WWW.ASTRONOMY.COM^65exposures between 10 and 20 minutes,
depending on the brightness of the target
and focal ratio of the imaging device.
Let’s compare
Now it’s time to answer the question that
everyone asks: Is this as good as a CCD
camera? No, but it is close. The main rea-
son is the CMOS system: Incoming light
has to be split among four separate recep-
tors for every point of RGB. Furthermore,
you’re limited to the specific colors that
the filters of the Bayer matrix give you.
In a CCD system, you image through
filters made specifically for astrophotogra-
phy, so each color fully covers the chip.
There’s no splitting up the light. Using
individual filters in front of a monochro-
matic chip is laborious and time consum-
ing by comparison, but the end result
benefits from each color getting full cover-
age. Additionally, you can expose the lumi-
nance separately from the color data,
greatly enhancing the depth of detail.
This brings up another important dif-
ference. With the COLDMOS camera, the
acquisition of a color image is instanta-
neous; with a CCD, it is sequential. If you
are trying to take a color photograph of
something moving fast, like meteors or
satellites, the COLDMOS camera works
great. The CCD does not. You also can
raise the gain of the COLDMOS to record
faint objects.
Although it is possible to add narrow-
band filters in front of a COLDMOS cam-
era, remember that there is only one
receptor out of the four that will record,
for example, Hydrogen-alpha (Hα) light.
The matrix’s red filter allows the Hα to
go through, but the green and blue filters
will block it. So, you are getting only one-
quarter the resolution and sensitivity that
you would get with a CCD camera where
100 percent of the Hα light is recorded. In
other words, don’t do that.We have a verdict
The 128C camera is easy to use. There’s no
filter wheel, no complicated registration,
and no combining of colors. It’s all done
for you via the Bayer matrix. And dare I
say it? This camera was also fun to use.
(But you do need to know how to stretch
and enhance raw data to get the results
you see in this article.) The camera has
limitations, of course, but if all you want
to do is take some good color images of
the night sky, you can do a lot with it.
In line with this, the COLDMOS cam-
era works well with a large variety of opti-
cal devices, from camera lenses and
refractors to long-focal-length telescopes.
The gain of the camera can be adjusted to
the f-ratio of your imaging device and the
nature of your target.
Furthermore, the camera is well suited
to situations where you have only one night
available for imaging. For example, each
photo in this article was made with two or
fewer hours of total exposure time.
QHYCCD’s 128C COLDMOS camera
brings a new perspective to astrophotogra-
phy. CMOS technology continues to evolve,
and this camera uses it in a new way to
image the night sky.QHYCCD 128C
Sensor: Sony IMX128 color CMOS
Sensor size: 36 mm by 24 mm,
24 megapixels
Pixel size: 5.97 microns square
Exposure times: 60 microseconds to
1 hour
Power consumption: 30 watts
Weight: 27.8 ounces (788 grams)
Price: $3,499
Contact: Michael Barber
QHYCCD
805.308.6976
[email protected]PRODUCT INFORMATION
To ny H a l l a s is a contributing editor of
Astronomy, one of the world’s top astroimagers,
and someone who loves new tech.Above: This image of the Orion Nebula (M42) took only one hour of
exposures to create. The author described a time that short to produce
a shot of this quality as “crazy!”
Top right: To create this wide-field image of the region around M78 in
Orion, the author connected the 128C to a Stellarvue SVQ-100 refractor.
He set the gain at 2,000 and combined eight 15-minute exposures.
Right: The author used this setup for all his shots, including both of the
pictures he shot for this story.