feat(time): Solar/lunar ephemerides #271

ketiltrout · 2024-07-25T20:31:31Z

This adds six methods to caput.time.Observer to calculate (solar/lunar) (transits/risings/settings).

These functions are originally from ch_util.ephemeris where they originally worked only on the chime Observer. They've since been enhanced to use any Observer, so there's no reason now not to have them in the Observer object directly.

CHANGE FROM CH_UTIL VERSION

There is one major change to these functions from what was in ch_util.ephemeris: instead of a diameter of 0.6 degrees = 36 arcminutes, these methods now use a diameter of 100 arcminutes.

This means these functions now compute astronomical sun/moon rise/set, which is conventionally taken to occur when the centre of the sun/moon is 50 arcminutes below the horizon.

The 50 arcminute number comes from a solar/lunar radius of 16 arcminutes plus 34 arcminutes of atmospheric refraction at the horizon.

This change fixes the 3-minute discrepancy Mateus noticed when these functions were first ported from PyEphem (which does account for atmospheric refraction) to skyfield (which does not account for the refraction), here: https://github.com/chime-experiment/ch_util_private/commit/b505cf099c1de4eb39f2e34828e8da545d3db8e0

Transit times are unchanged: the atmospheric refraction at zenith is zero.

This adds six methods to `caput.time.Observer` to calculate (solar/lunar) (transits/risings/settings). These functions are originally from `ch_util.ephemeris` where they originally worked only on the `chime` `Observer`. They've since been enhanced to use any `Observer`, so there's no reason now not to have them in the `Observer` object directly, now. CHANGE FROM CH_UTIL VERSION There is one major change to these functions from what was in `ch_util.ephemeris`: instead of a `diameter` of 0.6 degrees = 36 arcminutes, these methods now use a `diameter` of 100 arcminutes. This means these functions now compute astronomical sun/moon rise/set, which is conventionally taken to occur when the centre of the sun/moon is 50 arcminutes below the horizon. The 50 arcminute number comes from a solar/lunar radius of 16 arcminutes plus 34 arcminutes of atmospheric refraction at the horizon. This change fixes the 3-minute discrepancy Mateus noticed when these functions were first ported from PyEphem (which _does_ account for atmospheric refraction) to skyfield (which does _not_ account for the refraction), here: chime-experiment/ch_util_private@b505cf0

ljgray

I think this looks fine

Extracts a lot of `ch_util.ephemeris` into a separate package. General changes: * Solar and lunar ephemeris functions have been converted into `caput.time.Observer` methods: radiocosmology/caput#271 * Other functions that take a `Observer` object, now use `None` as a default, and load the `chime` observer during execution if necessary. More comments on specific submodules follow. Catalogs: This contains all the `ch_util/catalogs` plus a function (`ch_ephem.catalogs.load`) to read them and return the parsed JSON. The standard source catalogues loaded by the `sources` submodule need to move to `ch_ephem`. The other catalogues could stay in `ch_util`, but it seems simpler to me to keep them all in the same place and provide a uniform interface to them. Coord: Co-ordinate transforms etc. These are essentially unchanged from their versions in `ch_util.ephemeris`. Observers: Re-creates all the `caput.time.Observers` which used to be created by `ch_util.ephemeris`, but for the most part, they have to be fetched via name from the `get()` function. The exception to this is the `chime` Observer, which can be directly imported, since it's the one usually needed. Position data for the observers is now in a YAML data file `instruments.yaml` which is parsed at import time. New instrument `Observer` objects can be added to `ch_ephem` just by adding information for it to the YAML file. Also note that `Observers` returned by this submodule have an extra attribute, `rotation`, inserted into their `__dict__`, which is not in `caput`. This rotation is needed by `ch_ephem.coord.peak_ra`. If we don't want to do this to these `Observers`, one other options would be to keep `peak_ra` in `ch_util` (moving it to, say, `ch_util.tools`), and then there's no need for rotation information in this module. Like `sources`, this submodule reads data from disk at import time, so is not automatically imported into the base `ch_ephem` object. Pointing: Just Galt telescope pointing routines, unchanged from `ch_util.ephemeris`. These are another candidate we could consider putting somewhere else in ch_util, if we don't want them here. Sources: Loads the standard source catalogs, and provides the calibrator objects `CasA`, `CygA`, `TauA`, `VirA`. Like `observers`, this submodule reads data from disk at import time, so is not automatically imported into the base `ch_ephem` object. Time: Time utilities, largely unchanged from what was in `ch_util.ephemeris`.

