The C1 line of cameras is based on Sony IMX CMOS sensors. Cameras
are designed to be small and lightweight, yet robust due to
CNC-machined shell. The C1 camera series currently comprise of 3
||1456 × 1088 pixels
||3.45 × 3.45 μm
||5.02 × 3.75 mm
||2064 × 1544 pixels
||3.45 × 3.45 μm
||7.12 × 5.33 mm
||2464 × 2056 pixels
||3.45 × 3.45 μm
||8.50 × 7.09 mm
The telescope/lens interface conforms to CS-mount standard (C-mount
lens thread with shortened 12.5 mm back focal distance). This makes the C1 line
compatible with vast number of CCTV lens and adapters.
The C-mount standard uses the same thread, only the back
focal distance is 17.5 mm, which is 5 mm
longer compared to short CS version. Simple 5 mm thick threaded ring enables C1 cameras to use
lenses designed for C-mount.
The C-mount to 1.25" barrel adapter allows
inserting of C1 camera instead of telescope eyepiece and enjoying
digital images of astronomical and also terrestrial objects. Short
(just 10 mm) version of the C-mount to
1.25" adapter makes the C1 camera fully compatible
with all Off-Axis Guider adapters, used with larger cooled Gx and Cx
series of cameras.
Despite C1 camera is typically fixed on the telescope through its
telescope/lens adapter, the camera body is also equipped with standard
0.25" tripod thread as well as four metric M3 threads
on its bottom side.
USB3 connector is used to control the camera and download images as
well as to provide power to it. Standard 6-pin autoguider port is
located just beside the USB3 connector.
The very high speed USB3 interface ensures even a multi-megapixel
image download time in the order of hundredths of second. Still, USB3
interface operates reliably when the cameras is relatively close to
the host computer (USB3 cable length limit for reliable operation is
around 2 or 3 meters). But C1 cameras are
fully compatible with USB2 cables and PC interfaces, allowing much
longer connection between camera and host PC (5 m single cable, a few tens of meters with active
CMOS sensors are capable to digitize images very fast. But also
camera electronics has to be able to re-arrange image data and send
them to the host PC very quickly not to slow-down the entire system.
And fast electronics generates heat, which is a general rule known to
every PC enthusiast (the faster is the PC the better cooling is
necessary to keep it at proper working temperature). This is why we
paid great attention to temperature management of C1 cameras despite
this series is not equipped with active (Peltier) cooling.
The C1 camera case is equipped with a small fan, exchanging the air
inside the shell. What's more, there is a small heat sink inside the
case, removing the heat from the CMOS sensor itself. All this ensures
the sensor temperature is kept only a few degrees Celsius above the
environment air temperature. This keeps the dark current as low as
possible. When taking into account that the dark current doubles with
every 6 or 7 degrees Celsius and the sensor temperature can be up to a
few tens degrees Celsius above environment temperature in the case of
closed designs, the dark current limitation is very important.
Camera allows selection of two read modes — very fast 8-bit and somewhat slower (but still very
fast) 12-bit. Unfortunately, A/D converters are integrated with the
sensor chip in the case of CMOS detectors, so ADC resolution is
defined by the CMOS manufacturer and camera designer cannot influence
this. But at the same time IMX CMOS sensors used in C1 cameras offer
very low read noise (around 2 e- RMS), so the dynamic range is not
that worse compared with CCD cameras equipped with 16-bit ADC.
To our surprise the sensor response to light is perfectly linear.
This means the camera can be used also for entry-level research
projects, like for instance photometry or brighter variable stars
C1-3000 (IMX252) response to light
C1-3000 first light images
The very first prototype of C1-3000 camera was used by renowned
astro-photographer Martin Myslivec. He used the Borg 77ED
refractor telescope on the EQ6 mount co capture several unguided
exposures. Despite we understand Martin is highly skilled and
experienced astro-photographer, the performance of C1 camera is
very good also for deep-sky imaging.
C1-3000 first light: M31 Great Andromeda galaxy (left),
M42 Great Orion nebula (center) and nebulosity around stars in
M45 Pleiades open cluster (right)
The M31 Great Andromeda galaxy is a stack of 197
exposures 20 s long (approximately
1 hour and 5 minutes of total exposure time). No image processing
was performed beside individual frame calibration and slightly
The M42 Great Orion nebula image was combined from two
sets of exposures (kind of HDR image processing). Faint
nebulosity, far from the image center, was acquired using 100
exposures 20 s long (approximately 33 minutes of total exposure
time). The very bright central part of the nebula was captured
with only 2 s long exposures (again 100 of them), which leads to
approximately 3 minutes of total exposure time. The very short
exposures allowed to perfectly capture the 4 central stars (called
Trapezium) without over-exposing them.
The image of M45 Pleiades is a combination of 218
exposures 20 s long (approximately 1 hour and 12 minutes of total
exposure time). Again, no image processing was performed, only the
calibration and slight non-linearly stretch was performed.
The C1 cameras will be available very early next year (January
2019). More sophisticated, cooled C2, C3 and C4 series of CMOS based
cameras, compatible with very rich set of accessories of the Gx Mark
II cameras, will follow soon. We will keep you informed.