Narrow Band filter

[Loki1978]

Hi all, 

I have a question about filters. I recently bought a second hand ASI1600 and filter wheel. It's my first time using a mono with filters. The filter wheel has already been populated by the previous owner. They appear to be ZWO branded, and the old style as they don't have the purple coating on one side.

The problem I have is identifying the filters. I have four screw ins which are easy as it's written on the side. These are luminance then rgb. But the HA, SII and OIII are not the screw in type. Just filters. 

Is there a way I can tell which is which? Or do ppl usually install them in some logical order?

[Louis D]

When held up to a bright, white background with extraneous light blocked between it and your eye to keep reflections at bay, I would think the OIII would appear blue-green, the HA would be deep red, and the SII would appear super deep red, almost black because it's approaching the limit of human eyesight.

[Loki1978]

Louis, 

Thanks, I will give this a try and see if I can tell which is which.

[Loki1978]

Right, from what I can see. OIII is an obvious blue. With HA and SII I'm getting one filter which is a bright red when I look at a white surface. The second filter is a dark wine red. I'm guessing the HA is bright and the SII dark.

I checked again and the filters are purple on one side so I think they are ZWO 2nd gen. The OIII has a silver coating. The other two are bronze on what I think is the SII and gold coating on what I believe is the HA.