This re-imports stuff moved to `ch_ephem`. It both re-imports everything that was moved back into `ch_util.ephemeris` for backwards compatibility, but also removes references to `ch_util.epheremis` from the code, using the newly-exported versions of things directly. This PR requires both: * radiocosmology/caput#271 * chime-experiment/ch_ephem#1 Catalogs: All the catalogs have been moved to `ch_ephem`, which provides a standard interface to them via `ch_ephem.catalogs.load`. To make this change, `fluxcat.FluxCatalog.load` has been broken into two pieces. The new `fluxcat.FluxCatalog.load_dict` imports a catalog from an already-parsed JSON dict (which is what `ch_ephem` provides). The original `fluxcat.FluxCatalog.load` works as it used to, but tail-calls `load_dict` to do most of the importing. Position data: Position data (lat, lon, alt) is now obtained by fetching the parameter out of the `caput.time.Observer` objects provided by `ch_ephem`. The constants in `ch_util.ephemeris` are populated by doing this. Instrument rotation: `ch_ephem` has also taken on the rotation data that was in `tools` (where it's been re-imported from `ch_ephem`). Not sure this is ideal. Please comment on the `ch_ephem` PR if you can provide an opinion on this. Private objects deleted: I've also deleted a number of private objects which are no longer being used (i.e. objects whose names start with a leading underscore). Notable among these is the unused `ch_util.tools._LAT_LON` which had position data for various instruments which differed from the position data provided by `ch_util.ephemeris`. Also removed are the long-deprectated `ch_util.ephemeris._get_chime` and `ch_util.ephemeris.transit_RA`.

Extracts a lot of `ch_util.ephemeris` into a separate package. General changes: * Solar and lunar ephemeris functions have been converted into `caput.time.Observer` methods: radiocosmology/caput#271 * Other functions that take a `Observer` object, now use `None` as a default, and load the `chime` observer during execution if necessary. More comments on specific submodules follow. Catalogs: This contains all the `ch_util/catalogs` plus a function (`ch_ephem.catalogs.load`) to read them and return the parsed JSON. The standard source catalogues loaded by the `sources` submodule need to move to `ch_ephem`. The other catalogues could stay in `ch_util`, but it seems simpler to me to keep them all in the same place and provide a uniform interface to them. Coord: Co-ordinate transforms etc. These are essentially unchanged from their versions in `ch_util.ephemeris`. Observers: Re-creates all the `caput.time.Observers` which used to be created by `ch_util.ephemeris`, but for the most part, they have to be fetched via name from the `get()` function. The exception to this is the `chime` Observer, which can be directly imported, since it's the one usually needed. Position data for the observers is now in a YAML data file `instruments.yaml` which is parsed at import time. New instrument `Observer` objects can be added to `ch_ephem` just by adding information for it to the YAML file. Also note that `Observers` returned by this submodule have an extra attribute, `rotation`, inserted into their `__dict__`, which is not in `caput`. This rotation is needed by `ch_ephem.coord.peak_ra`. If we don't want to do this to these `Observers`, one other options would be to keep `peak_ra` in `ch_util` (moving it to, say, `ch_util.tools`), and then there's no need for rotation information in this module. Like `sources`, this submodule reads data from disk at import time, so is not automatically imported into the base `ch_ephem` object. Pointing: Just Galt telescope pointing routines, unchanged from `ch_util.ephemeris`. These are another candidate we could consider putting somewhere else in ch_util, if we don't want them here. Sources: Loads the standard source catalogs, and provides the calibrator objects `CasA`, `CygA`, `TauA`, `VirA`. Like `observers`, this submodule reads data from disk at import time, so is not automatically imported into the base `ch_ephem` object. Time: Time utilities, largely unchanged from what was in `ch_util.ephemeris`.

