M48/NGC 2548 - Great seeing but poor transparency

I reckon in the 6 weeks of owning my new scope, I have managed to get out
about 6 times.......not sure how to 'measure' transparency, clearness, etc
but suffice to say IMHO the skies have been pretty awful and even when I can
see stars theres that high level alto and cirro stratus which is just great
combined with LP.......I am glad I didnt break the bank and get a SCT on
credit........with the amount of use it wouldve got I would be feeling
pretty bad with a young family to spend my hard earned £s on.......

Still I hold out hope that soon I will be able to get a cloud free night sky
and drive to the Highlands of Scotland for some perfect dark skies......or
even just up the road to northern Angus for some 'almost' dark skies

--
M
------
"Any society that would give up a little liberty to gain a little security
will deserve neither and lose both."
[Benjamin Franklin]

"War is delightful to those who have had no experience of it."
[Erasmus]

"A collision at sea can ruin your entire day."
[Thucydides]

"Andy Hewitt" wrote in message
news:1htyh47.1out64zl7rnhoN%wildrover.andy@googlem ail.com...
Anthony Ayiomamitis wrote:

Hi Andy,

Hi Anthony

Nice pic. It's just not fair that I can't get them like that!

I have produced much better results under better transparency.

Indeed, I just know I haven't the equipment to start with anyway.

The viewing of late has been appalling hasn't it? I got a new 150mm Dob
last week, and my 105mm Mak arrived yesterday. I reckon I've got about
2
hours viewing in the last two weeks.


It seems every winter is worse than the previous one. This winter in
particular has been very atypical for us in the southeastern
Mediterranean who usually enjoy very good weather year-round.

That's more worrying than ever, I'm actually replying in the uk.s.a.
group, and posting from the north east of England. Doesn't hold much
hope for us here if you can't get a clear sky down there :-(

--
Andy Hewitt
http://web.mac.com/andrewhewitt1/

Starboard wrote:

Great shot. I'd like to see more.

Go wild: http://www.perseus.gr/Astro-DSO-Clust-Open.htm ... one or two
of the images are very bad due to bad seeing and will be reimaged during
the first available opportunity.


Thanks,.

Me too.

Anthony.


Errol
www.pasnola.org

M wrote:

I reckon in the 6 weeks of owning my new scope, I have managed to get out
about 6 times.......not sure how to 'measure' transparency, clearness, etc
but suffice to say IMHO the skies have been pretty awful and even when I can
see stars theres that high level alto and cirro stratus which is just great
combined with LP.......I am glad I didnt break the bank and get a SCT on
credit........with the amount of use it wouldve got I would be feeling
pretty bad with a young family to spend my hard earned £s on.......

Still I hold out hope that soon I will be able to get a cloud free night sky
and drive to the Highlands of Scotland for some perfect dark skies......or
even just up the road to northern Angus for some 'almost' dark skies


Spring and summer are not too far away. Patience as usual.

My primary concern is next weekend and the red object which will grace
the sky for about 75 minutes. Let's keep our fingers crossed that the
weather will do us a (huge) favour.

Anthony.

M wrote:

I reckon in the 6 weeks of owning my new scope, I have managed to get out
about 6 times.......not sure how to 'measure' transparency, clearness, etc
but suffice to say IMHO the skies have been pretty awful and even when I can
see stars theres that high level alto and cirro stratus which is just great
combined with LP.......I am glad I didnt break the bank and get a SCT on
credit........with the amount of use it wouldve got I would be feeling
pretty bad with a young family to spend my hard earned £s on.......

Yes, much the same here really, I usually measure the clarity of viewing
by seeing how much 'twinkle' the stars have (when I can see them at all
that is). It's also why I decided to set a maximum budget for the
scopes, I could easily have spent more, but didn't see the point.

--
Andy Hewitt
http://web.mac.com/andrewhewitt1/

Anthony Ayiomamitis wrote:

M wrote:

I reckon in the 6 weeks of owning my new scope, I have managed to get out
about 6 times.......not sure how to 'measure' transparency, clearness, etc
but suffice to say IMHO the skies have been pretty awful and even when I can
see stars theres that high level alto and cirro stratus which is just great
combined with LP.......I am glad I didnt break the bank and get a SCT on
credit........with the amount of use it wouldve got I would be feeling
pretty bad with a young family to spend my hard earned £s on.......

Still I hold out hope that soon I will be able to get a cloud free night sky
and drive to the Highlands of Scotland for some perfect dark skies......or
even just up the road to northern Angus for some 'almost' dark skies


Spring and summer are not too far away. Patience as usual.

