Cooled CCD cameras - recommendations?

I am interested in obtaining a color cooled CCD camera such as those
used in high level astrophotography. I would like to have input from
any users on some questions I have:

Software - Live imaging? Low light focusing? "white balance" issues?
Ease of export of the image to an IP software package?

Camera - IR blocking filter? Mounting methods? Spectral response?

My interest is in adapting such a camera to very low light imaging of
luminescent images with specific bandpass filters extending into the
NIR.

If any users of these cameras would be kind enough to help me out I
would be appreciative. Thanks.

Henry Barwood

Henry,

If you are going to be using bandpass filters, you probably want a
monochrome camera rather than a colour camera. There are a number of
companies (SBIG, FLI, Apogee) that make cameras for long exposures.
There are also companies that make video rate and faster cameras with
similar CCD sensors.
www.sbig.com
www.fli-cam.com
www.ccd.com
www.ptgrey.com
www.1394imaging.com

IR blocking filters are standard on most webcams and consumer digital
cameras, but astronomical cameras typically do not have an IR blocking
filters.

Focusing is always an issue with low light levels - I have to find a
star and focus at maybe 1 frame per second, and then take a long
exposure of whatever nebula, galaxy I'm going for. 'Real-time' focusing
doesn't happen at low light levels.

Take a look for "Handbook of CCD Astronomy" by Steve Howell for a good
technical overview on faint object imaging. Should be able to get it
used from Powell's Books for maybe $15. It's an astronomy book, but it
covers everything you'll run into with low light imaging.
www.powells.com

Many cameras ship with basic software. But once you figure out what
you're doing, you'll likely want something with more power and options.
CCD Soft and Maxim DL are aimed at astrophotography. Quantum Image is
more general and is very powerful.
www.bisque.com
www.cyanogen.com
www.quantimage.com

Eric.


wrote:
I am interested in obtaining a color cooled CCD camera such as those
used in high level astrophotography. I would like to have input from
any users on some questions I have:

Software - Live imaging? Low light focusing? "white balance" issues?
Ease of export of the image to an IP software package?

Camera - IR blocking filter? Mounting methods? Spectral response?

My interest is in adapting such a camera to very low light imaging of
luminescent images with specific bandpass filters extending into the
NIR.

If any users of these cameras would be kind enough to help me out I
would be appreciative. Thanks.

Henry Barwood

Hi Eric,

Thanks for your insightful comments.

Let me clarify a bit. I posed the question to astronomers, but my
actual use in in microscopy. I do a lot of cathodoluminescence
microscopy. I have a very old Vicam that I removed the IR blocking
filter from. Using this very low resolution, non-cooled camera, I
opened up a world of IR imaging that shows details simply not present
in visible images. I am trying to find a suitable camera to conduct
more rigorous examination of my samples, but have a problem. Cameras
for low light (fluorescence) microscopy are 2-3 orders of magnitude
beyond my budget.

Straining all my resources, I probably can afford an astrocam. Since I
build all my microscopes and instruments out of salvaged or donated
equipment (or stuff I buy off of E-bay!), I would adapt the camera
myself if it is suitably configured to begin with. In CL work, color
(even false-color) is a key component of recognition of different
luminescent substances.

Henry

Henry,

If you're looking for something inexpensive, Meade makes a camera called
the DIS-Pro. It's a monchrome CCD camera, long exposure, but uncooled. I
have seen a few mods here and there on the web detailing the addition of
a Peltier cooler. It's about US$400 and the coolers may be around $20
from Melcor and others.

BTW, what are you taking pictures of ?

Eric.

wrote:
Hi Eric,

Thanks for your insightful comments.

Let me clarify a bit. I posed the question to astronomers, but my
actual use in in microscopy. I do a lot of cathodoluminescence
microscopy. I have a very old Vicam that I removed the IR blocking
filter from. Using this very low resolution, non-cooled camera, I
opened up a world of IR imaging that shows details simply not present
in visible images. I am trying to find a suitable camera to conduct
more rigorous examination of my samples, but have a problem. Cameras
for low light (fluorescence) microscopy are 2-3 orders of magnitude
beyond my budget.

