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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