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Main
Date: 08 Sep 2007 07:40:02
From: Anthony Ayiomamitis
Subject: NGC 7635 - Bubble Nebula in Cassiopeia
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Dear group,
Last night I was privy to four hours of great transparency, great
seeing (FWHM ~1.7") and really stable temperature. I used the
opportunity to pursue the stunning Bubble Nebula in Cassiopeia. Two
additional hours of exposures had to be discarded due to high winds
and involved the one hour before and the one hour after my four-hour
window of pristine conditions.
The result from last night's effort is available at
http://www.perseus.gr/Astro-DSO-NGC-7635.htm and also includes the
best two exposures (10-min subs) from the two problematic hours used
as luminance.
For a glimpse of the result without these two additional luminance
subs and which is both smoother and richer, please see
http://www.astrovox.gr/forum/album_pic.php?pic_id=4543 .
I would love to hear which of the two versions you like the most.
Anthony.
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Date: 09 Sep 2007 13:41:21
From: atasselli@hotmail.com
Subject: Re: NGC 7635 - Bubble Nebula in Cassiopeia
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On 9 Sep, 19:21, Anthony Ayiomamitis <ayiomami...@yahoo.com > wrote:
> On Sep 9, 9:01 pm, "atasse...@hotmail.com" <atasse...@hotmail.com>
> wrote:
>
>
>
>
>
> > On 9 Sep, 13:26, Anthony Ayiomamitis <ayiomami...@yahoo.com> wrote:
>
> > > On Sep 9, 11:09 am, "atasse...@hotmail.com" <atasse...@hotmail.com>
> > > wrote:
>
> > > > On 8 Sep, 15:40, Anthony Ayiomamitis <ayiomami...@yahoo.com> wrote:
>
> > > > > Dear group,
>
> > > > > Last night I was privy to four hours of great transparency, great
> > > > > seeing (FWHM ~1.7") and really stable temperature. I used the
> > > > > opportunity to pursue the stunning Bubble Nebula in Cassiopeia. Two
> > > > > additional hours of exposures had to be discarded due to high winds
> > > > > and involved the one hour before and the one hour after my four-hour
> > > > > window of pristine conditions.
>
> > > > Given the results is hard to believe you had 1.7" seeing. Look like
> > > > more 2.7" to me, if anything. The colours rendition is rather poor and
> > > > the dark halos around the stars do not improve the picture.
>
> > > Would you have a link handy to a result with better colour rendition
> > > etc for my benefit and use?
>
> > > Thanks.
>
> > > Anthony.
>
> Andrea,
>
> > I assume what you really want is to see my stuff, isn't it?
>
> Not necessarily but one of yours is fine as well ....
>
> > There is
> > no shortage of images of ngc7635 in the net for sure...
>
> > There you go:http://www.geocities.com/andreatax/Temp/ngc7635_hargb_a_filtered_2.jpg
>
> I checked the histograms of your image against those of mine and the
> difference is in the red channel where yours is pushed (quite a bit)
> to emphasize the emission line. I did a quick adjustment so that my
> red channel would also be equally pushed and the results are VERY
> similar.
>
> I must confess I like the strong(er) emphasis of the emission line
> than what I had originally.
>
> Here is a new version using your histograms as reference:http://www.perseus.gr/Astro-DSO-NGC-7635c.htm... whereas the current
> version is available athttp://www.perseus.gr/Astro-DSO-NGC-7635b.htm
> .
>
> Thanks for the feedback!
>
> Anthony.
>
Now you have to get rid of those halos (the blue ones are really
annoying) and that yellow band around the top of the "bubble", where
the emission in Halpha is still many time stronger than that of OIII,
and you have a winner.
Best
Andrea T.
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Date: 09 Sep 2007 12:14:16
From: Anthony Ayiomamitis
Subject: Re: NGC 7635 - Bubble Nebula in Cassiopeia
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On Sep 9, 9:54 pm, AstroSketc...@gmail.com wrote:
> On Sep 8, 8:40 am, Anthony Ayiomamitis <ayiomami...@yahoo.com> wrote:
>
>
>
> > I would love to hear which of the two versions you like the most.
>
> Hi Anthony,
Hi Bill,
>
> Since you're using a refractor, it would have been interesting to see
> a third version without the diffraction spikes. Have you considered
> or tried imaging without the diffraction wires? It should be possible
Last night as well as this evening are down times due to windy
conditions. Perhaps there will be a window of opportunity tomorrow
evening.
