IDAS D2 or STC Duo Narrowband

[smr]

Hi all,

I'm thinking of buying a decent LP filter. There is mostly LED street lighting in the village. So I'm wondering about buying the D2 Filter with the following spectral response:

 

But then I was thinking, this is £175. There's another filter which is about £100 more, which may be a better filter... the STC Duo Narrowband filter with the following spectral response

 

So a few questions....

Apart from saving some money, would I be gaining anything by going for the D2? 
Do I need the 0-500nm  and 500-650nm blocking, or is there a reason why I wouldn't want to block out that range?
From what I understand the STC would block out all light except for the transmission at 500 and 650 so would this ok to use for all nebulae, galaxies etc.?
If thinking about the D2 why not just go for the STC (money aside) ?

 

Thanks for any advice. My Camera is an unmodified Canon 80D but I will probably be invested in an OSC 294MC Pro in the Summer. Would the filter provide for better images with my Canon80D?

 

[DaveS]

The STC won't be much (Any) good for galaxies as it's a dual NB filter for getting a NB image on OSC cameras. For BB imaging in a LP infested zone you'll need the D2, especially if you have LED LP.

[James]

44 minutes ago, DaveS said:

The STC won't be much (Any) good for galaxies as it's a dual NB filter for getting a NB image on OSC cameras. For BB imaging in a LP infested zone you'll need the D2, especially if you have LED LP.

I'd started typing a reply but realised Dave has said it better than I was going to.. so, what he says! ☝️

James

[smr]

Ok thanks, and what about emission nebulae?

[DaveS]

Well, it will give a reasonable HOO type image on emission nebulae, though un-modified DSLRs tend to be rather insensitive to H-alpha. With a DSLR or OSC I'd be inclined to forego NB for "natural colour".

TBH, if you have an interest in imaging emission nebulae, then mono CCD / CMOS and NB filters is the way to go.

[Adam J]

On 03/04/2019 at 14:22, smr said:

Ok thanks, and what about emission nebulae?

Well there are not many emission nebula available until later in the year anyway, not until after we start getting astro darkness back in August really save a few planetary nebula. The answer really is that the Duo is a better nebula filter and useless / counter productive for galaxies and the D2 is the better galaxy filter but can also do some nebula work and so if you get the ASI294mc pro in the future your probably going to want one of each.

But for now with an unmodified DSLR I see no point at all in owning the Duo Narrow-band filter at all so get the D2. 

I would give consideration to mono, in which case you can still use the D2 for luminance. 

Adam 

[DaveS]

The D2 looks to be a good all-round LP filter for today's light pollution, in fact I'm planning to get a 2" one to bung in the filter wheel of the Atik 16200 camera I'll be buying, as the Luminance filter, as although I have nominally (Dark) Bortle 4 skies there is significant LED and HPS LP from Bridport and Dorchester / Weymouth that brightens my East and West horizons.

[susan-parker]

IDAS do a Nebula filter wth two narrow passes, the NB1.

https://www.firstlightoptics.com/idas-filters/idas-narrow-band-nebula-nb1-filter.html