Pics from 8" APO v. lowly SCTs

I've seen planetary pics from webcams and dedicated ccd cameras
attached to very nice and big APOs (such as a TMB designed 8" scope)
that are okay but not in the same class as those from 12" and larger
SCTs. Those are just the Meade and Celestron mass-produced scopes.

Why would even a C14 be able to produce shots so superior to what
should be a superlative performer? I don't believe it's all size
either. Some C11 pics are much better as well. A shot claimed to be
from a C9.25, from a link posted in this group, is much better too.

So, why?

Is the visual experience altogether different?


Any links to the best pics from large refractors would of course be
welcome.

hooskerdoo wrote:

I've seen planetary pics from webcams and dedicated ccd cameras
attached to very nice and big APOs (such as a TMB designed 8" scope)
that are okay but not in the same class as those from 12" and larger
SCTs. Those are just the Meade and Celestron mass-produced scopes.

Why would even a C14 be able to produce shots so superior to what
should be a superlative performer? I don't believe it's all size
either. Some C11 pics are much better as well. A shot claimed to be
from a C9.25, from a link posted in this group, is much better too.

So, why?

Is the visual experience altogether different?


Any links to the best pics from large refractors would of course be
welcome.

Jim Phillips has gotten some stunning results with his 10" folded TMB.

But otherwise, a larger objective has an edge for showing detail, and a
longer focal length helps too.

Finally, the skill/talent of the photographer shouldn't be under estimated.

On Thu, 14 Jul 2005 21:13:26 -0400, "Mark S. Holden"
wrote:

hooskerdoo wrote:

I've seen planetary pics from webcams and dedicated ccd cameras
attached to very nice and big APOs (such as a TMB designed 8" scope)
that are okay but not in the same class as those from 12" and larger
SCTs. Those are just the Meade and Celestron mass-produced scopes.

Why would even a C14 be able to produce shots so superior to what
should be a superlative performer? I don't believe it's all size
either. Some C11 pics are much better as well. A shot claimed to be
from a C9.25, from a link posted in this group, is much better too.

So, why?

Is the visual experience altogether different?


Any links to the best pics from large refractors would of course be
welcome.

Jim Phillips has gotten some stunning results with his 10" folded TMB.

But otherwise, a larger objective has an edge for showing detail, and a
longer focal length helps too.

Finally, the skill/talent of the photographer shouldn't be under estimated.


I was thinking of Mr. Phillips's scope and his work. He also has an 8"
TMB.

http://www.tmboptical.com/picsRecord.asp?pic_id=27&

I was looking at his pics a few days ago as well...but I didn't see
any image I could call stunning, though.

So far, I can't say I understand why this should be.

Compare with Thierry Legault's (if I misspelled, sorry) work from his
12" Meade. I could find C11 pics of Jupiter that are clearly superior
too.

It's not just size in this case. Maybe lots more could be teased from
a big refactor by the imager!? If the great result is there I'd enjoy
it for sure.

Of course I've seen a bunch of planetary pics from the top end
6-inchers. Not great for detail either but the color and contrast
seemed quite nice.

Thanks for the reply. More would certainly be welcome.

"hooskerdoo" wrote in message

So, why?

Is the visual experience altogether different?


When you image with a webcam you can greatly reduce two issues which can
plague larger, obstructed, closed scopes like SCTs- contrast and image
stability. Just throw out the bad frames and crank up the contrast (ok,
there's more too it, but you get the picture).

Conversely, you cannot do much to increase the resolution deficit of smaller
scopes with Photoshop. And planetary imaging is mostly about resolution.

Visually, it comes down to what makes you happy and there is a range of
answers to that question.

Ed T.

hooskerdoo wrote:

On Thu, 14 Jul 2005 21:13:26 -0400, "Mark S. Holden"
wrote:


hooskerdoo wrote:


I've seen planetary pics from webcams and dedicated ccd cameras
attached to very nice and big APOs (such as a TMB designed 8" scope)
that are okay but not in the same class as those from 12" and larger
SCTs. Those are just the Meade and Celestron mass-produced scopes.

Why would even a C14 be able to produce shots so superior to what
should be a superlative performer? I don't believe it's all size
either. Some C11 pics are much better as well. A shot claimed to be
from a C9.25, from a link posted in this group, is much better too.

So, why?

Is the visual experience altogether different?


Any links to the best pics from large refractors would of course be
welcome.

Jim Phillips has gotten some stunning results with his 10" folded TMB.

But otherwise, a larger objective has an edge for showing detail, and a
longer focal length helps too.

Finally, the skill/talent of the photographer shouldn't be under estimated.



I was thinking of Mr. Phillips's scope and his work. He also has an 8"
TMB.

http://www.tmboptical.com/picsRecord.asp?pic_id=27&

I was looking at his pics a few days ago as well...but I didn't see
any image I could call stunning, though.

So far, I can't say I understand why this should be.

Compare with Thierry Legault's (if I misspelled, sorry) work from his
12" Meade. I could find C11 pics of Jupiter that are clearly superior
too.

It's not just size in this case. Maybe lots more could be teased from
a big refactor by the imager!? If the great result is there I'd enjoy
it for sure.

Of course I've seen a bunch of planetary pics from the top end
6-inchers. Not great for detail either but the color and contrast
seemed quite nice.

Thanks for the reply. More would certainly be welcome.



Jim recently took a Mars photo with his 10" that's currently on the
front page of the TMB yahoo group.

http://groups.yahoo.com/group/tmboptical/

Another factor is there are a lot more big SCTs in use because they've
been available for longer, and the cost is considerably lower.

"Mark S. Holden" wrote in message
-
Jim recently took a Mars photo with his 10" that's currently on the front
page of the TMB yahoo group.

http://groups.yahoo.com/group/tmboptical/

Another factor is there are a lot more big SCTs in use because they've
been available for longer, and the cost is considerably lower.


That is a great shot by Jim, especially considering the current size of
Mars.

Ed T.

Why would even a C14 be able to produce shots so superior to what
should be a superlative performer? I don't believe it's all size
either. Some C11 pics are much better as well. A shot claimed to be
from a C9.25, from a link posted in this group, is much better too.

The large SCTs are no where near as fine optically as the top APOs. But at
the same time, they have a lot more aperture. That can be a big advantage.
The SCTs biggest problem is the large central obstruction. This makes them
more sensitive to seeing and degrades the contrast. But with stacked photos,
you select only the best shots, during moments of best seeing. And, you can
then stretch the contrast with software. The end result is that with this
type of photography, it is the skill of the photographer/processor that is
the dominant factor.

Is the visual experience altogether different?

Yes. The lack of a CO vs the large CO of an SCT makes a difference visually.
The large CO basically takes light out of the airy disk and puts it into the
first diffraction ring. You can see how this would blur low contrast detail.
And, the human eye cannot stretch the contrast at that range the way
software can. At the same time, you have to compare apples to apples. A 14,
even with a large CO has a big head start on a much smaller APO.

Clear Skies

Chuck Taylor
Do you observe the moon?
Try http://groups.yahoo.com/group/lunar-observing/

To reply, remove Delete and change period com to period net
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It takes large apertures to get the resolution needed for those amazing
images.

And the most powerful image enhancement technique in the hands of amateurs
is wavelet processing--it greatly enhances detail even if the optics has
average quality and obstruction.

Without processing, the images look vague and low contrast.


John

Simply because good SCTs can be pretty good and the difference w.r.t.
to a much more costly APO is mostly in the eye of the beholder. APOs
are good for deep sky work, not for planetary shots. Besides, a largish
CO will help in resolving the smallest of the details, which is what
you want in planetary imaging.

Andrea T.

Unfortunately for your theories I've seen pics taken with SCTs of the
same/close to the size of larger APOs (i.e. 8" - 9.25") which are way
better than anything taken by those APOs. Go figure.

Andrea T.