> to add spikes (if so desired) afterwards via software. I would think
I prefer not to add something via software (such as spikes) since it
gets into the kind of manipulation which I prefer not to do (ethical
reasons). At least with the pair of strings on the dew shield, I am
affecting how the camera records something and which I consider a
lesser evil.
> it beneficial to not intentionally diffract light outside the bounds
> of celestial objects. Real diffraction affects not only stars; but
> everything else as well.
Fair enough!
>
> I (just a personal opinion) find the spikes around the brightest star
> in these two images to be somewhat overwhelming (more so than in most
> of your images) in comparison with the nebula.
Spikes add a nice touch (in my opinion) to both cluster and galaxy
images. I must rethink their presence in nebula photos.
>
> Neglecting the creation of diffraction spikes with a refractor, your
> images are very excellent indeed!
Thanks for the feedback, suggestions and thoughts ... and for the kind
words.
Anthony.
>
> Bill Greer
> To sketch is to see.
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Date: 09 Sep 2007 11:54:19
From:
Subject: Re: NGC 7635 - Bubble Nebula in Cassiopeia
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On Sep 8, 8:40 am, Anthony Ayiomamitis <ayiomami...@yahoo.com > wrote:
>
> I would love to hear which of the two versions you like the most.
>
Hi Anthony,
Since you're using a refractor, it would have been interesting to see
a third version without the diffraction spikes. Have you considered
or tried imaging without the diffraction wires? It should be possible
to add spikes (if so desired) afterwards via software. I would think
it beneficial to not intentionally diffract light outside the bounds
of celestial objects. Real diffraction affects not only stars; but
everything else as well.
I (just a personal opinion) find the spikes around the brightest star
in these two images to be somewhat overwhelming (more so than in most
of your images) in comparison with the nebula.
Neglecting the creation of diffraction spikes with a refractor, your
images are very excellent indeed!
Bill Greer
To sketch is to see.
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Date: 09 Sep 2007 11:21:41
From: Anthony Ayiomamitis
Subject: Re: NGC 7635 - Bubble Nebula in Cassiopeia
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On Sep 9, 9:01 pm, "atasse...@hotmail.com" <atasse...@hotmail.com >
wrote:
> On 9 Sep, 13:26, Anthony Ayiomamitis <ayiomami...@yahoo.com> wrote:
>
>
>
> > On Sep 9, 11:09 am, "atasse...@hotmail.com" <atasse...@hotmail.com>
> > wrote:
>
> > > On 8 Sep, 15:40, Anthony Ayiomamitis <ayiomami...@yahoo.com> wrote:
>
> > > > Dear group,
>
> > > > Last night I was privy to four hours of great transparency, great
> > > > seeing (FWHM ~1.7") and really stable temperature. I used the
> > > > opportunity to pursue the stunning Bubble Nebula in Cassiopeia. Two
> > > > additional hours of exposures had to be discarded due to high winds
> > > > and involved the one hour before and the one hour after my four-hour
> > > > window of pristine conditions.
>
> > > Given the results is hard to believe you had 1.7" seeing. Look like
> > > more 2.7" to me, if anything. The colours rendition is rather poor and
> > > the dark halos around the stars do not improve the picture.
>
> > Would you have a link handy to a result with better colour rendition
> > etc for my benefit and use?
>
> > Thanks.
>
> > Anthony.
>
Andrea,
> I assume what you really want is to see my stuff, isn't it?
Not necessarily but one of yours is fine as well ....
> There is
> no shortage of images of ngc7635 in the net for sure...
>
> There you go:http://www.geocities.com/andreatax/Temp/ngc7635_hargb_a_filtered_2.jpg
I checked the histograms of your image against those of mine and the
difference is in the red channel where yours is pushed (quite a bit)
to emphasize the emission line. I did a quick adjustment so that my
red channel would also be equally pushed and the results are VERY
similar.
I must confess I like the strong(er) emphasis of the emission line
than what I had originally.
Here is a new version using your histograms as reference:
http://www.perseus.gr/Astro-DSO-NGC-7635c.htm ... whereas the current
version is available at http://www.perseus.gr/Astro-DSO-NGC-7635b.htm
.
Thanks for the feedback!
Anthony.
>
> Andrea T.
