Saturn seeing

Now that Saturn is returning to the evening sky I have created a Saturn
Seeing Tutorial that illustrates it's visual resolution seen through a
range of telescope apertures. Gives you and idea what to expect especially
if you are newbie trying out or buying a scope.

http://astronomy.trilobytes.com.au/m...turnseeing.htm

Martin Lewicki

http://astronomy.trilobytes.com.au/m...turnseeing.htm


Martin, neat page. Thanks.=20

-Florian

Martin,

This is an interesting page, however, the image in my 105mm APE is much
better than the image that you posted. How did you obtain the images?

Regards,

-mij

"Martin Lewicki" wrote in message
...
Now that Saturn is returning to the evening sky I have created a Saturn
Seeing Tutorial that illustrates it's visual resolution seen through a
range of telescope apertures. Gives you and idea what to expect especially
if you are newbie trying out or buying a scope.

http://astronomy.trilobytes.com.au/m...turnseeing.htm

Martin Lewicki

A good attempt and will eventually help the newbie, Martin!

However, there's a problem with your current simulation. The
image in the "perfect seeing" is what I see through very bad seeing
in my 4-inch TV-102 APO refractor ;-). Herein lies the problem.
In order to simulate, you must use different image scale for different
scope. For example, to get Saturn that big in the 60mm refractor
will sure give you a fuzzy image. Likewise, the image of Saturn is
simply too large for a 4" telescope as well.

Similarly, my 8-inch Discovery PHDQ Dob gave a much crisper
view that the "perfect seeing" image with jet black Cassini Division
as well as much sharper detail in the globe as well better C Ring
and A Ring.

Please keep refining your simulation.

Ron B[ee]

-------------
"Martin Lewicki" wrote in message
...
Now that Saturn is returning to the evening sky I have created a Saturn
Seeing Tutorial that illustrates it's visual resolution seen through a
range of telescope apertures. Gives you and idea what to expect especially
if you are newbie trying out or buying a scope.

http://astronomy.trilobytes.com.au/m...turnseeing.htm

Martin Lewicki

On 11/20/03 14:33 +0900, Ron B[ee] wrote:

In order to simulate, you must use different image scale for different
scope. For example, to get Saturn that big in the 60mm refractor
will sure give you a fuzzy image. Likewise, the image of Saturn is
simply too large for a 4" telescope as well.

Right. It would be far more representative were the image to be
scaled to 50x-60x/in. of aperture. The combination of scale and
resolution would then be excellent.

trane
--
//------------------------------------------------------------
// Trane Francks Tokyo, Japan
// Practice random kindness and senseless acts of beauty.
// http://mp3.com/trane_francks/

Trane Francks wrote in :

On 11/20/03 14:33 +0900, Ron B[ee] wrote:

In order to simulate, you must use different image scale for different
scope. For example, to get Saturn that big in the 60mm refractor
will sure give you a fuzzy image. Likewise, the image of Saturn is
simply too large for a 4" telescope as well.

Was just thinking. With the unrealistic advertised magnifications slapped
on the box for many department store 60mm refactors - like 540x! - the 60mm
simulation ain't to far from the mark ;-)

Right. It would be far more representative were the image to be
scaled to 50x-60x/in. of aperture. The combination of scale and
resolution would then be excellent.

trane

Thanks. All good ideas to throw into the melting pot :-)

Martin

"Ron B[ee]" wrote in
news:LpYub.26786$Ro5.3380@fed1read07:

A good attempt and will eventually help the newbie, Martin!

However, there's a problem with your current simulation. The
image in the "perfect seeing" is what I see through very bad seeing
in my 4-inch TV-102 APO refractor ;-). Herein lies the problem.
In order to simulate, you must use different image scale for different
scope. For example, to get Saturn that big in the 60mm refractor
will sure give you a fuzzy image. Likewise, the image of Saturn is
simply too large for a 4" telescope as well.

Similarly, my 8-inch Discovery PHDQ Dob gave a much crisper
view that the "perfect seeing" image with jet black Cassini Division
as well as much sharper detail in the globe as well better C Ring
and A Ring.

Please keep refining your simulation.

Ron B[ee]

-------------
"Martin Lewicki" wrote in message
...
Now that Saturn is returning to the evening sky I have created a
Saturn Seeing Tutorial that illustrates it's visual resolution seen
through a range of telescope apertures. Gives you and idea what to
expect especially if you are newbie trying out or buying a scope.

http://astronomy.trilobytes.com.au/m...turnseeing.htm

Martin Lewicki



Thanks Mij and Ron for the comments. The benchmark is the Hubble image at
the top of the page that was scaled down to the same pixel size as the less
suitable Saturn image used in the Abberator software. I factored a central
obstruction of 25% for all but the 60mm aperture (which made very little
detectable difference anyway). The Abberator software and URL are credited
on the page.

The intention was to show the _comparative resolution_ of Saturn through a
range of telescope apertures rather than magnification. However others also
commented on the unrealistic image scale compared to actual apparent scale
in practice. Fair enough. I'll work on that one.

