Shimojo and Iwai (2023) presented the history of the Nobeyama Radio Polarimeters (NoRP) until about 2020. The NoRP operations have continued after 2020, and the observations are sometimes suspended due to various problems. This page shows suspensions and instrumental problems with long term (>1 week) since 2020 for users of NoRP data.
| Date | ||||
|---|---|---|---|---|
| Start | End | Obs. Freq. | Descriptions of troubles | Announcement Date |
| 2025/09/19 | Present | 35 GHz | After recovering the high-voltage power supply distributor system at the Nobeyama campus, we attempted to resume 35 GHz observations. Unfortunately, due to an issue with the receiver system, we cannot detect the 35 GHz solar signal. We are investigating the cause of this issue. | 25 Sep. 2025 |
| 2024/02/14 | Present | 80 GHz | The IF level has decreased since 14:30JST. On the other hand, the levels of correlation are not affected by the problem. We are investigating the cause. | 22 Mar. 2024 |
| 2025/07/22 | 2025/09/19 | All | Due to issues with the high-voltage power supply distributor system at the Nobeyama campus, the NoRP antennas and the Heliog building, which houses the NoRP backend and control systems, had lost all electric power around 15:00JST, 21 July. On 31 July, we installed a temporary power line from the main building to the Heliog building and then, we resumed the observations 3.75 GHz on 1 August, at 2 GHz on 5 August, at 9.4 GHz on 8 August, 1 GHz on 18 August, 17 GHz on 10 September. Due to limitations in power consumption, we could not operate all the antennas. For the same reason, we could not access the Internet from the Heliog building. As a result, the clocks on the antenna control PCs were slowing down. The time lag was about 10 seconds per day. As the pointing accuracy of the NoRP is controlled by the clock on the antenna control PCs, this time lag is unacceptable for total flux measurements. We found the issue on 25 August and stopped providing daily fluxes before 25 August and had been manually adjusting the clocks every business day. Due to the treatment, we do not provide daily fluxes on public holidays (i.e. Saturday and Sunday) until the full recovery of the electric power. The electric power system was recovered fully on 19 September and the observations of NoRP were back to normal on 20 September. We provide the raw data between 1 August and 19 September, but we cannot guarantee of the absolute fluxes during the period, except for the calibrated daily fluxes. |
Update 19 Sep. 2025 1st Ann. 24 Jul. 2025 |
| 2025/06/27 | 2025/09/10 | 17 GHz | The observation at 17 GHz had been suspended due to the broken bearings in the right ascension axis drive system. The bearings were repaired on 10 September during the manufacturer's yearly maintenance and the observation resumed the following day. | Update 11 Sep. 2025 1st Ann. 4 Jul. 2025 | 2024/12 | 2025/04 | 2 GHz | Since around December 2024, the Sun value has slowly increased after noon. The peak enhancement is less than 10% of the actual solar value and may depend on the sun's elevation. We investigated the radio environment and detected radio interference. Furthermore, the interference occurs after 11:00 JST (02:00 UTC) and originates mainly from the south of Nobeyama. Therefore, since December 2024, we have been calculating the 2 GHz daily flux using the solar value observed between 10 and 11 JST (01--02 UT). Based on this decision, we have re-released the modified daily fluxes for December 2024 to April 2025, which include 2 GHz data. | Update 17 Jun. 2025 1st Ann. 20 May 2025 |
2025/03/10 | 2025/03/18 | 35/80 GHz | Due to the trouble with the declination angle encoder, the observation is suspended. | 12 Mar 2025 | 2025/01/22 | 2025/02/26 | 1 GHz | Due to problems with the status signal interface board, there is no status flag data for calibrations (Sky, AMB, Zero) in the raw data. Therefore the automatic calibration with SSW+IDL cannot work. On the other hand, the 1GHz daily fluxes are not affected because they are calibrated manually. | 12 Mar 2025 | 2024/10/20 | 2024/11/14 | 1 GHz | Due to the trouble with the pointing sensor of the declination axis, the observation was suspended. | 15 Nov 2024 |
| 2023/10/17 | 2023/12/12 | 3.75 GHz | Due to problems with the declination angle encoder, observation was sometimes interrupted. | 17 Jan 2024 |
| 2023/02/10 | 2023/04/10 | 1 GHz | Due to the trouble with the mortor's axis of the declination axis, the observation was suspended. | May 2023 |
| 2022/12/14 | 2023/01/12 | 1 GHz | Due to the trouble with the angle encoder of the right ascension axis, the observation was suspended. | May 2023 |
| 2022/11/17 | 2023/02/01 | 35 GHz | The outputs in the morning (until 11:00JST) were unstable and anomalous. It was caused by the deteriorated power supply for the local ocsillator. | May 2023 |
| 2022/02/24 | 2022/04/05 | 3.75 GHz | Due to the trouble with the motor of the declination axis, the observation was suspended. | May 2023 |
| 2021/06/11 | 2021/11/07 | 1 GHz | As mentioned in Shimojo and Iwai (2023), the local oscillator of 1 GHz had a glitch between September 2020 and November 8, 2021. To validate the 2GHz absolute flux calibration (see below), we make the ratio plots between the 1, 2, and 3.75GHz. From the plots, we clearly see that the glitch worsened after the planned power outage on June 11, 2021, and found that the gain varied from the scheduled power outage to November 8, 2021. To calibrate the variation, we applied the correction factor "0.93" to 1 GHz data in several materials (daily flux [txt, CSV files], FITS database, etc.) | 25 Sep. 2023 |
| 2021/06/07 | 2021/06/28 | 17 GHz | During the observation, the output becomes the level of AMB and not be back to the level of the Sun. It was caused by the disconnection of the control line for polarization change. | May 2023 |
| 2021/02/22 | 2021/03/19 | 2 GHz | Due to the trouble with the control of the right ascension axis, the observation was suspended. | May 2023 |
| 2020/11/Mid | 2020/12/10 | 1 GHz | The solar flux was decreasing in the afternoon. It was caused by the shadow of a tree, and we cut down the tree. | May 2023 |
| 2020/10/08 | 2020/11/12 | 2 GHz | Due to the trouble with the pointing sensor of the declination axis, the observation was suspended. | May 2023 |
| 2019/11/29 | 2020/07/03 | 1 GHz | Due to the trouble with the pointing sensor of the declination axis, the observation was suspended. | May 2023 |
| 2019/10/29 | 2020/09/04 | 9.4 GHz | The outputs around noon (JST) became zero. It was caused by the trouble in the IF cable between the antenna to the buliding. | May 2023 |
| 2019/05/15 | 2 GHz | To avoid interference from the base stations of cell phones, we changed the FE system of 2GHz from the DSB to the SSB system. After the change, the solar fluxes obtained from NoRP data are overestimated. We performed the 2GHz solar observations using the standard horn antenna in July 2023 to calibrate the absolute fluxes. Finally, we obtained the correction factor "0.94". We applied the factor to the daily flux table [txt, CSV files], IDL procedures of reading raw data, FITS file database, and solar cycle plot. The calibration project was carried out with the essential contributions of Watanabe Lab., National Defence Academy of Japan. | 25 Sep. 2023 | |
| 2018/11/25 | 2021/10/16 | 35/80 GHz | Due to the trouble with the gears of the declination axis, the observation was suspended. | May 2023 |
