ZWO Color Astro Camera ASI294MC Pro cooled - Sony Sensor D=23.2 mm

ZWO ASI294MC Pro - cooled Colour CMOS Camera for Deep-Sky Photography

ASI cameras stand for very good workmanship and have modern CMOS sensors installed. This camera uses the state-of-the-art "back-illuminated" Sony IMX294CJK sensor with four thirds size.

Sony specifies a sensor diagonal of 21.63 mm. However, measurements by ZWO have shown a true diagonal of 23.2 mm. The 4.3 µm pixels of the ZWO ASI294MC make this camera an all-rounder with highest sensitivity for short exposure times.

The "single shot" color camera offers more comfort, compared with MONO cameras. Not everyone wants to follow through the laborious L-RGB technique for beautiful colored nebula or planetary images. The color cameras offer a possibility to get beautiful images without changing filters. However, good broadband nebula filters (see recommended accessories) reduce light pollution and increase contrast without being changed or colouring the image too much.

Advantages and features of the ASI MC294MCPro color camera:

USB 3.0 for a fast download - can also be used with USB 2.0

DDR3 memory buffer to help improve data transfer reliability. Additionally, the use of a memory buffer minimizes amp-glow, which is caused by the slow transfer speeds when the camera is used with a USB 2.0 port.

Powerful Peltier cooling up to 45 °C below environment.

Powerful Peltier cooling up to 35 °C below ambient

Sensitive CMOS sensor with 23.2 mm diagonal - 11.7 megapixels

Good resolution through 4.63 µm pixels

Comes with AR protection window - full transmission also in IR. If infrared should be blocked, an IR-cut filter is necessary.

Distance from T2 connection thread (female) to camera sensor: 17.5 mm

Very high sensitivity - QE more than 75% - ideal astronomy camera for dim objects

14bit ADC

HCG mode - if gain is higher than 120 (12 dB), read noise is reduced below 2e- - result: low-noise images despite extremely high sensitivity.

Full well capacity 63700 e - even bright stars do not burn out anymore, you get a better signal-to-noise ratio.

Application ranges of the camera:

Deep sky images (nebulae and galaxies): Due to the high sensitivity, nebulae and galaxies are captured after only a few seconds. By cooling down the camera up to 35 °C below ambient, the already low noise can be further reduced. By increasing gain (like the ISO setting of DSLR cameras), you can reduce exposure times below 30 seconds. Effects from seeing or inaccuracies of the drive are eliminated.

Lunar and planetary images: extremely short exposure times (due to high sensitivity) freeze the seeing. Through the high resolution of the sensor, many details can be reproduced even at shorter focal length. Video astronomy is also possible.

Important: external power supply required!

Please notice that all ZWO cameras with cooler need to be connected to an external 11-15 V power supply to work.

Even when the cooler is not being used the power supply must be used for the camera to be reliably recognized.

Optimal support by Teleskop-Service before and after purchase:

We work with the cameras ourselves and can offer you optimal advice. Which camera matches your telescope, how do you achieve optimal adaption ...

Teleskop-Service is one of the biggest ZWO dealers. Due to our contacts, we offer best possible service also after purchase.

Practical tip 1 from TS: Integration of 2" filters, 360° rotation and quick coupling

The camera is often used on correctors that do not have a filter thread. In addition, the filters should always be used as close as possible to the camera. Here we offer you a solution that can do much more.

2" filter holder directly in front of the camera

360° rotation for the right choice of the image section

Quick release - you can remove the camera from the remote ear at any time, without screws and thus entangling the cables

The adaptation is very simple, the 21 mm T2 extension is replaced by:

1x TSROTT2-T2 and 2x T2AbstimmA1

One tuning ring comes to the camera side, one tuning ring comes to the telescope side of the rotator. Then screw on the M42-M48 adapter with 16.5 mm length and you are in the right distance with the camera.

Practical tip 2 from TS: Storage of cameras and accessories

Especially in our latitudes, the nights are often very humid. This humidity condenses on your camera, eyepiece or filter when they come into the warm interior of the apartment. Especially cooled cameras are affected by this. Quickly a photo session is over because the sensor ices up.

