Sh2-176 - Planetary Nebula in Cas

Dear group,

I finally sat down to process Sh2-176 which was shot earlier this
month. Strange as it may seem, I could only find two other images of
this dim planetary nebula on the internet.

For my result based on nine hours total exposure time (HaLRGB @
300:60:60:60:60), please see http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-176b.htm
with details and background information available at
http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-176.htm .

I hope to reshoot this one late summer next year and hopefully under
much better seeing so as to have smaller disks for the brighter stars.
The transparency also could have been slightly better.

Anthony.

On 11/21/10 6:38 AM, Anthony Ayiomamitis wrote:
Dear group,

I finally sat down to process Sh2-176 which was shot earlier this
month. Strange as it may seem, I could only find two other images of
this dim planetary nebula on the internet.

For my result based on nine hours total exposure time (HaLRGB @
300:60:60:60:60), please see http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-176b.htm
with details and background information available at
http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-176.htm .

I hope to reshoot this one late summer next year and hopefully under
much better seeing so as to have smaller disks for the brighter stars.
The transparency also could have been slightly better.

Anthony.

Thank you Anthony!
-Sam

Anthony Ayiomamitis wrote:

Dear group,

I finally sat down to process Sh2-176 which was shot earlier this
month. Strange as it may seem, I could only find two other images of
this dim planetary nebula on the internet.

For my result based on nine hours total exposure time (HaLRGB @
300:60:60:60:60), please see
http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-176b.htm
with details and background information available at
http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-176.htm .

I hope to reshoot this one late summer next year and hopefully under
much better seeing so as to have smaller disks for the brighter stars.
The transparency also could have been slightly better.

Anthony.

That's a great photo of -- as you note -- a seldom-seen object. I tried
it with my Tak 150 some time ago but I was defeated by the weather.
It's on my list for next year, as well.

I see you got nine hours of integration over four nights. That blows my
mind. I would be grateful for nine hours in six months! You were
operating at 1.16 arc sec per pixel, while I would be at 1.7 arc
sec/pixel with my setup (FL 1090mm, STL w. 9 micron pixels).
Hypothetically--but only hypothetically until proven--I could expect a
result similar to yours.

Very nice.

davoud

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm

On 21 Î�οÎ*, 20:25, Davoud wrote:
Anthony Ayiomamitis wrote:
Dear group,

I finally sat down to process Sh2-176 which was shot earlier this
month. Strange as it may seem, I could only find two other images of
this dim planetary nebula on the internet.

For my result based on nine hours total exposure time (HaLRGB @
300:60:60:60:60), please see
http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-176b.htm
with details and background information available at
http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-176.htm.

I hope to reshoot this one late summer next year and hopefully under
much better seeing so as to have smaller disks for the brighter stars.
The transparency also could have been slightly better.

Anthony.

That's a great photo of -- as you note -- a seldom-seen object. I tried
it with my Tak 150 some time ago but I was defeated by the weather.
It's on my list for next year, as well.

I see you got nine hours of integration over four nights. That blows my
mind. I would be grateful for nine hours in six months! You were
operating at 1.16 arc sec per pixel, while I would be at 1.7 arc
sec/pixel with my setup (FL 1090mm, STL w. 9 micron pixels).
Hypothetically--but only hypothetically until proven--I could expect a
result similar to yours.

Very nice.

davoud

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm

David,

Please note that it was captured over TWO evenings ... Oct 31-Nov 1
and Nov 1-2 ...

I also have another equally dim and challenging planetary (Sh2-188 in
Cas) but the subs were taken at -30d C and I am waiting for cold(er)
evenings to shoot new master darks (at -30d C). As a result, I cannot
process the data for now. However, here is a teaser taken a few weeks
ago: http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-188.htm .

My Astro-Physics Riccardi-Honders astrograph arrived on Friday ... get
ready for some very exotic work. :-)

Anthony.

Davoud:

I see you got nine hours of integration over four nights. That blows my
mind. I would be grateful for nine hours in six months!

Anthony Ayiomamitis:
David,

Please note that it was captured over TWO evenings ... Oct 31-Nov 1
and Nov 1-2 ...

Aaaargh!

I also have another equally dim and challenging planetary (Sh2-188 in
Cas) but the subs were taken at -30d C and I am waiting for cold(er)
evenings to shoot new master darks (at -30d C). As a result, I cannot
process the data for now. However, here is a teaser taken a few weeks
ago: http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-188.htm .

Consider me teased! I have found that if I don't get the darks on the
same evening as the subs they don't always work as well at removing
chip defects. Another person has told me that he has the same
experience. I can only think that it is temperature related. So now
after I finish all of my light frames I park the A-P and turn it off
and cap the 'scope but I leave the camera on, set the software to take
a bunch of darks, then darken and lock up the observatory and go to
bed. Seems to work better that way.

