Homemade Filter Tilter

[andreahaku]

Hi everyone,

yesterday I got a couple of "CaK" filter that I wanted to try stacking together and reduce the bandpass by tilting them.

So I started to think how to build a filter tilter and then I came up with a simple yet working homemade filter tilter.

That's how it looks like:



It is made mainly out of a couple of T2/1.25" extentions. I glued two filter holders to the screws of each of them. That way by turning the screw I also tilt the filter. The two extention rings are also aligned so that the screws are 90° each other so I tilt both the axes.

Here's how it looks like when you dismantle it:







I also putted a rubber band around the two screws so that they better hold the position.

The other two pieces are simply a T2/1.25" nose and a T2/1.25" eyepiece holder. It is also quite "compact". Excluding the "nose" it is only 6cm.

Technically it works well. What I still have to test is if tilting the filters really helps reducing the bandpass or not.

Hope you'll find it useful.

Andrea

[Merlin66]

Double check the transmission curve. Any tilting will move the bandwidth towards the blue...
As the design "peak" is already on the centre wavelength, a tilting of the second filter can only reduce throughput and "clip" to red wing...I think the 80 A bandwidth could be reduced but this would be "Off" the CaK wavelength.
Neat idea...look forward to your reaults....

[andreahaku]

That's what I'm afraid also... but worth a try

[marktownley]

Ingenious! look forward to seeing how it works on the scope!