Calibration

Data calibration is a critical step in the data analysis process. Commonalibration ensures that systematic, instrumental, or environmental effects that occur during observations are accounted for and corrected to maintain the integrity of the data. Ensuring that measurements are appropriately adjusted, calibration safeguards against inaccuracies that could render the data unusable for scientific analysis, ultimately refining the precision and accuracy of the measurements obtained.

The process of data calibration involves several key steps which vary according to the frequency of observation.

The HartRAO 26m antenna currently monitors the following calibrators

HartRAO monitored calibrator sources

IVS

J2000

RA

Dec

Freq

Freq

Obs./Central

name

name

[deg]

[deg]

band

range

freqs[GHz]

Jupiter

K

20.346, 20.971, 22, 23.121

0433+296

3C123

69.26

29.67

1.668, 2.28, 4.874, 6.7, 8.4, 12.2

0134+329 (J0137+3309)

3C48

24.42

33.15

2.28, 4.874, 8.4

0624-058

3C161

96.79

-5.88

2.28, 4.874, 8.4

1328+307 (J1331+3030)

3C286

202.78

30.50

4.874, 8.4

0915-11

HYDRA A (3C218)

139.52

-12.09

1.668, 2.28, 4.874, 6.7, 8.4, 12.2

TAURUS A

83.63

22.01

1668

1228+127

VIRGO A (3C274)

187.80

12.39

4.874, 6.7, 8.4, 12.2, 20.346, 20.971, 22, 23.121

HartRAO observing parameters

Freq. band

Wavelength [cm]

Freq. range

Bandwidth

Central freq.

L

18

1000 - 2000

1668

S

13

2000 - 4000

2280

C

6

4000 - 8000

4800, 5040

X

3.5

8000 - 12000

8280, 8400

Ku

2.5

12000 - 18000

12218, 12178

K

1.3

18000 - 23000

23000

The radio astronomy flux-density scale has long been based on the polynomial expressions given in Ott et al. (1994) .

(1)\[log(S_{\nu}) = a_{0} + a_{1}*log(\nu) + a_{2}*log^{2}(\nu) [MHz]\]

The flux density equation

To calibrate HartRAO data, select one of the following paths: