Review/Test of Cooled QHY178M Astro Camera – part 1

First impressions

Not so long ago I received my shipment of QHY containing a test model camera QHY178M packed in a tasteful suitcase like Peli Case. This is new series QHY ColdMOS camera. Is mainly characterized by a two-stage cooling of the sensor allows the camera to cool down to 45° C below the ambient temperature. All this is to reduce thermal noise cameras and give the clearest possible picture …

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At first glance, the camera makes a very good impression. Black anodized aluminum housing is very good quality, everything is closely matched and there are no mismatch.

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Front camera equipped with a ring, the outer diameter of 2”. Dovetail mount allows to mount camera to a dedicated filter wheel QHY CFW2. Inside the ring is a standard thread T2, which already can be freely used to connect the camera to the telescope. Backfocus of camera is 17.5mm from the T2 thread. Under the ring is hidden glass window to protect the sensor and the chamber interior. The sensor chamber is airtight and pre-dried nonetheless manufacturer adds to each camera “cartridge” socket to which we can pack the typical bag of desiccant and, if necessary, dry the inside of the chamber. On the faceplate is also heating resistors to prevent unwanted fogging during rapid temperature changes.

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On the back we find a standard guide socket to use with typical cable with RJ12 plug, next is the socket for a dedicated filter wheel that is it powered and controlled – no need for an additional USB cable or power power cable. In addition to these outlets is of course USB 3.0 port for communication with the camera and 12V socket – standard 5.5mm plug. Camera operation does not require the power supply if you do not want to use cooling. This is a good solution when you want, eg. use the camera to photograph the solar system at short exposure times – then cooling is then unnecessary.

Software and drivers

The manufacturer does not provide with camera any CD with drivers or manual but these things are available for download from the manufacturer www.qhyccd.com. I have to install the main camera driver so that you can use it with software such as SharpCap, FireCapture or dedicated software EZCAP. Secondly, ASCOM driver eg. for APT, Maxim DL, SGP, SIPS and the like. The manufacturer also provides the NativeWDM driver so that you can use the camera even as a typical webcam. There is also a Live Broadcast driver, whose name already says it all.

It is also worth mentioning that QHY has provided UpdateCheck@Software, through which we can quickly check if you have installed all the drivers and whether they are the latest available versions. The target is to be possible to install the drivers in one click.

First run, test cooling.

The camera installed without any problems and first run in SharpCap went flawlessly. Since I connected the camera via USB 2.0 speed was not a knock and reached up to 5 fps. ASCOM driver also works correctly. After selecting the appropriate position starts we have a window of the basic settings Gain and Offset. How to properly set up can be found in the article http://www.astrocmos.com/2016/10/gain-and-offset-daemons/. Only after the approval of the settings you can connect a camera in our favorite program for acquisition.

Time to check the cooling system. It is possible only when you connect the 12V power supply to the camera – then the fan and predefined slow cooling begin. Turning on the cooling in the application we have the ability to set the target temperature, which is expected to reach by camera.

The chart above shows the time required to cool the camera. In this driver version full of cool and stabilize temperature took about 20 minutes. Temperature was set to -15°C. With the latest driver this time was shortened by almost 4 times and at this moment in 2-3 minutes we have fully cooled camera but more on that later. tbc …

UPDATE – cooling time with new driver.

As I wrote above new driver give us speed cooling. Now fully cooled camera is ready to use after 180s! This is the fastest cooling ever seen.

Look at chart below. Red line is old driver, blue is new. Ambient temperature during test was about 25°C and after 180s I got stable -23.8°C so it is Δt=47.8°C.

At the end of part 1 lets see how cooled and uncooled dark frames look. Booth the same stretch level.

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End of Part 1.

In the next section I will describe the measured camera parameters such as capacity of the well, gain and linearity.

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