.. _plot_fp:

Focal plane visualization
=========================

We can visualize detectors in the focal plane by:

.. code-block:: text

    python -m litebird_sim.plot_fp

This software loads the IMo, which is installed on the machine you are using.
As the conversation unfolds, an interactive Matplotlib window will appear.

Detectors corresponding to the specified channels are represented as blue dots.
Clicking on a dot reveals the `DetectorInfo` for that detector in real time, highlighted with a red star.

Additionally, if you agree during the conversation to generate a detector file,
a list of starred detectors will be saved into a text file at the designated location after you close the plot.

The format of the detector file is as follows:

+------------+---------+---------+------------+------------+-----------------------+
| Telescope  | Channel | IMO_NET | Number_det | Scaled_NET | Detector_name         |
+------------+---------+---------+------------+------------+-----------------------+
| LFT        | L1-040  | 114.63  | 2/48       | 13.51      | `000_003_003_UB_040_T`|
+------------+---------+---------+------------+------------+-----------------------+
| LFT        | L1-040  | 114.63  | 2/48       | 13.51      | `000_003_003_UB_040_B`|
+------------+---------+---------+------------+------------+-----------------------+

The description of each column is as follows:

- `Telescope`: The telescope name.
- `Channel`: The channel name.
- `IMO_NET`: The NET of the detector in IMo.
- `Number_det`: :math:`N_{\text{selected}}/N_{\text{total}}` where :math:`N_{\text{selected}}` is the number of selected detectors by clicking and :math:`N_{\text{total}}` is the total number of detectors in the channel.
- `Scaled_NET`: The scaled NET of the detectors is given by the following equation:

    .. math::

        \text{Scaled NET} = \text{NET}_{\text{IMO}} \sqrt{\frac{t_{\text{obs}}}{3} \frac{N_{\text{selected}}}{N_{\text{total}}}}

  where :math:`t_{\text{obs}}` is the observation time in years that you can specify in the conversation. The factor of 3 is the nominal observation time in years.
- `Detector_name`: The detector name.