[*Good storage is an important prevention against dew and also extends the life span.]

After use, put the camera immediately into the TS Protect Case and add some silica gel. During storage, the silica gel will suck the moisture out of the camera. At the same time, the penetration of humid room air is prevented. Dry storage even allows the small dry tablets in cooled cameras to partially regenerate. Your camera or accessories are always ready for you in optimal condition. You can find the silica gel and the case in our product recommendations.

The cameras are not airtight, so if the camera remains on the telescope, it is exposed to moisture. The small amount of desiccant in the camera can protect the sensor and the inside of the protective glass from moisture for the duration of the exposure, but not for days on end. Moisture problems can be the result. A simple trick is to stretch a plastic bag around the focuser to which the camera is attached so that no air can get in. Silica gel is placed in a small cloth bag inside the plastic bag. This will also create a "dry climate zone" for the camera on the telescope. This allows you to leave the camera on the telescope for a few days for an imaging session lasting several days.

In the medium and long term, however, this is no substitute for proper storage in an airtight case with silica gel.

Downloads, drivers:

ZWO provides software and drivers online for free download.

Software and drivers for all ZWO cameras

Frequently asked questions about ZWO cameras:

The FAQ area is constantly updated by ZWO, here you will find answers to many questions.

FAQ about ZWO cameras

ZWO Users Forum

Manuals for ZWO products:

The manuals page is constantly updated by ZWO, here you can find user guides for ZWO products.

Link to the manuals

How to clean my ZWO camera:

The manufacturer provides a manual that covers how to clean an ASI camera and regenerate the desiccant tablets: Please click here.

Astrophotographic results obtained with this camera on Astrobin

Here you can find some astrophotographs made with this camera model: Link to Astrobin

Astrophotographic results obtained with this camera on Astrobin

Here you can find some astrophotographs made with this camera model: Link to Astrobin

Cooled ASI cameras - quick guide

Quick Guide for the quick first use of your cooled ASI camera.

Link to the manual in English - PDF file

Sensor cleaning and desiccant cartridge replacement

Here you will find tips on how to identify where the dirt is and how to clean the sensor or change the drying cartridges.

Link to the manual in English - PDF file

Deep-sky photography with cooled ASI cameras with high resolution - without guiding - "lucky imaging" principle

The cooled cameras from ZWO offer new and extremely exciting opportunities in the field of deep-sky photography. Finally highly resolving, smooth deep-sky images without great effort!

With conventional CCDs, there is still a race taking place to the longest single exposure times (some of us know that from imaging with film). But long exposure times for each single frame place various demands and come with a few problems:

Perfect guiding / autoguiding

Calm air for fine details

Furthermore, airplane and satellite tracks on long exposure single frames are very annoying.

With the new CMOS sensors which are have been installed in the cooled ASI cameras from ZWO, you can tread indeed entirely new paths. It does not count anymore how long you expose, but how often!

Two of the biggest advantages of these new cameras are the extremely low readout noise, despite the high frame rates, and the enormous sensitivity of the sensors. In combination, these advantages are the key to impressive high-resolution images. The signal-to-noise ratio is excellent. The more frames are recorded, the more noiseless and deeper the summary image will become. Basically it is the same as with planetary imaging. Hundreds or even thousands frames are stacked.

The limit is set mainly by the capacity of the hard disk. The following should be kept in mind: while a conventional 16 megapixel CCD camera need up to 15 seconds for transfering a single frame to the PC, a CMOS camera like the ASI1600 can transfer up to 23 frames per second (of course depending on the exposure time). At an exposure time of 5 seconds, the CCD would achieve just under 3 images per minute, an ASI1600 approximately 12 images! So we can take 300% more exposures in the same time.

There are several free programs for imaging and editing (stacking) which can help us here, for example Firecapture. Many know this software already from planetary photography, but Firecapture can also be used for deep-sky images. It can control the cooling of the camera, create a dark and also a flat and subtract automatically, save in FITS format, and even do autoguiding. But we only need the latter for this type of deep-sky photography if the mount is not polar aligned properly or other extreme tracking errors are foreseeable.

Apart from that, we now just have to: set the exposure time to a value between 1 and 15 seconds. Set gain not too high but also not overcautiously low (approximately between 100 and 350), and take at least 200 single images.

A concrete example (Fig. 1):

We use a ZWO ASI1600MMC, a 300/1500 Newtonian telescope plus coma corrector on an EQ6. A fast(er) aperture ratio promotes short exposure times, of course.

Firecapture is started and the image is focused on a bright star with still short exposure times (<1s). Normally, a usable star can be found in the preset image field.

A check mark is set at 16Bit (top left) and the file type FITS is chosen. Exposure time is set to 5 seconds, gain set to 321 (without particular reason). Thereby the image noise still stays within acceptable limits. Cooling can be set at pleasure or matching the power supply. Gamma stays at 50. USB traffic is not relevant in this case.

Now set the mark at Dark Frame. Firecapture then takes the selescted number od dark frames (don´t forget to cover the telescope aperture) and subtracts their mean value from the single images. The few hot pixels disappear. Amplifier glow is no longer an issue.

Set as exposure number limit are, for example 1000 frames. However, it should be kept in mind that, in the case of the ASI1600, a single image has a size of 16 MB. A few hundred single images quickly result in a few gigabytes of data. It should always be ensured that a storage location is selected which is able to handle this amount of data.



Abb. 1


When the sleep-stealing part is over and the hard disk filled with raw images, it is recommended (for example with the program Fitswork) to classify them and to sort out possible "duds" with satellites, airplanes, wobbles, etc. One could also stack the frames with Fitswork, but with Autostakkert!, stars and details become finer. However, stacking with Fitswork makes sense if manual intervention is necessary, for example if much displacement between the single frames.

Attention - if you want to load the single images in Autostakkert!, the file type "Image files" has to be chosen. Then a bright star is selected as anchor point and clicked on "Surface" under "Image stabilisation" (just under the "open" button). "Planet (COG)" can also work with bright objects which have an obvious centre of brightness, but mostly, "Surface" is more succesfull. At this point, you click the button "Analyse". (Fig. 2)



Fig. 2


When this has been completed, a bright star is selected as "alignment point" again. You can set several ones, but it is not necessary (except with image rotation or similar problems).

Time to click on the "Stack" button. Now the single images are stacked.

The final result is saved by Autostakkert! in the chosen image file format (in any case, choose a 16-bit format like TIF or FITS).

The difference between a single frame and the summarized image becomes astonishing. (Fig. 3)



Fig. 3 histogram enhanced



At the beginning of the processing, the summary image will seem quite unremarkable and dark, but with the help of a histogramm adjustment, the object of desire emerges quickly. (Fig.4)



Fig. 4


Important! For further processing, a program should be used which can handle 16 bit and the corresponding formats! Once again, Fitswork is well suited for that. However, many amateur astronomers will use Photoshop for the final touches.

We suspect that one could intensely debate how long the maximal single exposure time should be. However this rule applies: the shorter, the crispier. Short exposures are less disturbed by seeing. Guiding errors carry no weight. Therefore, the attainable accuracy is accuracy is significantly better than with exposures of several minutes.

On the other hand, the (areal) brightness of the object must be taken into account, after all we need a bit of signal on the sensor.

Of course, you can also expose several minutes with the cooled cameras from ZWO. There is nothing to stop you from taking short focal length photographs, for example of nebula regions. One can definitely use the ASIs like a ctandard CCD camera. But this slightly different approach with short exposure times offers many amateurs astronomers the possibility for imaging nebulae and galaxies with additional details. Given the increasing light pollution in many places, this might possibly the long-awaited life belt for this wonderful hobby.

This photo technique is only just beginning and still offers many opportunities. We will continue, get involved!

Your Teleskop-Service Team

Question:
Will my Pro camera work without extra power supply if I don´t turn on the cooling?

Answer from Teleskop-Service:
No, the current Pro cameras always require extra power supply, even without cooling.

Safety informations: PDF Download