From s.littlefair at sheffield.ac.uk Tue Dec 1 04:55:52 2020 From: s.littlefair at sheffield.ac.uk (Stuart P Littlefair) Date: Tue, 1 Dec 2020 09:55:52 +0000 Subject: [AstroPy] Telescope pointing with astropy, atmospheric refraction, and precession In-Reply-To: <1e3d5d5b-4b29-7bdf-bd2e-4049d5541b8d@gmail.com> References: <1e3d5d5b-4b29-7bdf-bd2e-4049d5541b8d@gmail.com> Message-ID: That's great Tony! We're always interested in more comparisons to benchmark the astropy code against. There has been a lot of recent progress on this front; astropy 4.2 has an "apparent" RA/Dec frame (TETE) included and we hope to include the HA/Dec frame in 4.3. We have also been working on comparison to Skyfield and can get very precise (fractions of milli-arcseconds between the two). These changes should appear in 4.3 as well. For these kind of precisions you need to use the JPL ephemerides with astropy. I'd be very interested to see a comparison with CASA measures. Would you be prepared to post the values you get from the CASA measures tool? On Tue, 1 Dec 2020 at 01:03, Tony Willis wrote: > I've been following this thread with interest. About 2 years ago I went > through the effort of computing and comparing apparent position > calculations from astropy, skyfield, PyEphem and CASA Measures. I'm > attaching the script I used to test the output using the radio source > 3C147. Lines up to about 160 just have some conversion functions I put > in so the script was more or less self-contained. The actual tests begin > at about line 161. The outputs generally agree to within about 0.5 arcs > or so. Personally I tend to use CASA Measures code for this sort of > thing. That particular part of CASA was written by Wim Brouw, who used > to be on the IAU SOFA board. But both astropy and skyfield give very > close answers. > > Cheers > > Tony Willis > > _______________________________________________ > AstroPy mailing list > AstroPy at python.org > https://mail.python.org/mailman/listinfo/astropy > -- Stuart Littlefair ------------------------------------------------------- *I don't expect you to respond to my email outside your working hours. * *At the University of Sheffield we value and encourage flexible working patterns, so please be assured that I respect your working pattern and I am looking forward to your response when you are next working. * ------------------------------------------------------- Dept. of Physics & Astronomy, Univ. of Sheffield, Sheffield, S3 7RH. email: S.Littlefair at sheffield.ac.uk phone: +44 114 2224525 -------------- next part -------------- An HTML attachment was scrubbed... URL: From tony.willis.research at gmail.com Tue Dec 1 12:57:37 2020 From: tony.willis.research at gmail.com (Tony Willis) Date: Tue, 1 Dec 2020 09:57:37 -0800 Subject: [AstroPy] AstroPy Digest, Vol 171, Issue 1 In-Reply-To: References: Message-ID: <60e9e251-6825-55a8-63f1-ea6aae068aa2@gmail.com> Hi Stuart Sure - tell me exactly what you would like done. Tony On 2020-12-01 9:00 a.m., astropy-request at python.org wrote: > Send AstroPy mailing list submissions to > astropy at python.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://mail.python.org/mailman/listinfo/astropy > or, via email, send a message with subject or body 'help' to > astropy-request at python.org > > You can reach the person managing the list at > astropy-owner at python.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of AstroPy digest..." > > > Today's Topics: > > 1. Re: Telescope pointing with astropy, atmospheric refraction, > and precession (Stuart P Littlefair) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Tue, 1 Dec 2020 09:55:52 +0000 > From: Stuart P Littlefair > To: Astronomical Python mailing list > Subject: Re: [AstroPy] Telescope pointing with astropy, atmospheric > refraction, and precession > Message-ID: > > Content-Type: text/plain; charset="utf-8" > > That's great Tony! > > We're always interested in more comparisons to benchmark the astropy code > against. > > There has been a lot of recent progress on this front; astropy 4.2 has an > "apparent" RA/Dec frame (TETE) included and we hope to include the HA/Dec > frame in 4.3. We have also been working on comparison to Skyfield and can > get very precise (fractions of milli-arcseconds between the two). These > changes should appear in 4.3 as well. > > For these kind of precisions you need to use the JPL ephemerides with > astropy. I'd be very interested to see a comparison with CASA measures. > Would you be prepared to post the values you get from the CASA measures > tool? > > On Tue, 1 Dec 2020 at 01:03, Tony Willis > wrote: > >> I've been following