The camera of the farthest photographer from the earth

[Panama Hat & Camera]

LORRI (Long Range Reconnaissance Imager) is the camera name of the space probe New Horizons which is near the dwarf planet Pluto, 3.07 billion miles (4.94 billion kilometers) from Earth.

Two of my friends saw some photos of Pluto and its satellite Charon taken by the space probe and they were talking how was possible to take so good pictures in so unfavorable light conditions.

I like very much astronomy (and photography) and I decided to study the subject.

According the sites http://pluto.jhuapl.edu/ and https://www.nasa.gov/mission_pages/n...ain/index.html, Pluto was about 33 AU distant from the sun (one AU is the average distance between the Sun and Earth, about 93 million miles or 149.6 million kilometers) when the photos were taken.
LORRI is a narrow angle (field of view=0.29°), high resolution (4.95 μrad/pixel), Ritchey-Chrétien telescope camera with a 208mm diameter primary mirror and a focal length of 2630mm (f/12.6), designed to obtain high resolution, monochromatic images under low light conditions.

At Pluto encounter, 33 AU from the Sun, the illumination level is ~1/1000 that at Earth, but Pluto is an unusually bright object with a visible albedo of ~0.55 (albedo is the ratio of reflected radiation from the surface to incident radiation upon it).
LORRI was designed for an exposure time range between 50 and 200 milliseconds (1/20 second and 1/5 second), with 100 milliseconds (1/10 second) the nominal design value. The sensor is a 13,3mm x 13,3mm CCD with high performance low noise output amplifiers, suitable for use in slow-scan imaging systems. The image area contains a full 1024 by 1024 photosites which are 13 micrometer square (169 μmm²).

Lets see if it is possible to take the photos:

According the sunny 16 rule, "on a sunny day set aperture to f/16 and shutter speed to the [reciprocal of the] ISO film speed [or ISO setting] for a subject in direct sunlight".

For example:
On a sunny day and with ISO 100 film / setting in the camera, one sets the aperture to f/16 and the shutter speed to 1/100 second.

For a camera (on Earth):
On a sunny day and with shutter speed to 1/10 second, one sets the aperture to f/16 and ISO number to 10.

For Lorri (on Earth):
On a sunny day and with shutter speed to 1/10 second and aperture to f/12.6, one sets the ISO number to (12.6/16)² x 10 = 6.2.

For Lorri (on Pluto):
On a sunny day and with shutter speed to 1/10 second and aperture to f/12.6, one sets the ISO number to 6.2 x 1000 = 6200.

So, thanks to the large photosites (169 μmm²) it is possible to take good pictures of Pluto and Charon (f/12.6; 1/5 to 1/20; ISO 3100 to 12400). The difficult is to point correctly the camera (field of view=0.29°). See more at www.boulder.swri.edu/pkb/ssr/ssr-lorri.pdf and http://www.e2v.com/resources/account...datasheet/1427

[JohnRostron]

A nice, helpful analysis Antonio. I had wondered about this myself.

John

[xpatUSA]

. . . The sensor is a 13,3mm x 13,3mm CCD with high performance low noise output amplifiers, suitable for use in slow-scan imaging systems. The image area contains a full 1024 by 1024 photosites which are 13 micrometer square (169 μm²) . . .

I like big pixels

I often shoot my Sigma cameras in 2x2 binned low res, and reap the benefits of slightly better noise performance and of much smaller file sizes. The SD14 binned 2x2 comes out as 15.6um pixel pitch. The SD1M, just about 10um.

However, the noise performance of the LORRI cam might be just slightly better than mine
.

[Panama Hat & Camera]

Bill, James, Ted and Bruce,
Thank you very much for yours "Mark as helpful".
Cheers,
Antonio.

[Panama Hat & Camera]

A nice, helpful analysis Antonio. I had wondered about this myself.

John

John,
A tried to write a simple analysis focused in the photography subject.
There are many others interesting aspects involved with the New Horizons mission and I like very much to read about it.
Thank you very much for your kind words and comments.
Best regards,
Antonio.

[Panama Hat & Camera]

I like big pixels

I often shoot my Sigma cameras in 2x2 binned low res, and reap the benefits of slightly better noise performance and of much smaller file sizes. The SD14 binned 2x2 comes out as 15.6um pixel pitch. The SD1M, just about 10um.

However, the noise performance of the LORRI cam might be just slightly better than mine
.

Ted,
On-chip 4×4 pixel binning is available on Lorri sensor for very low light level situations as expected on the Kuiper Belt. After the pixels binning the 1024 x 1024 CCD behaves like a 256 x 256 CCD with "super pixels" (4 x 169 μmm²) and very, very low noise level.
Thanks for seeing and commenting.
All the best,
Antonio.

[Otavio]

Hello, Antônio.

Very interesting information. Thanks for taking your time on preparing and presenting them to us. Cheers,

[Panama Hat & Camera]

Bill, James, Ted and Bruce,
Thank you very much for yours "Mark as helpful".
Cheers,
Antonio.

Rachel and David,
Revisiting this thread, I noticed that you marked it as helpful and I didn't thank you.
I appreciateyours acknowledgment and I thank you (somewhat late) for it.
Thank you very much.
Antonio.

[Tringa]

Thanks for the information, Antonio. I, like others, wondered how many of the distant images are recorded when there is so little light.

Dave

[Panama Hat & Camera]

Thanks for the information, Antonio. I, like others, wondered how many of the distant images are recorded when there is so little light.

Dave

Dave
I was revisiting this thread today and noticed that you wrote a comment about it. I appreciate your feedback and thank you (a bit late) for this.
Thank you very much.
Antonio.

[Panama Hat & Camera]

When I posted this topic (in July 2015), the New Horizons spacecraft was taking pictures of Pluto, about 33 AU away from the Sun. Two days ago, New Horizons has passed a rare milestone in deep space - 50 astronomical units from Sun, or 50 times farther from the Sun than the Earth is.
Cheers,
Antonio.


https://www.nasa.gov/feature/nasa-s-...pace-milestone