My Astro-Physics Riccardi-Honders astrograph arrived on Friday ... get
ready for some very exotic work. :-)

Congratulations on the new 'scope! I drooled on one at NEAF. Use it in
good health!

Davoud

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm

On 22 ÍïÝ, 06:00, Davoud wrote:
Davoud:

I see you got nine hours of integration over four nights. That blows my
mind. I would be grateful for nine hours in six months!

Anthony Ayiomamitis:

David,

Please note that it was captured over TWO evenings ... Oct 31-Nov 1
and Nov 1-2 ...

Aaaargh!

I also have another equally dim and challenging planetary (Sh2-188 in
Cas) but the subs were taken at -30d C and I am waiting for cold(er)
evenings to shoot new master darks (at -30d C). As a result, I cannot
process the data for now. However, here is a teaser taken a few weeks
ago:http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-188.htm.

Consider me teased! I have found that if I don't get the darks on the
same evening as the subs they don't always work as well at removing
chip defects. Another person has told me that he has the same
experience. I can only think that it is temperature related. So now
after I finish all of my light frames I park the A-P and turn it off
and cap the 'scope but I leave the camera on, set the software to take
a bunch of darks, then darken and lock up the observatory and go to
bed. Seems to work better that way.

My Astro-Physics Riccardi-Honders astrograph arrived on Friday ... get
ready for some very exotic work. *:-)

Congratulations on the new 'scope! I drooled on one at NEAF. Use it in
good health!

Davoud

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm

David,

I regenerate my master darks once a month using 15 individual subs
(ex. 15x20' @ -25d - master dark for 20' @ -25d). A few weeks ago we
had a couple of evenings which were much colder than usual and when I
just happened to image Sh2-188 in Cas. However, once the temperatures
returned to normal (and in fact we have been above normal for some
time), I got caught in the trap of not having a sufficiently low
ambient temperature at night to drop the CCD camera down to -30d C
and, hence, for the delay in processing my results.

The only trouble I have experienced with dark frames is on the two
occasions I gave dark scaling a shot. I was very disappointed at the
results on both occasions and I swore never again. Each month and
around full moon (and/or on overcast days), I will produce fresh
master darks for 3-, 6-, 10-, 20- and 30-min subs using 2.5d C
intervals for the typical night time temps of the season (ex. -20d C,
-22.5d C, -25d C for right now).

I have also done some testing and there is relatively little gain once
we are down to -20d C (ex. -20d C vs -25d C) but I go ahead anyway
just to be safe.

Finally, I looked into the age of the master darks. I can easily get
away with using the same master dark for a couple of months but I
regenerate them every month as a precautionary measure.

Anthony.

On 11/22/10 7:05 AM, Anthony Ayiomamitis wrote:
On 22 Î�οÎ*, 06:00, wrote:
Davoud:

I see you got nine hours of integration over four nights. That blows my
mind. I would be grateful for nine hours in six months!

Anthony Ayiomamitis:

David,

Please note that it was captured over TWO evenings ... Oct 31-Nov 1
and Nov 1-2 ...

Aaaargh!

I also have another equally dim and challenging planetary (Sh2-188 in
Cas) but the subs were taken at -30d C and I am waiting for cold(er)
evenings to shoot new master darks (at -30d C). As a result, I cannot
process the data for now. However, here is a teaser taken a few weeks
ago:http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-188.htm.

Consider me teased! I have found that if I don't get the darks on the
same evening as the subs they don't always work as well at removing
chip defects. Another person has told me that he has the same
experience. I can only think that it is temperature related. So now
after I finish all of my light frames I park the A-P and turn it off
and cap the 'scope but I leave the camera on, set the software to take
a bunch of darks, then darken and lock up the observatory and go to
bed. Seems to work better that way.

My Astro-Physics Riccardi-Honders astrograph arrived on Friday ... get
ready for some very exotic work. :-)

Congratulations on the new 'scope! I drooled on one at NEAF. Use it in
good health!

Davoud

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm

David,

I regenerate my master darks once a month using 15 individual subs
(ex. 15x20' @ -25d - master dark for 20' @ -25d). A few weeks ago we
had a couple of evenings which were much colder than usual and when I
just happened to image Sh2-188 in Cas. However, once the temperatures
returned to normal (and in fact we have been above normal for some
time), I got caught in the trap of not having a sufficiently low
ambient temperature at night to drop the CCD camera down to -30d C
and, hence, for the delay in processing my results.