This re-imports stuff moved to `ch_ephem`. It both re-imports everything that was moved back into `ch_util.ephemeris` for backwards compatibility, but also removes references to `ch_util.epheremis` from the code, using the newly-exported versions of things directly. This PR requires both: * radiocosmology/caput#271 * chime-experiment/ch_ephem#1 Catalogs: All the catalogs have been moved to `ch_ephem`, which provides a standard interface to them via `ch_ephem.catalogs.load`. To make this change, `fluxcat.FluxCatalog.load` has been broken into two pieces. The new `fluxcat.FluxCatalog.load_dict` imports a catalog from an already-parsed JSON dict (which is what `ch_ephem` provides). The original `fluxcat.FluxCatalog.load` works as it used to, but tail-calls `load_dict` to do most of the importing. Position data: Position data (lat, lon, alt) is now obtained by fetching the parameter out of the `caput.time.Observer` objects provided by `ch_ephem`. The constants in `ch_util.ephemeris` are populated by doing this. Instrument geormetry: `ch_ephem` has also taken on the geometry data (rotation, roll, offset) that was in `tools` (where it's been re-imported from `ch_ephem`). Private objects deleted: I've also deleted a number of private objects which are no longer being used (i.e. objects whose names start with a leading underscore). Notable among these are the geometry constants from `ch_util.tools` and the unused`ch_util.tools._LAT_LON` which had position data for various instruments which differed from the position data provided by `ch_util.ephemeris`. Also removed are the long-deprectated `ch_util.ephemeris._get_chime` and `ch_util.ephemeris.transit_RA`.

Extracts a lot of `ch_util.ephemeris` into a separate package. General changes: * Solar and lunar ephemeris functions have been converted into `caput.time.Observer` methods: radiocosmology/caput#271 * Other functions that take a `Observer` object, now use `None` as a default, and load the `chime` observer during execution if necessary. More comments on specific submodules follow. Catalogs: This contains all the `ch_util/catalogs` plus a function (`ch_ephem.catalogs.load`) to read them and return the parsed JSON. The standard source catalogues loaded by the `sources` submodule need to move to `ch_ephem`. The other catalogues could stay in `ch_util`, but it seems simpler to me to keep them all in the same place and provide a uniform interface to them. Coord: Co-ordinate transforms etc. These are essentially unchanged from their versions in `ch_util.ephemeris`. Observers: Re-creates all the `caput.time.Observers` which used to be created by `ch_util.ephemeris`, but for the most part, they have to be fetched via name from the `get()` function. The exception to this is the `chime` Observer, which can be directly imported, since it's the one usually needed. Position data for the observers is now in a YAML data file `instruments.yaml` which is parsed at import time. New instrument `Observer` objects can be added to `ch_ephem` just by adding information for it to the YAML file. Also note that `Observers` returned by this submodule have an extra attribute, `rotation`, inserted into their `__dict__`, which is not in `caput`. This rotation is needed by `ch_ephem.coord.peak_ra`. If we don't want to do this to these `Observers`, one other options would be to keep `peak_ra` in `ch_util` (moving it to, say, `ch_util.tools`), and then there's no need for rotation information in this module. Like `sources`, this submodule reads data from disk at import time, so is not automatically imported into the base `ch_ephem` object. Pointing: Just Galt telescope pointing routines, unchanged from `ch_util.ephemeris`. These are another candidate we could consider putting somewhere else in ch_util, if we don't want them here. Sources: Loads the standard source catalogs, and provides the calibrator objects `CasA`, `CygA`, `TauA`, `VirA`. Like `observers`, this submodule reads data from disk at import time, so is not automatically imported into the base `ch_ephem` object. Time: Time utilities, largely unchanged from what was in `ch_util.ephemeris`.

This re-imports stuff moved to `ch_ephem`. It both re-imports everything that was moved back into `ch_util.ephemeris` for backwards compatibility, but also removes references to `ch_util.epheremis` from the code, using the newly-exported versions of things directly. This PR requires both: * radiocosmology/caput#271 * chime-experiment/ch_ephem#1 Catalogs: All the catalogs have been moved to `ch_ephem`, which provides a standard interface to them via `ch_ephem.catalogs.load`. To make this change, `fluxcat.FluxCatalog.load` has been broken into two pieces. The new `fluxcat.FluxCatalog.load_dict` imports a catalog from an already-parsed JSON dict (which is what `ch_ephem` provides). The original `fluxcat.FluxCatalog.load` works as it used to, but tail-calls `load_dict` to do most of the importing. Position data: Position data (lat, lon, alt) is now obtained by fetching the parameter out of the `caput.time.Observer` objects provided by `ch_ephem`. The constants in `ch_util.ephemeris` are populated by doing this. Instrument geormetry: `ch_ephem` has also taken on the geometry data (rotation, roll, offset) that was in `tools` (where it's been re-imported from `ch_ephem`). Private objects deleted: I've also deleted a number of private objects which are no longer being used (i.e. objects whose names start with a leading underscore). Notable among these are the geometry constants from `ch_util.tools` and the unused`ch_util.tools._LAT_LON` which had position data for various instruments which differed from the position data provided by `ch_util.ephemeris`. Also removed are the long-deprectated `ch_util.ephemeris._get_chime` and `ch_util.ephemeris.transit_RA`.

