Needs some advice on H-alpha filter

[sadia]

Hello,

I am thinking of buying a H-Alpha filter after seeing some amazing post by diffrent forum member. Knowing little about H-Alpha filter I am not sure about few things:

1. First of all I use QHY8 with the default IR filter nosepiece. I use it with either WO .8x FR or Baader MPCC. So my first question once i get a filter where do i place it? Do i need to replace the default IR or do I thread it some other place like in between Qhy8 and Focal reducer/MPCC?

2. I am quite sure I need a 2" filter but not sure of what kind of filter mounting should i order it with. For example Baader ones mentions about 2" cell where Astronomik ones mentions about 2"Cell or T threaded ones.

3. Will QHY8 have any impact on Baader vs Astronomik decision?

4. What should i consider when deciding between 13nm vs 6nm?

all together a bit lost, please help :).

Regards
Sad

[gbeal]

Get the Baader 7Nm, 2" (also known as 48mm) filter from wherever you can buy it cheapest. I got mine from Hong Kong.
The QHY8 works well with it, exceptionally.
It will screw directly onto the front of the MPCC, and in my case also the TV 0.8x reducer, so I assume also the W/O Reducer.
I didn't remove the default I/R filter nose piece, and neither should you, unless you want all that moisture in there.
Gary

[Gerald Sargent]

I got a few 2" Baader filters and when I tried to use them in my
Lumicon Multiple Filter Selector found that every one of them
had "oversize" threads. The Astronomic filters fitted perfectly.
I ended up removing the glass filters from 4 Baader filters and
getting an a professional optician to grind them down to fit into
some cheap filters I got from Bintel. The Baader glasses were all
0.3mms oversize compared to the glasses that came out of the
Bintel filters. When I coimplained to the American supplier they
said that they had measured theri stock and I was wrong - well
I am never going to buy a Baader filter again for certain. It was
a costly mistake. Anyone who want to dispute this can have one
of the Baader filterholders (on loan) to try themselves. They did
fit into some 2" things, but the critical thing they did not.

[sadia]

Thank you for the input guys :).

[marki]

I use an astronomiks 2" (48mm threads) on my QHY 8 to good effect. You would need to buy a T thread to 2" adaptor to make it work as the filter will not screw into the T thread on the front of the nose piece (42mm).

Mark