Straining all my resources, I probably can afford an astrocam. Since I
build all my microscopes and instruments out of salvaged or donated
equipment (or stuff I buy off of E-bay!), I would adapt the camera
myself if it is suitably configured to begin with. In CL work, color
(even false-color) is a key component of recognition of different
luminescent substances.

Henry

Hi Eric,

I am making cathodoluminescent images of petrographic thin sections of
rocks, refractories, fossils, etc. I use a vacuum stage with a cold
cathode electron gun called a Luminoscope. Many common minerals and
compounds luminesce under electron bombardment. Computer monitors and
television screens (well, at least the non-liquid crystal ones!)
generate an image using cathodoluminescent phosphors. Essentially no
work has been done on NIR luminescence.

Henry

So it's like an electron microscope - scan the target with an electron
beam, but I don't measure the backscattered electrons, I image the
luminescence through a window in the side of the vacuum chamber ?

So you could get bandpas filters or use a spectrograph to look for very
specific items in the rock.

What kind of electron energy are you using ? Probably only need
something around 100 eV ? Or do you vary the incoming energy ?

Eric.

wrote:
Hi Eric,

I am making cathodoluminescent images of petrographic thin sections of
rocks, refractories, fossils, etc. I use a vacuum stage with a cold
cathode electron gun called a Luminoscope. Many common minerals and
compounds luminesce under electron bombardment. Computer monitors and
television screens (well, at least the non-liquid crystal ones!)
generate an image using cathodoluminescent phosphors. Essentially no
work has been done on NIR luminescence.

Henry

Hi Eric,

Actually, it is much less hi-tech than that. You establish a vacuum
chamber at about 50 microns and then use a cold cathode to generate an
electron beam at 4-20KV. The beam will make a lot of things "glow" (in
living color!). Technique goes back to Crookes, but only became popular
in the late 1960's when a commercial device, the Luminoscope, was
marketed. I've used one for years to look at alkali syenites,
carbonates, refractory materials, etc. With the development of digital
imaging, a lot of new uese have cropped up!

Henry

That sounds very interesting. Particularly the bit about fossils.

Thanks, Henry.

Eric.

wrote:
Hi Eric,

Actually, it is much less hi-tech than that. You establish a vacuum
chamber at about 50 microns and then use a cold cathode to generate an
electron beam at 4-20KV. The beam will make a lot of things "glow" (in
living color!). Technique goes back to Crookes, but only became popular
in the late 1960's when a commercial device, the Luminoscope, was
marketed. I've used one for years to look at alkali syenites,
carbonates, refractory materials, etc. With the development of digital
imaging, a lot of new uese have cropped up!

Henry

Henry

If you want something real cheap to play with, I'd recommend a monochrome
CCTV camera using the Sony EXview HAD chip. They will see to under 0.01
lux, and mine (as an uncased PCB) cost about $80. They have quite a good
near IR response. www.rfconcepts.co.uk is one supplier. (There is a mod to
increase video gain - mail me if you need it).

Then look for a group called QCUIAG - they specialise in getting low light
images out of uncooled cameras, and some of their results are spectacular.

None of this stuff will beat a cooled CCD, but then it doesn't cost the
same...

Good luck - oh, at 20KV I guess you get some very soft Xrays. Not sure
CCDs will cope well with that - this might limit your sensitivity

Sounds great fun

--David


wrote:
Hi Eric,

Actually, it is much less hi-tech than that. You establish a vacuum
chamber at about 50 microns and then use a cold cathode to generate an
electron beam at 4-20KV. The beam will make a lot of things "glow" (in
living color!). Technique goes back to Crookes, but only became popular
in the late 1960's when a commercial device, the Luminoscope, was
marketed. I've used one for years to look at alkali syenites,
carbonates, refractory materials, etc. With the development of digital
imaging, a lot of new uese have cropped up!

Henry

Thanks for the information. My present camera is rated at 1 lux, so
that would be two orders of magnitude better. I've visited the QCUIAG
groups before and they have some excellent information.

The Luminoscope is fully encased and all observation is done through a
lead glass port.

Henry