Baader 35nm H-alpha filter to be discontinued?

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thesmiths
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Baader 35nm H-alpha filter to be discontinued?

Post by thesmiths »

I was trying to buy a 2-inch Baader 35nm recently and there did not seem to be much in stock in the UK. I got in touch with Rupert @ Astrograph and he sent me a message:
Baader have now discontinued the 35nm filter. They have some stock so I am ordering while I can. Do you still want one as by next year there will be none.
I assume since he is a distributer he should know. I suspect the filter is not a big seller with most deep sky users -- they seem to like more narrowband. Rupert confirmed they are very much a solar thing and normally he doesn't keep them in stock during the winter months.

I told Rupert to order one for me now (I was going to wait until next summer). I don't really have a need at the moment since a 2-inch UV/IR filter does the job for which I intended to use the 35nm H-alpha filter. But the Baader seems like a good thing to have in the filter box.


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Re: Baader 35nm H-alpha filter to be discontinued?

Post by marktownley »

Thanks for the heads up Douglas.


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Re: Baader 35nm H-alpha filter to be discontinued?

Post by TareqPhoto »

I bought a very cheap Ha 40nm somewhere and it looks like as a red filter rather than Ha, but i can't tell how great it is or bad due to very cheap price, i will use it in addition to UV/IR cut filter, which i will just place this Ha 40nm right on the Quark nose.


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Re: Baader 35nm H-alpha filter to be discontinued?

Post by marktownley »

TareqPhoto wrote: Thu Nov 03, 2022 6:40 pm which i will just place this Ha 40nm right on the Quark nose.
I would place it as far from the quarks nose as possible (along with the uv/ir filter). That way the filter intercepts a wider lightcone. The closer you put the filter to the focal point the more likely it is to crack and also be prone to wavefront distortion.


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Re: Baader 35nm H-alpha filter to be discontinued?

Post by thesmiths »

marktownley wrote: Sat Nov 05, 2022 10:29 am
TareqPhoto wrote: Thu Nov 03, 2022 6:40 pm a very cheap Ha 40nm
prone to wavefront distortion.
In general, I would say using a cheap filter has the potential for causing optical distortion. I think with filters, you get what you pay for.

I did some calculations a while ago and for a typical refractor (around f/7) and a 2-inch filter, a distance of 15cm to 20cm in front of the focal point of the telescope was about right. This assumed you did not want the light cone to be too close to the edge of the filter. For most refractors, this places the filter somewhere inside the focuser (which typically has a 2-inch diameter adapter).


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Re: Baader 35nm H-alpha filter to be discontinued?

Post by TareqPhoto »

So where and how to place the filter somewhere? I mean i could manage to place the UC/IR cut filter by the adapter that is going right inside the focuser for example, but then where to place that Ha filter?

Pity and shame that the filter turned out to be a bit larger than 1.25" thread, i feel it is maybe 33mm or 35mm instead of 31.75mm which 1.25", so now i think i can't use this filter at all unless i can find a right thread mount for it, which means i will buy another filter maybe.


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Re: Baader 35nm H-alpha filter to be discontinued?

Post by OlegLviv »

Hello everybody! In my modification Lunt 60 with my 127/f9.5 tescope use UV/IR CUT+rg360 stock lunt filter and behind rg360 put astronomik 6nm Ha and have good result!


https://www.facebook.com/oleg.lavigne/
https://www.astrobin.com/users/RamonLviv/
https://www.astroclub.kiev.ua/forum/ind ... ic=46758.0


Telescope: TS 152/900/Bresser 102/1350
Baader D-ERF 160MM
2xBaader 1.25 GPC
2xLunt 50mm
Lunt Cak B1200
Coronado BF15
Camera: Apollo Max 432M/ Apollo Mini 429M/Player One Mars II 462M/QHY 290MM
Mounh: 2xSky Watcher AZEQ6
Telecentric Lense: Televue Powermate 2/2.5x/4X/5X
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