T-Thread (in chain) 1.25" Filter Holder

[Stephen]

Does anyone know where I can source one of these in a hurry?

There was one on Astroboot, but a week after I ordered it, they finally let me know it's not T-T but T-M42

I want to put an IR cut filter into my guide cam chain which is:

Guide cam (DSIc) -> T-ext (80mm) -> ST80 T-thread

I don't like using a diagonal hence me looking for a T solution.

The inbuilt IR cut with the DSIc is a bit pants to be honest

Thanks in advance!

[Merlin66]

Telescope Service have a T thread adaptor which has an internal 1.25" filter thread... sounds just what you need.

264 Adapter ... auf T-2 Gewinde - Teleskop-Express: Astro-Shop + Fotografie + Naturbeobachtung

[Stephen]

Thanks for the link, that looks to be exactly what I need - just a shame it's TS (shipping costs + time)

I'll look at ordering it after Kelling.

[Stephen]

If anyone stumbles across this, I found another solution I'm going to give a go before I fork out lots to TS

ScopeStuff

[Merlin66]

Good simple idea!

You'll still need to add the cost of a couple of T thread spacers (6mm?); this then brings the overall length of the "filter sandwich" to about 12mm - is this space available??

[Stephen]

Good simple idea!

You'll still need to add the cost of a couple of T thread spacers (6mm?); this then brings the overall length of the "filter sandwich" to about 12mm - is this space available??

Yes you're quite right.

This is initially going into a non distance sensitive setup, so I can add a smaller spacer (I have a collection of between 5 and 20mm spacers, don't know where I have got them all from!) before my big spacer (80mm to give enough back focus on the ST80) and the filter should not come into contact with the CCD

Lot of faffing around just because I refuse to use a diagonal with my guide camera lol

[Merlin66]

Hmmm

Why did you not consider just screwing the 1.25" filter directly to the nosepiece of the guide camera???

EDIT:

Ahh I think you want to use the Thread connection on the DSI rather than a T thread to 1.25" nosepiece...maybe easier/ cheaper etc to go for a nosepiece??

[Stephen]

Hmmm

Why did you not consider just screwing the 1.25" filter directly to the nosepiece of the guide camera???

EDIT:

Ahh I think you want to use the Thread connection on the DSI rather than a T thread to 1.25" nosepiece...maybe easier/ cheaper etc to go for a nosepiece??

Absolutely, I wouldn't have this problem if I used the nosepiece.

Unfortunately my stock diagonal is very wobbly, and unless I cover it all in duck tape every time, it moves about.

That's why I went the t-thread route as I had the big spacer already. The IR cut was the last hurdle

[Merlin66]

Might be better in the long run to fix up the focuser!

Sounds like it will always give you problems......

(I ended up replacing the focuser on my ST80 with a 2" TS Crayford - probably now the focuser is worth more than the scope!)