First attempt at lunar photography

Thanks to everyone who offered advice. Of the shots I took tonight,
this is the one that came out the best:

http://farm5.static.flickr.com/4021/...d587607a_o.jpg

To get more of the background info, see

http://www.flickr.com/photos/35853148@N05/4291914387/

One pixel in this image represents one pixel on the camera sensor.
I have a few questions about optical quality:

First, the resolution limit appears to be a few pixels wide; i.e.,
at the extreme limit of magnification, the optics are almost but not
quite up to the resolution of the sensor. Is that typical? It seems
to make more sense to me than having the sensor be the limiting factor.

Second, I had been warned that the teleconverter would magnify without
improving anything; indeed, that it would just degrade the image with
chromatic aberation, etc. Does the image I linked to above look over
magnified, or does it look like what you would expect for a scope near
its limit?


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Paul Ciszek wrote:
Thanks to everyone who offered advice. Of the shots I took tonight,
this is the one that came out the best:

http://farm5.static.flickr.com/4021/...d587607a_o.jpg

To get more of the background info, see

http://www.flickr.com/photos/35853148@N05/4291914387/

One pixel in this image represents one pixel on the camera sensor.
I have a few questions about optical quality:

First, the resolution limit appears to be a few pixels wide; i.e.,
at the extreme limit of magnification, the optics are almost but not
quite up to the resolution of the sensor. Is that typical? It seems
to make more sense to me than having the sensor be the limiting factor.

The sensor should be just slightly oversampling the image formed by the
optics to avoid getting jaggies on sharp edges. Most cameras have an
anti-alias filter to enforce this bandlimited signal before the CCD.

Unsharp masking will regain some contrast at a further cost in signal to
noise. You might want to experiment with exposure bracketting to try and
get a better initial signal to noise ratio. The image looks a bit noisy
which limits any of the otherpost processing tricks.

However, the point spread is a bit on the wide side in this case. It is
more common to see adjacent pixels dependent on their neighbours rather
than a half dozen across. I suspect the teleconverter is to blame and
probably also for the cyan fringe on the rhs.

Second, I had been warned that the teleconverter would magnify without
improving anything; indeed, that it would just degrade the image with
chromatic aberation, etc. Does the image I linked to above look over
magnified, or does it look like what you would expect for a scope near
its limit?

What may work better is to take an afocal image looking through a decent
pair of binoculars or small telescope using your camera.

Regards,
Martin Brown

In article ,
Martin Brown wrote:

However, the point spread is a bit on the wide side in this case. It is
more common to see adjacent pixels dependent on their neighbours rather
than a half dozen across. I suspect the teleconverter is to blame and
probably also for the cyan fringe on the rhs.

I discovered that my Auto Focus was still functioning in "AF Macro"
mode, which might have something to do with it. Also, I will aim for
a shorter exposure time, and it has been suggested that I increase the
delay from two seconds to 10. Unfortunately, the sky did not co-
operate last night. I will not have another oportunity until the moon
is well past half full. :-(

When I finally do get good seeing again, I will attempt to take a pair
of pictures with and without the teleconverter, all other parameters
being as similar as possible. I will "stretch" the non-telephoto image
by a factor of 1.7 and confirm once and for all whether the TC adds
detail or not.



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Paul Ciszek wrote:

I discovered that my Auto Focus was still functioning in "AF Macro"
mode, which might have something to do with it. Also, I will aim for
a shorter exposure time, and it has been suggested that I increase the
delay from two seconds to 10. Unfortunately, the sky did not co-
operate last night. I will not have another oportunity until the moon
is well past half full. :-(

When I finally do get good seeing again, I will attempt to take a pair
of pictures with and without the teleconverter, all other parameters
being as similar as possible. I will "stretch" the non-telephoto image
by a factor of 1.7 and confirm once and for all whether the TC adds
detail or not.

Very good. You will, in other words, learn by doing. It's a time-tested
and proven method. Barring unusual luck, one's first efforts don't look
so great, but one tends to improve quickly.

Davoud

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(Paul Ciszek) wrote in news:hjd0t2$i2s$1
@reader1.panix.com:

Looks like you are on your way. The next steps to consider in your
imaging evolution a

1) Build a Hartman mask to aid in focusing at full Moon. Focusing at
the full Moon is much harder than when there is a shadowed terminator

http://www.dabsonastronomy.com/index_files/Page356.htm
http://www.cloudynights.com/item.php?item_id=518

2) Shoot a number of images at different exposures Your image looks
slightly underexposed.

3) Get some imaging software that includes a sharpen function and
histogram levels. Google's Picassa has it. The images of the full Moon
that you see online have been imaged processed. The images do not look
that clear when they are raw.

- Canopus56

On Jan 21, 12:29 am, (Paul Ciszek) wrote:
Thanks to everyone who offered advice. Of the shots I took tonight,
this is the one that came out the best:

http://farm5.static.flickr.com/4021/...d587607a_o.jpg

To get more of the background info, see

http://www.flickr.com/photos/35853148@N05/4291914387/

One pixel in this image represents one pixel on the camera sensor.
I have a few questions about optical quality:

First, the resolution limit appears to be a few pixels wide; i.e.,
at the extreme limit of magnification, the optics are almost but not
quite up to the resolution of the sensor. Is that typical? It seems
to make more sense to me than having the sensor be the limiting factor.

Second, I had been warned that the teleconverter would magnify without
improving anything; indeed, that it would just degrade the image with
chromatic aberation, etc. Does the image I linked to above look over
magnified, or does it look like what you would expect for a scope near
its limit?

--
Please reply to: | "If more of us valued food and cheer and song
pciszek at panix dot com | above hoarded gold, it would be a merrier world."
Autoreply is disabled | --Thorin Oakenshield

Where are those complex mineral colors?

Canon 300D and a 10" Newtonian (real mineral colors)
http://www.atalaia.org/filipe/moon/colorofthemoon.htm

~ BG

In article ,
canopus56 wrote:

2) Shoot a number of images at different exposures Your image looks
slightly underexposed.

Here is another attempt at f/5.6, 1/200 sec:
http://www.flickr.com/photos/3585314...78153/sizes/o/

This may also look a little underexposed, but this time it would be
because I adjusted the exposure of the RAW file downward a tad.

3) Get some imaging software that includes a sharpen function and
histogram levels. Google's Picassa has it. The images of the full Moon
that you see online have been imaged processed. The images do not look
that clear when they are raw.

That is a matter of philosophy, bordering on ethics even, among amateur
photographers. So far I have limited manipulation to adjusting the
exposure using the software that Panasonic provided for handling the
RAW files, and cropping the result.

For anyone who is interested, I did the comparison I mentioned earlier;
the teleconverter definately does provide more detail:
http://www.flickr.com/photos/3585314...33104/sizes/l/

Unfortunately, Flickr has reduced the size of the composite. If I give
them money, will they let me upload full size images?


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In article ,
canopus56 wrote:

3) Get some imaging software that includes a sharpen function and
histogram levels. Google's Picassa has it. The images of the full Moon
that you see online have been imaged processed. The images do not look
that clear when they are raw.

I gave in to temptation and used Panasonic's developer program to fix
chromatic aberration and contrast:

http://www.flickr.com/photos/3585314...83982/sizes/o/


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