C1 camera models are equipped with Sony IMX CMOS detectors with
3.45 × 3.45 μm
square pixels. Individual models differ in resolution only:
||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
||4112 × 3008 pixels
||3.45 × 3.45 μm
||14.19 × 10.38 mm
The C1 cameras are designed to work in cooperation with a
host Personal Computer (PC). As opposite to digital still cameras,
which are operated independently on the computer, the scientific
cameras usually require computer for operation control, image
download, processing and storage etc. To operate the camera, you
need a computer which:
Is compatible with a PC standard and runs modern 32 or 64-bit
Windows operating system.
Is compatible with a PC standard and runs 32 or 64-bit Linux
Support for x64 based Apple Macintosh computers is also
C1 cameras are designed to be connected with the host PC through
USB 3.0 interface, operating at 5 Gbps. Cameras are also compatible
with USB 2.0 port to communicate with a host PC.
Alternatively, it is possible to use the Gx Camera Ethernet
Adapter device. This device can connect up to four Cx (with CMOS
sensors) or Gx (with CCD sensors) cameras of any type and offers 1
Gbps and 10/100 Mbps Ethernet interface for direct connection to the
host PC. Because the PC then uses TCP/IP protocol to communicate with
the cameras, it is possible to insert WiFi adapter or other networking
device to the communication path.
Please note that the USB standard allows usage of cable no
longer than approx. 5 meters and USB 3.0 cables are even shorter to
achieve very fast transfer speeds. On the other side, the TCP/IP
communication protocol used to connect the camera over the Ethernet
adapter is routable, so the distance between camera setup and the host
PC is virtually unlimited.
The C1 cameras do not need an external power supply to operate,
they are powered through the USB connection from the host PC.
Note the camera must be connected to some optical system (e.g. the
telescope) to capture images. The camera is capable of long exposures,
necessary to acquire the light from faint objects. If you plan to use
the camera with the telescope, make sure the whole telescope/mount
setup is capable to track the target object smoothly during long
CMOS camera electronics primary role, beside the sensor
initialization and some auxiliary functions, is to transfer data
from the CMOS detector to the host PC for storage and processing.
So, as opposite to CCD cameras, CMOS camera design cannot
influence number of important camera features, like the dynamic
range (bit-depth of the digitized pixels).
C1 cameras offer two read modes:
Fast 8-bit mode with more than 100 MPx/s digitization
speed (5 MPx image from C1-5000 is
downloaded in less than 0.05 s). Number of bytes transferred to
the PC equals to number of pixels.
Slightly slower (but still very fast) 12-bit mode with
~80 MPx/s digitization speed (5MPx image from C1-5000 is
downloaded in ~0.06 s). Every pixel then occupies 2 bytes (1
word), only the upper 4 bits of every word are always
The download times mentioned above are valid for USB 3.0
Please note the download times do not necessarily lead to
corresponding FPS, because every image downloaded has to be
processed and displayed, which also consumes time. This time is
negligible, if slow-scan camera needs many seconds for image
download, but in the case of fast CMOS cameras, time for image
processing in the PC (e.g. calculation of image standard deviation
etc.) can be longer than image download itself.
C1 cameras are capable of very short exposures. The shortest
exposure time is 125 μs (1/8000 of second).
This is also the step, by which the exposure time is expressed.
So, the second shortest exposure is 250 μs
Long exposure timing is controlled by the host PC and there is
no upper limit on exposure time. In reality the longest exposures
are limited by saturation of the sensor either by incoming light
of by dark current (see the following sub-chapter).
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 etc.
C1-3000 (IMX252) response to light
Dark current is an inherent feature of all silicone circuits.
It is called dark, because it is generated regardless if
the sensor is exposed to light or not. Dark current, injected into
individual pixels, appear in image as noise. The longer exposure,
the greater amount of noise is present in every image. As it is
generated by random movement of particles, it depends on the
temperature exponentially (this is why the noise generated by dark
current is also denoted thermal noise). Typically,
lowering the sensor temperature by 6 or 7 °C halves the dark current.
While the C1 cameras are not equipped with active
thermo-electric (Peltier) cooling, they are still equipped with a
small fan, exchanging the air inside the camera body. What's more,
a small heat sink is located directly on the sensor (with the
exception of the C1-1500 model, which sensor is too small for heat
sink) to remove as much heat as possible. So, the C1 sensor cannot
be cooled below the ambient temperature, but its temperature is
kept as close to environment as possible. Compared to closed
designs, the sensor temperature in the C1 camera can be up to 10°C
lower and resulting dark current may be less than half.
Cooling air intake is on the left side of the camera
(left image), while the output vents are on the opposite side
The fan operation can be controlled from the software. SIPS
directly offers a slider controlling fan in the Cooling
tab of the main camera control tool window. Camera drivers for
other software must rely on driver configuration dialog box to
With fan off, sensor temperature quickly rises more
than 10 °C above ambient. Turning fan on lowers the temperature
by 5 °C or more.
A lot of astronomical telescope mounts (especially the
mass-manufactured ones) are not precise enough to keep the star
images perfectly round during long exposures without small
corrections. Cooled astronomical cameras and digital SLR cameras
allow perfectly sharp and high-resolution images, so even a small
irregularity in mount tracking appears as star image deformations.
C1 cameras were designed especially with automatic mount guiding
C1 cameras were designed to operate without any mechanically
moving parts (with the exception of magnetically levitating fan).
Electronic shutter allows extremely short exposures and also
obtaining thousands of images in a short time, which is necessary
for quality guiding.
C1 cameras work in connection with a host computer (PC).
Guiding corrections are not calculated in the camera itself, it
only sends acquired images to the PC. The software running on the
PC calculates the difference from required state and sends
appropriate corrections to the telescope mount. The plus side of
using a host PC CPU to process images is the fact, that current
PCs provide overwhelming computational power compared to any
embedded processor inside the guiding camera. Guiding algorithms
then can determine star position with sub-pixel precision, can
match multiple stars to calculate average difference, which limits
the effects of seeing, etc.
Calculated corrections can be sent back to mount using
PC-to-mount link. If the mount controller does not support
so-called Pulse Guide commands, it is possible to use
Autoguider port. It is enough to connect the C1 camera
and the mount using standard 6-wire cable and guide the mount
through the camera.
The maximum sinking current of each pin of the C1 camera is
150 mA. If the mount does not treat the autoguider port as logical
input only, but switches the guiding motors directly by these
signals, a relay box must be inserted between the camera and the
mount. The relay box ensures switching of currents required by the
Standard 6-pin Autoguider Port is located beside the
USB3 port on the top side of C1 camera
The Autoguider port follows the de-facto standard introduced by
SBIG ST-4 autoguider. The pins have the following functions:
||R.A. + (Right)
||Dec + (Up)
||Dec – (Down)
||R.A. – (Left)
C1 camera head is designed to be lightweight and compact to be
easily attached even to small telescopes or finders. Compact and
robust camera head measures only 57 × 57 × 48 mm not
including the lens adapter.
The head is CNC-machined from high-quality aluminum and black
anodized. The head itself contains USB-B 3.0 (device) connector
and standard 6-pin autoguider connector.
|Internal mechanical shutter
|Shortest exposure time
|Longest exposure time
||Limited by chip saturation only
||57 mm × 57 mm × 48 mm (excluding lens adapter)
|Back focal distance
for 1/32 UN thread (CS-mount compatible)
for M42 × 0.75
|Camera head weight
C1 cameras are supplied with two types of
Adapter with 1/32 UN thread and
12.5 mm Back
Focal Distance (CS-mount).
Adapter with M42 × 0.75 thread (T-thread)
and 18.5 mm
Back Focal Distance. This adapter also contains inner thread
1/32 UN with 12.5 mm BFD (CS-mount).
C1 camera with T-thread (M42 × 0.75) adapter (left)
and with CS-mount adapter (right)
CS-mount it compatible with vast number of CCTV lenses. If
C-mount lens has to be used (with 17.5 mm Back Focal Distance), simple 5 mm thick adapter ring can be used.
If the C1 camera should be used with OAG for
cooled Cx or Gx cameras, short 10 mm C-to-1.25” barrel adapter
has to be used. This adapter, shipped with respective OAG, is
fully compatible with C1 camera.
Note the C1 camera with
M42 × 0.75
(T-thread) adapter cannot be used with OAG, despite the short
CS-to-1.25" barrel adapter can be attached to it. The
large-diameter M42 adapter interferes with screws fixing the
camera in the OAG guider port. This is why C1 variant with
CS-mount only adapter is still supplied.
C-to-1.25” barrel adapter, compatible with standard 1.25”
eyepieces, is included into camera package. So, the C1 camera
can be easily mounted into virtually every astronomical
telescope instead of an eyepiece.
The T-mount interface (also known as T-thread adapter) is
defined by thread dimensions M42 × 0.75 as well as by
55 mm Back focal Distance.
T-thread adapter for C1 cameras does not comply to the second
parameter, its BFD is only 18.5 mm. The 55 mm
BFD is not required in all applications and keeping such
relatively large BFD would make the adapter quite bulky.
Still, an extension tube with male M42 × 0.75 thread is
available. This extension tube converts the C1 camera BFD to
55 mm, required by numerous
focal-reducers, field-flatteners, coma-correctors and other
There are two variants of the 55 mm BFD extension tubes
C1 camera with 55 mm
BFD extension tube with M48 × 0.75 thread (left) and
extension tube with M42 × 0.75 thread
The extension tube outer diameter is exactly
(50.8 mm), so it
can allow using of the C1 camera with any 2" focuser instead
of 2" eyepiece.
Tripod and metric threads
C1 camera bottom contains standard 0.25" (tripod)
thread and 4 metric M3 threaded holes
If the C1 camera is not attached to the telescope focuser
through its telescope/lens adapter, it can be attached to
standard photographic tripod using 0.25” thread. Another
possibility is to use 4 metric M3 threaded holes, also located
on the bottom side of the camera head.
Position of the four M3 threaded holes on the
bottom of C1 camera head
C1 Camera Dimensions
C1 camera head with CS-mount adapter front view
dimensions (left) and side view dimensions and Back Focal
C1 camera head with M42 × 0.75 adapter front
view dimensions (left) and side view dimensions and Back
Focal Distance (right)
Software and driver support of the Cx series CMOS cameras is as
rich as is the case of their Gx series CCD camera siblings.
However, latest versions of all software packages and
drivers has to be installed to use Cx cameras.
If the C1 camera is connected directly to host PC using
USB cable, a new system driver CxCamera.sys must be installed
(see the Installing and Using Drivers and Software
manual, shipped with every camera). The system driver
pre-installation package version 2.0 and later contains
When the C1 camera is connected through the Camera
Ethernet Adapter device, the device should be updated to
firmware version 34 or later to work with CMOS cameras
(see the Ethernet Adapter User's Guide for firmware
When the SIPS is connected to the
camera using the Camera Ethernet Adapter device, it shows the
attached device firmware version in the Windows Action Center
Linux driver packages and libraries must be upgraded to
latest versions, too. See the Download section of this site for
The SIPS (Scientific Image Processing System) software
package version 3.12 or later is necessary to control C1
Support for CMOS based Cx cameras was gradually added
to individual SIPS version. While previous minor SIPS versions
could be able to recognize C1 cameras, always use v3.12 or later
for reliable camera operation.
C1 camera drivers for 3rd party software
packages also need to be updated to work with C1 cameras.
Minimum versions for respective drivers are:
ASCOM drivers version 4.4
Drivers for TheSkyX (all versions for Windows,
MacOS and Linux) version 2.1
Astroart drivers version 3.1
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.