<<<<< Q20139 >>>>> <<< IN320-139 >>> Matthias Schartner(1), Christian Ploetz(2), Arno Mueskens(3), (1) Technische Universitaet Wien, Austria (2) Geodatisches Observatorium Wettzell, Germany (3) IGG University of Bonn, Germany Date of experiment: 2020,May,18 Nominal Start Time: 07h00 UT Nominal End Time: 08h00 UT Duration: 1.0 hr Correlator: BONN Participating stations: (5) ISHIOKA Is NYALES20 Ny SESHAN25 Sh WETTZ13N Wn WETTZELL Wz scheduler: VieSched++ AUTO Contact ======= Matthias Schartner (1) matthias.schartner@geo.tuwien.ac.at +43 (1) 58801 - 128 11 Christian Ploetz (2) ploetz@fs.wettzell.de Arno Mueskens (3) mueskens@mpifr-bonn.mpg.de Notes: =========================================================== This is an automatically generated schedule The template was generated by Matthias Schartner Purpose ======= The project is the first implementation of a third INTENSIVE-observation routine to improve UT1-determination. The project started with regular observations each Monday on August 27th 2007. The goal is to bring up final processed data in less than a few hours to the IVS data centers. Schedule ======== The schedule was produced by using the latest version of VieSched++. The minimum scan duration was fixed to 20 seconds. The minimum snr was set to 23/18 for all baselines. Station down times: none Tagalong mode used: none =========================================================== Session Notes for session: Q20139 =========================================================== Experiment: Q20139 Description: IN320-139 Scheduler: BONN Correlator: BONN Start: 2020-139-07:00:00 End: 2020-139-08:00:00 Current yyyyddd: 2020139 (2020.38) ( 58987 MJD, MON. 18MAY.) =========================================================== Software: VieSched++ Version: b85e0a4 GUI: VieSched++ Version: 2e5138b scheduler: VieSched++ AUTO mail: matthias.schartner@geo.tuwien.ac.at =========================================================== First observations Observation listing from file q20139.skd for experiment Q20139 Source Start DURATIONS name yyddd-hhmmss Is Ny Sh Wn Wz 0420+022 20139-070000| 65 58 30 65 60 Last observations 0805+410 20139-075910| 50 50 50 50 50 =========================================================== Schedule was created using multi scheduling tool version 1 weight sky coverage 0 =========================================================== Key: Is=ISHIOKA Ny=NYALES20 Sh=SESHAN25 Wn=WETTZ13N Wz=WETTZELL Is Ny Sh Wn Wz Avg % obs. time: 64.28 53.53 36.03 68.03 67.03 57.78 % cal. time: 11.11 11.11 11.11 11.11 11.11 11.11 % slew time: 15.50 28.69 46.19 4.44 12.72 21.51 % idle time: 2.44 0.00 0.00 9.75 2.47 2.93 % field system: 6.67 6.67 6.67 6.67 6.67 6.67 total # scans: 41 41 41 41 41 41 # scans/hour: 41.00 41.00 41.00 41.00 41.00 41.00 total # obs: 164 164 164 164 164 164 # obs/hour: 164.00 164.00 164.00 164.00 164.00 164.00 Avg scan (sec): 56.44 47.00 31.63 59.73 58.85 50.73 # Mk5 tracks: 32 32 32 32 32 Total TB(M5): 0.28 0.24 0.16 0.30 0.29 0.25 # OF OBSERVATIONS BY BASELINE | Is Ny Sh Wn Wz Total ------------------------------------ Is| 41 41 41 41 164 Ny| 41 41 41 164 Sh| 41 41 164 Wn| 41 164 Wz| 164 Number of 2-station scans: 0 ( 0.00 %) Number of 3-station scans: 0 ( 0.00 %) Number of 4-station scans: 0 ( 0.00 %) Number of 5-station scans: 41 (100.00 %) Total number of scans: 41 Total number of obs: 410 Total integrated obs-time: 17938 Average obs-time: 43.8 =========================================================== Recording mode: Mode: 1024-16(AU) Freq: GEOSX Recording mode for: Is Ny Sh Wn Wz Tot.Rate Tot.BandW Chan.BW #BBC #bits Tracks 1024 Mbit/s 256 MHz 16.00 MHz 14 2 32 S-band spanned bw = 140.0 MHz rms spanned bw = 55.8 MHz X-band spanned bw = 720.0 MHz rms spanned bw = 312.1 MHz ================================================================================================================================================ ADDITONAL NOTES FOR SCHEDULER ================================================================================================================================================ #scans #obs --------------------------------- total 41 410 --------------------------------- single source 41 410 subnetting 0 0 --------------------------------- standard 41 410 fillin mode 0 0 weight factors: duration: 1 sky coverage score (1 means perfect distribution) .---------------------------------------------------------------------------------. | | ISHIOKA NYALES20 SESHAN25 WETTZ13N WETTZELL | average | |-------------------|--------------------------------------------------|----------| | 13 areas @ 30 min | 0.52 0.54 0.56 0.52 0.52 | 0.53 | | 25 areas @ 30 min | 0.39 0.40 0.38 0.43 0.43 | 0.41 | | 37 areas @ 30 min | 0.32 0.34 0.32 0.35 0.35 | 0.34 | |---------------------------------------------------------------------------------| | 13 areas @ 60 min | 0.54 0.62 0.62 0.54 0.54 | 0.57 | | 25 areas @ 60 min | 0.46 0.42 0.42 0.48 0.48 | 0.45 | | 37 areas @ 60 min | 0.41 0.39 0.36 0.42 0.42 | 0.40 | '---------------------------------------------------------------------------------' number of scans per 15 minutes: .-----------------------------------------------------------------------------------------------------------------------------------------. | time since session start (1 char equals 15 minutes) | #SCANS #OBS | OBS Time [s] | | STATION |0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | | sum average | |---------|+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---|-------------|----------------| | ISHIOKA|XX9X | 41 164 | 2314 56.4 | | NYALES20|XX9X | 41 164 | 1927 47.0 | | SESHAN25|XX9X | 41 164 | 1297 31.6 | | WETTZ13N|XX9X | 41 164 | 2449 59.7 | | WETTZELL|XX9X | 41 164 | 2413 58.9 | '-----------------------------------------------------------------------------------------------------------------------------------------' number of available sources: 301 number of scheduled sources: 23 number of scans per 15 minutes: .-----------------------------------------------------------------------------------------------------------------------------------------. | time since session start (1 char equals 15 minutes) | #SCANS #OBS | OBS Time [s] | | SOURCE |0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | | sum average | |---------|+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---|-------------|----------------| | 0016+731|1 1 | 2 20 | 121 60.5 | | 0059+581|1 1 | 2 20 | 96 48.0 | | 0133+476|1 1 | 2 20 | 85 42.5 | | 0202+319|1 1 | 2 20 | 100 50.0 | | 0322+222|1 1 | 2 20 | 111 55.5 | | 0420+022|1 1 | 2 20 | 126 63.0 | | 0529+483| 1 | 1 10 | 50 50.0 | | 0552+398| 1 | 1 10 | 107 107.0 | | 0613+570| 1 1 | 2 20 | 114 57.0 | | 0642+449| 1 1 | 2 20 | 171 85.5 | | 0716+714| 1 1 | 2 20 | 113 56.5 | | 0738+491| 1 | 1 10 | 65 65.0 | | 0805+410| 1 1 | 2 20 | 99 49.5 | | 0814+425| 1 1 | 2 20 | 85 42.5 | | 0821+394| 1 | 1 10 | 120 120.0 | | 0955+476| 1 | 1 10 | 68 68.0 | | 1039+811|1 1 | 2 20 | 90 45.0 | | 1053+704|1 1 | 2 20 | 137 68.5 | | 1418+546| 