More filter questions

[bomberbaz]

Well two really, both surrounding filters.

Firstly and about my most recent post regarding IR/UV cut filters. I want to stick one permanently light path and I have read mention of both ZWO basic filter as a decent option but also this one here from Astronomik. Astronomik L-2 UV+IR Blocking Luminance Filter | First Light Optics

I am in a light polluted place but as I am using a colour camera I wanted to avoid broadband filters such as the optolong L-pro as that will take away the colour or am I wrong here?

Assuming I am right about avoiding broadband and bearing in mind that ZWO and Astronomic are both good makes, what is it that astronomik are giving that warrants double the price of the ZWO?

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Second question:

I am also going to start putting some narrowband subs into my work to hopefully improve on results and looked at a few makes and will use this Askar one as an example https://www.firstlightoptics.com/narrowband/askar-duo-band-narrowband-filter.html

However would not an astronomik visual UHC also provide a similar result to the askar as according to the diagram, they cover the same bandwidths Astronomik UHC Filter | First Light Optics. I ask because I already own one.

Thanks for any help in this one

steve

[vlaiv]

2 hours ago, bomberbaz said:

I am in a light polluted place but as I am using a colour camera I wanted to avoid broadband filters such as the optolong L-pro as that will take away the colour or am I wrong here?

Yes, LPS type filter such as L-Pro - or similar filters like Hutech IDAS LPS P2 for example do disturb color balance, but effect is much lesser if one does proper color calibration of the data.

Quite a bit color information can be restored even when using such filters.

2 hours ago, bomberbaz said:

Assuming I am right about avoiding broadband and bearing in mind that ZWO and Astronomic are both good makes, what is it that astronomik are giving that warrants double the price of the ZWO?

Astronomik L2 filter is specialty item and is therefore probably priced accordingly.

L3 and L2 remove some of far regions of 400-700nm range. L3 is a bit more aggressive than L2 at this.

This helps bring down star bloat with faster doublets that don't have perfect color correction. Usually far ends of visible spectrum are most out of focus with such scopes and these L2 and L3 serve to remove those offending parts of spectrum.

2 hours ago, bomberbaz said:

they cover the same bandwidths

Actually no.

Askar DUO band filter is much narrower around 7nm, and while both will show same part of spectrum that is of interest - Ha+OIII, Askar filter will remove much more of the LP.

You can still use UHC, and it will work, but Askar will probably work better in the same role.

[bomberbaz]

Thanks @vlaiv for the information.  I actually noticed at the bottom of the page for the astronomik uhc it is suitable when using a suitable IR/UV filter so for now I think I will try out the UHC filter before deciding whether to move to a dedicated filter such as the askar.

As for the UV/IR filter, I will also leave broadband filters for now and I shall have a look at other types such as the optolong, hutech etc and maybe spend a little more getting something better than a basic one. I am using an F4.8 doublet so it should be beneficial for only a relatively modest extra spend. 

Thanks

Steve