

In [1]:

    
from nustar_pysolar import planning, io
from imp import reload
reload(planning)
import astropy.units as u









    



WARNING: AstropyDeprecationWarning: astropy.utils.compat.odict.OrderedDict is now deprecated - import OrderedDict from the collections module instead [astropy.utils.compat.odict]

Download the list of occultation periods from the MOC at Berkeley.

Note that the occultation periods typically only are stored at Berkeley for the future and not for the past. So this is only really useful for observation planning.



In [2]:

    
fname = io.download_occultation_times(outdir='../data/')
print(fname)









    



../data/NUSTAR.2017_197.SHADOW_ANALYSIS.txt

Download the NuSTAR TLE archive.

This contains every two-line element (TLE) that we've received for the whole mission. We'll expand on how to use this later.

The times, line1, and line2 elements are now the TLE elements for each epoch.



In [3]:

    
tlefile = io.download_tle(outdir='../data')
print(tlefile)
times, line1, line2 = io.read_tle_file(tlefile)









    



../data/NuSTAR.tle

Here is where we define the observing window that we want to use.

Note that tstart and tend must be in the future otherwise you won't find any occultation times and sunlight_periods will return an error.



In [4]:

    
tstart = '2017-07-18T12:00:00'
tend = '2017-07-18T20:00:00'
orbits = planning.sunlight_periods(fname, tstart, tend)

We want to know how to orient NuSTAR for the Sun.

We can more or less pick any angle that we want. But this angle has to be specified a little in advance so that the NuSTAR SOC can plan the "slew in" maneuvers. Below puts DET0 in the top left corner (north-east with respect to RA/Dec coordinates).

This is what you tell the SOC you want the "Sky PA angle" to be.



In [5]:

    
pa = planning.get_nustar_roll(tstart, 0)
print("NuSTAR Roll angle for Det0 in NE quadrant: {}".format(pa))









    



NuSTAR Roll angle for Det0 in NE quadrant: 5.219171016059789 deg

Set up the offset you want to use here:

The first element is the direction +WEST of the center of the Sun, the second is the offset +NORTH of the center of the Sun.

If you want multiple pointing locations you can either specify an array of offsets or do this "by hand" below.



In [6]:

    
offset = [-190., -47.]*u.arcsec

Loop over each orbit and see what the difference between the two methods is

Note that you may want to update the pointing for solar rotation. That's up to the user to decide and is not done here.

Looks like a fixed shift...probably some time-ephemeris issue.



In [7]:

    
from astropy.coordinates import SkyCoord
for ind, orbit in enumerate(orbits):
    midTime = (0.5*(orbit[1] - orbit[0]) + orbit[0])
    sky_pos = planning.get_sky_position(midTime, offset)
    print("Orbit: {}".format(ind))
    print("Orbit start: {} Orbit end: {}".format(orbit[0].isoformat(), orbit[1].isoformat()))
    print('Aim time: {} RA (deg): {} Dec (deg): {}'.format(midTime.isoformat(), sky_pos[0], sky_pos[1]))
    skyfield_pos = planning.get_skyfield_position(midTime, offset, load_path='../data')
    print('SkyField Aim time: {} RA (deg): {} Dec (deg): {}'.format(midTime.isoformat(), skyfield_pos[0], skyfield_pos[1]))
    skyfield_ephem = SkyCoord(skyfield_pos[0], skyfield_pos[1])
    sunpy_ephem = SkyCoord(sky_pos[0], sky_pos[1])
    print("")
    print("Offset between SkyField and Astropy: {} arcsec".format(skyfield_ephem.separation(sunpy_ephem).arcsec))
    print("")









    



Orbit: 0
Orbit start: 2017-07-18T11:27:00 Orbit end: 2017-07-18T12:28:50
Aim time: 2017-07-18T11:57:55 RA (deg): 117.84681928915637 deg Dec (deg): 20.96388011768501 deg
SkyField Aim time: 2017-07-18T11:57:55 RA (deg): 117.85271277014857 deg Dec (deg): 20.962841263623886 deg

