2019 June

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June 01

12:18 UT Just a note to say the data archive disk is getting full, so we need to stage some data off. One option is to move data prior to 2017 off. Here are the data usages by year:

  • 2014 (0.3 TB)
  • 2015 (1 TB)
  • 2016 (9.5 TB)
  • 2017 (6 TB)
  • 2018 (5.4 TB)
  • 2019 (5.4 TB)

Note that 2019 is less than half over, so we are looking at more than 10 TB/year (actually should be more than 20 TB/year by my calculation of 60 GB/day).

June 04

15:05 UT More on the storage issue. Looking at tape backup, one can purchase a HP Ultrium tape drive for about $1600, with 1.5/3 TB cartridges costing $25 each. I also find an 80 GB Stonefly rackmount storage system costs about $7000 (with 8 x 10 TB drives). The latter could store up to 3.5 years of data at our current rate (or 2 years in addition to our current database). We really need to have one unit at OVRO and a second one at NJIT. We could solve our current problem, then, by spending $2600 on tape backup (for long-term storage) plus $365/year going forward, and $14,000 for dual-capacity storage. Total for the next two years: $17,500. This is certainly a good investment! In two years, there may be other storage options.

June 19

23:09 UT Just a note to say that I (--Dgary (talk) 23:11, 19 June 2019 (UTC)) am at OVRO this week and will be messing with the system. Today is a good example--several calibrations, correlator restart, setting of delays, etc., have pretty much messed up today's data. I am chasing a long-standing problem with low signal levels at high frequencies, and will also be working on improving total power calibration.

June 29

17:52 UT As predicted, the system was in disarray for about a week as I did various tests and a long series of pointing measurements. The update to pointing went awry, however, when I had antenna 4 out of the subarray, not realizing that the software does not work well with missing antennas when updating the pointing. This morning I finally realized what was wrong, and have put ant4 back in the array. I am doing another SOLPNTCAL after updating the pointing correctly, I hope.

18:04 UT Yes, the pointing is now very good for this moment. Later I will check the other SOLPNTCALs for the day and see how well they do at other times.