1 1 | 2 20 | 162 81.0 | | 1803+784|1 1 | 2 20 | 126 63.0 | | 3C371|1 1 | 2 20 | 103 51.5 | | 1849+670|1 1 | 2 20 | 87 43.5 | | 2229+695|1 1 | 2 20 | 113 56.5 | '-----------------------------------------------------------------------------------------------------------------------------------------' Summary of observing mode(s): band S mean frequency 2290.990 [MHz] band X mean frequency 8588.990 [MHz] observing mode: 1024-16(AU): band: S recording rate 384.00 [Mbit/s] with efficiency factor 0.6062: (10) Is-Ny Is-Sh Is-Wn Is-Wz Ny-Sh Ny-Wn Ny-Wz Sh-Wn Sh-Wz Wn-Wz band: X recording rate 640.00 [Mbit/s] with efficiency factor 0.6062: (10) Is-Ny Is-Sh Is-Wn Is-Wz Ny-Sh Ny-Wn Ny-Wz Sh-Wn Sh-Wz Wn-Wz average theoretical SNR for S-band per baseline: .------------------------------------------------------------------------. | STATIONS | ISHIOKA NYALES20 SESHAN25 WETTZ13N WETTZELL | AVERAGE | |----------|--------------------------------------------------|----------| | ISHIOKA | 41.60 47.71 48.75 45.52 | 45.89 | | NYALES20 | 41.73 61.30 57.72 | 50.59 | | SESHAN25 | 47.64 44.87 | 45.49 | | WETTZ13N | 88.25 | 61.48 | | WETTZELL | | 59.09 | '------------------------------------------------------------------------' average theoretical SNR for X-band per baseline: .------------------------------------------------------------------------. | STATIONS | ISHIOKA NYALES20 SESHAN25 WETTZ13N WETTZELL | AVERAGE | |----------|--------------------------------------------------|----------| | ISHIOKA | 81.71 100.53 68.97 91.43 | 85.66 | | NYALES20 | 111.42 111.36 148.51 | 113.25 | | SESHAN25 | 91.47 122.24 | 106.41 | | WETTZ13N | 157.24 | 107.26 | | WETTZELL | | 129.85 | '------------------------------------------------------------------------' scan observing durations: scan duration: 0- 19 | 20- 39 | 40- 59 | ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 60- 79 | ++++++++++++++++++++ 80- 99 | +++++ 100-119 | +++++++ 120-139 | scheduled scan length: .-----------------------------------------------------------------------------------. | S1-S2 | min 10% 50% 90% 95% 97.5% 99% max | sum average | |-------|---------------------------------------------------------|-----------------| | ALL | 42 43 55 81 107 116 116 120 | 2449 59.7 | |-------|---------------------------------------------------------|-----------------| | Is-Ny | 30 30 43 61 83 92 92 99 | 1927 47.0 | | Is-Sh | 30 30 30 37 40 42 42 50 | 1297 31.6 | | Ny-Sh | 30 30 30 30 34 37 37 50 | 1262 30.8 | | Is-Wn | 33 41 53 76 101 111 111 120 | 2314 56.4 | | Ny-Wn | 30 30 43 61 83 92 92 99 | 1927 47.0 | | Sh-Wn | 30 30 30 37 40 42 42 50 | 1297 31.6 | | Is-Wz | 33 38 52 76 101 111 111 120 | 2278 55.6 | | Ny-Wz | 30 30 43 61 83 92 92 99 | 1926 47.0 | | Sh-Wz | 30 30 30 37 40 42 42 50 | 1297 31.6 | | Wn-Wz | 38 43 53 81 107 116 116 120 | 2413 58.9 | '-----------------------------------------------------------------------------------' First Scans: .----------------------------------------------------------------------------------------------------------------------------------------------. | scan: no0000 (id: 318) duration: 07:00:00 - 07:01:05 | | Source: 0420+022 (id: 54) type: target single source scan | |----------------------------------------------------------------------------------------------------------------------------------------------| | station | delay | slew | idle | preob | obs | duration | az [deg] | unaz [deg] | el [deg] | | | [s] | [s] | [s] | [s] | [s] | start - end | start - end | start - end | start - end | |--------------|-------|-------|-------|-------|-------|---------------------|---------------------|-----------------------|-------------------| | ISHIOKA | 0 | 0 | 0 | 0 | 65 | 07:00:00 - 07:01:05 | 250.0487 - 250.2495 | 250.0487 - 250.2495 | 28.6240 - 28.4179 | (id: 86638 and 96846) | NYALES20 | 0 | 0 | 0 | 0 | 58 | 07:00:00 - 07:00:58 | 106.5805 - 106.8197 | 466.5805 - 466.8197 | 5.6055 - 5.6501 | (id: 86641 and 96850) | SESHAN25 | 0 | 0 | 0 | 0 | 30 | 07:00:00 - 07:00:30 | 237.5896 - 237.7117 | 597.5896 - 597.7117 | 45.0511 - 44.9604 | (id: 86646 and 96856) | WETTZ13N | 0 | 0 | 0 | 0 | 65 | 07:00:00 - 07:01:05 | 102.5200 - 102.7349 | 102.5200 - 102.7349 | 13.6976 - 13.8709 | (id: 86651 and 96862) | WETTZELL | 0 | 0 | 0 | 0 | 60 | 07:00:00 - 07:01:00 | 102.5201 - 102.7185 | 462.5201 - 462.7185 | 13.6972 - 13.8572 | (id: 86654 and 96866) |----------------------------------------------------------------------------------------------------------------------------------------------| | scan: no0001 (id: 804) duration: 07:01:35 - 07:02:31 | | Source: 0322+222 (id: 36) type: target single source scan | |----------------------------------------------------------------------------------------------------------------------------------------------| | ISHIOKA | 6 | 14 | 35 | 10 | 56 | 07:01:35 - 07:02:31 | 278.1598 - 278.2834 | 278.1598 - 278.2834 | 28.4566 - 28.2697 | (id: 97269 and 110841) | NYALES20 | 6 | 21 | 28 | 10 | 48 | 07:01:35 - 07:02:23 | 117.4569 - 117.6632 | 477.4569 - 477.6632 | 27.9752 - 28.0093 | (id: 97271 and 110860) | SESHAN25 | 6 | 49 | 0 | 10 | 30 | 07:01:35 - 07:02:05 | 272.3018 - 272.3623 | 632.3018 - 632.3623 | 43.7734 - 43.6662 | (id: 97273 and 110890) | WETTZ13N | 6 | 6 | 43 | 10 | 56 | 07:01:35 - 07:02:31 | 99.5777 - 99.7750 | 99.5777 - 99.7750 | 38.1970 - 38.3479 | (id: 97275 and 110920) | WETTZELL | 6 | 19 | 30 | 10 | 53 | 07:01:35 - 07:02:28 | 99.5784 - 99.7651 | 459.5784 - 459.7651 | 38.1966 - 38.3394 | (id: 97277 and 110951) |----------------------------------------------------------------------------------------------------------------------------------------------| | scan: no0002 (id: 1488) duration: 07:03:00 - 07:03:51 | | Source: 0202+319 (id: 24) type: target single source scan | |----------------------------------------------------------------------------------------------------------------------------------------------| | ISHIOKA | 6 | 13 | 26 | 10 | 49 | 07:03:00 - 07:03:49 | 297.4196 - 297.5161 | 297.4196 - 297.5161 | 17.8006 - 17.6540 | (id: 112552 and 123691) | NYALES20 | 6 | 21 | 18 | 10 | 44 | 07:03:00 - 07:03:44 | 137.1774 - 137.3802 | 497.1774 - 497.3802 | 40.7810 - 40.8050 | (id: 112553 and 123695) | SESHAN25 | 6 | 39 | 0 | 10 | 30 | 07:03:00 - 07:03:30 | 291.8083 - 291.8499 | 651.8083 - 651.8499 | 30.1229 - 30.0233 | (id: 112554 and 123699) | WETTZ13N | 6 | 5 | 34 | 10 | 51 | 07:03:00 - 07:03:51 | 108.0974 - 108.3287 | 108.0974 - 108.3287 | 58.0624 - 58.1948 | (id: 112555 and 123703) | WETTZELL | 6 | 16 | 23 | 10 | 51 | 07:03:00 - 07:03:51 | 108.0988 - 108.3301 | 468.0988 - 468.3301 | 58.0619 - 58.1943 | (id: 112556 and 123707) |----------------------------------------------------------------------------------------------------------------------------------------------| Last Scans: .