Offset between SkyField and Astropy: 20.162088182148317 arcsec

Orbit: 1
Orbit start: 2017-07-18T13:03:40 Orbit end: 2017-07-18T14:05:30
Aim time: 2017-07-18T13:34:35 RA (deg): 117.91422476578671 deg Dec (deg): 20.951959754615196 deg
SkyField Aim time: 2017-07-18T13:34:35 RA (deg): 117.92011737743438 deg Dec (deg): 20.950918573733055 deg

Offset between SkyField and Astropy: 20.16232329399357 arcsec

Orbit: 2
Orbit start: 2017-07-18T14:40:20 Orbit end: 2017-07-18T15:42:10
Aim time: 2017-07-18T15:11:15 RA (deg): 117.98162045586982 deg Dec (deg): 20.940012769306016 deg
SkyField Aim time: 2017-07-18T15:11:15 RA (deg): 117.98751219671894 deg Dec (deg): 20.938969263324555 deg

Offset between SkyField and Astropy: 20.162558174862244 arcsec

Orbit: 3
Orbit start: 2017-07-18T16:17:00 Orbit end: 2017-07-18T17:18:50
Aim time: 2017-07-18T16:47:55 RA (deg): 118.04900634435941 deg Dec (deg): 20.928039181357505 deg
SkyField Aim time: 2017-07-18T16:47:55 RA (deg): 118.05489721294917 deg Dec (deg): 20.926993352002278 deg

Offset between SkyField and Astropy: 20.162792781909907 arcsec

Orbit: 4
Orbit start: 2017-07-18T17:53:40 Orbit end: 2017-07-18T18:55:30
Aim time: 2017-07-18T18:24:35 RA (deg): 118.11638241616286 deg Dec (deg): 20.916039010412867 deg
SkyField Aim time: 2017-07-18T18:24:35 RA (deg): 118.12227241055632 deg Dec (deg): 20.914990859496836 deg

Offset between SkyField and Astropy: 20.163025465679457 arcsec

Okay, now check to see what the parallax does in each orbit.

Compare Astropy/Sunpy to what you get when you correct for the orbital parallax. Every step below is 100 seconds.



In [16]:

    
from astropy.coordinates import SkyCoord
from datetime import timedelta


for ind, orbit in enumerate(orbits):
    midTime = orbit[0]
    while(midTime < orbit[1]):
        
        sky_pos = planning.get_sky_position(midTime, offset)

        skyfield_pos = planning.get_skyfield_position(midTime, offset, load_path='../data', parallax_correction=True)
        skyfield_geo = planning.get_skyfield_position(midTime, offset, load_path='../data', parallax_correction=False)

        
        skyfield_ephem = SkyCoord(skyfield_pos[0], skyfield_pos[1])
        skyfield_geo_ephem = SkyCoord(skyfield_geo[0], skyfield_geo[1])
#        sunpy_ephem = SkyCoord(sky_pos[0], sky_pos[1])
        print('Offset between parallax-corrected positions and geoenctric is {} arcsec'.format(
            skyfield_geo_ephem.separation(skyfield_ephem).arcsec)
             )
        dra, ddec = skyfield_geo_ephem.spherical_offsets_to(skyfield_ephem)
        print('{0} delta-RA, {1} delta-Dec'.format(dra.to(u.arcsec), ddec.to(u.arcsec)))
        print('')
        midTime += timedelta(seconds=100)
        
    break









    



