Anthony Ayiomamitis

Dear friends,

Perhaps the oldest open cluster in our galaxy is NGC 6791 in Lyra which
has been estimated by Salaris (2004) to be 10.2 billion years old (ie.
about 80% the age of the universe). For an image of this galactic
survivor taken early this morning and under volatile seeing, please see
http://www.perseus.gr/Astro-DSO-NGC-6791.htm .

Clear skies!

Anthony.

Sam Wormley

Anthony Ayiomamitis wrote:
> Dear friends,
>
> Perhaps the oldest open cluster in our galaxy is NGC 6791 in Lyra which
> has been estimated by Salaris (2004) to be 10.2 billion years old (ie.
> about 80% the age of the universe). For an image of this galactic
> survivor taken early this morning and under volatile seeing, please see
> http://www.perseus.gr/Astro-DSO-NGC-6791.htm .
>
> Clear skies!
>
> Anthony.

Thanks Anthony!
-Sam

Sam Wormley

Anthony Ayiomamitis wrote:
> Dear friends,
>
> Perhaps the oldest open cluster in our galaxy is NGC 6791 in Lyra which
> has been estimated by Salaris (2004) to be 10.2 billion years old (ie.
> about 80% the age of the universe). For an image of this galactic
> survivor taken early this morning and under volatile seeing, please see
> http://www.perseus.gr/Astro-DSO-NGC-6791.htm .
>
> Clear skies!
>
> Anthony.

Thanks Anthony!
-Sam

William R. Mattil

Anthony Ayiomamitis wrote:
> Dear friends,
>
> Perhaps the oldest open cluster in our galaxy is NGC 6791 in Lyra which
> has been estimated by Salaris (2004) to be 10.2 billion years old (ie.
> about 80% the age of the universe). For an image of this galactic
> survivor taken early this morning and under volatile seeing, please see
> http://www.perseus.gr/Astro-DSO-NGC-6791.htm .
>

Anthony,

Refractors don't have diffraction spikes

Bill

William R. Mattil

Anthony Ayiomamitis wrote:
> Dear friends,
>
> Perhaps the oldest open cluster in our galaxy is NGC 6791 in Lyra which
> has been estimated by Salaris (2004) to be 10.2 billion years old (ie.
> about 80% the age of the universe). For an image of this galactic
> survivor taken early this morning and under volatile seeing, please see
> http://www.perseus.gr/Astro-DSO-NGC-6791.htm .
>

Anthony,

Refractors don't have diffraction spikes

Bill

Anthony Ayiomamitis

William R. Mattil wrote:
> Anthony Ayiomamitis wrote:
>
>> Dear friends,
>>
>> Perhaps the oldest open cluster in our galaxy is NGC 6791 in Lyra
>> which has been estimated by Salaris (2004) to be 10.2 billion years
>> old (ie. about 80% the age of the universe). For an image of this
>> galactic survivor taken early this morning and under volatile seeing,
>> please see http://www.perseus.gr/Astro-DSO-NGC-6791.htm .
>>
>
> Anthony,

Hi Bill,

>
> Refractors don't have diffraction spikes

They were added with the help of a pair of strings for the purposes of
this imaging project and purely for aesthetic purposes. ;-) :-)

Anthony.

>
> Bill

Anthony Ayiomamitis

William R. Mattil wrote:
> Anthony Ayiomamitis wrote:
>
>> Dear friends,
>>
>> Perhaps the oldest open cluster in our galaxy is NGC 6791 in Lyra
>> which has been estimated by Salaris (2004) to be 10.2 billion years
>> old (ie. about 80% the age of the universe). For an image of this
>> galactic survivor taken early this morning and under volatile seeing,
>> please see http://www.perseus.gr/Astro-DSO-NGC-6791.htm .
>>
>
> Anthony,

Hi Bill,

>
> Refractors don't have diffraction spikes

They were added with the help of a pair of strings for the purposes of
this imaging project and purely for aesthetic purposes. ;-) :-)

Anthony.

>
> Bill

Ben

On May 17, 4:29 pm, Anthony Ayiomamitis <anth...@perseus.no2spam.gr>
wrote:
> William R. Mattil wrote:
> > Anthony Ayiomamitis wrote:
>
> >> Dear friends,
>
> >> Perhaps the oldest open cluster in our galaxy is NGC 6791 in Lyra
> >> which has been estimated by Salaris (2004) to be 10.2 billion years
> >> old (ie. about 80% the age of the universe). For an image of this
> >> galactic survivor taken early this morning and under volatile seeing,
> >> please seehttp://www.perseus.gr/Astro-DSO-NGC-6791.htm.
>
> > Anthony,
>
> Hi Bill,
>
>
>
> > Refractors don't have diffraction spikes
>
> They were added with the help of a pair of strings for the purposes of
> this imaging project and purely for aesthetic purposes. ;-) :-)
>
> Anthony.
>
>
>
>
>
> > Bill- Hide quoted text -
>
> - Show quoted text -

Antoni,

Excellent capture of my old nemesis. To date I have only resolved
one star here and that is U Lyrae and I am completely confident
that it is not part of the cluster.

I noticed on your high resolution image the foreground stars seem
to take on a light green color. You can get the same sort of effect
playing around with ALADIN images by manipulating the color
channels. This could be a potentially useful device for eliminating
the background / foreground contamination which is a problem
in many open clusters. (compare NGC 7789).

What do you think?

Ben

Ben

On May 17, 4:29 pm, Anthony Ayiomamitis <anth...@perseus.no2spam.gr>
wrote:
> William R. Mattil wrote:
> > Anthony Ayiomamitis wrote:
>
> >> Dear friends,
>
> >> Perhaps the oldest open cluster in our galaxy is NGC 6791 in Lyra
> >> which has been estimated by Salaris (2004) to be 10.2 billion years
> >> old (ie. about 80% the age of the universe). For an image of this
> >> galactic survivor taken early this morning and under volatile seeing,
> >> please seehttp://www.perseus.gr/Astro-DSO-NGC-6791.htm.
>
> > Anthony,
>
> Hi Bill,
>
>
>
> > Refractors don't have diffraction spikes
>
> They were added with the help of a pair of strings for the purposes of
> this imaging project and purely for aesthetic purposes. ;-) :-)
>
> Anthony.
>
>
>
>
>
> > Bill- Hide quoted text -
>
> - Show quoted text -

Antoni,

Excellent capture of my old nemesis. To date I have only resolved
one star here and that is U Lyrae and I am completely confident
that it is not part of the cluster.

I noticed on your high resolution image the foreground stars seem
to take on a light green color. You can get the same sort of effect
playing around with ALADIN images by manipulating the color
channels. This could be a potentially useful device for eliminating
the background / foreground contamination which is a problem
in many open clusters. (compare NGC 7789).

What do you think?

Ben

Anthony Ayiomamitis

Ben wrote:
> On May 17, 4:29 pm, Anthony Ayiomamitis <anth...@perseus.no2spam.gr>
> wrote:
>
>>William R. Mattil wrote:
>>
>>>Anthony Ayiomamitis wrote:
>>
>>>>Dear friends,
>>

<snip>

>>
>>
>
> Antoni,

Hi Ben,

>
> Excellent capture of my old nemesis. To date I have only resolved
> one star here and that is U Lyrae and I am completely confident
> that it is not part of the cluster.
>

This DSO has been on my list of targets for some time and it is now
getting into position. I must revisit it, for the result could be better.

> I noticed on your high resolution image the foreground stars seem
> to take on a light green color. You can get the same sort of effect
> playing around with ALADIN images by manipulating the color
> channels. This could be a potentially useful device for eliminating
> the background / foreground contamination which is a problem
> in many open clusters. (compare NGC 7789).
>
> What do you think?

My seeing last night was volatile with differing FWHM between sets of
images. The night started out well when capturing the luminance portion
but things degraded thereafter with the blue being impacted the most.

I was debating about posting the result since it is not exactly where I
want it to be. However, it is a baseline image and which I will build
upon shortly with a follow-up image at the first opportunity.

In fact I had a slightly different problem with M92 (also from last
night) and which I purposely did not post. Anyway, since the cat is now
out of the bag, here you go:
http://www.perseus.gr/Astro-DSO-NGC-6341.htm ... this one will also
require a repeat visit.

Anthony.

>
> Ben
>
>

Anthony Ayiomamitis

Ben wrote:
> On May 17, 4:29 pm, Anthony Ayiomamitis <anth...@perseus.no2spam.gr>
> wrote:
>
>>William R. Mattil wrote:
>>
>>>Anthony Ayiomamitis wrote:
>>
>>>>Dear friends,
>>

<snip>

>>
>>
>
> Antoni,

Hi Ben,

>
> Excellent capture of my old nemesis. To date I have only resolved
> one star here and that is U Lyrae and I am completely confident
> that it is not part of the cluster.
>

This DSO has been on my list of targets for some time and it is now
getting into position. I must revisit it, for the result could be better.

> I noticed on your high resolution image the foreground stars seem
> to take on a light green color. You can get the same sort of effect
> playing around with ALADIN images by manipulating the color
> channels. This could be a potentially useful device for eliminating
> the background / foreground contamination which is a problem
> in many open clusters. (compare NGC 7789).
>
> What do you think?

My seeing last night was volatile with differing FWHM between sets of
images. The night started out well when capturing the luminance portion
but things degraded thereafter with the blue being impacted the most.

I was debating about posting the result since it is not exactly where I
want it to be. However, it is a baseline image and which I will build
upon shortly with a follow-up image at the first opportunity.