this thread with interest. About 2 years ago I went >> through the effort of computing and comparing apparent position >> calculations from astropy, skyfield, PyEphem and CASA Measures. I'm >> attaching the script I used to test the output using the radio source >> 3C147. Lines up to about 160 just have some conversion functions I put >> in so the script was more or less self-contained. The actual tests begin >> at about line 161. The outputs generally agree to within about 0.5 arcs >> or so. Personally I tend to use CASA Measures code for this sort of >> thing. That particular part of CASA was written by Wim Brouw, who used >> to be on the IAU SOFA board. But both astropy and skyfield give very >> close answers. >> >> Cheers >> >> Tony Willis >> >> _______________________________________________ >> AstroPy mailing list >> AstroPy at python.org >> https://mail.python.org/mailman/listinfo/astropy >> > From s.littlefair at sheffield.ac.uk Tue Dec 1 17:09:42 2020 From: s.littlefair at sheffield.ac.uk (Stuart P Littlefair) Date: Tue, 1 Dec 2020 22:09:42 +0000 Subject: [AstroPy] AstroPy Digest, Vol 171, Issue 1 In-Reply-To: <60e9e251-6825-55a8-63f1-ea6aae068aa2@gmail.com> References: <60e9e251-6825-55a8-63f1-ea6aae068aa2@gmail.com> Message-ID: Thanks Tony, If you could just post the output of the script you attached, to save me from installing CASA tools, that would be great! Stuart On Tue, 1 Dec 2020 at 17:58, Tony Willis wrote: > Hi Stuart > > Sure - tell me exactly what you would like done. > > Tony > > On 2020-12-01 9:00 a.m., astropy-request at python.org wrote: > > Send AstroPy mailing list submissions to > > astropy at python.org > > > > To subscribe or unsubscribe via the World Wide Web, visit > > https://mail.python.org/mailman/listinfo/astropy > > or, via email, send a message with subject or body 'help' to > > astropy-request at python.org > > > > You can reach the person managing the list at > > astropy-owner at python.org > > > > When replying, please edit your Subject line so it is more specific > > than "Re: Contents of AstroPy digest..." > > > > > > Today's Topics: > > > > 1. Re: Telescope pointing with astropy, atmospheric refraction, > > and precession (Stuart P Littlefair) > > > > > > ---------------------------------------------------------------------- > > > > Message: 1 > > Date: Tue, 1 Dec 2020 09:55:52 +0000 > > From: Stuart P Littlefair > > To: Astronomical Python mailing list > > Subject: Re: [AstroPy] Telescope pointing with astropy, atmospheric > > refraction, and precession > > Message-ID: > > < > CAOrDc-9JOPrd9fAhfEr5Uwd5J_v07O-iu5b1EdNEER0uGoGPgg at mail.gmail.com> > > Content-Type: text/plain; charset="utf-8" > > > > That's great Tony! > > > > We're always interested in more comparisons to benchmark the astropy code > > against. > > > > There has been a lot of recent progress on this front; astropy 4.2 has an > > "apparent" RA/Dec frame (TETE) included and we hope to include the HA/Dec > > frame in 4.3. We have also been working on comparison to Skyfield and can > > get very precise (fractions of milli-arcseconds between the two). These > > changes should appear in 4.3 as well. > > > > For these kind of precisions you need to use the JPL ephemerides with > > astropy. I'd be very interested to see a comparison with CASA measures. > > Would you be prepared to post the values you get from the CASA measures > > tool? > > > > On Tue, 1 Dec 2020 at 01:03, Tony Willis > > > wrote: > > > >> I've been following this thread with interest. About 2 years ago I went > >> through the effort of computing and comparing apparent position > >> calculations from astropy, skyfield, PyEphem and CASA Measures. I'm > >> attaching the script I used to test the output using the radio source > >> 3C147. Lines up to about 160 just have some conversion functions I put > >> in so the script was more or less self-contained. The actual tests begin > >> at about line 161. The outputs generally agree to within about 0.5 arcs > >> or so. Personally I tend to use CASA Measures code for this sort of > >> thing. That particular part of CASA was written by Wim Brouw, who used > >> to be on the IAU SOFA board. But both astropy and skyfield give very > >> close answers. > >> > >> Cheers > >> > >> Tony Willis > >> > >> _______________________________________________ > >> AstroPy mailing list > >> AstroPy at python.org > >> https://mail.python.org/mailman/listinfo/astropy > >> > > > _______________________________________________ > AstroPy mailing list > AstroPy at python.org > https://mail.python.org/mailman/listinfo/astropy > -- Stuart Littlefair ------------------------------------------------------- *I don't expect you to respond to my email outside your working hours. * *At the University of Sheffield we value and encourage flexible working patterns, so please be assured that I respect your working pattern and I am looking forward to your response when you are next working. * ------------------------------------------------------- Dept. of Physics & Astronomy, Univ. of Sheffield, Sheffield, S3 7RH. email: S.Littlefair at sheffield.ac.uk phone: +44 114 2224525 -------------- next part -------------- An HTML attachment was scrubbed... URL: From ostiavamos at gmail.com Thu Dec 3 07:56:49 2020 From: ostiavamos at gmail.com (Al va) Date: Thu, 3 Dec 2020 13:56:49 +0100 Subject: [AstroPy] sigma filter in astropy Message-ID: Hi I have this function in IDL that compares the value of each pixel with the mean of the box around it and if the value of the pixel is bigger than the mean plus 3sigma it is replaced by the mean of the box. Is there any function in astropy doing something similar to that? Thanks! -------------- next part -------------- An HTML attachment was scrubbed... URL: From tony.willis.research at gmail.com Thu Dec 3 14:20:04 2020 From: tony.willis.research at gmail.com (Tony Willis) Date: Thu, 3 Dec 2020 11:20:04 -0800 Subject: [AstroPy] Telescope pointing with astropy, atmospheric, refraction, and precession In-Reply-To: References: Message-ID: Hi Stuart As you requested, I'm attaching the output from that script I posted. Cheers Tony On 2020-12-02 9:00 a.m., astropy-request at python.org wrote: > Send AstroPy mailing list submissions to > astropy at python.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://mail.python.org/mailman/listinfo/astropy > or, via email, send a message with subject or body 'help' to > astropy-request at python.org > > You can reach the person managing the list at > astropy-owner at python.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of AstroPy digest..." > > > Today's Topics: > > 1. Re: AstroPy Digest, Vol 171, Issue 1 (Tony Willis) > 2. Re: AstroPy Digest, Vol 171, Issue 1 (Stuart P Littlefair) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Tue, 1 Dec 2020 09:57:37 -0800 > From: Tony Willis > To: astropy at python.org > Subject: Re: [AstroPy] AstroPy Digest, Vol 171, Issue 1 > Message-ID: <60e9e251-6825-55a8-63f1-ea6aae068aa2 at gmail.com> > Content-Type: text/plain; charset=utf-8; format=flowed > > Hi Stuart > > Sure - tell me exactly what you would like done. > > Tony > > On 2020-12-01 9:00 a.m., astropy-request at python.org wrote: >> Send AstroPy mailing list submissions to >> astropy at python.org >> >> To subscribe or unsubscribe via the World Wide Web, visit >> https://mail.python.org/mailman/listinfo/astropy >> or, via email, send a message with subject or body 'help' to >> astropy-request at python.org >> >> You can reach the person managing the list at >> astropy-owner at python.org >> >> When replying, please edit your Subject line so it is more specific >> than "Re: Contents of AstroPy digest..." >> >> >> Today's Topics: >> >> 1. Re: Telescope pointing with astropy, atmospheric refraction, >> and precession (Stuart P Littlefair) >> >> >> ---------------------------------------------------------------------- >> >> Message: 1 >> Date: Tue, 1 Dec 2020 09:55:52 +0000 >> From: Stuart P Littlefair >> To: Astronomical Python mailing list >> Subject: Re: [AstroPy] Telescope pointing with astropy, atmospheric >> refraction, and precession >> Message-ID: >> >> Content-Type: text/plain; charset="utf-8" >> >> That's great Tony! >> >> We're always interested in more comparisons to benchmark the astropy code >> against. >> >> There has been a lot of recent progress on this front; astropy 4.2 has an >> "apparent" RA/Dec frame (TETE) included and we hope to include the HA/Dec >> frame in 4.3. We have also been working on comparison to Skyfield and can >> get very precise (fractions of milli-arcseconds between the two). These >> changes should appear in 4.3 as well. >> >> For these kind of precisions you need to use the JPL ephemerides with >> astropy. I'd be very interested to see a comparison with CASA measures. >> Would you be prepared to post the values you get from the CASA measures >> tool? >> >> On Tue, 1 Dec 2020 at 01:03, Tony Willis >> wrote: >> >>> I've been following this thread with interest. About 2 years ago I went >>> through the effort of computing and comparing apparent position >>> calculations from astropy, skyfield, PyEphem and CASA Measures. I'm >>> attaching the script I used to test the output using the radio source >>> 3C147. Lines up to about 160 just have some conversion functions I put >>> in so the script was more or less self-contained. The actual tests begin >>> at about line 161. The outputs generally agree to within about 0.5 arcs >>> or so. Personally I tend to use CASA Measures code for this sort of >>> thing. That particular part of CASA was written by Wim Brouw, who used >>> to be on the IAU SOFA board. But both astropy and skyfield give very >>> close answers. >>> >>> Cheers >>> >>> Tony Willis >>> >>> _______________________________________________ >>> AstroPy mailing list >>> AstroPy at python.org >>> https://mail.python.org/mailman/listinfo/astropy >>> > > ------------------------------ > > Message: 2 > Date: Tue, 1 Dec 2020 22:09:42 +0000 > From: Stuart P Littlefair > To: Astronomical Python mailing list > Subject: Re: [AstroPy] AstroPy Digest, Vol 171, Issue 1 > Message-ID: > > Content-Type: text/plain; charset="utf-8" > > Thanks Tony, > > If you could just post the output of the script you attached, to save me > from installing CASA tools, that would be great! > > Stuart > > On Tue, 1 Dec 2020 at 17:58, Tony Willis > wrote: > >> Hi Stuart >> >> Sure - tell me exactly what you would like done. >> >> Tony >> >> On 2020-12-01 9:00 a.m., astropy-request at python.org wrote: >>> Send AstroPy mailing list submissions to >>> astropy at python.org >>> >>> To subscribe or unsubscribe via the World Wide Web, visit >>> https://mail.python.org/mailman/listinfo/astropy >>> or, via email, send a message with subject or body 'help' to >>> astropy-request at python.org >>> >>> You can reach the person managing the list at >>> astropy-owner at python.org >>> >>> When replying, please edit your Subject line so it is more specific >>> than "Re: Contents of AstroPy digest..." >>> >>> >>> Today's Topics: >>> >>> 1. Re: Telescope pointing with astropy, atmospheric refraction, >>> and precession (Stuart P Littlefair) >>> >>> >>> ---------------------------------------------------------------------- >>> >>> Message: 1 >>> Date: Tue, 1 Dec 2020 09:55:52 +0000 >>> From: Stuart P Littlefair >>> To: Astronomical Python mailing list >>> Subject: Re: [AstroPy] Telescope pointing with astropy, atmospheric >>> refraction, and precession >>> Message-ID: >>> < >> CAOrDc-9JOPrd9fAhfEr5Uwd5J_v07O-iu5b1EdNEER0uGoGPgg at mail.gmail.com> >>> Content-Type: text/plain; charset="utf-8" >>> >>> That's great Tony! >>> >>> We're always interested in more comparisons to benchmark the astropy code >>> against. >>> >>> There has been a lot of recent progress on this front; astropy 4.2 has an >>> "apparent" RA/Dec frame (TETE) included and we hope to include the HA/Dec >>> frame in 4.3. We have also been working on comparison to Skyfield and can >>> get very precise (fractions of milli-arcseconds between the two). These >>> changes should appear in 4.3 as well. >>> >>> For these kind of precisions you need to use the JPL ephemerides with >>> astropy. I'd be very interested to see a comparison with CASA measures. >>> Would you be prepared to post the values you get from the CASA measures >>> tool? >>> >>> On Tue, 1 Dec 2020 at 01:03, Tony Willis >> >>> wrote: >>> >>>> I've been following this thread with interest. About 2 years ago I went >>>> through the effort of computing and comparing apparent position >>>> calculations from astropy, skyfield, PyEphem and CASA Measures. I'm >>>> attaching the script I used to test the output using the radio source >>>> 3C147. Lines up to about 160 just have some conversion functions I put >>>> in so the script was more or less self-contained. The actual tests begin >>>> at about line 161. The outputs generally agree to within about 0.5 arcs >>>> or so. Personally I tend to use CASA Measures code for this sort of >>>> thing. That particular part of CASA was written by Wim Brouw, who used >>>> to be on the IAU SOFA board. But both astropy and skyfield give very >>>> close answers. >>>> >>>> Cheers >>>> >>>> Tony Willis >>>> >>>> _______________________________________________ >>>> AstroPy mailing list >>>> AstroPy at python.org >>>> https://mail.python.org/mailman/listinfo/astropy >>>> >> _______________________________________________ >> AstroPy mailing list >> AstroPy at python.org >> https://mail.python.org/mailman/listinfo/astropy >> > -------------- next part -------------- ('3C147 J2000 deg ', 85.65110416666668, 49.85196666666667) ******************** astropy analysis ******************************* ('drao', ) ('astropy 3C147 az and elev deg', 282.459299465802, 87.11199137214359) ('astropy 3C147 az and alt dms', 282, 27, 33.47807688726789, ' ', 87, 6, 43.16893971693162) ('Astropy time, app_ra app_dec:',