Offset between parallax-corrected positions and geoenctric is 8.664131980754892 arcsec
8.654283660118677 arcsec delta-RA, -0.4129858468939972 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 9.00997682125181 arcsec
9.009464612674924 arcsec delta-RA, -0.09607139237710091 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 9.261767536115142 arcsec
9.259108154863679 arcsec delta-RA, 0.22193258081934353 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 9.415587542643516 arcsec
9.400244500410418 arcsec delta-RA, 0.5373007587981358 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 9.469071719804337 arcsec
9.431173504717664 arcsec delta-RA, 0.8463365522920199 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 9.421373066533983 arcsec
9.35148630520005 arcsec delta-RA, 1.145414485410706 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 9.2731548028721 arcsec
9.162072399638658 arcsec delta-RA, 1.431023879783298 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 9.026602642848644 arcsec
8.86511158025356 arcsec delta-RA, 1.699809384432711 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 8.685460540076058 arcsec
8.464049703906705 arcsec delta-RA, 1.9486116609922257 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 8.255105703336524 arcsec
7.963560894034961 arcsec delta-RA, 2.1745040958533086 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 7.742689069019857 arcsec
7.369492765981517 arcsec delta-RA, 2.3748284978666394 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 7.157402550992357 arcsec
6.688800348787051 arcsec delta-RA, 2.5472261721909364 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 6.51097869900048 arcsec
5.929463396184131 arcsec delta-RA, 2.6896667924333477 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 5.818647487702127 arcsec
5.100393347367169 arcsec delta-RA, 2.800472511801016 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 5.100992647783857 arcsec
4.211329457107673 arcsec delta-RA, 2.8783380964206806 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 4.387575194581332 arcsec
3.272721244726833 arcsec delta-RA, 2.9223469579449493 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 3.7237523944524007 arcsec
2.2956074377209634 arcsec delta-RA, 2.9319819896347337 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 3.181091273073924 arcsec
1.2914818494985472 arcsec delta-RA, 2.90713197501412 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 2.861066977422684 arcsec
0.27215978524909473 arcsec delta-RA, 2.8480929234667087 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 2.8559033894886796 arcsec
-0.7503657880152428 arcsec delta-RA, 2.755564434781449 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 3.1673641049200594 arcsec
-1.7640637480997443 arcsec delta-RA, 2.630641455177755 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 3.7048279030625424 arcsec
-2.7570112231197728 arcsec delta-RA, 2.474800781285738 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 4.366189635011349 arcsec
-3.7175320754866075 arcsec delta-RA, 2.289883664589568 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 5.078925346239241 arcsec
-4.634338640906368 arcsec delta-RA, 2.078073154539999 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 5.7970489405853485 arcsec
-5.4966623525089116 arcsec delta-RA, 1.8418684540764894 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 6.4906468305774805 arcsec
-6.294383874367273 arcsec delta-RA, 1.5840542676992995 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 7.1389368091060845 arcsec
-7.018149512608069 arcsec delta-RA, 1.3076682244650943 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 7.72656907822444 arcsec
-7.659483488218246 arcsec delta-RA, 1.0159637867068065 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 8.241729215933077 arcsec
-8.21088460854411 arcsec delta-RA, 0.7123723853405992 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 8.675163388219122 arcsec
-8.665915428142023 arcsec delta-RA, 0.40046174023999503 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 9.019664915105022 arcsec
-9.019274742464082 arcsec delta-RA, 0.08389458500102592 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 9.269803864109035 arcsec
-9.26685963255147 arcsec delta-RA, -0.23361556049109009 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 9.42178103864035 arcsec
-9.405810620341233 arcsec delta-RA, -0.5483470732570842 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 9.473352589782722 arcsec
-9.434543986603021 arcsec delta-RA, -0.8566148815242782 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 9.42379210826588 arcsec
-9.35276781046106 arcsec delta-RA, -1.1548125316714453 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 9.273877801221813 arcsec
-9.16148340934576 arcsec delta-RA, -1.4394551790395802 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 9.025899829639066 arcsec
-8.862971888819823 arcsec delta-RA, -1.7072190934437994 arcsec delta-Dec

Offset between parallax-corrected positions and geoenctric is 8.683691340440026 arcsec
-8.460765006641436 arcsec delta-RA, -1.9549810235411589 arcsec delta-Dec



In [ ]: