According to such a map for France, I'm in a yellow-to-orange zone located
about 50 km (30 miles) south of Paris (11,500,000 people in the whole urban
area !) I shoot the deep sky from this place: http://goo.gl/maps/FsbE9
Le 16/10/2013 22:50, Darren Addy a écrit :
I have not yet learned how to do a real accessment of the night sky
conditions (transparency, minimum magnitude, etc). I need to do that.
This image was taken before the 23% moon had set in the extreme west,
and I was about 7 miles outside of a town of 35,000 people, but
looking away from it. I did have an airport beacon about 5 miles north
of me (and another about 20 miles to the SE).
A dark sky map with my location can be found here:
http://www.flickr.com/photos/pixelsmithy/10316900456/
On Wed, Oct 16, 2013 at 3:35 PM, poirierstephane
<[email protected]> wrote:
Yes of course I already known you Darren, but I'd didn't pay attention to
your name in your original message, my apologizes !
About the calibration, I proceed not particulary slowly, only the time it
takes for me to carefully rotate the camera around the 3 axis.
45 seconds exposures for 135mm lens, it's a bit short, yes, but it not
surprise me. I suppose the maximum exposure time depends more or less of
the angular distance to the pole and/or the angular distance to the horizon,
or both. With my 200mm I'm often limited to 30s. The best I've got without
star trailling is 75 seconds with M33, an exceptionnal value !!
Actually the camera is very optimistic with long focals, but more realistic
with shorters ones. 3 minutes exposures time is possible with a 50mm lens, I
tested it.
And about your night sky, how is it ?
Stéphane
Le 16/10/2013 22:17, Darren Addy a écrit :
Hi Stéphane,
Your work is my inspiration and I have shared the link to your
K-5/O-GPS1 work in many, many places. (We have corresponded via email
in the past).
Thanks for your link to your procedure.
I was wondering if you could describe the way you do the "precise
calibration". For example, do you proceed slowly? Do you always do the
three axis calibration in the same order (if so, what order)? I was a
little disappointed that with my 135mm lens I could only do 45 second
exposures before I got some trailing. The camera told me I should be
able to do a lot more.
-Darren
On Wed, Oct 16, 2013 at 2:45 PM, poirierstephane
<[email protected]> wrote:
Very cool result :) But I suspect you benefit of good sky conditions,
isn't
it ?
I also use DSS and I got a very similar result (although with the a K-5 &
DA*200): poirierstephane.free.fr/photos/picture.php?/3542/category/132
<http://poirierstephane.free.fr/photos/picture.php?/3542/category/132>
For this picture I stacked 8 good images (30s each @1600 ISO) together
with
a dark frame (but I consider now that dark frames are useless with the
latest camera sensors). The way I procede is described here:
poirierstephane.free.fr/photos/index.php?/page/astrophotography_without_equatorial_mount
<http://poirierstephane.free.fr/photos/index.php?/page/astrophotography_without_equatorial_mount>
Stéphane
Le 16/10/2013 01:00, Darren Addy a écrit :
Y'all may recall
(hey, that rhymes!)
the m31 (Andromeda galaxy) image I shared a few days ago. It was a
single 45 second exposure and made from a single in-camera JPEG (not
even the RAW file).
Refresher link: http://www.flickr.com/photos/pixelsmithy/10181475554/
Well, I finally got to attempt my first use of the freeware
DeepSkyStacker (version 3.3.3 beta 51) and with it I stacked the 11
"good" RAW images that I had taken that evening. Added together, they
represent a 6 minute "integrated" exposure time.
The latest versions of DSS also let you work with the histogram (in R,
G, & B), luminance, and saturation, along with the curves. I then
applied a few Photoshop astrophotography-related actions and adjusted
the color-balance, which seemed a bit green to my eye. Here is the
result:
http://www.flickr.com/photos/pixelsmithy/10299785464/
This is still not even doing everything "right" because I was working
with no "dark frames", "bias frames", or "flats" which would make for
an even better stacked image (especially where noise is concerned).
Still I'm pretty pleased with the result, for my "maiden DSS voyage".
K-5ii, O-GPS1, ISO 800 K135mm f2.5 @ f4
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