----------------------------------------------------------------------------------------------------------------------------------------------. | scan: no0038 (id: 16137) duration: 07:56:35 - 07:57:43 | | Source: 0955+476 (id: 125) type: target single source scan | |----------------------------------------------------------------------------------------------------------------------------------------------| | ISHIOKA | 6 | 20 | 81 | 10 | 57 | 07:56:35 - 07:57:32 | 38.8211 - 38.4085 | 398.8211 - 398.4085 | 74.7582 - 74.8781 | (id: 487485 and 491512) | NYALES20 | 6 | 32 | 69 | 10 | 54 | 07:56:35 - 07:57:29 | 31.7360 - 31.9284 | 751.7360 - 751.9284 | 38.1983 - 38.2211 | (id: 487489 and 491516) | SESHAN25 | 6 | 101 | 0 | 10 | 30 | 07:56:35 - 07:57:05 | 47.7439 - 47.6834 | 767.7439 - 767.6834 | 59.9998 - 60.0792 | (id: 487493 and 491520) | WETTZ13N | 6 | 5 | 96 | 10 | 68 | 07:56:35 - 07:57:43 | 25.6171 - 25.7960 | 25.6171 - 25.7960 | 12.0924 - 12.1730 | (id: 487496 and 491524) | WETTZELL | 6 | 15 | 86 | 10 | 68 | 07:56:35 - 07:57:43 | 25.6171 - 25.7960 | 385.6171 - 385.7960 | 12.0933 - 12.1740 | (id: 487499 and 491528) |----------------------------------------------------------------------------------------------------------------------------------------------| | scan: no0039 (id: 16294) duration: 07:58:07 - 07:58:50 | | Source: 0814+425 (id: 111) type: target single source scan | |----------------------------------------------------------------------------------------------------------------------------------------------| | ISHIOKA | 6 | 19 | 27 | 10 | 34 | 07:58:07 - 07:58:41 | 308.3952 - 308.1038 | 308.3952 - 308.1038 | 79.3388 - 79.2488 | (id: 492114 and 497190) | NYALES20 | 6 | 22 | 24 | 10 | 34 | 07:58:07 - 07:58:41 | 55.1149 - 55.2427 | 775.1149 - 775.2427 | 36.5960 - 36.6184 | (id: 492115 and 497194) | SESHAN25 | 6 | 46 | 0 | 10 | 30 | 07:58:07 - 07:58:37 | 26.6120 - 26.2527 | 746.6120 - 746.2527 | 77.2042 - 77.2520 | (id: 492116 and 497198) | WETTZ13N | 6 | 3 | 43 | 10 | 43 | 07:58:07 - 07:58:50 | 44.0892 - 44.1988 | 44.0892 - 44.1988 | 17.2730 - 17.3549 | (id: 492117 and 497202) | WETTZELL | 6 | 8 | 38 | 10 | 43 | 07:58:07 - 07:58:50 | 44.0892 - 44.1988 | 404.0892 - 404.1988 | 17.2737 - 17.3555 | (id: 492118 and 497206) |----------------------------------------------------------------------------------------------------------------------------------------------| | scan: no0040 (id: 16505) duration: 07:59:10 - 08:00:00 | | Source: 0805+410 (id: 109) type: target single source scan | |----------------------------------------------------------------------------------------------------------------------------------------------| | station | delay | slew | idle | preob | obs | duration | az [deg] | unaz [deg] | el [deg] | | | [s] | [s] | [s] | [s] | [s] | start - end | start - end | start - end | start - end | |--------------|-------|-------|-------|-------|-------|---------------------|---------------------|-----------------------|-------------------| | ISHIOKA | 6 | 13 | 4 | 10 | 50 | 07:59:10 - 08:00:00 | 297.2140 - 296.9723 | 297.2140 - 296.9723 | 78.2005 - 78.0504 | (id: 497754 and 502907) | NYALES20 | 6 | 13 | 4 | 10 | 50 | 07:59:10 - 08:00:00 | 57.8584 - 58.0482 | 777.8584 - 778.0482 | 35.5497 - 35.5837 | (id: 497755 and 502911) | SESHAN25 | 6 | 17 | 0 | 10 | 50 | 07:59:10 - 08:00:00 | 21.5954 - 20.8061 | 741.5954 - 740.8061 | 79.4380 - 79.5027 | (id: 497756 and 502915) | WETTZ13N | 6 | 2 | 15 | 10 | 50 | 07:59:10 - 08:00:00 | 46.6567 - 46.7854 | 46.6567 - 46.7854 | 17.3099 - 17.4094 | (id: 497757 and 502919) | WETTZELL | 6 | 4 | 13 | 10 | 50 | 07:59:10 - 08:00:00 | 46.6568 - 46.7855 | 406.6568 - 406.7855 | 17.3106 - 17.4101 | (id: 497758 and 502923) |----------------------------------------------------------------------------------------------------------------------------------------------| .