Could you tell me which of the simulated apertures did Saturn most compare?
Eg was the 8" dob more like the 10" sim. Was the 105mm more like the
127mm?

Thanks
Martin

My 105 MM APO gives a view similar to your 8 inch.

Regards,

-Mij

"Martin Lewicki" wrote in message
...
"Ron B[ee]" wrote in
news:LpYub.26786$Ro5.3380@fed1read07:

A good attempt and will eventually help the newbie, Martin!

However, there's a problem with your current simulation. The
image in the "perfect seeing" is what I see through very bad seeing
in my 4-inch TV-102 APO refractor ;-). Herein lies the problem.
In order to simulate, you must use different image scale for different
scope. For example, to get Saturn that big in the 60mm refractor
will sure give you a fuzzy image. Likewise, the image of Saturn is
simply too large for a 4" telescope as well.

Similarly, my 8-inch Discovery PHDQ Dob gave a much crisper
view that the "perfect seeing" image with jet black Cassini Division
as well as much sharper detail in the globe as well better C Ring
and A Ring.

Please keep refining your simulation.

Ron B[ee]

-------------
"Martin Lewicki" wrote in message
...
Now that Saturn is returning to the evening sky I have created a
Saturn Seeing Tutorial that illustrates it's visual resolution seen
through a range of telescope apertures. Gives you and idea what to
expect especially if you are newbie trying out or buying a scope.

http://astronomy.trilobytes.com.au/m...turnseeing.htm

Martin Lewicki



Thanks Mij and Ron for the comments. The benchmark is the Hubble image at
the top of the page that was scaled down to the same pixel size as the
less
suitable Saturn image used in the Abberator software. I factored a central
obstruction of 25% for all but the 60mm aperture (which made very little
detectable difference anyway). The Abberator software and URL are credited
on the page.

The intention was to show the _comparative resolution_ of Saturn through a
range of telescope apertures rather than magnification. However others
also
commented on the unrealistic image scale compared to actual apparent scale
in practice. Fair enough. I'll work on that one.

Could you tell me which of the simulated apertures did Saturn most
compare?
Eg was the 8" dob more like the 10" sim. Was the 105mm more like the
127mm?

Thanks
Martin

Martin Lewicki wrote in message ...

Now that Saturn is returning to the evening sky I have created a Saturn
Seeing Tutorial that illustrates it's visual resolution seen through a
range of telescope apertures. Gives you and idea what to expect especially
if you are newbie trying out or buying a scope.

http://astronomy.trilobytes.com.au/m...turnseeing.htm

It's a great idea, but somehow, it seems to me that I see Saturn much
better than these views suggest. What I see through a 60mm scope is
about what you show for a 90mm scope, and I am almost sure that I can
see the Cassini division clearly all the way around the planet in a
90mm scope.

The other issue is seeing. I sort of get what you are trying to do
there, but it is misleading. Seeing that degrades the view through
a 60mm scope to the extent shown is very rare; on the other hand,
it is a rare night indeed that my 12" scope shows a view as good
as the one you show in your "moderate seeing" column , let alone
the "good seeing" column.

Put another way, in any given degree of bad seeing, all scopes above
a certain aperture will give essentially identical views, and in many
locations (like my own in New England), that limit is probably around
4 inches on a typical night.

- Tony Flanders

(Tony Flanders) wrote in
:

Martin Lewicki wrote in message
...

Now that Saturn is returning to the evening sky I have created a
Saturn Seeing Tutorial that illustrates it's visual resolution seen
through a range of telescope apertures. Gives you and idea what to
expect especially if you are newbie trying out or buying a scope.

http://astronomy.trilobytes.com.au/m...turnseeing.htm

It's a great idea, but somehow, it seems to me that I see Saturn much
better than these views suggest. What I see through a 60mm scope is
about what you show for a 90mm scope, and I am almost sure that I can
see the Cassini division clearly all the way around the planet in a
90mm scope.

The other issue is seeing. I sort of get what you are trying to do
there, but it is misleading. Seeing that degrades the view through
a 60mm scope to the extent shown is very rare; on the other hand,
it is a rare night indeed that my 12" scope shows a view as good
as the one you show in your "moderate seeing" column , let alone
the "good seeing" column.

True. I think I recall seeing Saturn better in my trusty 60mm. But that was
some 10 odd years ago when Saturn was at south declinations and almost
overhead here in the SH. These days it only culminates 30 deg north in
Australia so we don't get seeing at that altitude delivers a clean Saturn.

I must add that the simulations were complied with the output from the
Abberator software. It has facilties to factor in seeing, central (and non
central) obstructions, lens/mirror aberrations, optical missalignmaents,
wavelength selection and other stuff.

I got a feeling that the author of the software should be listening in here
:-) http://aberrator.astronomy.net

Put another way, in any given degree of bad seeing, all scopes above
a certain aperture will give essentially identical views, and in many
locations (like my own in New England), that limit is probably around
4 inches on a typical night.

- Tony Flanders

Yes I get your point. At a certain level of bad seeing above a certain
aperture one just merely magnifies the bad seeing Saturn with no added
resolution.

Thanks
Martin