obstools.deveny_collfocus module

DeVeny Collimator Focus Range Estimator GUI Module

LDTObserverTools contains python ports of various LDT Observer Tools

Lowell Discovery Telescope (Lowell Observatory: Flagstaff, AZ) https://lowell.edu

This file contains the deveny_collfocus routine for computing the estimated collimator focus value and range for the LOUI Focus Sequence tab. The GUI can gather current information (mount temperature and grating angle) from the ActiveMQ broker, if available, but the user may also manually enter these values when the tool is used away from the telescope.

This calculator was originally written by B. Shafransky (LDT TO), and has been incorporated into the LDTObserverTools package.

class obstools.deveny_collfocus.DevenyCollfocus

Bases: ScriptBase

Script class for deveny_collfocus tool

Script structure borrowed from pypeit.scripts.scriptbase.ScriptBase.

classmethod get_parser(width=None)

Construct the command-line argument parser.

Parameters:

• description (str, optional) – A short description of the purpose of the script.

• width (int, optional) – Restrict the width of the formatted help output to be no longer than this number of characters, if possible given the help formatter. If None, the width is the same as the terminal width.

• formatter (HelpFormatter) – Class used to format the help output.

Returns:

ArgumentParser – Command-line interpreter.

static main(args)

Main Driver

Simple function that calls the main driver function.

obstools.deveny_collfocus.calculate_collimator_focus(mount_temp: float, grating_tilt: float, order_blocker: bool) → float

Calculate Collimator Focus Value

Using the formula presented in the DeVeny manual (built from collimator focus values from 2017-2020), compute the approximate focus value given the current conditions.

The smallest value returned is 7.75mm – a physical limit due to the limit switch on the collimator focus stage.

Parameters:

• mount_temp (float) – The current mount temperature in degrees Celsius

• grating_tilt (float) – The current grating tilt angle in degrees

• order_blocker (bool) – Whether an order-blocking filter (e.g., OG570) is in place

Returns:

float – The estimated collimator focus value

obstools.deveny_collfocus.calculate_focus_sequence(estimated_focus: float) → tuple[float, float, int]

Calculate Estimated Focus Sequence

The DeVeny LOUI Focus Sequence tab requests three pieces of information in order to execute a focus run: starting position, step size, and number of steps. This function computes these three values based on the estimated focus value (from temperature and tilt) and some prior information about the behavior of the collimator.

Parameters:

estimated_focus (float) – The estimated focus value from the equation

Returns:

• startpos (float) – The initial position of the Focus Sequence

• stepsize (float) – The stepsize to be used

• n_steps (int) – The number of steps for the Focus Sequence

obstools.deveny_collfocus.deveny_collfocus(debug: bool = False)

Main Driver for the DeVeny Collimator Focus Sequence Estimator GUI

Compute the estimated focus and LOUI Focus Sequence range given the mount temperature, grating tilt angle, and presence of an order-blocking filter. Optionally, read in the current mount temperature and grating tilt angle from the ActiveMQ broker, if running at the site.

Parameters:

debug (bool, optional) – Print debug statements? (Default: False)

obstools.deveny_collfocus.extract_broker_values(status_dict: dict) → tuple[str, str]

Get Current Values from the Broker

When running at LDT, we can use the ActiveMQ broker to get the current mount temperature and grating tilt. This is a fancy little trick that will make the software developer very happy.

Parameters:

status_dict (dict) – The status dictionary from the broker listener

Returns:

str – The string value (or "~ Not Found ~") corresponding to this dictionary