alternative for Astrodon filters

[KathyNS]

I see that Astrodon has been bought out by Farpoint, and some of the old Astrodon filters are out of stock. Does anyone have a recommendation for something equivalent? I'd prefer the Astrodon, since they are parfocal with each other. But I'm willing to look elsewhere if the Astrodons are going to be hard to find.

I am looking for a 36mm unmounted 5nm Oiii.

[edit]What would be the effect of mixing an 8.5nm filter with my existing 5nm filter? I see someone has one for sale second-hand.

[dcrowson]

Chroma is the goto these days. Astrodon has largely fallen out of favor at the high-end.

https://www.chroma.com/

Dan

[yobbo89]

Dosn't astrodon do orders to make? Second in line is chroma, they even do custom filters, I got my nii filter from them,took about a month to make/order.

I think going different nm width gives you slightly different star fwhm profiles, not too hard to process with psf. If you have lots of lp, I'd probs would get something tighter then 8.5nm

If you use a oag then you'll probably definitely want the same brand for parfocal.

Also at an expense , I'm sure chroma can make a filter at a given substrate thickness to match your astrodons. But it ain't cheap..