Table 2.
Auxiliary coefficients in the GBT pointing model.
| Coefficient name | Coordinate | Functional form | Description | Value (″) | Error (″) |
|---|---|---|---|---|---|
| A12E | ΔEL | λ1 | Track term | 0.705 | 0.15 |
| A13V | ΔAZcos(EL) | λ2 * sin(EL) | Track term | −1.01 | 0.21 |
| A14A | ΔAZcos(EL) | λ3 * cos(EL) | Track term | −0.83 | 0.46 |
| A2S | ΔAZcos(EL) | τ2 | Horizontal feedarm and el. bearings (thermal) | 6.79 | 1.57 |
| A3S | ΔAZcos(EL) | τ3 | Backup structure and el. bearings (thermal) | −0.49 | 0.75 |
| A4S | ΔAZcos(EL) | τ4 | Vertical feedarm (thermal) | 0.34 | 1.67 |
| A5E | ΔEL | τ5 | Backup structure (thermal) | −1.65 | 1.94 |
| A6E | ΔEL | τ6 | Horizontal feedarm and el. bearings (thermal) | −0.50 | 0.13 |
| A7E | ΔEL | τ7 | Vertical feedarm (thermal) | −3.28 | 0.38 |
| A8E | ΔEL | τ8 | Alidade (thermal) | 7.19 | 1.69 |
| A9E | ΔEL | τ9 | Structural temp. average (thermal) | −0.35 | 0.09 |
| A10V | ΔAZcos(EL) | τ10*sin(EL) | Alidade and el. bearings (thermal) | 10.73 | 4.24 |
| A11A | ΔAZcos(EL) | τ11*cos(EL) | Alidade thermal term | −0.43 | 0.56 |
Notes. This table summarizes the auxiliary coefficients in the GBT pointing model and their corresponding functional forms, values (in arcseconds), and the error associated with the determination of each coefficient. As in Table 1, EL stands for mount elevation and AZ for mount azimuth, and the coefficients’ signs follow TPOINT conventions; therefore, in order to reproduce this model in a TPOINT session, these terms must be plugged in exactly as they appear above.
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