Articles Gx cameras articles  | | New cooled CMOS cameras C1+7000 and C2-7000 offer quite large
pixels of 4.5 μm, especially compared to majority of other CMOS based
cameras available. As CCD sensors, often employing much bigger pixels,
are no longer available, even relatively small increase in pixel size of
a CMOS sensor significantly increases some key parameters like dynamic
range (pixel area and thus also a number of electrons each pixel can
accommodate corresponds to the square of pixel dimension). (more...) |
 | | C1 cameras can be newly equipped with adapters for Canon EOS
and Nikon bayonet photographic lenses in addition to already announced
adapters with M42 × 0.75
(T-thread) and M48 × 0.75
threads with 55 mm Back Focal Distance.
Similarly to threaded adapters, bayonet lens adapters are attached to
combined M42 × 0.75/CS-mount adapter on the C1
camera body. So, they are not compatible with C1 cameras with CS-mount
adapter only. (more...) |
 | | Small, uncooled CMOS cameras of the C1 series (as well as G1
series with CCD sensors) are traditionally equipped with CS-mount
threaded adapter. This adapter allows usage of wide variety of CCTV
lenses with CS-mount (and with the help of simple 5 mm thick ring also with C-mount).
CS-to-1.25" barrel adapter, supplied with every camera,
enables using of these cameras with virtually any telescope instead of
standard 1.25" eyepiece. But 1" diameter of the
CS-mount thread is a limiting factor for newly introduced C1-12000
camera with large sensor. So, new adapter, combining both CS-mount and
T-mount threads, was introduced for all C1 cameras. (more...) |
 | | Gx Mark II cameras are available in many variants — individual G2, G3 and G4 series offer camera integration
with internal or external filter wheels, Off-Axis Guider adapters,
various threaded adapters as well as standard Canon EOS and Nikon lens
bayonet adapters etc. One of the distinguishing feature of Mark II
cameras is the telescope/lens adapter interface allowing precise
adjustment of optical axis (sensor tilt). Despite the vast variability
and many options, the Gx Mark II camera system was designed to maintain
adapter-specified back focal distance of adjustable adapters on all
camera variants. (more...) |
 | G3 Mark II cameras | Updated: 26.11.2020 |
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 | | G3 CCD cameras offer all essential astronomical camera
features like great sensitivity, low noise, efficient and regulated
cooling, robust design, rich set of accessories and software support and
especially large sensor area for affordable price. And Mark II series of
G3 cameras inherits all these features, but brings some significant
enhancements, like much faster download speeds and adjustable (tiltable)
telescope adapters. (more...) |
 | G4 Mark II cameras | Updated: 26.11.2020 |
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 | | G4 Mark II cameras inherited all proven design concepts and
features from the previous generation, like precise electronics
providing uniform frames and extremely low read noise, efficient
regulated CCD cooling, reliable mechanical shutter, modular mechanical
construction ensuring compatibility with wide variety of accessories
including off-axis guider adapters, external filter wheels, Ethernet
adapters, guiding cameras etc. But Mark II cameras bring some important
enhancements, like much faster download speeds and adjustable (tiltable)
telescope adapters. (more...) |
 | G2 Mark II cameras | Updated: 26.11.2020 |
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 | | The cooled G2 series Mark II CCD
cameras were developed for imaging under extremely low-light conditions
in astronomy, microscopy and similar areas. Design of this series
inherits from earlier G2 Mark I cameras but
brings some significant enhancements. G2 cameras employ precise
electronics providing uniform frames and extremely low read noise
limited only by CCD detector itself. Modular mechanical construction
allows various camera variants to be combined with rich set of
accessories, including telescope adapters, off-axis guider adapters,
internal or external filter wheels, Ethernet adapters, guiding cameras
etc. (more...) |
 | | Gx series of cooled astronomical cameras evolved through many
revisions, each bringing improvements, new features or just more
aesthetic design. We are proud these cameras are now used to capture
state-of-the-art astrophotographs (just see our Gallery section) as well as to acquire
professional-grade research data. Now we introduce redesigned cameras
with important enhancements, so they deserve denotation Mark
II. (more...) |
 | | Fast Newtonian telescopes provide excellent price/performace
ratio. They offer greatest aperture for the money, because their optical
design if very simple, elegant and efficient. When a Newtonian telescope
is build from high quality component (Pyrex mirrors, carbon tube, robust
mirror holders and focuser, ...), they are hard to beat by any other
optical design. The only problem remains — parabolic mirror creates perfect image on the optical axis
only, aberration called coma distorts the image as the field of view
increases. Fortunately advanced refracting correctors eliminate this
aberration and help to make Newtonian the perfect wide-field
instrument. (more...) |
 | | While the Gx cameras are firmly attached to the telescope
focuser in most cases, sometimes they are used with photographic lenses,
which lack any means for attachment to the telescope mount. While the G2
camera body offers standard tripod thread, larger G3 and G4
models did not allow for such threaded hole due to internal arrangement
of CCD cold chamber. But we slightly redesigned the G3 and G4 front
shell as a response to request from our users and introduced two
standard 1/4" threaded holes close to the edges of the camera top side.
These holes can be used to attach new 1.75" dovetail
adapter (Vixen standard) for safe attachment of camera head to almost
any telescope mount. (more...) |
 | | It is always encouraging when we realize that our users love
their Gx cameras, that they are not only satisfied with their
state-of-the-art performance and functionality, but they also appreciate
the industrial design and manufacturing quality. Still, many users, in
particular among the amateur astronomer's community, appreciate also the
aesthetics of their equipment — color anodized parts of mounts,
telescopes or focusers are good examples. Despite the camera head
dimensions and shape are constrained by its features, we always took
care to achieve the clean and functional design. Now we decided to offer
variants of our G2, G3, and G4 cameras with a slight color touch to
allow users to unify the camera appearance with the rest of their
setup. (more...) |
 | | The smallest XS variant of the external filter wheel for G2
cameras offers 7 positions for unmounted D36 mm filters. Because filters are further from the
sensor in the case of external filter wheel compared to internal filter
wheel, greater filter diameter allows usage of the G2-8300 camera with
largest sensor within G2 series to be used with fast optics without
vignetting. But other models of the G2 series contain smaller sensors
and they can work D31 mm filters. A
possibility to build a new variant of the XS external filter wheel for
D31 mm filters occurred. Smaller filter
diameter allows increasing of the number of filter positions from 7 to
8, despite the external filter wheel dimensions remain
unchanged.. (more...) |
 | | The Gx Camera Ethernet Adapter allows connection of up to four
Gx cameras of any type over an Ethernet. Because the communication is
handled over the TCP/IP network, the distance between camera and the
host PC is virtually unlimited. The Ethernet port of the adapter device
can be attached to arbitrary WiFi bridge device to access attached
cameras wirelessly. However, such solution needs another box (the
Ethernet/WiFi bridge device) with another power supply etc. This is why
the Gx Camera Ethernet Adapter firmware was extended with support for
USB/WiFi interfaces. (more...) |
 | | While answers to many questions cannot be universally true, as
it depends on who you ask, the answer to question What is the
optimal number of filter wheel positions? is 7 for vast majority of
users. Astrophotographers need Red, Green and Blue filters for
true-color photography and narrow-band Hα, OIII
and SII filters, plus one position for clear or luminance filter.
Researchers could live with 6 positions for NUBVRI filters, but one
spare position, which could be left clear, is often useful. (more...) |
 | | No optical setup is capable to cover really wide field of view
without refracting correction elements. Even the best and most expensive
APO refractors and RC reflectors need field-flatteners if a 50 mm diameter field has to be utilized. With a little
exaggeration, spending money for premium optics, which must be corrected
either way, is not necessary when much cheaper optics with a quality
corrector provide the same results. And in reality well corrected
Newtonian reflectors proved to be the best wide-filed, large-diameter
telescopes available to amateurs. The trick is in the refracting
correction element just in front of the camera, which eliminates the
so-called coma aberration, inherent to simple parabolic
mirrors. And the 3" Wynne coma correctors belong among the best
available. (more...) |
 | | CCD dark current halves with every ~6°C, so keeping the CCD sensor at low temperatures is a
key feature of scientific CCD cameras, allowing long exposures not
ruined by excessive dark current. The CCD cooling can achieve up to
50°C below the ambient temperature, which
leads to below-freezing temperatures of the sensor in all cases. This is
why it is crucially important to place the cooled detector in the
hermetically sealed chamber else it would be covered by the water ice
within minutes. And the chamber must be dried by a desiccant, because
even the residual humidity in the air is enough to create frozen ice
patterns on the sensor, harming the images. New design of the desiccant
containers of the Gx cameras allows more comfortable desiccant exchange
and easier desiccant regeneration. Also a new variant of the container
was introduced, designed to allow tool-less container
replacement. (more...) |
 | | We are proud our company could provide feedback when OnSemi
designed the new KAF-16200 CCD sensor. What is so special about this
CCD? Simply put, it is designed to be the best possible sensor for vast
majority of astrophotographers and astro-imaging enthusiasts around the
world. While there are even greater detectors available, like KAF-16803
in the G4-16000 camera, such huge sensors require at last 3" focusers
and field correctors to cover them with good quality image. As opposite,
KAF-16200 in the newly introduced G3-16200 camera fits within the field
of view of typical 2" focusers and optical correctors, used on absolute
majority of amateur scopes. And at the same time it leaves almost no
field of view area uncovered, so it allows capturing of really stunning
wide field images. In association with great 16MPx resolution and 6μm pixels, low read noise and
dark current, above average sensitivity and especially uniform and clean
field of view, G3-16200 is an ultimate imaging camera for majority of
amateur telescopes. (more...) |
 | | Dark current, injecting electrons into CCD pixels regardless
if the sensor is illuminated or not, is the most important source of the
unwanted signal. As the dark current is caused by random processes, it
exponentially depends of the sensor temperature — typically the dark current is halved with temperature drop
by every 5 or 7 degrees Celsius, depending on the particular sensor.
While dark current can be to some extend removed from images during
calibration (subtraction of the so-called dark frame), the
random portion of the signal always remains in the image. This is why
the CCD sensors in cameras intended for very low light imaging (and thus
allowing for many minutes long exposures) are always cooled. Despite the
inherent dark current of the OnSemi detectors, used in the Gx series of
CCD cameras, is relatively small, sometimes the camera is used in hot
environments and more effective cooling is required to lower the dark
current. (more...) |
 | | Adapter complying to the newly emerging de-facto standard of
the M48 × 0.75 thread, but
preserving the 55 mm distance to focal
plane similarly to M42 × 0.75 based T-thread, is available
for G2 and G3 cameras. (more...) |
 | | G2 series of small format CCD cameras uses high sensitive, low
noise OnSemi Full-Frame and Interline-Transfer CCD detectors. While
high-speed USB 2.0 interface allows plug-and-play operation and ensures
download time within a few seconds, optional Ethernet interface provides
camera connection to practically unlimited distance. Advanced analog
electronics ensures uniform frames without artifacts and very low read
noise. Efficient, regulated two-stage Peltier cooling keeps detectors
frozen to minimize dark current. Compact and robust camera head
integrates all electronics, mechanical shutter and optional internal
filter wheel. Various threaded and bayonet adapters enable attaching of
the camera to almost any optical system and numerous accessories like
autoguiding cameras, off-axis guider adapters, external filter wheel
etc. allow tailoring of the imaging system to almost every
application. (more...) |
 | | All technical products undergo incremental refinements and
numerous innovations affected also the cooled CCD cameras of the Gx
series. Changes are only subtle from the outside point of view, despite
a small facelift of the G2 camera head. Updates of the internal design
are more significant, but key features like extremely low read noise,
efficient cooling etc., which position Gx cameras on top among similar
products, are of course remained. (more...) |
 | | Despite the fact that the G2 and G3 cameras share the same
adapter mounting interface, Off-Axis guiders
for G2 cameras with either M42 or M48 variant of mounting thread
cannot be used with G3 cameras. The mirror reflecting light to guiding
camera inside the G2 OAG is positioned too
close to the optical axis that it partially shadows larger CCD detectors
of G3 cameras. And G4 cameras use even greater detectors and their
adapter mounting interface is also larger. Off-Axis guiders for G3 and
G4 cameras have to be designed from the ground up to place the mirror
feeding the guiding camera with light as close to the optical axis as
possible on the one side, but not to cause vignetting (shield the main
CCD detector) on the other side. (more...) |
 | | New autoguiding camera G1-0301 has the same resolution like
the G1-0300 model, but it has bigger pixels and thus also bigger CCD
detector. Greater detector area (6.5 × 4.9 mm compared to
4.9 × 3.7 mm) and especially 80% larger pixel area bring
proportionally higher sensitivity compared to G1-0300. This is why
G1-0301 can be used with guiding telescopes with long focal length and
also with Off-Axis Guider adapters. (more...) |
 | | Several reviews of Gx CCD cameras appeared in both printed and
online publications. The printed review of G2-8300 was published in the
British Astronomy Now magazine, online site cloudynights.com published
review of G4-16000 and external filter wheel. You can check them for
yourselves. (more...) |
 | | Front-Illuminated Full-Frame CCD detectors suffer from kind of
visual memory effect. Bright parts of the previously acquired
image are visible as weak and blurred image on the following exposures,
even if they are dark frames, taken with a shutter closed. This effect
is called Residual Bulk Image (RBI) and it can harm long exposures,
create false images of nebulae or traces of bright stars. It is possible
to deal with RBI if we understand mechanisms behind this
effect—we can adopt the observing program or it
is possible to eliminate RBI by leveling the conditions within CCD using
the near infra-red light flood before every exposure (IR
preflash). (more...) |
 | | The G1 series of CCD cameras was extended with a new model
G1-1200. The Sony ICX445 CCD detector, used in this camera, is produced
using EXview HAD technology and offers high
quantum efficiency, comparable to cameras employing much more expensive
ICX285 CCD. The 1/3" detector format (4.9 × 3.6 mm) as well as small
pixels (3.75 × 3.75 μm)
suit to short focal length guiding telescopes. G1-1200 is also good for
capturing Moon and planets. (more...) |
 | | Guiding of telescope mount is a necessity for really long
exposures even if a high-quality mount is used and mass produced
cheap mounts require guiding even for short exposures. Guiding
camera repeatedly images a selected star or a star pattern. Computer
calculates differences in measured position and performs slight
corrections to the mount to compensate for mechanical irregularities and
other factors, e.g. refraction. Guiding camera can be attached to
separate guiding telescope or off-axis guider can be used to feed the
guiding camera with the light gathered by the main telescope, used for
imaging. If the guider camera uses the same optics as the main imaging
camera, it is crucially important to divert the light for it before the
light reaches the filters. Numerous filter has so low light transmission
(e.g. photometric B or UV filters, narrow-band filters etc.), that they
effectively disable guiding with the exception of a very few very bright
stars. (more...) |
 | | Cooled CCD cameras of G4 series contain detectors with
36 × 36 mm area, which is 50% more than
photographic full-frame format. G4 camera dimensions are the
same like dimensions of G3 series, with the exception of camera head
thickness—G4 cameras are somewhat slimmer,
because they do not contain internal filter wheel. Also camera handling,
software control, power supply and connection to the host PC using fast
USB 2.0 interface is the same like in the case of G3 cameras. Filter
wheel for 50 × 50 mm square filters (round filters of 50 mm diameter cause vignetting on such large CCD chips)
cannot be placed inside the camera head due to limited space. But it is
possible to connect external filter wheel for 5 large filters to the G4
camera, the camera head already contains connector for external filter
wheel control. (more...) |
 | | Gx CCD cameras are available in many variants. There are small
guiding and planetary G0 and G1 cameras, cooled G2 series, large format
G3 and G4 series. G2, G3 and G4 cameras are provided without filter
wheel and with internal or external filter wheel. These variants have
different mechanical dimensions and naturally offer different back focal
distance. (more...) |
 | | Cooled CCD cameras of G4 series contain detectors with
36 × 36 mm area, which is 50% more than
photographic full-frame format. G4 camera dimensions are the
same like dimensions of G3 series. Also camera handling, software
control, power supply and connection to the host PC using fast USB 2.0
interface is the same like in the case of G3 cameras. Filter wheel for
50 × 50 mm
square filters (round filters of 50 mm
diameter cause vignetting on such large CCD chips) cannot be placed
inside the camera head due to limited space. But it is possible to
connect external filter wheels for 5 or 7 large filters to the G4
camera, the camera head already contains connector for external filter
wheel control. (more...) |
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