Does cooled camera can works without 12V power

What does 12v power supply can do?

It can power up the cooling system, and provide a extra power for USB HUB on the camera.

Do I need to plugin 12v power supply?

Not necessary. ASI cooled camera can work through USB3.0 cable, without extra power supply. The camera won’t be cooling, but it can works well like a uncooled camera.

Further more, if you have accessories (such as filter wheel) connected to cooled camera, it also can works without extra power supply.

What is Amp-glow and how do I manage it?

What is amp-glow?

Amp-glow is a generalized term and has been used in CCD era. It originally referred to “amplifier glow”, however these days it generally refers to any kind of “glow” in the image that is caused by the camera itself. Glows are areas of the image that become brighter than neighboring areas due to circuitry within the camera or sensor. Historically it was usually caused by aging amplifier circuit in CCD cameras, often appearing in an area of the frame near to the amplifier. With a CCD camera, most readout electronics are off the sensor, located on the circuit board around the sensor.

When it comes to CMOS cameras, “amp glow” is usually not from an amplifier. CMOS sensors are usually “fully integrated” which means that, unlike a CCD, readout electronics are included on the sensor die along with all the pixels themselves. Each sensor has at least one, often many, ADC (analog to digital conversion) and CDS (noise reduction) units on it. There are also other support circuits on the sensor die itself these days…clock generators and power supply regulators and such. These support circuits can generate heat or may even emit NIR light, both of which can cause glows. Additionally, many modern CMOS sensors include high performance image processing as part of the sensor package, either in the form of on-die processing or a secondary processor that is directly integrated into the sensor by attaching it (often to the reverse side of the sensor.) This processing circuitry can often generate heat that may produce glows.

Heat can increase the dark current accumulated in pixels. Pixels that exhibit roundish glows, usually soft without any obvious structure, are caused by heat sources. NIR, or Near Infra-Red, may also be emitted by some sensor circuitry. NIR glows can exhibit anywhere on a sensor, may often exhibit distinct structure, and are often radiated from specific locations around the periphery of the sensor. Not all pixels in a sensor will be affected, nor will those affected be affected uniformly. Glows may not “grow” with time the same way dark current itself does, and may accelerate over time becoming brighter faster than dark current itself as exposures become longer.

In some discussion forums, the term “amp” has been dropped, and the word “glow” alone is often used to describe the kinds of glows that occur with CMOS cameras.

What does the amp-glow look like?

The first step in managing glows is to understand how they present. Amp-glow patterns are often different from camera to camera depending on the kind of sensor used. Cameras such as the ASI128, ASI094, and ASI071 utilize high quality color digital camera (DSLR and mirrorless) sensors. These sensors are designed to more exacting standards as demanded by your average photographer, and amp glows are usually minimal and barely visible at worst (often just a very slight brightening in one corner or along an edge), and non-existent at best.

Other cameras that use more specialized sensors may exhibit amp-glow. The ASI1600, ASI294, ASI183 and ASI178 have distinct patterns. Here are a few examples:

ASI1600, it’s not so obvious


294 sensor


183 sensor


178 sensor


Does cooling help reduce amp-glow?

Generally speaking glows are not temperature sensitive. They are usually a more intense and often generated over a very short period of time (the duration over which the sensor is read), so even if there is a temperature dependency, the time involved often does not allow for much change with temperature. Heat-sourced glows may be affected to a small degree by temperature, however often by too little to matter in most cases, especially with the amount by which the sensor may vary during an imaging session (which should be no more than +/- 0.1 to 0.5 C).

Glows are usually not bright, however due to the exceptionally low read noise and very low dark current of most astro-specific cooled cameras, glows are often more visible. In this sense, glows can be affected by temperature, becoming easier to see under the low noise conditions of a properly cooled camera.

Does a DDR buffer reduce amp-glow?

Usually a DDR memory buffer will help minimize glows for many CMOS cameras. A DDR buffer allows the readout speed of the sensor to be maximized. This improved readout speed also applies for both USB 3 as well as USB 2 connections, although the benefits are usually more pronounced when used with USB 2.

A DDR buffer can help as much of the support circuitry for the sensor can be put into a low power mode during exposure. This additional circuitry then only “wakes up” during readout, which may only last for a short period of time, before they are returned to their low power mode. Minimizing readout time can minimize the intensity of the glows by restricting the amount of time they can affect the sensor. This process may work better for some cameras than others, and may affect some glows more than others, depending on the nature of each specific glow.

What is the Anti Amp-Glow Function?

