Can an Ra be used for infra-red landscape photography?

I'll start by quoting Canon about the Ra:

"Because it is designed for astrophotography, shooting normal subjects is not recommended. Subjects may appear redder than they actually are, and may not be able to obtain appropriate color balance when shooting normal subjects."

I've previously had a Pentax K-7 camera converted for infra-red by having the IR filter removed. Then I've used a filter to block as much visible light as possible. Using a tripod and long exposures.

In other words, I'm not talking about "appropriate color balance when shooting normal subjects". I'm talking about exploring subjects (typically landscapes) in the IR part of the spectrum. Often converted to monochrome.

(This is speculation at the moment. I have an R and I've pre-ordered an R5.
I certainly couldn't afford an Ra at the moment!)

No. The Ra is just enhaned until the Ha line. But IR is still cut. It would look similar to the Baader line of the following. (Canon is non modified, Baader modified like the Ra)

https://s12.directupload.net/images/200913/wibcf977.png

klausd wrote:

No. The Ra is just enhaned until the Ha line. But IR is still cut. It would look similar to the Baader line of the following. (Canon is non modified, Baader modified like the Ra)

https://s12.directupload.net/images/200913/wibcf977.png

Thanks for that comprehensive answer.

klausd wrote:

No. The Ra is just enhaned until the Ha line. But IR is still cut. It would look similar to the Baader line of the following. (Canon is non modified, Baader modified like the Ra)

https://s12.directupload.net/images/200913/wibcf977.png

I now accept that an Ra wouldn't have a full IR spectrum, for the reasons you identify.

But would it have significantly more of the spectrum than the R?

I've just put a Hoya R72 infra-red filter on my RF 70-200mm f/2.8 lens on my (unmodified!) R. And shot (hand-held!) some trees, in and around my garden.

These are the results after significant (minutes!) work in Photoshop.
(No cropping, though).
There is some IR remaining after the R72.
(I realise the R72 probably isn't a perfect visible-light filter).

Would the Ra have significantly more?

Barry Pearson wrote:

klausd wrote:

No. The Ra is just enhaned until the Ha line. But IR is still cut. It would look similar to the Baader line of the following. (Canon is non modified, Baader modified like the Ra)

https://s12.directupload.net/images/200913/wibcf977.png

I now accept that an Ra wouldn't have a full IR spectrum, for the reasons you identify.

But would it have significantly more of the spectrum than the R?

I've just put a Hoya R72 infra-red filter on my RF 70-200mm f/2.8 lens on my (unmodified!) R. And shot (hand-held!) some trees, in and around my garden.

These are the results after significant (minutes!) work in Photoshop.
(No cropping, though).
There is some IR remaining after the R72.
(I realise the R72 probably isn't a perfect visible-light filter).

The R72 filter does appear to be a near-perfect filter.
See Hoya diagram in red below.

Its cut-off excludes visibility of the H-alpha line.
So my Canon R (not Ra) must be accepting infra-red light well beyond the H-alpha line.

Since my Canon R is doing that, what is the upper-spectrum-limit of the Ra?
Does the Ra simply have a very narrow pass around H-alpha?
Or does its variation from the R extend well beyond the R's own limit?

In other words:
Would the Ra make a good camera for infra-red landscape photography?