Applying a minor tilt to an inline 2" filter????

[Merlin66]

Here's a challenge to the DIY guys....


How can you apply a small tilt say a few degrees to a standard 2" filter sitting in a 2" extension tube?????


The "conventional" way so far is to cross thread the filter and hope it stays in place!!!
(The reason for the need to tilt? Well, to fine tune the narrow band transmission wavelength. A small tilt moves the centre line towards the blue)

[bojan]

3D printed spacers (2x) (like the leftmost on the attached image)..
I made that cell to mount round prism next to diffraction grating.

Another way is to cut spacers from machined aluminium tube with mitre circular saw.. like this one (https://www.ebay.com.au/itm/394092367531?chn=ps&_ul=AU&_trkparms=ispr%3D1&amdata=enc%3A1igMDqEmnTK65CqHWBN8xs w32&norover=1&mkevt=1&mkrid=705-139619-5960-0&mkcid=2&mkscid=101&itemid=394092367531&targetid=&device=c&mktype=pla&googleloc=9071438&poi=&campaignid=15984321586&mkgroupid=&rlsatarget=&abcId=9300814&merchantid=510833176&gclid=EAIaIQobChMIg7_q1vuJ-wIV3JNmAh1gTQGLEAQYBCABEgI_EvD_BwE) , only bigger. I am using 180 mm saw from Bunnings (it was $50 when I bought it).
And, you can try with small spacers placed at 180° inside the filter holder

[Merlin66]

Bojan,
I see what you have in mind.
How would that work with conventional M48 filter threads on the adaptor???

[bojan]

Depends how thick is the adaptor.

Maybe you have to machine the thicker one.

[bojan]

I bought some adaptors (https://www.aliexpress.com/item/1005003787690593.html?spm=a2g0o.ord er_list.0.0.4b381802Chqg9u)at Aliexpress.. for various things like that one.

There is enough material in it to machine the tilted spacer for your filter

[Boozlefoot]

How much "tilt" do you require? Would a collimating ring work - M48 F&F? There are several versions available. Possibly you could convert one if not sufficient angle achieved and alter stock springs/fasteners. Dependant on how much room you have in the box for the outer diameter. Some collimation rings are much "narrower"than the one depicted here.

https://agenaastro.com/artesky-collimation-ring-tilt-adapter-m48-threads-art8022.html

[Merlin66]

The minor tilt needs to be applied to 2” narrowband filters within the 2” extension tube.
Maximum outside diameter would have to be less than 2”.