Extracts a lot of `ch_util.ephemeris` into a separate package. General changes: * Solar and lunar ephemeris functions have been converted into `caput.time.Observer` methods: radiocosmology/caput#271 * Other functions that take a `Observer` object, now use `None` as a default, and load the `chime` observer during execution if necessary. More comments on specific submodules follow. Catalogs: This contains all the `ch_util/catalogs` plus a function (`ch_ephem.catalogs.load`) to read them and return the parsed JSON. The standard source catalogues loaded by the `sources` submodule need to move to `ch_ephem`. The other catalogues could stay in `ch_util`, but it seems simpler to me to keep them all in the same place and provide a uniform interface to them. Coord: Co-ordinate transforms etc. These are essentially unchanged from their versions in `ch_util.ephemeris`. Observers: Re-creates all the `caput.time.Observers` which used to be created by `ch_util.ephemeris`, but for the most part, they have to be fetched via name from the `get()` function. The exception to this is the `chime` Observer, which can be directly imported, since it's the one usually needed. Position data for the observers is now in a YAML data file `instruments.yaml` which is parsed at import time. New instrument `Observer` objects can be added to `ch_ephem` just by adding information for it to the YAML file. Also note that `Observers` returned by this submodule have an extra attribute, `rotation`, inserted into their `__dict__`, which is not in `caput`. This rotation is needed by `ch_ephem.coord.peak_ra`. If we don't want to do this to these `Observers`, one other options would be to keep `peak_ra` in `ch_util` (moving it to, say, `ch_util.tools`), and then there's no need for rotation information in this module. Like `sources`, this submodule reads data from disk at import time, so is not automatically imported into the base `ch_ephem` object. Pointing: Just Galt telescope pointing routines, unchanged from `ch_util.ephemeris`. These are another candidate we could consider putting somewhere else in ch_util, if we don't want them here. Sources: Loads the standard source catalogs, and provides the calibrator objects `CasA`, `CygA`, `TauA`, `VirA`. Like `observers`, this submodule reads data from disk at import time, so is not automatically imported into the base `ch_ephem` object. Time: Time utilities, largely unchanged from what was in `ch_util.ephemeris`.

This re-imports stuff moved to `ch_ephem`. It both re-imports everything that was moved back into `ch_util.ephemeris` for backwards compatibility, but also removes references to `ch_util.epheremis` from the code, using the newly-exported versions of things directly. This PR requires both: * radiocosmology/caput#271 * chime-experiment/ch_ephem#1 Catalogs: All the catalogs have been moved to `ch_ephem`, which provides a standard interface to them via `ch_ephem.catalogs.load`. To make this change, `fluxcat.FluxCatalog.load` has been broken into two pieces. The new `fluxcat.FluxCatalog.load_dict` imports a catalog from an already-parsed JSON dict (which is what `ch_ephem` provides). The original `fluxcat.FluxCatalog.load` works as it used to, but tail-calls `load_dict` to do most of the importing. Position data: Position data (lat, lon, alt) is now obtained by fetching the parameter out of the `caput.time.Observer` objects provided by `ch_ephem`. The constants in `ch_util.ephemeris` are populated by doing this. Instrument geormetry: `ch_ephem` has also taken on the geometry data (rotation, roll, offset) that was in `tools` (where it's been re-imported from `ch_ephem`). Private objects deleted: I've also deleted a number of private objects which are no longer being used (i.e. objects whose names start with a leading underscore). Notable among these are the geometry constants from `ch_util.tools` and the unused`ch_util.tools._LAT_LON` which had position data for various instruments which differed from the position data provided by `ch_util.ephemeris`. Also removed are the long-deprectated `ch_util.ephemeris._get_chime` and `ch_util.ephemeris.transit_RA`.

