What color is the moon?

In article ,
Paul Ciszek wrote:

In article ,
Chris.B wrote:

I was shocked when I took Venus transit images with a new Canon Ixus
digital compact when the Sun came out as brown as hens eggs!

My relatively ancient Sony makes the Sun pink. In both cases I used
the same old, Baader foil, full aperture filter.

Even further off topic, is it true that you can get a colored glass
"hydrogen alpha" filter that does not cost thousands of dollars, but
has a wider FWHM that the serious ones?

You can get something like
http://www.astronomik.com/en/photogr...cd-filter.html
which costs a few hundred dollars and has a 12nm bandpass; or 50% more
for a 6nm bandpass; they'll get you lovely pictures of hydrogen
emission in the Milky Way and the Local Group but are no use for solar
work. The cloudnights forum suggests that 1nm bandpass is absolutely
the bare minimum for visual solar work.

http://www.daystarfilters.com/Quantum.shtml are tunable etalon filters
with down to 0.03nm bandpass, but price is roughly inversely
proportional to bandpass.

Tom

In article ,
Thomas Womack wrote:
In article ,
Paul Ciszek wrote:

Even further off topic, is it true that you can get a colored glass
"hydrogen alpha" filter that does not cost thousands of dollars, but
has a wider FWHM that the serious ones?

You can get something like
http://www.astronomik.com/en/photogr...cd-filter.html
which costs a few hundred dollars and has a 12nm bandpass; or 50% more
for a 6nm bandpass; they'll get you lovely pictures of hydrogen
emission in the Milky Way and the Local Group but are no use for solar
work. The cloudnights forum suggests that 1nm bandpass is absolutely
the bare minimum for visual solar work.

Well, I was thinking that a colored glass filter plus a suitable neutral
density filter might get me more interesting results than just a mylar
"neutral density" filter alone. My earlier picture was taken with a
mylar filter, the green channel isolated to minimize chromatic aberration,
and the contrast blown way up to show sunspot structure and granularity.
If a 6nm BP filter can make the sunspots and granularity more noticable--
still requiring contrast enhancement, just not as much--that would be great.

--
"Remember when teachers, public employees, Planned Parenthood, NPR and PBS
crashed the stock market, wiped out half of our 401Ks, took trillions in
TARP money, spilled oil in the Gulf of Mexico, gave themselves billions in
bonuses, and paid no taxes? Yeah, me neither."

On 2012-09-26, Paul Ciszek wrote:

Well, I was thinking that a colored glass filter plus a suitable neutral
density filter might get me more interesting results than just a mylar
"neutral density" filter alone. My earlier picture was taken with a
mylar filter, the green channel isolated to minimize chromatic aberration,
and the contrast blown way up to show sunspot structure and granularity.
If a 6nm BP filter can make the sunspots and granularity more noticable--
still requiring contrast enhancement, just not as much--that would be great.

The Baader Solar Continuum filter with a 10 nm pass band centered on
540 nm works pretty well to filter out of focus colors. The pass band
is located at the wavelength where most achromatic telescopes are best
corrected for spherical aberration. With one of those and a Herschel
wedge plus an ND3.8 neutral density filter I get a sharp view visually.
A Baader solar filter plus a Solar Continuum filter also works well
for photography. I can't focus an SLR with the Herschel wedge because
I don't have enough back focus.

Bud

On 2012-09-26, Paul Ciszek wrote:

Even further off topic, is it true that you can get a colored glass
"hydrogen alpha" filter that does not cost thousands of dollars, but
has a wider FWHM that the serious ones? Where would I find one? When
I try to search for one, I just find fractional angstrom filters that
cost more than my car did new.


The problem there is that with a wider pass band the hydrogen
alpha filters will not work to show any detail at that wavelength.
You basically have just a deep red filter. The least expensive hydrogen
alpha viewers I know about are the small Coronado PST and Lunt LS35T
that cost about 600 US dollars.

Bud

On Sep 21, 12:39*am, (Paul Ciszek) wrote:
My camera has a choice of "white balance" settings. *If I use "Sunlight"
on the assumption that the moon is a sunlight landscape, photos of the
moon come out looking a little brownish. *If I use "Auto", the moon
appears nearly colorless. *The former coloration is not implausible,
but which is closer to the truth?

Fortunately, I can make this decision retroactively for photos shot
in RAW mode.

--
"Remember when teachers, public employees, Planned Parenthood, NPR and PBS
crashed the stock market, wiped out half of our 401Ks, took trillions in
TARP money, spilled oil in the Gulf of Mexico, gave themselves billions in
bonuses, and paid no taxes? Yeah, me neither."

How exactly did our naked and physically dark moon become so unusually
monochromatic, reflective and inert?

The moon is not actually monochromatic nor inert:
Moon’s natural surface colors are those of all the perfectly natural
minerals as they unavoidably react to the visible and UV spectrum, as
only better viewed with having their natural color/hue saturation
cranked up, as otherwise there’s no false or artificial colors added.
http://spaceweather.com/submissions/...1346444660.jpg
http://www.spaceweather.com/swpod200...4dnmol44vuaf43

Oddly the NASA/Apollo era and their rad-hard Kodak version of our
physically dark and paramagnetic moon is apparently the one and only
off-world location that becomes more inert as well as more reflective
and monochromatic by the closer you get to it, and any planet other
than Earth simply can’t be recorded within the same FOV as having the
horizon of that naked moon (regardless of the FOV direction or use of
any given lens, as well as not even possible when using the world’s
best film and optics along with a polarized optical filter to reduce
the local surface glare doesn’t seem to help).

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Brad Guth,Brad_Guth,Brad.Guth,BradGuth,BG,Guth Usenet/”Guth Venus”