficult SNR in Cassiopeia CTB 1. This particular SNR was catalogued by George Abell as a planetary nebula in his now well-known catalog as the eighty-fifth and second-last entry (ie. Abell 85) but it was suggested by van den Bergh in 1960 and comfirmed by Willis & Dickel in 1971 to be, in fact, not a planetary nebula but rather a galactic SNR whose emissions include signal in the optical (ex. [url]http://adsabs.harvard.edu/abs/1997AJ....113..767F[/url] ), radio (ex. [url]http://www.narcis.info/publication/RecordID/oai:openaccess.leidenuniv.nl:1887%2F6952[/url] ) and x-ray (ex. [url]http://aas.org/archives/BAAS/v36n5/aas205/1420.htm[/url] ) portions of the spectrum. CTB 1 is approximately 3000 pc (9784 light-yrs away) and physically spans another 30 pc (98 light-yrs) in diameter while it is dated to be approximately 10,000 years-old.

Please note that at the 11 o'clock position, one is left with the impression that the "urn" has a "spout" and material is flowing out. Studies have confirmed this "shell rupture" and which extends up to 30' to the east and past the main shell (see [url]http://adsabs.harvard.edu/abs/1997AJ....113..767F[/url] ). Also of interest is the stronger O-III emission on the western section of the shell which I detected in my exposures and which coincides with scientific findings and is believed to represent "large-scale, incomplete shock cooling" (again, see [url]http://adsabs.harvard.edu/abs/1997AJ....113..767F[/url] ).

Similarly, the greater contrast of the southern half of CTB 1 is consistent with scientific findings and which has been linked to the various dust clouds in the immediate area and also visible in my image. Finally, there is a neutron star in the immediate area and which I am working on its precise identification and location (see [url]http://iopscience.iop.org/1538-4357/455/2/L151/5389.text.html[/url] ). For a rich survey of academic literature related to CTB 1, please see [url]http://www.mrao.cam.ac.uk/surveys/snrs/snrs.G116.9+0.2.html[/url] .

This particular SNR is one of the holy grails of amateur astronomy (ex.
[url]http://www.astronomy-mall.com/Adventures.In.Deep.Space/ctb1.htm[/url] ) and is a most-difficult target for imagers as well owing to a very dim magnitude spread over a diameter of 35.2 arc-minutes.

Further details in relation to this result are available on my website at [url]http://www.perseus.gr/Astro-DSO-Nebulae-SNR-CTB-1-NB.htm[/url] .

[img]http://www.perseus.gr/Images/dso-nebulae-ctb-1-hybrid-hires.jpg[/img]

[url]http://www.perseus.gr/Images/dso-nebulae-ctb-1-hybrid-hires.jpg[/url] ([b]for much higher resolution[/b])