Which H Alpha Filter for f/5 moderate to severe Light Polution

[AstroAndy]

Hello all

I was wondering which H Alpha filter I should go for for above conditions, bandwith wise, 3 or 5nm?

Andy

[lensman57]

Hello all

I was wondering which H Alpha filter I should go for for above conditions, bandwith wise, 3 or 5nm?

Andy

If you can afford the 3nm go for it but otherwise an Astronomik 12nm or Baader 7 nm kill off the LP and save you a lot of money.

A.G

[AstroAndy]

Ah, that's good to know, A.G., thanks.

[Thalestris24]

Hi

Of course, you don't get the best out of an Ha filter if using an osc though you can get images - have tried it myself What sort of lp do you suffer from? Are you wanting to image Ha targets or is the idea to defeat the lp? If you have very severe lp, you can still find it interfering if it's largely white light.

Louise

[AstroAndy]

Aye, I know, the Bayer matrix interfering w/ the red that comes through (hello long exposure times)..the idea is to cut down on lp, mostly, I've "narrowed" it down to s/thing like 3nm bandpass, I live in a  zone with maybe 50% of London's LP (I can see, very faintly, the Milkyway).

[Thalestris24]

Hi

You're lucky if you can see the Milky Way - I can't! I can only see the brightest stars here in Glasgow - on a good night!

I use lp filters and I've tried using a Baader 7nm but the skyglow still bleeds through. However, one can do quite a lot to mitigate it in processing. 3nm filters are very expensive and if there's a lot of background white light, I think it may still come through to some extent. I'm guessing a bit - maybe someone else can confirm?

Louise

[AstroAndy]

Looks like the 7nm it is, seems like the best all around option..I feel more lucky @ my dark site, but from what you tell me, you're probably not the one to complain to.

[lensman57]

Aye, I know, the Bayer matrix interfering w/ the red that comes through (hello long exposure times)..the idea is to cut down on lp, mostly, I've "narrowed" it down to s/thing like 3nm bandpass, I live in a  zone with maybe 50% of London's LP (I can see, very faintly, the Milkyway).

If you can see the Milky way then the LP is not severe, even good LP filter like IDAS will do it. The 7nm Baader is probably the best all around considering the price.

A.G

[Thalestris24]

If you can see the Milky way then the LP is not severe, even good LP filter like IDAS will do it. The 7nm Baader is probably the best all around considering the price.

A.G

I wish!!

[lensman57]

I wish!!

So do I, all I see recently is the Mancunian way in the sky and that is the clouds .

A.G

[Thalestris24]

So do I, all I see recently is the Mancunian way in the sky and that is the clouds .

A.G

Yeah but at least you acquire some lovely images when it's clear! I'm going to try to do some imaging with my ST-80 and AVX from my bedroom. It faces west and is much darker Mind you, not sure when that will be - forecast is still grim here

Louise

[AstroAndy]

Hhm, that is nice to know..on one of the LP charts I saw that my LP is rated moderate to severe..maybe it's not that severe, still 'n all, my current dark spot is perfect, except for the dew..I'd rather dew not..there should be a shirt saying astrophotographers dew it in the dark on the grass, lol.

[lensman57]

Hhm, that is nice to know..on one of the LP charts I saw that my LP is rated moderate to severe..maybe it's not that severe, still 'n all, my current dark spot is perfect, except for the dew..I'd rather dew not..there should be a shirt saying astrophotographers dew it in the dark on the grass, lol.

Dew is a pain but if you make a dewshield 12" long it will delay the formation of dew quite considerably. There are also some dew stip heaters for the secondary mirror from Altair Astro, I think that they are the kendrick brand , anyway a 2" Ha filter is always useful

A.G

[AstroAndy]

Got it all.