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December 14, 2018: PhoSim v5.0.2 is available

Compiler flag issue has been fixed.

December 12, 2018: PhoSim v5.0 is available!

The fifteenth major release of the Photon Simulator (PhoSim) is completed, tagged, and validated. This contains a major fundamental upgrade (hence, v5.0) that we describe below as well as 150+ other changes.

We are continuing to push towards a complete pure ab initio Monte Carlo simulation code. To that end, this release contains a major upgrade where we have now fully represented the complete physics of the deformation of optics! Thus, PhoSim does a complete opto-mechanical simulation of any telescope. It uses the deformation of the three-dimensional mirror and lens shapes due to thermal changes and elastic, actuator, and gravitational forces to predict the exact surfaces of the optics prior to complete optical raytracing. The approach uses a number of novel numerical techniques and couples a number of physics modules. The environment is simulated as well as the response of the control system for active optics telescopes. It is implemented in a very efficient manner, and the calculation is fully multithreaded so you will barely notice a run-time speed change for chip-scale simulations. The complete detailed description is described in Peterson et al. 2019, ApJ 873, 98. Here is an example of the mirror control simulation.

Other physics improvements in v5.0 include: complete dome seeing physics, Milky Way structure of generated star catalog, repeatability in generic catalog production, improvements to weather modelling, sky brightness validation, and wind shake implementation. The usability improvements include the splitting of bright star between multiple cores, Hubble tuning fork/jupiter & moons examples, better multithreading efficiency, HA & Sidereal time in header, additional tabs in the GUI, more operation parameter in the GUI, more numerical parameters in the GUI, editing of instrument and site files in the GUI, implementation of Galileo's telescope, and updates to various telescopes/cameras. The full list is available on release notes page.

You can download the new version at the tagged release page and follow the documentation through the main site.

As always, please file tickets for bugs at the issue tracker page and feel free to email for anything else.

-JRP

October 3, 2018: PhoSim v4.0.4 is available

This patch fixes a bug in the sensor data of certain telescopes. In particular, the bug removed all photons from Subaru simulations.

August 22, 2018: PhoSim v4.0.3 is available

This patch fixes a bug in the segmentation of LSST wavefront sensors, and adds the hour angle and local sidereal time to the image header.

August 17, 2018: PhoSim v4.0.2 is available

This patch fixes a bug in dispersion at low altitudes, re-centers the OPD calculation for off-axis pointings, and unnecessary print statements when dust is on.

August 16, 2018: PhoSim v4.0.1 and v3.7.16 is available

These patches improve performance for large multithreaded environments.

June 8, 2018: PhoSim v4.0 is available!

The fourteenth major release of the Photon Simulator (PhoSim) is completed, tagged, and validated. Its called PhoSim v4.0. As the version number implies, it is probably the most significant upgrade for a number of reasons. There have been 400+ improvements and a number of major changes.

First, there is now a PhoSim GUI (Graphical User Interface)! This should be particularly helpful to busy new users as it is in general much more intuitive than reading pages of documentation. After compiling phosim, it is run simply with the command "phosim_gui". See the walkthrough pages.

Second, the required inputs has now been simplified to be nothing! Previously, a large number of parameters were required to describe pointing, sun/moon position, time, etc., but now these are entirely optional. You now can simply set any parameter that is important, and let PhoSim self-consistently calculate the rest or choose them from appropriate distributions. This applies to all parameters. So with no inputs, PhoSim will simply make a realistic typical observation. If you want to point at a particular ra/dec, just use those commands. If you want the Moon below the horizon, then add that in, but you will no longer have to figure out how to calculate what you consider to be nuisance parameters for your study.

Third, there are a few simple catalog options to make quick catalogs: a star grid option, a random star maker with correct brightnesses, a random galaxy maker with correct brightnesses/sizes/shapes, and an example using the Yale Bright Star Catalog. There is also integration with ds9 (by using --ds9) when PhoSim completes and integration with the PhoSim visualizer (by using --visualizer) when event files are made to look at the ray trajectories.

Finally, there have been a large number of technical improvements. Some of the important ones include: a series of complex galaxy morphology models and nebulae models, an ab initio atmospheric dispersion calculation, greater self-consistency of 3-d background & opacity calculations, fixes for wavelength & spatial dependence for background, time correlation of clouds, improvements for CMOS readout systems & alternative chip materials, options to calculate precession/nutation/aberration, and various updates to JWST NIRCAM, WIYN ODI, Subaru HSC, and LSST data. The full list is available on release notes page.

You can download the new version at the tagged release page and follow the documentation through the main site.

As always, please file tickets for bugs at the issue tracker page. We are currently expanding the GUI, so email me suggestions based on your experience.

-JRP

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