In fact I had a slightly different problem with M92 (also from last
night) and which I purposely did not post. Anyway, since the cat is now
out of the bag, here you go:
http://www.perseus.gr/Astro-DSO-NGC-6341.htm ... this one will also
require a repeat visit.

Anthony.

>
> Ben
>
>

Ben

<snip snip snip>
> In fact I had a slightly different problem with M92 (also from last
> night) and which I purposely did not post. Anyway, since the cat is now
> out of the bag, here you go:http://www.perseus.gr/Astro-DSO-NGC-6341.htm... this one will also
> require a repeat visit.
>
> Anthony.

That's really interesting. Is it a problem on the blue channel
or are you picking up on authentic spectral information?

One used to expect a certain homogenous distribution of
spectral classes in the globulars but this has proven to
be not necessarily the case. I doubt those are "blue
stragglers". Why then the blue tint in those particular
stars? Requires repeated visits....

Ben

Ben

<snip snip snip>
> In fact I had a slightly different problem with M92 (also from last
> night) and which I purposely did not post. Anyway, since the cat is now
> out of the bag, here you go:http://www.perseus.gr/Astro-DSO-NGC-6341.htm... this one will also
> require a repeat visit.
>
> Anthony.

That's really interesting. Is it a problem on the blue channel
or are you picking up on authentic spectral information?

One used to expect a certain homogenous distribution of
spectral classes in the globulars but this has proven to
be not necessarily the case. I doubt those are "blue
stragglers". Why then the blue tint in those particular
stars? Requires repeated visits....

Ben

Ben

<snip snip snip>
> In fact I had a slightly different problem with M92 (also from last
> night) and which I purposely did not post. Anyway, since the cat is now
> out of the bag, here you go:http://www.perseus.gr/Astro-DSO-NGC-6341.htm... this one will also
> require a repeat visit.
>
> Anthony.

That's really interesting. Is it a problem on the blue channel
or are you picking up on authentic spectral information?

One used to expect a certain homogenous distribution of
spectral classes in the globulars but this has proven to
be not necessarily the case. I doubt those are "blue
stragglers". Why then the blue tint in those particular
stars? Requires repeated visits....

Ben

Ben

<snip snip snip>
> In fact I had a slightly different problem with M92 (also from last
> night) and which I purposely did not post. Anyway, since the cat is now
> out of the bag, here you go:http://www.perseus.gr/Astro-DSO-NGC-6341.htm... this one will also
> require a repeat visit.
>
> Anthony.

That's really interesting. Is it a problem on the blue channel
or are you picking up on authentic spectral information?

One used to expect a certain homogenous distribution of
spectral classes in the globulars but this has proven to
be not necessarily the case. I doubt those are "blue
stragglers". Why then the blue tint in those particular
stars? Requires repeated visits....

Ben

Anthony Ayiomamitis

Ben wrote:
> <snip snip snip>
>
>>In fact I had a slightly different problem with M92 (also from last
>>night) and which I purposely did not post. Anyway, since the cat is now
>>out of the bag, here you go:http://www.perseus.gr/Astro-DSO-NGC-6341.htm... this one will also
>>require a repeat visit.
>>
>>Anthony.
>
>
> That's really interesting. Is it a problem on the blue channel
> or are you picking up on authentic spectral information?

What is very odd is that the histograms are perfectly matched and, as
such, I cannot explain the blue tint. I also corrected for the
differential QE of the camera between R, G and B as well as atmospheric
extinction.

>
> One used to expect a certain homogenous distribution of
> spectral classes in the globulars but this has proven to
> be not necessarily the case. I doubt those are "blue
> stragglers". Why then the blue tint in those particular
> stars? Requires repeated visits....

I have a second CCD camera coming (SBIG ST-10XME) and I am interested to
see if it also behaves the same.

Anthony.

>
> Ben
>

Anthony Ayiomamitis

Ben wrote:
> <snip snip snip>
>
>>In fact I had a slightly different problem with M92 (also from last
>>night) and which I purposely did not post. Anyway, since the cat is now
>>out of the bag, here you go:http://www.perseus.gr/Astro-DSO-NGC-6341.htm... this one will also
>>require a repeat visit.
>>
>>Anthony.
>
>
> That's really interesting. Is it a problem on the blue channel
> or are you picking up on authentic spectral information?

What is very odd is that the histograms are perfectly matched and, as
such, I cannot explain the blue tint. I also corrected for the
differential QE of the camera between R, G and B as well as atmospheric
extinction.

>
> One used to expect a certain homogenous distribution of
> spectral classes in the globulars but this has proven to
> be not necessarily the case. I doubt those are "blue
> stragglers". Why then the blue tint in those particular
> stars? Requires repeated visits....

I have a second CCD camera coming (SBIG ST-10XME) and I am interested to
see if it also behaves the same.

Anthony.

>
> Ben
>