Patrick Moore's 15" Reflector - DSLR first light

After spending Tuesday night getting the recoated mirrors back into
the 15" OTA, last night it looked like we would be blessed with
wonderful clear skies.

However, on arriving at the observatory dome, the weather decided to
play up. After an amusing game of cat and mouse with cloud gaps, we
managed to get one early decent DSLR image from the scope - a single
21s image! It really was that cloudy!

We would have liked more but the clouds were a real pain and the scope
had a few tracking issues - we think due to balance problems. Later
on in the evening, the clouds did go away and the temperature dropped
significantly. The dome has a concrete floor which is lovely and warm
- ok, I'm lying - it's like observing in a freezer!

By the time the sky cleared, M42 had moved behind a neighbouring tree
and the opportunity was lost. A pity really as stacking a number of
these short exposures would have been interesting.

Still, considering this is only a 21 second image, it bodes well
assuming we can get the tracking sorted out.

http://www.digitalsky.org.uk/temp/15...1st_light.html

--
Pete
http://www.digitalsky.org.uk

Pete Lawrence wrote:
After spending Tuesday night getting the recoated mirrors back into
the 15" OTA, last night it looked like we would be blessed with
wonderful clear skies.

However, on arriving at the observatory dome, the weather decided to
play up. After an amusing game of cat and mouse with cloud gaps, we
managed to get one early decent DSLR image from the scope - a single
21s image! It really was that cloudy!

We would have liked more but the clouds were a real pain and the scope
had a few tracking issues - we think due to balance problems. Later
on in the evening, the clouds did go away and the temperature dropped
significantly. The dome has a concrete floor which is lovely and warm
- ok, I'm lying - it's like observing in a freezer!

By the time the sky cleared, M42 had moved behind a neighbouring tree
and the opportunity was lost. A pity really as stacking a number of
these short exposures would have been interesting.

Still, considering this is only a 21 second image, it bodes well
assuming we can get the tracking sorted out.

http://www.digitalsky.org.uk/temp/15...1st_light.html



Nicely resolved Trap there Pete !

Hope it works out OK.

DH

"Pete Lawrence" wrote in message
...
After spending Tuesday night getting the recoated mirrors back into
the 15" OTA, last night it looked like we would be blessed with
wonderful clear skies.

However, on arriving at the observatory dome, the weather decided to
play up. After an amusing game of cat and mouse with cloud gaps, we
managed to get one early decent DSLR image from the scope - a single
21s image! It really was that cloudy!

We would have liked more but the clouds were a real pain and the scope
had a few tracking issues - we think due to balance problems. Later
on in the evening, the clouds did go away and the temperature dropped
significantly. The dome has a concrete floor which is lovely and warm
- ok, I'm lying - it's like observing in a freezer!

By the time the sky cleared, M42 had moved behind a neighbouring tree
and the opportunity was lost. A pity really as stacking a number of
these short exposures would have been interesting.

Still, considering this is only a 21 second image, it bodes well
assuming we can get the tracking sorted out.

http://www.digitalsky.org.uk/temp/15...1st_light.html

--
Pete
http://www.digitalsky.org.uk

Hi Pete,
As a point of reference, the bottom image (M42) on my website was taken with
a 200mm F5 reflector on a GP mount using a 300D with the IR Filter replaced
with optical glass. It's a stack of 6 images taken at ISO800 for 10 seconds.

I think it shows comparatively the benefit of the modification. Notice the
improvement in red response with the IR filter removed. Otherwise I think
our images are quite similar!! Great work!

Stephen Paul
Shun Pike Farm Observatory
http://home.comcast.net/~smarshallpaul/index.html

PS. For what it's worth, I've been enjoying your work as I also have a
Celestron/Vixen 102F9ED refractor... your work is partially responsible for
my choosing to go ahead and get the modified 300D. Thanks for publishing
your work!!.

On Fri, 4 Mar 2005 11:42:51 -0500, "Stephen Paul"
wrote:

Still, considering this is only a 21 second image, it bodes well
assuming we can get the tracking sorted out.

http://www.digitalsky.org.uk/temp/15...1st_light.html

Hi Pete,
As a point of reference, the bottom image (M42) on my website was taken with
a 200mm F5 reflector on a GP mount using a 300D with the IR Filter replaced
with optical glass. It's a stack of 6 images taken at ISO800 for 10 seconds.

I think it shows comparatively the benefit of the modification. Notice the
improvement in red response with the IR filter removed. Otherwise I think
our images are quite similar!! Great work!

Stephen Paul
Shun Pike Farm Observatory
http://home.comcast.net/~smarshallpaul/index.html

PS. For what it's worth, I've been enjoying your work as I also have a
Celestron/Vixen 102F9ED refractor... your work is partially responsible for
my choosing to go ahead and get the modified 300D. Thanks for publishing
your work!!.

Hi Stephen, glad that I've inspired someone ;-)

To be honest, I feel that the 15" was being held back because of the
sky conditions. The image I've posted has an overlay of ruddiness due
to cloud. Later in the evening, the viewfinder of my camera was
consistantly lit up with the output of the scope - it was all very
impressive and exciting.

--
Pete
http://www.digitalsky.org.uk

"Pete Lawrence" wrote in message
...
On Fri, 4 Mar 2005 11:42:51 -0500, "Stephen Paul"
wrote:

Still, considering this is only a 21 second image, it bodes well
assuming we can get the tracking sorted out.

http://www.digitalsky.org.uk/temp/15...1st_light.html

Hi Pete,
As a point of reference, the bottom image (M42) on my website was taken
with
a 200mm F5 reflector on a GP mount using a 300D with the IR Filter
replaced
with optical glass. It's a stack of 6 images taken at ISO800 for 10
seconds.

http://home.comcast.net/~smarshallpaul/index.html


To be honest, I feel that the 15" was being held back because of the
sky conditions. The image I've posted has an overlay of ruddiness due
to cloud.

Not to sound like I'm chasing this around, but mine also was taken under
average to less than average transparency. I have some 20 second and 30
second exposures, but they are awash in skyfog.

I've got another stacked image created with Registax (yes, this works for
DLSR output as well, in jpg mode anyway) that has a lot more detail in the
nebula, with a burnt out Trapezium and surrounding core. It's available on
alt.binaries.astro.pictures under the subject: ASTRO: M42 Digital
Rebel; 200mm F5 reflector

What I did here was to push all 33 images of varying ISO and exposure times
through Registax and allow the software to pick the best images to stack (16
total selected). The result was actually pretty amazing after working the
image for a while. The first image in the post, is pretty much exactly the
way it came out of Regsitax after applying some color balancing. The second
image is a crop of the first, with some additional contrast, brightness, and
gamma correction, and then pushed through Neat Image, to clean up some of
the noise. IIRC, I also did a reduction in Adobe PhotoDeluxe Home Edition,
which came with my Minolta Digicam.

Everyone is welcome to go take a look. I've yet to put this one on my
website, which has limited storage right now, and is really just in infancy.

Anyway, Enjoy!
Stephen Paul
Shirley, MA