The “Anti Amp-Glow Function” is a feature of ZWO cameras that utilizes a combination of software and/or hardware techniques to reduce the power consumption of the CMOS sensor and it’s support circuitry. This allows the glows to be better controlled…sometimes eliminated entirely, greatly mitigated or otherwise reduced in other cases. The Anti Amp-Glow Function’s benefits are most obvious on sensors such as the IMX224, IMX385, etc.

How to remove the glow in my light frame?

It is possible to remove amp glow from most CMOS cameras. Glows, like dark current, generally behave in a consistent manner under consistent conditions. As long as you control the conditions, then proper management of glows, their removal from your lights and minimization of their impact, can be done with ease.

The first step is to control the conditions. Glows are removed by subtracting a master dark frame from each of your light frames during the calibration process. The dark frame “models” the nature of the fixed pattern noise and glows of the camera. For this subtraction to be effective, you must make sure that your dark frames match the light frames in terms of exposure time & sensor temperature. You must also make sure that the dark frames are acquired at the same gain and offset settings as the light frames. This ensures that the pattern of the glows matches that in the lights identically.

The next step is to properly subtract the glows out of the lights. You must first create a proper master dark frame. Acquire a number of individual dark frames at properly matching settings to the light frames you wish to calibrate. Usually 20-30 frames will do, however if you are stacking hundreds of thousands of frames, a cleaner master produced from as many as 50 or more dark frames may help. Once you have created a master dark frame, calibrate your lights. Unlike CCD cameras, to ensure you properly remove glows, you should only subtract just the master dark. Do not use a master bias. A master flat may still be used.

Most importantly, make sure you disable any dark optimization feature of your calibration program. DSS, PI, and other programs have dark optimization features, and they are often enabled by default. Optimization will scale the master dark, which will usually result in a mismatch with the glows in the light frames. This can leave behind “remnant glow” as a small amount of slightly brighter pixels in the area where the glow was that eventually sum up to re-form the glow in the final integrated image. Alternatively it may leave behind “inverted glow” or “ghost glow”, which is a small amount of slightly  darker pixels in the area where the glow was that eventually produce a dark, inverted version of the glow in the final integrated image. By disabling dark optimization or dark scaling in your calibration program, you will ensure that the master dark frame properly calibrates each light frame.


Naming Rule of ASI Cameras

Applicable Product(s) : All ASI Cameras

Description: Help you to understand naming rules  of ASI cameras.

What should I prepare?

Buy an ASI camera 😀

Why the cooler does not work?

Applicable Product(s) : ASI Cool and Pro Cameras

Description:  Why the fan does not run? Why the temperature does not go down?

What should I prepare?

  1. Install ASI Camera drivers
  2. install latest capture softwares


  1. Make sure a 12V DC power cable is connected and the red LED is on. You can use an AC-DC adapter, or a 9V-15V battery. And the connector must be a 2.1×5.5mm center positive standard. The red LED indicates that the external power supply works.
  2. Check the fan runs normally .(The fan only runs when you enable the camera cooler in compatible software. The fan will not run when the cooler is not powered .)
  3. If the cooling temperature does not change, but the cooling power rise and reach 100%, and the camera body is warm   the Temperature sensor probably is damaged.
  4. If the cooling temperature does not change, but cooling power rises and reaches 100%. And camera body does not getting warm, the power chip probably is damaged.
  5. Try another power adapter to check.

Why is the preview screen completely white but the FPS appears to be normal?

Applicable Product(s) :All ASI Cameras
Description: When you use ASI camera for the first time, you may bump into some problems, this post will help you get familiar with your camera ASAP.

What should I prepare for imaging?
Install ASI Camera drivers
Install latest capture softwares
Q: Why is the preview screen completely white but the FPS appears to be normal?
A: It may occur due to the overexposure. You need to reduce the exposure setting or reduce the gain setting until you can see the image on the screen. If you can see the fps changes ,then the camera is working properly.

Why the preview screen is black and the fps is “0”?

Applicable Product(s) : All ASI Cameras

Description: When you use ASI camera for the first time, you may bump into some problems, this post will help you get familiar with your camera ASAP.

What should I prepare for imaging?

  1. Install ASI Camera drivers
  2. Install latest capture softwares


  1. Please try to slow down the capture speed by reducing the “USB Traffic”. Also try to connect the camera to your PC directly without a USB hub or extender if reducing “USB Traffic” still does not work.
  2. Use another USB cable and try again.
  3. Use another USB port of the computer and try again.
  4. Use another computer and try again.

Which configuration gives me maximum FPS?

Applicable Product(s) : All ASI Cameras

Description: Some settings will cause your FPS to drop below peak rates, this post will tell you how to reach maximum FPS for your camera.

What should I prepare?

  1. Install ASI Camera drivers
  2. Install latest capture softwares


  1. Make sure the camera is connected to USB3.0 port if it’s a USB3.0 camera. Check that the camera is recognized as “via USB3.0”. (Device Manager in Windows) Update the computer’s USB Host Controller driver if your port is USB3, but camera is not showing up as USB3.0 device.
  2. Make sure that the “High Speed Mode” is on in the capture software, location varies by software.
  3. Adjust “USB Traffic”, we recommend 80-90%. This value depends on your computer, higher percentages require more resources to be successful and not drop frames.
  4. Exposure time limits FPS, your frame rate will never exceed your exposure time settings. For example, the FPS will be 1FPS when the exposure time is 1 second, 4fps at .25 seconds, etc.
  5. The write speed of an SSD (solid state disk) is significantly faster than an HDD (spinning platter traditional hard drive). SSDs usually have a buffer of about 1GB, over a 1GB data steam and the write speed of  an SSD will slow down.

Reason of Field Tilt problems and how to solve it

Applicable Product(s) : For All ASI Cameras Description: Field tilt problems usually happen in imaging. Optical axis, flattener lens, adapters, and sensor tilt are all causes of field tilt in images. This post is to help diagnose which issue is causing your field tilt problem.
What do I setup to test? Your imaging setup is connected to the computer and there are many stars in the field of view.
Q: How do Itest if a tilt problem is caused by my telescope or by my camera?
A: Take an image with your camera then rotate the camera 180 degrees (the telescope telescope doesn’t move). Thentake another image of the same field of view. Analyze the images with software, such as CCDInspector 2.5.3.
If the field has an identical pattern after rotation, then the camera has a tilt problem.
If the field has the same problem, but it has rotated 180 degrees, the telescope has a tilt problem.

Q: How to make sure tilt problem caused by adapters?
A: 1. Remove suspect adapters, connect the camera directly to the telescope.
2. Try another adapter.
3. Take another set of images to test if the problem is gone
Q: I use a field flattener or a flattener/reducer, but I see coma in the corner of image.
1. Usually this is caused by incorrect back focus (spacing between the reducer and camera sensor). Use suitable adapters make sure your camera is at critical back focus for that flattener or reducer.
2. Your image circle for that flattener or reducer is smaller than the camera sensor.

How to get the best performance from your cooled camera?

We always got feedback from the customer that the camera cannot cool to the advertised temperature

Here may be the reason the camera cannot cool so much:

  1. Misunderstanding: 30 delta degree means 30 degrees below ambient instead of -30 °C.
  2. Make sure you plug in the 12V DC power supply and the LED is on which mean there is power.
  3. Make sure the 12v power supply can provide enough power for cooler, we recommend 12V @3A and up, such as 12V@5A is ok too.
  4. The sensor emits more heat when run video streaming mode, so cooler cannot cool it so deeply, you can cool it deeper with long exposure mode.
  5. The cooler runs effectively in summer than winter, so if it’s already 0 degree, the camera maybe can only cool to -20 degrees.
  6. If you use ASI071, ASI094, or ASI128 cameras, you can turn off the anti-dew function to maximize cooling capability.
Why does “Unknown device” show in the device manager after connecting the camera?

Applicable Product(s) : For All ASI Cameras Description: When you use ASI camera for the first time, you may bump into some problems, this post will help you get familiar with your camera ASAP.
What should I prepare?

  1. Install ASI Camera drivers
  2. Install latest capture softwares

Answer: Because the driver was not installed properly. Try to install the driver again. You may need to stop any anti-virus software to run the installer program. (
NOTE: Make sure you download the driver from the ZWO official web site or from the CD-ROM to prevent any malware problem!)

Please update the driver manually if re-installation doesn’t work.

Right click the “Unknown device”, choose the “Update Driver Software…”option and choose the driver directory. Normally, the driver directory is under:
C:\Program Files (x86)\ZWO Design\ZWO_USB_Cameras_driver\

Why won’t my camera run continuously on a laptop without external power?

Applicable Product(s) : All ASI Cameras
Description: When you use ASI camera for the first time, you may bump into some problems, this post will help you get familiar with your camera ASAP.
What should I prepare?

  1. Install ASI Camera drivers
  2. Install latest capture softwares

Due to the power saving mode of your laptop (mostly by default option), many laptops allows the USB power to suspend operating when your laptop enters to Low Power Mode. You need to disable power saving option of the USB port:
Disable power saving option of the USB port