We are very excited about these filters. Look out for a featured review on their LRGB filters (by Terry Hancock from Australia) that will be posted on AC by tomorrow. These look very promising, and every filter comes with an actual test transmission curve.

We received our first shipment of filters from Optolong this afternoon, and we will soon have them up for sale on our site. Detailed descriptions and photos will be posted soon too. The prices on our site are placeholders and will likely be revised downwards a bit, making these a very compelling buy. These are not your run-of-the-mill generic Chinese filters, and the initial response to Optolong's filters from imagers worldwide has been very positive.

 

A correction - it turns out that while every filter is individually tested by Optolong as part of their QC process, the actual filter transmission curve is provided only for select filters at this time.

 

I have tested these and have actual measurement data.
The UHC filter has a bandwidth of about 46-47nm
And the O-III filter has a bandwidth of ~25nm
That is at half-maximum.
Additionally, these filters transmit the red wavelengths, with H-alpha at 656nm coming through strongly.
Those figures suggest:
--they would be good in very small apertures.
--they would be good in very large apertures for those wanting the red transmission.
--they would yield lower degrees of enhancement than narrower filters (for example, the ideal bandwidths for a UHC is 23-24nm and an O-III 12-15nm) but much better than nearly all broadbands.

Spec-wise, they are similar to the Nebustar and O-III filters TeleVue sold for several years (now discontinued except for what is at dealers).
In the field, they didn't perform up to the level of Lumicon or DGM or Orion, but they weren't bad.
Transmission seems high at the necessary wavelengths, and optical quality good.
I appreciated the larger number of stars in the field.

One side effect of a wider than average bandwidth is that the filters can be used at higher powers.

I did not test the photographic filters, only the visual ones.

 

I am a certified Filter-Nut. I have 35 of the little beasts, and counting. So I'll devour any and all information I may come across. Never heard of Optolong until I came in here. But my curiosity has been kick-started. So I'll be happy to share a bit of info I have on the use of filters for some deep-sky objects.

This is written by David Knisely, who hangs his hat at the Prairie Astronomy Club. As long as he is mentioned and credited, he's fine with this being freely shared. So thank you, David!

http://www.prairieastronomyclub.org...formance-comparisons-for-some-common-nebulae/

And more -

http://www.prairieastronomyclub.org.../useful-filters-for-viewing-deep-sky-objects/

When asked "...what filters should I get for deep-sky?" the two most mentioned are the UHC, and the OIII. Armed with the right information, I'd suggest tossing a coin. Or both. And hold off the Hb (Hydrogen-beta) unless you'll never be a happy person unless you've tried everything under the Sun to glimpse the Horsehead Nebula - B33. And even then - there is no guarantee. It's very shy.

Have fun -

Dave