Effect of chopping frequency on data quality
During VM observations on March 7 and 9 of 2007, different chopping
frequencies were used with MIDI on the UTs. This page summarizes some of
the results.
First, we compare results obtained on a bright target, HD 61935. We only plot results for UT3.
| 0.5 Hz | 2 Hz | 4 Hz |
|---|
| 03/07 (UT3/A) | 03/09 (UT3/B) | 03/09 (UT3/B) |
|---|
| DIMM 1.09 | DIMM 1.32 | DIMM 1.84 |
|---|
| 41 cycles, 46 frames/cycle | 167 cycles, 10 frames/cycle | 333 cycles, 4 frames/cycle |
|---|
 |  | 
|
|---|
 |  | 
|
|---|
 |  | 
|
|---|
 |  | 
|
|---|
Now results for a faint star, HD 69830. First, compare all UT3 results, then (in the second row), results for the other two telescopes.
| 0.5 Hz (UT3/A) | 2 Hz (UT3/B) | 4 Hz (UT3/B) | 4 Hz (UT3/B) |
|---|
| 03/07 | 03/09 | 03/09 | 03/09 |
|---|
| DIMM 1.30 | DIMM 1.60 | DIMM 1.49 | DIMM 1.73 |
|---|
 |  |  |  |
|---|
| 0.5 Hz (UT4/B) | 2 Hz (UT2/A) | 4 Hz (UT2/A) | 4 Hz (UT2/A) |
|---|
 |  |  |  |
|---|