Every year, *HZ 43* is observed with gratings on both *HRC-I* and *HRC-S*.
Recently, due to concern over the rapidly declining gain, the cadence has
been increased to twice yearly. *HZ 43* is usually observed with the gratings
in place, so we can monitor how the count rates vary with wavelength.

Since *HZ 43* is a point source, the center part is defined as a 200 pixel radius area
around the source position. The unit is *counts/sec* (the background counts is
normalized for per pixel; so the unit is *counts/sec/pix*.)

For the dispersion arm parts, *HRC-I* has enough data only in the wavelength 70-90Å
cell to provide the decent statistics (more than 100 data points).
On the other hand, *HRC-S* has enough data in the most of 10Å cells
from 50Å to 170Å, separately for both *+ve* and *-ve* orders.

Since polygonal areas are used to estimate the count rates of each wavelength,
the unit used on the dispersion arms is *counts/sec/pixel*.

The tables blow list the links to the time trend of *Scaled Sum Amp* and *PI*,
both positive and negative dispersion arms. The *Scaled Sum Amp* is defined by:

where:

*Cosnt* is 148 for *HRC-I |* and 128 for *HRC-S*.

For the detail discussion about the *Scaled Sum Amp*, please see:
*
Sumamps Gain Maps (J. Posson-Brown, V. Kashyap, 2009).
*

Since there is a discontinuity around year 2012, two lines are fitted before and after year 2012. If there are not enough data points, only one fitting is applied (the second slope is displayed as '0.000'). In the tables below, the top value is the slope before year 2012, and the bottom one is that of after year 2012.

To see the interactive trend plots, click a thumbnail plot in the table below.

Scaled Sum Amp | PI | |||
---|---|---|---|---|

HRC-I |
-1.837+/-0.195 -4.198+/-0.290 |
1.103+/-0.175 -2.149+/-0.841 |
||

HRC-S |
-1.001+/-0.140 -2.162+/-0.330 |
1.346+/-0.711 6.509+/-1.042 |

To see the interactive trend plots, click a thumbnail plot in the table below.

Scaled Sum Amp | PI | |||||||
---|---|---|---|---|---|---|---|---|

Negative | Positive | Negative | Positive | |||||

60 - 80Å | 0.000+/-0.000 -2.647+/-0.550 | 0.200+/-0.254 -3.907+/-0.790 | 0.000+/-0.000 1.175+/-1.619 | 3.592+/-0.782 1.852+/-1.542 |

To see the interactive trend plots, click a thumbnail plot in the table below.

**Note:** the following values are used to estimate the dispersion positions in the arms.

- 1 pixel = 4.265e-5 degrees (tg_d in degree).
- 1 tap = 256 pixels = 1.88893Å

Last modified: Nov 29, 2021.

If you have any questions, please contact swolk@cfa.harvard.edu