Horsehead region - single 15-min exposure with 90mm refractor & DSLR
I ran a little experiment with myself a couple of nights ago to see what I could pick up in a single 900-sec exposure in the B33 region with my little Sky-90 running at f/4.5 and a bog-standard Canon 40D at ISO800. It ain't the smoothest (no stacking), but I'm reasonably impressed with how much light this little 90mm scope can suck in in 15 minutes. Given that the 40D is un-modded, it is a pretty reasonable result I reckon.
EDIT: Just added one I did at ISO1600, merely converted from RAW in Canon DPP and tweaked a little in Photoshop. The colour is better when initially processed by DPP than Camera RAW, as is evident. Again - single exposure for 900 seconds, no dark, no flat, no nothin'.
Thanks Peter, Humayun, Fred, Guy, Barry & Lester. I've just uploaded its ISO1600 brother. I pre-processed the RAW in DPP this time (rather than Camera RAW), and the purpleish neb cam out a more faithful hydrogen-red. 'Mazing!
whoa, OK, the noise is starting to intrude there (1600iso).
Hang on, you saying both images have NO dark?.
No, thats impossible, you cant do 15mins with no dark (or cooling), fess up Chris, whats up?
Nope - no darks at all Fred, and no cooling. Ambient temp was about zero deg C. The ISO1600 version was very over-exposed after 15 minutes, given that while the sky was reasonably dark, it wasn't a Coonabarabran sky by any means. DPP flattened the highlights (most of the frame) and a gaussian blur in Photoshop reduced the noise somewhat. Rooly-trooly, scout's honour. The 40D leaves the amps off until read-out, and thermal noise is minimal in this camera. Maybe lucky it's a good one?
Having a history in astrophotography that dates back to 1982 I remember when the HH was "the" challenge target photographically with film, the idea that a single 15min exposure with a little telescope could show this (and almost intantly too if you process it on the spot) would have been fanciful and out right preposterous
Chris, I'm getting excited already as because I am still only just starting to experiment with stacking, I often do 1 frame shots and trying to get the best out of 1 frame for now as I learn more. The moon is the only one I am starting to get confident with stacking (with your tips too!)
Can't wait now for a good night and go and try my 40D!
One of the reasons why I joined IIS was that I had the 40D and a telescope but never genuinely attempted astrophotography until about June this year when I saw a truly beautiful photo from Octane I think posted late last year with the 40D and 200mm lense (both I have) of the horsehead area and your single shot gives me some idea what I could theoretically get as I start to move into deep sky.
You're coming along uhmm... rather quickly... and you'll be posting deep sky images in no time. I guess that the point of this post was to show how a photographically quick scope (f/4.5) and a decent DSLR can perform given a chance. Guiding will be of real importance - as this was a 15 minute exposure, so polar alignment is also very important.
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as because I am still only just starting to experiment with stacking, I often do 1 frame shots and trying to get the best out of 1 frame for now as I learn more. The moon is the only one I am starting to get confident with stacking (with your tips too!)
photo from Octane I think posted late last year with the 40D and 200mm lense (both I have) of the horsehead area and your single shot gives me some idea what I could theoretically get as I start to move into deep sky.
for the link - I love that pic!
