WSO Raw Observation Files

WSO has since the 1970s made two basic kinds of observations, mean fields (meanfld) and magnetograms (magscan). In several early years Doppler Observations (dopobs) were collected as well.

Raw Observation Files

The raw observation files are named with the date and time, the kind of observation, and a daily sequence number, e.g.

• 0825:1939_MF07 is the seventh mean field (MF) taken on August 25
• 0825:2312_MG02 is the second magnetogram (MG) taken on August 25

Observation files are created at WSO by the control computer and transferred to campus for further reduction. The files consist of a series of records of different types.

• Each observation file begins with a standard Open record (Type 10).

• Each complete observation file ends with a standard Close record (Type 18).

• The records in between contain the measurements taken during the observation.

Records

Each record begins with variables that indicate the Type of the record, the Record ID sequence number, and the Name_Time of the observation.

The Type defines the format and contents of the data in the record.

• Type 10 is an Open record. It includes the values of the 100 standard variables.

• Type 12 is an All record. It includes the same list of 100 standard variables.

• Type 14 is a short set of parameters recorded after each integration in a dopobs.

• Type 16 is a list of 11 parameters recorded after each magscan integration.

• Type 18 is a Close record. Type 18 includes the same 99 variables.

The Record ID increments by one for each record in the observation.

The Name_Time is the time of the first record in the observation.

Observations

Meanfld

A standard meanfld has 8 records. It starts with an Open record followed by six All records and a Close record. The observation takes 25-30 minutes to perform six 180-second integrations with

• 5250 KDP Off
• 5124 KDP Off
• 5124 KDP On
• 5250 KDP On
• 5124 KDP On
• 5247 KDP On

A time critical meanfld has 6 records and takes about half the time making four integrations of 60 seconds with

• 5250 KDP Off
• 5124 KDP On
• 5250 KDP On
• 5124 KDP On

Magscan

A standard magscan takes about 2.25 hours has 310 records. After centering the image, it starts with an Open record, followed by an All record with a 180s 5124 magnetic zero-level calibration; 89 Type-16 records for the smaller 5247 scan; an All record with a 5-minute 5250 velocity calibration; 195 Type-16 records comprising the 5250 full-disk scan, then 21 Type-16 records for the N-S Scan; an All record with the post-scan 300s 5250 velocity calibration, and a Close record with the results of the post-scan 5124 magnetic zero.

A time-critical magscan skips the 5247 scan. [Verify]

Other

• Wscantel -- lists the records in an observation
• Wlooktel -- lists all the variables in an observation

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