BACHES Echelle Spectrograph

Of course, we will gladly sell you such a UV/IR-cut-filter. It doesn't do any harm, as long as it is of good quality and doesn't cause reflexions.
Such a filter may even be a wise choice if you decide to use the prism with ND-filters by other manufacturers, where you don't know if they let UV/IR pass or not. However, if you use our included filters, they do not only dim the visible light, but also block the remaining UV/IR.

At f/10 or even with the 0.7x reducer, you do not need the highspeed filters, the regular filters will work better. To deal with the steeper light cone at faster f/ratios, the filters need to be pre-shifted, so that a ilter for f/2 needs to be different from a filter for f/3 and from one for f/4 or slower.
Please take a look at our filter selector at
https://www.baader-planetarium.com/en/baader-narrowband-highspeed-filter-selector/
and this blog post:
https://www.baader-planetarium.com/en/blog/preshift-and-further-information-concerning-baader-cmos-filters/

You can find the transmission curve of our filter at the product website, if you click on the filter size, and compare it to that of ZWO. Our filter lets light pass between 420 and 685 nm.
If the ZWO already completely blocks UV/IR and starts at the same wavelength, then it doesn't matter if you use a clear or a UV/IR-cut filter. Otherwise, the transmission window is defined by the narrower filter.
I can't find info about the UV/IR-cut-filter of that camera - only a graph for its QE value, which shows sensitivity in the UV and IR, too. So a UV/IR-cut should be an improvement.

But in general, we would recommend the UV/IR-cut-filter, anyway - then you can use it even if you chose sometime in the futur to get a new camera without an integrated UV/IR-cut-filter.

The adapter will give you a male T-thread on both sides, so you'll also need Baader T-2 Conversion Ring # 2958110
We have also have 1¼" Filter Holder for T-2 and 2" Filter Threads # 1508031. This set contains these two adapters and some more parts, with which you can use the filter either in a T-2-thread or a 2" filter thread.

These lenses inside the 1.25" nose piece are similar to a Barlow element, and are necessary to make the eyepieces work with the desired focal length. You can find the resulting focal lengths in these PDFs:
https://www.baader-planetarium.com/en/downloads/dl/file/id/134/product/1206/hyperion_eyepieces_application_examples.pdf
and
https://www.baader-planetarium.com/en/downloads/dl/file/id/155/product/1206/hyperion_68_eyepieces_brief_description_and_recommended_use.pdf
Unfortunately, we haven't documented yet, which nosepiece belongs to which eyepiece - but as a rule of thumb, the shorter the eyepiece's focal length, the smaller is the lens in the nose piece. You can try this out by sorting the eyepieces by focal length and lens diameter. Then the magnification should increase, when you switch through all the focallengths from the longest to the shortest focal length.