Indeed, although in mid-summer the sky doesn't really get quite dark
enough for ideal viewing, and you do tend to get a lot more pollution in
the air too.

My primary concern is next weekend and the red object which will grace
the sky for about 75 minutes. Let's keep our fingers crossed that the
weather will do us a (huge) favour.

I'm not holding out any hope for that, my local weather forecast is for
clouds for the next 5 days.

--
Andy Hewitt
http://web.mac.com/andrewhewitt1/

On Thu, 22 Feb 2007 20:04:57 +0200, Anthony Ayiomamitis
wrote:

Dear group,

The skies finally cleared last night for the first time in about three
weeks. With 92% humidity, the seeing was exceptional for this time of
the year ranging from 1.8-1.9" (FWHM) at the start of the session and
which was down to 1.52" a few hours thereafter. However, the
transparency was poor and partially impacted the net result.

The open cluster M48 in Hydra is most impressive and I am disappointed
the poor transparency did not permit for an even better result. For
those interested, the result is available at
http://www.perseus.gr/Astro-DSO-NGC-2548.htm .

Clear skies!

Anthony.

Lovely shot Anthony and an excellent presentation as usual. One
question though - isn't the Starfire a refractor? If so - where did
the diffraction spikes come from?
--
Pete
http://www.digitalsky.org.uk

Pete Lawrence wrote:
On Thu, 22 Feb 2007 20:04:57 +0200, Anthony Ayiomamitis
wrote:


Dear group,

The skies finally cleared last night for the first time in about three
weeks. With 92% humidity, the seeing was exceptional for this time of
the year ranging from 1.8-1.9" (FWHM) at the start of the session and
which was down to 1.52" a few hours thereafter. However, the
transparency was poor and partially impacted the net result.

The open cluster M48 in Hydra is most impressive and I am disappointed
the poor transparency did not permit for an even better result. For
those interested, the result is available at
http://www.perseus.gr/Astro-DSO-NGC-2548.htm .

Clear skies!

Anthony.



Hi Pete,

Lovely shot Anthony and an excellent presentation as usual. One
question though - isn't the Starfire a refractor? If so - where did
the diffraction spikes come from?

Glad you like the photo. Now, if I could have a dollar for each time I
have been asked about the spikes and my refractor I would have enough
money to pick up a 20" RC.

Anyway, with two pieces of string in the form of a cross and placed at
the front of the dew shield, we are able to generate the difraction
pattern for the bright member stars of an image. It is also a great way
to converge towards focus when initially setting up.

I have experimented shooting open clusters with and without the
diffraction spikes and much prefer the latter. I have also asked quite a
few others as to their preference and we literally have a 50-50 split.

What are your thoughts on the spikes? Roland Christen calls them
"distraction spikes". LOL!

Anthony.

On Fri, 23 Feb 2007 14:54:20 +0200, Anthony Ayiomamitis
wrote:

Lovely shot Anthony and an excellent presentation as usual. One
question though - isn't the Starfire a refractor? If so - where did
the diffraction spikes come from?

Glad you like the photo. Now, if I could have a dollar for each time I
have been asked about the spikes and my refractor I would have enough
money to pick up a 20" RC.

Anyway, with two pieces of string in the form of a cross and placed at
the front of the dew shield, we are able to generate the difraction
pattern for the bright member stars of an image. It is also a great way
to converge towards focus when initially setting up.

I have experimented shooting open clusters with and without the
diffraction spikes and much prefer the latter. I have also asked quite a
few others as to their preference and we literally have a 50-50 split.

What are your thoughts on the spikes? Roland Christen calls them
"distraction spikes". LOL!

Ah ha - I suspected as much. My own thoughts are that I like the
aesthetic result but I have trouble with diffraction/distraction
spikes because they are not supposed to be there. When they appear
they play to our childhood memories of the large professional
observatory images of stars with those massive spikes.
--
Pete
http://www.digitalsky.org.uk

Hi Anthony,

That is one fine, crisp image.

GOOD WORK,
Ben

Andy Hewitt wrote:
Yes, much the same here really, I usually measure the clarity of viewing
by seeing how much 'twinkle' the stars have (when I can see them at all
that is).

Twinkling is an indication of atmospheric turbulence, but it doesn't
generally correlate very well to telescopic seeing. The stars can seem
perfectly still to the unaided eye, yet the planets will seem very fuzzy
at best focus in the telescope; and correspondingly (though less often,
it seems to me), the stars can twinkle noticeably, and yet the planets
will seem pretty sharp in the telescope.

How often either of these situations happens seems to vary considerably
with your observing site, judging from comments on SAA over the years.

--
Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.html