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Date: 09 Sep 2007 11:01:33
From: atasselli@hotmail.com
Subject: Re: NGC 7635 - Bubble Nebula in Cassiopeia
|
On 9 Sep, 13:26, Anthony Ayiomamitis <ayiomami...@yahoo.com > wrote:
> On Sep 9, 11:09 am, "atasse...@hotmail.com" <atasse...@hotmail.com>
> wrote:
>
> > On 8 Sep, 15:40, Anthony Ayiomamitis <ayiomami...@yahoo.com> wrote:
>
> > > Dear group,
>
> > > Last night I was privy to four hours of great transparency, great
> > > seeing (FWHM ~1.7") and really stable temperature. I used the
> > > opportunity to pursue the stunning Bubble Nebula in Cassiopeia. Two
> > > additional hours of exposures had to be discarded due to high winds
> > > and involved the one hour before and the one hour after my four-hour
> > > window of pristine conditions.
>
> > Given the results is hard to believe you had 1.7" seeing. Look like
> > more 2.7" to me, if anything. The colours rendition is rather poor and
> > the dark halos around the stars do not improve the picture.
>
> Would you have a link handy to a result with better colour rendition
> etc for my benefit and use?
>
> Thanks.
>
> Anthony.
>
I assume what you really want is to see my stuff, isn't it? There is
no shortage of images of ngc7635 in the net for sure...
There you go:
http://www.geocities.com/andreatax/Temp/ngc7635_hargb_a_filtered_2.jpg
Andrea T.
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Date: 09 Sep 2007 05:26:03
From: Anthony Ayiomamitis
Subject: Re: NGC 7635 - Bubble Nebula in Cassiopeia
|
On Sep 9, 11:09 am, "atasse...@hotmail.com" <atasse...@hotmail.com >
wrote:
> On 8 Sep, 15:40, Anthony Ayiomamitis <ayiomami...@yahoo.com> wrote:
>
> > Dear group,
>
> > Last night I was privy to four hours of great transparency, great
> > seeing (FWHM ~1.7") and really stable temperature. I used the
> > opportunity to pursue the stunning Bubble Nebula in Cassiopeia. Two
> > additional hours of exposures had to be discarded due to high winds
> > and involved the one hour before and the one hour after my four-hour
> > window of pristine conditions.
>
> Given the results is hard to believe you had 1.7" seeing. Look like
> more 2.7" to me, if anything. The colours rendition is rather poor and
> the dark halos around the stars do not improve the picture.
Would you have a link handy to a result with better colour rendition
etc for my benefit and use?
Thanks.
Anthony.
>
> Andrea T.
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Date: 09 Sep 2007 01:09:09
From: atasselli@hotmail.com
Subject: Re: NGC 7635 - Bubble Nebula in Cassiopeia
|
On 8 Sep, 15:40, Anthony Ayiomamitis <ayiomami...@yahoo.com > wrote:
> Dear group,
>
> Last night I was privy to four hours of great transparency, great
> seeing (FWHM ~1.7") and really stable temperature. I used the
> opportunity to pursue the stunning Bubble Nebula in Cassiopeia. Two
> additional hours of exposures had to be discarded due to high winds
> and involved the one hour before and the one hour after my four-hour
> window of pristine conditions.
Given the results is hard to believe you had 1.7" seeing. Look like
more 2.7" to me, if anything. The colours rendition is rather poor and
the dark halos around the stars do not improve the picture.
Andrea T.
|
| |
Date: 08 Sep 2007 13:06:19
From: Ben
Subject: Re: NGC 7635 - Bubble Nebula in Cassiopeia
|
>http://www.astrovox.gr/forum/album_pic.php?pic_id=4543.
>
> > I would love to hear which of the two versions you like the most.
Anthony,
I like the first one because the star points seem a bit sharper
and the point which may be the central star shows a bit better.
Either /or - It's really great work.
Ben
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Date: 08 Sep 2007 11:07:34
From: AM
Subject: Re: NGC 7635 - Bubble Nebula in Cassiopeia
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Anthony Ayiomamitis wrote:
> Dear group,
>
> Last night I was privy to four hours of great transparency, great
> seeing (FWHM ~1.7") and really stable temperature. I used the
> opportunity to pursue the stunning Bubble Nebula in Cassiopeia. Two
> additional hours of exposures had to be discarded due to high winds
> and involved the one hour before and the one hour after my four-hour
> window of pristine conditions.
>
> The result from last night's effort is available at
> http://www.perseus.gr/Astro-DSO-NGC-7635.htm and also includes the
> best two exposures (10-min subs) from the two problematic hours used
> as luminance.
>
> For a glimpse of the result without these two additional luminance
> subs and which is both smoother and richer, please see
> http://www.astrovox.gr/forum/album_pic.php?pic_id=4543 .
>
> I would love to hear which of the two versions you like the most.
>
> Anthony.
>
I preffer the second one, if for nothing else
it is smoother like you say.
--
AM
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