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How do I set lower bit high speed mode
Posted: Sun Aug 27, 2023 6:40 pm
by Prasad
I use a Zwo ASI178MM and it's specs say that it "runs at 30 fps (14bit, normal mode) or 60 fps (10bit, high speed mode) at full resolution(6.4Mega)". I always seem to get only its 14-bit normal mode speed of about 30 fps. What do I need to change in high speed to get the higher rate of 60 fps? My settings are Turbo USB set at 100, and High-speed mode is ON. The frame rate limit is set at Max. I tried changing these, but it did not give me any higher frame rate. I do mostly solar H-alpha imaging.
Thanks
Re: How do I set lower bit high speed mode
Posted: Mon Aug 28, 2023 1:21 pm
by admin
Hi,
the main thing you need to change is the 'Colour Space' option, which you need to swap from MONO16 to MONO8. In MONO16 mode, the camera will run at its full bit depth (14 bits for this sensor, 12 or 16 for others, although the data is always brought up to 16 bit values). In MONO8 mode, the camera will produce 8 bit image data and give you higher frame rates since only half as much data per frame needs to be transferred over the USB connection.
In addition to this, the 'High Speed Mode' option may have an effect when you are in MONO8 mode, changing the camera to a potentially faster mode using the 10 bit ADC. Depending on the sensor model, changing this can also affect image brightness.
So, the short answer is - set 'MONO8' to get the higher frame rates.
cheers,
Robin