Eclipse of moon on Oct. 27

In rec.photo.digital William Graham wrote:

"Paul J Gans" wrote in message
...
In rec.photo.digital Sander Vesik wrote:
In rec.photo.equipment.35mm wrote:
On Sat, 16 Oct 2004 03:27:13 GMT, Gordon Zola
wrote:

... turn off ... the flash. :-/

Yeah, one guy could wreck it for everyone. :-)

yeah it was bloody well time people gave up on flash
setups that were powered off nuclear reactors and cost
more than the dept of State of California just so they
can capture shadow delail on the Moon :P

It was a government project.....

It must have been a spin-off of the "Star Wars" project.

Sure. After all, something has to keep the moon lit
up at night... ;-)

----- Paul J. Gans

In rec.photo.digital Prometheus wrote:
In article , Alan Browne
writes
William Graham wrote:

Unless you've got a flash with a guide number of 250 thousand miles........

That would require an f/1 lens for ISO 100. If the lens is f/4 then a
GN of 1,000,000 miles would be required...

Don't forget the flash would have to fire about 2.69s before the shutter
is fully open.

Isn't that delay automatic with all 1,000,000 guide number flash guns?

---- Paul J. Gans

"Brad Templeton" wrote in message
...
In article ,
Frank ess wrote:
Or consider other unusual shots. For example, I did a panorama of a
NASA lab with the moon:



http://pic.templetons.com/cgi-bin/im...es-eclipse.jpg

Which captures cool buildings, lights, people watching the eclipse,
and the moon. Try for something in this direction.
--
How to fix the DNS system and break up ICANN
http://www.templetons.com/brad/dns/

I have neither the skill nor the patience to make a work like that. I
appreciate your doing it so I can see an exciting, strangely serene
view. Thank you for the opportunity.

It takes no particular skill or patience. If you don't want calculate
the azimuth of the moon (any web planetarium program will show you
that, I think heavens-above star maps will show it) then because an
eclipse lasts an hour, you can hunt around your subject easily enough.

If you don't want to drive, try putting something local, such as trees,
or a model. Seat the model on something higher like a ladder if the
moon will be high during the eclipse.

Just the moon and the horizon can sometimes be interesting, because the
moon, when under a partial eclipse, won't "hold water" like it usually does
when its at the quarter phase. So it looks funny....Of course, you could do
the same thing with Photoshop......

In article , Crownfield
writes
Prometheus wrote:

In article OwCcd.265533$D%.83619@attbi_s51, William Graham
writes
"Prometheus" wrote in message
...
In article , Lassi Hippeläinen
writes
Prometheus wrote:
I wonder if there are any nuclear bomb pumped lasers left over
from the star wars project.

Even if there were, you would have to remote them quite a ways from your
camera.........

Ah, yes. The neutron flux could overload the sensor, and as for what the
NEMP would do to the non-hardened electronics...

and as for the photographer...

I thought it obvious that I would be the other side of the Earth.

--
Ian G8ILZ

In article , Paul J Gans
writes
In rec.photo.digital Prometheus wrote:
In article , Alan Browne
writes
William Graham wrote:

Unless you've got a flash with a guide number of 250 thousand miles........

That would require an f/1 lens for ISO 100. If the lens is f/4 then a
GN of 1,000,000 miles would be required...

Don't forget the flash would have to fire about 2.69s before the shutter
is fully open.

Isn't that delay automatic with all 1,000,000 guide number flash guns?

Only the ones where the release is on the gun and connecting to the
remote shutter release on the camera, then you have an adjustable delay
between the flash and the shutter.

--
Ian G8ILZ

In article , C J Donoghue
writes
Alan Browne wrote:

William Graham wrote:

Unless you've got a flash with a guide number of 250 thousand miles........

That would require an f/1 lens for ISO 100. If the lens is f/4 then a GN of
1,000,000 miles would be required...

Uhh, why flash the moon to capture an eclipse?

Do you rely think we are serious about guide numbers of 1,000,000 miles
(1,620,000,000 metres) and nuclear pumped lasers.

The whole point about
photographing an eclipse is that the moon is *dark*.

For a lunar eclipse, which is what we are discussing, it will be a dull
red due to the illumination passing through the Earth's atmosphere.
--
Ian G8ILZ

Brad Templeton wrote:


The truth is shooting an eclipse of the moon with a lens like that is
fine if you want to practice a bit, but you will shoot the moon
without context and get a shot like 1000 other people are taking unless
you have very good equipment.

Far more interesting to do a context shot. To do that, calculate where
the moon will be exactly from any typical PC planetarium program,
getting altitude and azumith.

Been done a 1000 times too:
http://www.mreclipse.com/Special/LEprimer.html

My own lunar eclipse shots have been rather bad.

Cheers,
Alan.

--
-- rec.photo.equipment.35mm user resource:
-- http://www.aliasimages.com/rpe35mmur.htm
-- e-meil: there's no such thing as a FreeLunch.--

Brad Templeton wrote:


The truth is shooting an eclipse of the moon with a lens like that is
fine if you want to practice a bit, but you will shoot the moon
without context and get a shot like 1000 other people are taking unless
you have very good equipment.

Far more interesting to do a context shot. To do that, calculate where
the moon will be exactly from any typical PC planetarium program,
getting altitude and azumith.

Been done a 1000 times too:
http://www.mreclipse.com/Special/LEprimer.html

My own lunar eclipse shots have been rather bad.

Cheers,
Alan.

--
-- rec.photo.equipment.35mm user resource:
-- http://www.aliasimages.com/rpe35mmur.htm
-- e-meil: there's no such thing as a FreeLunch.--

Alan Browne wrote:

Lassi Hippeläinen wrote:

Alan Browne wrote:

The diameter of the moon is ca. 3.48E6 meters. For the edges you
would need
1/2 of that. C is about 3E8 m/s, giving an image return of about 5.8ms.
so a shutter speed up to 1/172 of a second would work if rear curtain
began
falling 1/172 of a second after leading edge of light returned.
(Call it
1/160 then).



But this is radar business. The light has to travel there and back
again, so
the total delay is twice the difference in distance, or 1/86. 1/60 leaves
some room for inaccuracies.



Ach! you're right! When the first photons are already one-half moon
diameter back towards earth, the last photons are just reaching the
horizon of the moon and beginning their return trip... Argh!

Now that we agree on that point, we can progress to the finer points ;-)

With a too short exposure time you can get a dot or a ring - assuming
your camera has a leaf shutter. But with a focal plane shutter, will it
be an ellipse? (You may assume perfectly spherical Moon and constant
curtain speed.)

-- Lassi

Alan Browne wrote:

Lassi Hippeläinen wrote:

Alan Browne wrote:

The diameter of the moon is ca. 3.48E6 meters. For the edges you
would need
1/2 of that. C is about 3E8 m/s, giving an image return of about 5.8ms.
so a shutter speed up to 1/172 of a second would work if rear curtain
began
falling 1/172 of a second after leading edge of light returned.
(Call it
1/160 then).



But this is radar business. The light has to travel there and back
again, so
the total delay is twice the difference in distance, or 1/86. 1/60 leaves
some room for inaccuracies.



Ach! you're right! When the first photons are already one-half moon
diameter back towards earth, the last photons are just reaching the
horizon of the moon and beginning their return trip... Argh!

Now that we agree on that point, we can progress to the finer points ;-)

With a too short exposure time you can get a dot or a ring - assuming
your camera has a leaf shutter. But with a focal plane shutter, will it
be an ellipse? (You may assume perfectly spherical Moon and constant
curtain speed.)

-- Lassi