by Richard Crisp
It is a shame I didn't do this target last weekend when the seeing was really good. As it stands, last night I was getting about 3.2 to 3.5 arc-second stars during focus runs. Not great but not terrible either. I think I would have been in the low twos had I taken it during better seeing conditions.
The real test was the guiding and what I was seeing was a guide star that was falling to pieces and then regrouping from cycle to cycle. Not exactly the result I was seeking but characteristic of the seeing conditions I was experiencing. In comparison to last weekend where I could look up and see absolutely steady stars with no visible scintillation, I was observing moderate twinkling last night with the naked eye. But it was clear and the scope was ready to use so I shot two hours of Ha in the neck of the Pelican.
The C14 with all the trimmings works out to be about f/12.46 so even with the 24 micron pixels of the Dream Machine, going through the 3nm Cust Sci Ha filter it takes some serious exposure time to get any signal density.
On Sunday night I had first attempted the object after getting things all working and tuned, but I shot 10 minute exposures. There just wasn't enough signal in the 10 minute exposures so last night I boosted them to a half hour. I took four such exposures before being shut down by clouds.
I plan to shoot [OIII] and [SII] data and perhaps will do some [NII] as well on this object. I think the "elephant trunk" has some interesting structure that shows up in those filters. Stay tuned.
In the meantime, here is the first processing of the data I did take: two hours (4 x 30 minutes) of Ha.
http://www.narrowbandimaging.com/ic5070_pelican_neck_page.htm
Posted on sf-bay-tac Jun 29, 2004 08:52:39 PT
Converted by report.pm 1.2 Jan 02, 2005 14:25:03 PT