# HSC ENG-R1 filter seems to have wrong band

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#### Details

• Type: Story
• Status: Done
• Resolution: Done
• Fix Version/s: None
• Component/s:
• Labels:
None
• Story Points:
0.5
• Team:
Architecture
• Urgent?:
No

#### Description

Looking at the physical filter -> band mapping for HSC I see:

 \$ butler query-dimension-records tmp physical_filter instrument name band  ---------- ----------------------------- -----------------------------  HSC ENG-R1 r1  HSC HSC-G g  HSC HSC-I i  HSC HSC-I2 i  HSC HSC-R r  HSC HSC-R2 r  HSC HSC-Y y  HSC HSC-Z z  HSC IB0945 I945  HSC NB0387 N387  HSC NB0400 N400  HSC NB0468 N468  HSC NB0515 N515  HSC NB0527 N527  HSC NB0656 N656  HSC NB0718 N718  HSC NB0816 N816  HSC NB0921 N921  HSC NB0926 N926  HSC NB0973 N973  HSC NB1010 N1010  HSC NONE UNRECOGNISED  HSC PH PH  HSC SH SH 

• Shouldn't ENG-R1 map to band r?
• NONE implies "no filter" aka "white" rather than "unrecognised" (why UK spelling?) See also RFC-737.

#### Activity

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Tim Jenness added a comment -

Given Robert Lupton's comment I'm more than happy to fix the ENG-R1 – I don't see any reason for us to confuse the gen3 registry by leaving an "r1" band hanging around in there.

John Parejko I'm more than happy for Paul Price to comment but the current situation does not match the comment from him you posted above.

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Tim Jenness added a comment - Given Robert Lupton 's comment I'm more than happy to fix the ENG-R1 – I don't see any reason for us to confuse the gen3 registry by leaving an "r1" band hanging around in there. John Parejko I'm more than happy for Paul Price to comment but the current situation does not match the comment from him you posted above.
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Jim Bosch added a comment -

I have no recollection of intentionally special-casing "r1" or "ENG-R1", and it's plausible I just missed it (and miscommunicated with John on that). I think I would have remembered doing it if I did have a good reason, unless it was just out of a no-unnecessary-changes paranoia, which might have been a good reason to leave it "r1" back then, but would not be a good reason to leave it "r1" now.

Nobody's going to be able to come up with a solid answer to NONE vs UNRECOGNI[ZS]ED without digging in and looking at the data that actually uses them, I fear, and I suspect that's not a good use of anyone's time. I'm not sure what to do about that.

Show
Jim Bosch added a comment - I have no recollection of intentionally special-casing "r1" or "ENG-R1", and it's plausible I just missed it (and miscommunicated with John on that). I think I would have remembered doing it if I did have a good reason, unless it was just out of a no-unnecessary-changes paranoia, which might have been a good reason to leave it "r1" back then, but would not be a good reason to leave it "r1" now. Nobody's going to be able to come up with a solid answer to NONE vs UNRECOGNI [ZS] ED without digging in and looking at the data that actually uses them, I fear, and I suspect that 's not a good use of anyone's time. I'm not sure what to do about that.
Hide
Tim Jenness added a comment -

Paul Price can you take a quick look?

I do feel that we should match bands so if you object to UNRECOGNISED becoming "unknown" and NONE becoming "empty" then I still think we should unify the band name of "unknown" and "white" to match the recent RFC and obs_lsst.

I can easily change the metadata translator to convert UNRECOGNISED and NONE in the headers (are all those other aliases used in headers?) to unknown and empty but wanted your feedback first.

Show
Tim Jenness added a comment - Paul Price can you take a quick look? I do feel that we should match bands so if you object to UNRECOGNISED becoming "unknown" and NONE becoming "empty" then I still think we should unify the band name of "unknown" and "white" to match the recent RFC and obs_lsst. I can easily change the metadata translator to convert UNRECOGNISED and NONE in the headers (are all those other aliases used in headers?) to unknown and empty but wanted your feedback first.
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Paul Price added a comment -

Seems reasonable to me.

It's possible "Unrecognised" is Subaru's choice of value when the true value isn't available to the header writer, but it's at least equally likely (due to the English spelling) it's something I chose for when we didn't have the filter name in our list. In any case, you should have HSC correspond to other obs packages as much as possible, and we can worry about corner cases if and when they arise.

Show
Paul Price added a comment - Seems reasonable to me. It's possible "Unrecognised" is Subaru's choice of value when the true value isn't available to the header writer, but it's at least equally likely (due to the English spelling) it's something I chose for when we didn't have the filter name in our list. In any case, you should have HSC correspond to other obs packages as much as possible, and we can worry about corner cases if and when they arise.
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Tim Jenness added a comment -

Okay. Thanks. I will go ahead with modifying the metadata translator to catch the aliases and convert them to standard form.

Show
Tim Jenness added a comment - Okay. Thanks. I will go ahead with modifying the metadata translator to catch the aliases and convert them to standard form.

#### People

Assignee:
Tim Jenness
Reporter:
Tim Jenness
Reviewers:
Paul Price
Watchers:
Jim Bosch, John Parejko, Krzysztof Findeisen, Paul Price, Robert Lupton, Tim Jenness