IR Pass filter advice

[Swoop1]

If I had to choose one of these filters for planetary imaging, which would be best to go for first?

685nm OR 850nm.

Thanks.

[neil phillips]

8 minutes ago, Swoop1 said:

If I had to choose one of these filters for planetary imaging, which would be best to go for first?

685nm OR 850nm.

Thanks.

Definitely 685. 850 is overkill with a loss of resolution. And sensitivity. 

[Cosmic Geoff]

It depends on your camera's infrared response.  IR850 should give a greater improvement as regards seeing, as the deterioration is worse at shorter wavelengths, but only if the camera has useful sensitivity at that wavelength.  Less response = longer exposures, which may be a problem.

ZWO offer an inexpensive IR850 filter for use with their cameras.  I use this with my ZWO ASI224MC and ASI462MC cameras, and it definitely improved the resolution with the ASI224MC, but I have yet to observe an improvement in IR resolution over the already good colour performance of the ASI462MC.  

Another result of infrared imaging is that it can show up things like transiting moons that are more or less invisible in visual band colour imaging.

The OP apparently has an ASI290MC, which has a strong response at IR850.

Edited December 1, 2022 by Cosmic Geoff

[drjolo]

Which telescope you want to use? If 150mm aperture, then it may be not much benefit using IR pass filter, because the telescope resolution also decreases with wavelength increase. 150mm telescope has theoretical resolution 0.8" at green light, 1.2" at 685nm and 1.4" at 850nm. 

[Swoop1]

I currently image through a C6 SCT BUT, who knows what the future holds?