ASI 178 MC IR/cut filter

hyu2016

I have purchased an ASI 178 MC intended for planetary imaging. Yesterday I used this camera with C11 to image Mars. I noticed a quite bit of defocus of mars while visual observing at high mag is perfect.

I heard that 178 comes with a built-in IR window. But I am not sure if I should add an IR/UV cut filter for planetary imaging.

riklaunim

"Ir cut" and "IR/UV cut" are the same thing.

Note that ASI178 has very small pixels and it reaches optimal/maximal f/ratio at around f/12-14.

hyu2016

riklaunim wrote:
"Ir cut" and "IR/UV cut" are the same thing.

Note that ASI178 has very small pixels and it reaches optimal/maximal f/ratio at around f/12-14.

Thanks riklaunim. I was operating the C11 at f/10 which is pretty close to the optimal f/ ratio. What puzzles me is that I couldn't obtain a sharp focus through the camera even though it appeared to be sharp in a 8mn eyepiece (350x). I suspect it was the IR messed up the focus. But I cannot test my theory before puchasing an IR filter.

Sam@ZWO

you don't need extra IR-CUT filter for ASI178MC

you need very good seeing to run at f10 for 178mc

it's very close to maximum maginification

hyu2016

Sam wrote:
you don't need extra IR-CUT filter for ASI178MC

you need very good seeing to run at f10 for 178mc

it's very close to maximum maginification

Sam, you are absolutely right. Today I was able to obtain sharp focus with good to excellent seeing.

I guess the seeing deteriorated quickly after I swapped the eyepiece for the camera yesterday.

But everything worked out today. Thanks guys.