noise estimation off by factor of sqrt(2)

[bennahugo]

SEFD 425 Jy, channel width 3328 khz, integration 30.0s
Meqtrees (gui) says the visibility noise is 0.0425340 Jy/beam
This is missing a factor of two in the sqrt. It should be 0.0300761

See SI II Eqn 9-15

[o-smirnov]

Deja vu. I remember discussing it with @twillis449 at least 10 years ago! Can't believe it's still wrong...

[twillis449]

@o-smirnov well, your memory is certainly better than mine - LOL! I'm not sure what SI II Eqn 9-15 refers to.

[o-smirnov]

The White Book, I guess. Synthesis Imaging in Radio Interferometry II?

[bennahugo]

Yup the one and only

…

On Tue, Aug 24, 2021 at 8:51 PM Oleg Smirnov ***@***.***> wrote: The White Book, I guess. Synthesis Imaging in Radio Interferometry II? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#111 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AB4RE6WGI7VTV422XLRUNALT6PSZJANCNFSM5CVB5EOA> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&utm_campaign=notification-email> .

-- -- Benjamin Hugo PhD. student, Centre for Radio Astronomy Techniques and Technologies Department of Physics and Electronics Rhodes University Junior software developer Radio Astronomy Research Group South African Radio Astronomy Observatory Black River Business Park Observatory Cape Town

[twillis449]

Wow - I see that on Amazon a hardcover copy of that book goes for about $500 Canadian! My book collection is growing in value! Anyway - where is this error in the GUI? I would assume that its in some part of a simulation specification? You're more than welcome to change wherever the error is.

[bennahugo]

Yes that book has been on my long term wishlist! - only have a soft copy

I will it is within the gui when filling out the parameters for turbosim. I'm busy doing a bucketload of simulations for the next meerkat continuum sensitivity calculator and only spotted this after trying to compare to my own derivation of untapered noise. Will see if I can dig it out and submit a fix.