Incorrect airmass written into FITS header

[Matt Armstrong]

Evora header seems to display an incorrect airmass. Header airmass = sec(Z). Problem seems to stem from an incorrect zenith angle.

[Tristan J. Hillis]

Can confirm it is likely from the logs reporting a wrong zenith angle. Line 554 of the evora_server.py in the getHeader_2 method is where I compute the airmass for the image headers based on the Z reported by Heimdall (at the time of writing this). It is a simple computation of 1/cos(Z). Not much to go wrong there.

[Matt Armstrong]

That sounds about right. I will see if I can track down the cause of the incorrect zenith angle this weekend. Is there an easy way to access the log stream from Heimdall to watch what data is being fed to Evora?

…

On Tue, Jul 10, 2018 at 9:39 AM, Tristan J. Hillis ***@***.*** > wrote: Can confirm it is likely from the logs reporting a wrong zenith angle. Line 554 of the evora_server.py in the getHeader_2 method is where I compute the airmass for the image headers based on the Z reported by Heimdall (at the time of writing this). It is a simple computation of 1/cos(Z). Not much to go wrong there. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#26 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AL4_mrebMLAmd_ya6K7Jn1tNganpF-D5ks5uFNi2gaJpZM4VGPPt> .

[Tristan J. Hillis]

I would recommend you just call tail -f on the most current Heimdall log file to see a live feed and verify that zenith angle is correct.

My code seems to pull the most recent log from the following directory on Heimdall: "/home/mro/storage/tcc_data/positionlogs/*.txt"

My code will parse the most recent log and read the columns in as ['time','ra', 'dec', 'epoch', 'lst', 'za'].

Hope that helps.

[Matt Armstrong]

That is super helpful, thank you.

…

-Matt

On Tue, Jul 10, 2018 at 10:02 AM, Tristan J. Hillis < ***@***.***> wrote: I would recommend you just call tail -f on the most current Heimdall log file to see a live feed and verify that zenith angle is correct. My code seems to pull the most recent log from the following directory on Heimdall: "/home/mro/storage/tcc_data/positionlogs/*.txt" My code will parse the most recent log and read the columns in as ['time','ra', 'dec', 'epoch', 'lst', 'za']. Hope that helps. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#26 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AL4_moYPvaHfgB0fqUIXhfVRLz8bi7eTks5uFN4kgaJpZM4VGPPt> .

[Matt Armstrong]

I checked a tail on the log and it appears the issue is coming from Bifrost. The reported ZA is a constant 46.4109 no matter what the actual ZA is. I am looking for the source of this reporting issue now. Doug, any ideas on where in Bifrost I could look for such an issue?

…

-Matt From: Matt Armstrong <[e-mail]> Sent: Tuesday, July 10, 2018 10:22 To: UWMRO/ScienceCamera <[e-mail]> Cc: UWMRO/ScienceCamera <[e-mail]>; Author <[e-mail]> Subject: Re: [UWMRO/ScienceCamera] Airmass error (#26) That is super helpful, thank you.

-Matt On Tue, Jul 10, 2018 at 10:02 AM, Tristan J. Hillis <[e-mail] <mailto:[e-mail]> > wrote: I would recommend you just call tail -f on the most current Heimdall log file to see a live feed and verify that zenith angle is correct. My code seems to pull the most recent log from the following directory on Heimdall: "/home/mro/storage/tcc_data/positionlogs/*.txt" My code will parse the most recent log and read the columns in as ['time','ra', 'dec', 'epoch', 'lst', 'za']. Hope that helps. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#26 (comment)> , or mute the thread <https://github.com/notifications/unsubscribe-auth/AL4_moYPvaHfgB0fqUIXhfVRLz8bi7eTks5uFN4kgaJpZM4VGPPt> . <https://github.com/notifications/beacon/AL4_mmgVFELVzqdIgi1nrTJZnOjFjonwks5uFN4kgaJpZM4VGPPt.gif>

[Oliver Fraser]

Appears fixed, closing...