Filter set identification

[jimchelt]

Can anyone help to identify this set of Trutek filters, please. Three have highly reflective surfaces. When viewing a light source the colour is quite different from the colour when there is  topside light source, as in the photo. I am putting together some gear for my first serious attempts at imaging and I wonder if these will be useful. I will be using a Skymax 127, and a Skymax 180 with a ZWO ASI 224MC . Any advice grateful accepted. Thanks in advance.

[ollypenrice]

Filters which behave as you describe are interferomtric and reflect the wavelengths not wanted. The cheaper filters work by absorption and are not as good. I think that if you look at natural daylight through your filters, while excluding ambient light from getting to the back surface, you'll see the colour you'd expect to see. Obviously, don't look at the sun.

They should be good filters.

Olly

[vlaiv]

It looks like LRGBC interference filter set.

You could possibly use L filter with ASI224MC. Others won't really be useful with that camera and scopes you intend to use it with.

ASI224MC has AR coated window (that is the same as C - or clear filter). You want IR/UV cut filter - which is L filter in that set. Not sure how are you going to differentiate between the two - they both look like clear glass when looking thru them - no color what so ever.

L or UV/IR cut filter might show reflections when looked at from an angle - but effect will be subtle. Clear/C filter on the other hand should be transparent at any angle (except for perhaps anti reflexive coating).

[Ian McCallum]

Are they like this?

https://web.archive.org/web/20050923061253fw_/http://www.trutek-uk.com/truetech/filters.html

Edited November 24, 2021 by Ian McCallum

[The Lazy Astronomer]

1 hour ago, vlaiv said:

Not sure how are you going to differentiate between the two - they both look like clear glass when looking thru them - no color what so ever.

To identify the UV/IR cut filter, would it be possible to use a common household IR source (like a TV remote) and a camera which detects IR? 

So, put the filter over camera sensor, get a live view going, and point and shoot the remote at the camera. If the camera detects the flashes, then it must be the clear filter. Repeat with other filter to confirm.

Might even be able to do it with a phone camera as well - I know my Samsung does detect the flashes from a remote, but my partner's iPhone doesn't. 

[vlaiv]

2 minutes ago, The Lazy Astronomer said:

To identify the UV/IR cut filter, would it be possible to use a common household IR source (like a TV remote) and a camera which detects IR? 

So, put the filter over camera sensor, get a live view going, and point and shoot the remote at the camera. If the camera detects the flashes, then it must be the clear filter. Repeat with other filter to confirm.

Might even be able to do it with a phone camera as well - I know my Samsung does detect the flashes from a remote, but my partner's iPhone doesn't. 

Yes, you can also look at color balance if you have camera without IR/UV cut filter - clear will have "washed" out colors in comparison to uv/ir cut filter.

[Franklin]

1 hour ago, Ian McCallum said:

Are they like this?

That looks like it's the same thing. RGB, IR cut and clear focusing.

[jimchelt]

Thanks guys. Very helpful, and yes, Ian, I think they are the same. I'll use the trick with a remote and a camera to find the ir filter.

Thanks again to all. I knew I'd get help. It's what makes sites like these so good.

[jimchelt]

Did the trick with a remote and a camera and successfully identified the IR filter! Result!

Thanks to all.