Autoguiding Cam ASI178MC or 120MM-S

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Michael Timm avatar
Hi fellow APs,

until now i used a ASI120MM-S (mono) as an autoguider and the ASI178MC (color) for imaging. Due to an update i will use a new 294MC Pro as imaging camera in the future. So now i have two cams available for autoguiding. Which one should i use? I am using a 8" RC (203/1624) with an OAG, see this image: OAG.

From the manufacturers website i know that the 178 (178 specs) is less noisy compared to the 120 (120 specs). But i believe the 120 to be more sensitive due to its monochrome sensor. Am i right or did i misunderstood the diagrams? Which decision should i make? Are there any obvious advantages / disadvantages i do not see?

Any advice appreciated, thanks and greetings,
Michael
Engaging
GregGurdak avatar
Hi, in my opinion avoid using  colour camera for guiding because stars looks bloated,  bigger about 20% than in mono camera on your PHD screen, especially when you’re shooting with long focal length telescope and  you need more precise guiding than short FL telescopes
Michael Timm avatar
Thank you, Greg. You made a point here for the ASI120. I will include your suggestion in my reflections.
Well Written Respectful
Tele avatar
120mm-c is a very good auto-guider. Transfers data very fast on a short usb3 cable, small pixels, mono, very sensitive, just load black frame for noise compensation.
Michael Timm avatar
Yes, i am using the 120MM-S mono and it works great. Thanks again, all!