Extracts a lot of `ch_util.ephemeris` into a separate package. General changes: * Solar and lunar ephemeris functions have been converted into `caput.time.Observer` methods: radiocosmology/caput#271 * Other functions that take a `Observer` object, now use `None` as a default, and load the `chime` observer during execution if necessary. More comments on specific submodules follow. Catalogs: This contains all the `ch_util/catalogs` plus a function (`ch_ephem.catalogs.load`) to read them and return the parsed JSON. The standard source catalogues loaded by the `sources` submodule need to move to `ch_ephem`. The other catalogues could stay in `ch_util`, but it seems simpler to me to keep them all in the same place and provide a uniform interface to them. Coord: Co-ordinate transforms etc. These are essentially unchanged from their versions in `ch_util.ephemeris`. Observers: Re-creates all the `caput.time.Observers` which used to be created by `ch_util.ephemeris`, but for the most part, they have to be fetched via name from the `get()` function. The exception to this is the `chime` Observer, which can be directly imported, since it's the one usually needed. Position data for the observers is now in a YAML data file `instruments.yaml` which is parsed at import time. New instrument `Observer` objects can be added to `ch_ephem` just by adding information for it to the YAML file. Also note that `Observers` returned by this submodule have an extra attribute, `rotation`, inserted into their `__dict__`, which is not in `caput`. This rotation is needed by `ch_ephem.coord.peak_ra`. If we don't want to do this to these `Observers`, one other options would be to keep `peak_ra` in `ch_util` (moving it to, say, `ch_util.tools`), and then there's no need for rotation information in this module. Like `sources`, this submodule reads data from disk at import time, so is not automatically imported into the base `ch_ephem` object. Pointing: Just Galt telescope pointing routines, unchanged from `ch_util.ephemeris`. These are another candidate we could consider putting somewhere else in ch_util, if we don't want them here. Sources: Loads the standard source catalogs, and provides the calibrator objects `CasA`, `CygA`, `TauA`, `VirA`. Like `observers`, this submodule reads data from disk at import time, so is not automatically imported into the base `ch_ephem` object. Time: Time utilities, largely unchanged from what was in `ch_util.ephemeris`.

This re-imports stuff moved to `ch_ephem`. It both re-imports everything that was moved back into `ch_util.ephemeris` for backwards compatibility, but also removes references to `ch_util.epheremis` from the code, using the newly-exported versions of things directly. This PR requires both: * radiocosmology/caput#271 * chime-experiment/ch_ephem#1 Catalogs: All the catalogs have been moved to `ch_ephem`, which provides a standard interface to them via `ch_ephem.catalogs.load`. To make this change, `fluxcat.FluxCatalog.load` has been broken into two pieces. The new `fluxcat.FluxCatalog.load_dict` imports a catalog from an already-parsed JSON dict (which is what `ch_ephem` provides). The original `fluxcat.FluxCatalog.load` works as it used to, but tail-calls `load_dict` to do most of the importing. Position data: Position data (lat, lon, alt) is now obtained by fetching the parameter out of the `caput.time.Observer` objects provided by `ch_ephem`. The constants in `ch_util.ephemeris` are populated by doing this. Instrument geormetry: `ch_ephem` has also taken on the geometry data (rotation, roll, offset) that was in `tools` (where it's been re-imported from `ch_ephem`). Private objects deleted: I've also deleted a number of private objects which are no longer being used (i.e. objects whose names start with a leading underscore). Notable among these are the geometry constants from `ch_util.tools` and the unused`ch_util.tools._LAT_LON` which had position data for various instruments which differed from the position data provided by `ch_util.ephemeris`. Also removed are the long-deprectated `ch_util.ephemeris._get_chime` and `ch_util.ephemeris.transit_RA`.

ketiltrout requested a review from ljgray July 25, 2024 20:31

ketiltrout force-pushed the solar-lunar_ephemerides branch from 9f4bb1b to 7417cdb Compare July 25, 2024 20:38

ljgray approved these changes Jul 25, 2024

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ketiltrout mentioned this pull request Jul 25, 2024

feat(ch_ephem): CHIME ephemeris refactored from ch_util. chime-experiment/ch_ephem#1

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ketiltrout mentioned this pull request Jul 25, 2024

refactor(ephemeris): Use ch_ephem chime-experiment/ch_util#77

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ketiltrout requested a review from rikvl July 25, 2024 23:09

ketiltrout merged commit ce80fee into master Jul 28, 2024
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ketiltrout deleted the solar-lunar_ephemerides branch July 28, 2024 17:27

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feat(time): Solar/lunar ephemerides #271

feat(time): Solar/lunar ephemerides #271

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feat(time): Solar/lunar ephemerides #271

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CHANGE FROM CH_UTIL VERSION

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