Duel Narrow Band Filters, wishes do come true.

[Adam J]

A year or so back I remember joking about how much I wished that it was possible to have a narrow band filter that allowed both OIII and Ha through at the same time to enable me to image both emission lines simultaneously with a OSC camera.....apparently someone somewhere was listening to me and wishes do come true.

See link below.

www.stcoptics.com/en/astro_duo_narrowband/

Problem is no one in the UK stocks it ( @FLO ) and its seems sold out everywhere.

Here is a link to an example image:

https://www.astrobin.com/full/329743/0/

Adam

[Thalestris24]

There is this triband one too but $775 for the 2" version. I guess that would be £775 plus shipping... I suspect that these sort of filters will only work well with certain targets though results might generally be acceptable. I'm thinking that usually you'd be exposing OIII for much longer than Ha. I'd be interested to see some results from uk skies. Also you'd probably want a cooled osc.

Louise

[Astrobits]

A number of filters transmit both O111 and Ha  and have been available for years. Most also transmit some longer IR which can be cut with a second suitable filter.

For example:

 

 

Though I must say that the filter referred to is very neatly done.

Nigel

 

[Adam J]

8 hours ago, Thalestris24 said:

There is this triband one too but $775 for the 2" version. I guess that would be £775 plus shipping... I suspect that these sort of filters will only work well with certain targets though results might generally be acceptable. I'm thinking that usually you'd be exposing OIII for much longer than Ha. I'd be interested to see some results from uk skies. Also you'd probably want a cooled osc.

Louise

I get results I like with my cooled DSLR exposing OIII and Ha seperatly this would just allow me to do both at the same time.

Also not sure about the one you mention but they are selling this one for 240 dollers for the APS-c clip ad 330 dollers for the 2 inch,

[Adam J]

7 minutes ago, Astrobits said:

A number of filters transmit both O111 and Ha  and have been available for years. Most also transmit some longer IR which can be cut with a second suitable filter.

For example:

 

Nigel

 

Those are not close to anything that you could class a narrow band, not even the Astronomik UHC. The one I linked is not a UHC filter its 10nm wide at OIII and 12nm wide at Ha. The astronomik you just linked is a good 40nm wide at OIII and actually gets the H-b line to as a result and again 40nm wide at H-a getting the SII line too. The new filter is much more selective and will be greatly more tollerant to LP.

[Astrobits]

Those were just two that I pulled up from my files.

20+ years ago I commissioned a company in Essex ( Image Optics/Galvoptics ) to produce some LP/Nebula filters to my specification. ( I am sure that they could have done any specification had they been asked ). When I used these in the dark skies of Norfolk there was no advantage to the narrowest transmission filter over the broader one. In the more light polluted skies elsewhere then the narrowest transmission filter did perform better than the wider one. If you have a lot of light pollution then maybe line filters would be even better than the one you mentioned. I also agree with Louise that you might need to give different exposures to the two wavelengths which could not be done with that particular filter.

Nigel

 

 

[Adam J]

2 hours ago, Astrobits said:

Those were just two that I pulled up from my files.

20+ years ago I commissioned a company in Essex ( Image Optics/Galvoptics ) to produce some LP/Nebula filters to my specification. ( I am sure that they could have done any specification had they been asked ). When I used these in the dark skies of Norfolk there was no advantage to the narrowest transmission filter over the broader one. In the more light polluted skies elsewhere then the narrowest transmission filter did perform better than the wider one. If you have a lot of light pollution then maybe line filters would be even better than the one you mentioned. I also agree with Louise that you might need to give different exposures to the two wavelengths which could not be done with that particular filter.

Nigel

 

 

Realistically my maximum exposure is 20 - 30 mins and I use that exposure with both my current OIII and Ha filters. So I am sure that for me this would be fantastic for my set of circumstances at any rate.

Not sure why all the negativity about this development to be honest at the very least you can think of it as a narrower UHC filter for imaging and that is no bad thing. I would rather expose OIII and Ha in parallel for twice the total integration time, than use the separate narrow band filters in series and in effect half my integration total in each channel. That is  worth more than any slight difference in exposure settings between channels...if indeed that is something I would want to do. 

How much did the custom filter cost you? Guessing more than 230 dollars?

 

 

[Thalestris24]

39 minutes ago, Adam J said:

Realistically my maximum exposure is 20 - 30 mins and I use that exposure with both my current OIII and Ha filters. So I am sure that for me this would be fantastic for my set of circumstances at any rate.

Not sure why all the negativity about this development to be honest at the very least you can think of it as a narrower UHC filter for imaging and that is no bad thing. I would rather expose OIII and Ha in parallel for twice the total integration time, than use the separate narrow band filters in series and in effect half my integration total in each channel. That is  worth more than any slight difference in exposure settings between channels...if indeed that is something I would want to do. 

How much did the custom filter cost you? Guessing more than 230 dollars?

 

 

I think it's quite a good idea for dslrs or oscs to do narrowband more efficiently

Louise

[Astrobits]

Not negative at all, I was just merely pointing out that filters that perform the required function have been available for some time. The new one is just an improved version which will suit more light polluted skies.

Regarding price, Image Optics started selling the filters to my spec for around £50. I was retailing them for less than that. Can't see them on their web site now.

Nigel