The only trouble I have experienced with dark frames is on the two
occasions I gave dark scaling a shot. I was very disappointed at the
results on both occasions and I swore never again. Each month and
around full moon (and/or on overcast days), I will produce fresh
master darks for 3-, 6-, 10-, 20- and 30-min subs using 2.5d C
intervals for the typical night time temps of the season (ex. -20d C,
-22.5d C, -25d C for right now).

I have also done some testing and there is relatively little gain once
we are down to -20d C (ex. -20d C vs -25d C) but I go ahead anyway
just to be safe.

Finally, I looked into the age of the master darks. I can easily get
away with using the same master dark for a couple of months but I
regenerate them every month as a precautionary measure.

Anthony.

Thanks Anthony -- Nice to understand those details.
-Sam

On 22 Î�οÎ*, 16:05, Sam Wormley wrote:
On 11/22/10 7:05 AM, Anthony Ayiomamitis wrote:





On 22 Î�οÎ*, 06:00, Â*wrote:
Davoud:

I see you got nine hours of integration over four nights. That blows my
mind. I would be grateful for nine hours in six months!

Anthony Ayiomamitis:

David,

Please note that it was captured over TWO evenings ... Oct 31-Nov 1
and Nov 1-2 ...

Aaaargh!

I also have another equally dim and challenging planetary (Sh2-188 in
Cas) but the subs were taken at -30d C and I am waiting for cold(er)
evenings to shoot new master darks (at -30d C). As a result, I cannot
process the data for now. However, here is a teaser taken a few weeks
ago:http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-188.htm.

Consider me teased! I have found that if I don't get the darks on the
same evening as the subs they don't always work as well at removing
chip defects. Another person has told me that he has the same
experience. I can only think that it is temperature related. So now
after I finish all of my light frames I park the A-P and turn it off
and cap the 'scope but I leave the camera on, set the software to take
a bunch of darks, then darken and lock up the observatory and go to
bed. Seems to work better that way.

My Astro-Physics Riccardi-Honders astrograph arrived on Friday ... get
ready for some very exotic work. Â*:-)

Congratulations on the new 'scope! I drooled on one at NEAF. Use it in
good health!

Davoud

--
I agree with almost everything that you have said and almost everything that
you will say in your entire life.

usenet *at* davidillig dawt cawm

David,

I regenerate my master darks once a month using 15 individual subs
(ex. 15x20' @ -25d - Â*master dark for 20' @ -25d). A few weeks ago we
had a couple of evenings which were much colder than usual and when I
just happened to image Sh2-188 in Cas. However, once the temperatures
returned to normal (and in fact we have been above normal for some
time), I got caught in the trap of not having a sufficiently low
ambient temperature at night to drop the CCD camera down to -30d C
and, hence, for the delay in processing my results.

The only trouble I have experienced with dark frames is on the two
occasions I gave dark scaling a shot. I was very disappointed at the
results on both occasions and I swore never again. Each month and
around full moon (and/or on overcast days), I will produce fresh
master darks for 3-, 6-, 10-, 20- and 30-min subs using 2.5d C
intervals for the typical night time temps of the season (ex. -20d C,
-22.5d C, -25d C for right now).

I have also done some testing and there is relatively little gain once
we are down to -20d C (ex. -20d C vs -25d C) but I go ahead anyway
just to be safe.

Finally, I looked into the age of the master darks. I can easily get
away with using the same master dark for a couple of months but I
regenerate them every month as a precautionary measure.

Anthony.

Â* Â*Thanks Anthony -- Nice to understand those details.
Â* -Sam

My pleasure, Sam!

Anthony.

On Nov 21, 3:30*pm, Anthony Ayiomamitis wrote:

Please note that it was captured over TWO evenings ... Oct 31-Nov 1
and Nov 1-2 ...

I also have another equally dim and challenging planetary (Sh2-188 in
Cas) but the subs were taken at -30d C and I am waiting for cold(er)
evenings to shoot new master darks (at -30d C). As a result, I cannot
process the data for now. However, here is a teaser taken a few weeks
ago:http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-188.htm.

Hi Anthony,

That is an excellent image of Sh2-188. What is that faint circular
object in the bottom left corner?

Rolando

On 22 nov, 18:13, uncarollo wrote:
On Nov 21, 3:30*pm, Anthony Ayiomamitis wrote:

Please note that it was captured over TWO evenings ... Oct 31-Nov 1
and Nov 1-2 ...

I also have another equally dim and challenging planetary (Sh2-188 in
Cas) but the subs were taken at -30d C and I am waiting for cold(er)
evenings to shoot new master darks (at -30d C). As a result, I cannot
process the data for now. However, here is a teaser taken a few weeks
ago:http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-188.htm.

Hi Anthony,

That is an excellent image of Sh2-188. What is that faint circular
object in the bottom left corner?

Rolando

looks like the glare of SAO 22389