Which IR pass filter?

[bosun21]

Which is the most suitable IR pass filter for a 150 Maksutov with a ASI585MC camera? Is it the 685nm or 850nm? Thanks in advance.

[Elp]

From what I read about them there's a slight reduction in noise between them (think the 850nm is lower) the 850nm would receive less signal, but planets are quite bright. It also depends on whether your camera is quantum sensitive at such wavelengths. As a result I bought a decent 685 (Antlia) and a basic 850 (Zwo). But as usual haven't had a chance to try them.

Edited November 20, 2023 by Elp

[tooth_dr]

2 hours ago, bosun21 said:

Which is the most suitable IR pass filter for a 150 Maksutov with a ASI585MC camera? Is it the 685nm or 850nm? Thanks in advance.

I think for a 6” scope, the 850nm will block out too much light and the 685nm will be a better choice.

[Space Cowboy]

850 way too dark for a 6" scope.

[Kon]

As the others said an 850 will be very dark, you are almost close to the methane band. A 610/642/650 will be the best. I tend to experiment with 650, 685 and 742 although the most signal comes from the 650. I have read before that a red filter will do a decent job too as it leaks most the IR signal.

You don't need to break the bank, I use the Astromania, 640, sv bony, 685, zwo, 742.

 

Your camera has a QE of 90% at 610. 650 will be great too. So nice camera for IR imaging.

Edited November 20, 2023 by Kon

[bosun21]

650nm it is then. Thanks gentlemen.