[Leica] IMG: Galileo was right

[boulanger.croissant at gmail.com (Peter Klein)]

Thanks for the tips, Howard.? You clearly know a great deal about 
astrophotography. I'm just an occasionaly dabbler.

I did bracket exposures extensively. Unfortunately, at the exposure 
where Jupiter is not overexposed, the darkest moon dropped out of the 
picture entirely, and the others were barely out of the noise and 
smudged. So only a composite picture would have gotten everything into 
sensor's usable brightness range. I did play with a well-exposed Jupiter 
image in Capture One. There is just a hint of the angled cloud bands in 
this 400% screen clip:
<http://gallery.leica-users.org/v/pklein/temp/Jupiter400pct.JPG.html>

But it did appear that I was operating at the limits of my equipment and 
current conditions.

Tonight is cloudy. Next time we have clear weather, I will have to try a 
wider f-stop and see if that gets me more detail. I stuck with f/11 last 
night because earlier, I had tested the 300mm lens on a local water 
tower with cellular antennas on top, 1/2 mile from my house and visible 
from my yard. f/11 clearly best resolved the details of the cell antennas.

Oh, and I misidentified my bargain-bin 300mm lens.? The lens *case* says 
Soligor. But the lens is a 300/5.5 Vivitar T-mount from the 1970s. It 
actually has a fairly good reputation.

A local astronomy club has public star parties every month in a park 
near my house, so I've seen the moon and some planets through their 
huge, impressive scopes. Sometimes I get envious. But from what I hear, 
Leica prices are a notch below what some of them pay for their equipment.

--Peter

------------
Howard Ritter wrote:
 > That?s a pretty good image for the lens, Peter, and some optimization 
would
 > make it even more impressive.
 >
 > In your shot, the relatively small image size of the moons, which are
 > effectively point sources at this FL, suggests that you could capture
 > Jupiter's atmospheric cloud bands if you avoid the overexposure of this
 > image. In photographing the rich but low-contrast detail in the 
atmosphere,
 > overexposure is your enemy. Underexposure, with enhancement in 
post-exposure
 > processing, can record nice detail, while overexposure that saturates
 > anything more than a few of the brightest pixels irretrievably 
obliterates
 > detail. You might try it again at 1/30 and shorter, and play with the 
result
 > in PS Camera Raw, especially the exposure, contrast, clarity, and dehaze
 > sliders. You might lose the moons at optimal exposure for the 
atmosphere,
 > but you could do a composite image.
 >
 > And of course the sweet spot for resolution is somewhere between wide 
open,
 > where diffraction-limited resolution is best but aberrations can 
occur, and
 > fully stopped down, where aberrations are negligible but 
diffraction-limited
 > resolution is worst. If you can find resolution-vs-aperture data for 
this
 > lens, that might guide you. At f/11, the effective aperture of a 
300-mm lens
 > is just over 1 inch, which by the Rayleigh criterion has a resolving 
power
 > of about 4.5 seconds of arc. (The angular diameter of the Galilean 
moons is
 > about 1 arcsec, and of Jupiter, currently at opposition, about 45 
arcsec.)
 > You might experiment with larger apertures once you?ve found the optimal
 > exposure time at f/11. If your lens goes to f/5.6, you could double your
 > resolution ? even if that?s wide open, the aberrations might affect 
mostly
 > the off-axis portions of the image.
 >
 > Sorry if I?ve turned a trip to the playground into a regimented 
chore! If
 > you try any of this, please post. If I ever get clear weather, I?ll 
put my
 > M240 on my 155-mm f/7 apo refractor and see what I can get.
 >
 > ?howard
 >
 >
 > > On Jun 17, 2019, at 5:06 AM, Peter Klein via LUG <lug at 
leica-users.org>
 > > wrote:
 > >
 > > 
<https://www.flickr.com/photos/24844563 at 
N04/48078173256/in/dateposted-public/>
 > >
 > > Jupiter and its four largest moons.? E-M5 on tripod, my $30 
bargain-bin
 > > 300mm Soligor lens, 1/8 sec at f/11, 100% pixels. One could do 
better with
 > > a telescope, but I thought it would be fun to see what I could get 
with
 > > what I had on hand.? Enjoy!
 > >
 > > --Peter