------------------------------------------. | sun position: | earth velocity: | |----------------------|-------------------| | RA: 03h 42m 15.01s | x: 24639 [m/s] | | DEC: +19° 40' 21.71" | y: -14785 [m/s] | | | z: -6409 [m/s] | '------------------------------------------' .--------------------------------------------------------------------. | earth nutation: | | time | X Y S | |---------------------|----------------------------------------------| | 2020.05.18 07:00:00 | +1.944534e-03 -5.440254e-06 -6.113256e-09 | | 2020.05.18 08:00:00 | +1.944538e-03 -5.443108e-06 -6.110487e-09 | | 2020.05.18 09:00:00 | +1.944542e-03 -5.446094e-06 -6.107590e-09 | '--------------------------------------------------------------------' ================================================================================================================================================ FULL SCHEDULING SETUP ================================================================================================================================================ Can be used to recreate schedule: VieSched++ GUI 2e5138be4437b5b1aaec61603f39fcae3e0aca7f VieSched++ AUTO matthias.schartner@geo.tuwien.ac.at Q20139 2020.05.18 07:00:00 2020.05.18 08:00:00 false true true true WETTZELL WETTZ13N SESHAN25 NYALES20 ISHIOKA start info info IN320-139 BONN BONN Matthias Schartner matthias.schartner@geo.tuwien.ac.at +43 (1) 58801 - 128 11 Technische Universitaet Wien, Austria Christian Ploetz ploetz@fs.wettzell.de Geodatisches Observatorium Wettzell, Germany Arno Mueskens mueskens@mpifr-bonn.mpg.de IGG University of Bonn, Germany This is an automatically generated schedule\nThe template was generated by Matthias Schartner\n\nPurpose\n=======\nThe project is the first implementation of a third INTENSIVE-observation\nroutine to improve UT1-determination.\nThe project started with regular observations each Monday on August 27th 2007.\nThe goal is to bring up final processed data in less than a few hours to the\nIVS data centers.\n\nSchedule\n========\nThe schedule was produced by using the latest version of VieSched++.\nThe minimum scan duration was fixed to 20 seconds.\nThe minimum snr was set to 23/18 for all baselines. true true false true true true false true false false /home/auto/VieVS/VieSchedpp_auto/CATALOGS/antenna.cat /home/auto/VieVS/VieSchedpp_auto/CATALOGS/equip.cat /home/auto/VieVS/VieSchedpp_auto/CATALOGS/flux.cat /home/auto/VieVS/VieSchedpp_auto/CATALOGS/freq.cat /home/auto/VieVS/VieSchedpp_auto/CATALOGS/hdpos.cat /home/auto/VieVS/VieSchedpp_auto/CATALOGS/loif.cat /home/auto/VieVS/VieSchedpp_auto/CATALOGS/mask.cat /home/auto/VieVS/VieSchedpp_auto/CATALOGS/modes.cat /home/auto/VieVS/VieSchedpp_auto/CATALOGS/position.cat /home/auto/VieVS/VieSchedpp_auto/CATALOGS/rec.cat /home/auto/VieVS/VieSchedpp_auto/CATALOGS/rx.cat /home/auto/VieVS/VieSchedpp_auto/CATALOGS/source.cat.geodetic.good /home/auto/VieVS/VieSchedpp_auto/CATALOGS/tracks.cat __all__ default hard 1 1 1 30 120 0 600 175 0 600 5 9999 6 10 3 0 5 5 0 0 __all__ default hard 1 1 1 0 4 0 9999 5 1700 0.05 999 __all__ default hard 0 0 9999 1 30 3600 0 cosine cosine 0.02 1 900 0 0.01 0.02 0.029999999999999999 0.040000000000000001 0.059999999999999998 0.080000000000000002 0.10000000000000001 auto guided 0 1024-16(AU) 23 required required 18 required required