Settings

The Settings workspace, at the bottom of the navigation rail, holds everything Sidralune needs to know about you, your sites and your equipment, plus the data manager. Settings are saved automatically to %LOCALAPPDATA%\Sidralune\Settings\settings.json.

Contents

• Location
• Equipment
• Observer & accounts
• Appearance
• Data
• About

Location

A site describes where you observe and what your sky is like. You can keep as many sites as you like and switch between them.

The list on the left shows your sites. New site adds one, Delete removes the selected one, Save site stores your edits and Use this site makes it the active site used by every calculation.

Field	Meaning	Used by
Name	A label for the site	Clock, printed charts, reports
Latitude (°, N positive)	Geodetic latitude. Decimal (51.4769) or sexagesimal (51 28 38 N)	Everything
Longitude (°, E positive)	Decimal (-0.0005) or sexagesimal (0 00 02 W)	Everything
Elevation (m)	Height above sea level	Topocentric positions, satellite passes, occultations
Time zone	Windows time zone, including daylight saving rules	Every displayed time
Sky brightness (SQM, mag/arcsec²)	Zenith sky brightness on a moonless night	Visibility predictions, exposure calculations, meteor rates
Bortle class	Derived from the SQM value	Display only
Extinction k(V) (mag/airmass)	How much the atmosphere dims stars per airmass	Visibility predictions
Typical seeing (arcsec)	Typical star FWHM	Visibility of small objects, focal length recommendations
Temperature (°C) for refraction / Pressure (hPa)	Typical night-time conditions	Refraction near the horizon
MPC observatory code	Your Minor Planet Center station code	MPC reports
Horizon profile (az:alt, …)	Pairs of azimuth and altitude in degrees, for example 0:10, 45:18, 90:25, 180:5, 270:15. Values in between are interpolated	Sky chart ground, planner "up" times, best targets

If you do not know your SQM value, the Getting started page has a table of typical values. Online light-pollution maps also give SQM estimates for any location.

Equipment

Three lists describe your equipment. Select an entry to edit its properties in the grid below the list. Add creates an entry, Remove deletes it and Use makes it active (marked with ●).

Telescopes

Property	Meaning
Name	For example 8" f/6 Dobsonian
Aperture mm	Clear aperture
Focal mm	Focal length, including any reducer or Barlow you normally use
Obstruction	Central obstruction as a fraction of the aperture diameter (0.22 for a typical Newtonian, 0.33 for an SCT, 0 for a refractor)
Transmission	Fraction of light reaching the eye or sensor (0.85 for a reflector with an eyepiece, 0.92 for a good refractor)

Eyepieces

Property	Meaning
Name	For example 10 mm 82°
Focal mm	Focal length
Afov deg	Apparent field of view

Cameras

Property	Meaning
Name	For example IMX571 APS-C
Pixel um	Pixel size in micrometres
Width / Height	Sensor size in pixels
Read noise	Read noise in electrons at the gain you use
Qe	Peak quantum efficiency (0–1)
Color	True for one-shot-colour (Bayer) sensors

Combination summary

The summary at the bottom combines the active telescope with the active eyepiece and camera:

• Visual: magnification, true field of view, exit pupil and Dawes resolution limit.
• Imaging: image scale in arcseconds per pixel, field of view, focal ratio, the optimal sub-exposure length for your sky (when read noise becomes negligible compared with sky noise) and the focal ratio that samples your pixels at the Nyquist limit for planetary imaging.

Observer & accounts

Field	Meaning
Age (affects dark-adapted pupil)	The eye's maximum pupil shrinks with age (about 7.8 mm at 20, about 0.45 mm less per decade), which limits useful low magnifications and changes visibility predictions
Visual experience	Beginner, Average, Experienced or Expert. Experienced observers detect fainter, lower-contrast objects; the visibility model accounts for this
AAVSO observer code	Written into AAVSO photometry reports
Default MPC station code	Used for MPC astrometry reports when the site has no code
nova.astrometry.net API key	Needed only for online plate solving via astrometry.net. Get a free key from your nova.astrometry.net profile. Stored locally and hidden on screen
Image folder	Default folder for captured images

Click Save to store the changes.

Appearance

Setting	Meaning
Night vision (red) mode	Replaces every colour with deep reds. Same as the moon button and Ctrl+Shift+N; this box and the moon button always show the same state
Atmospheric refraction	Apply refraction to altitudes, so objects near the horizon appear where you actually see them. Turn it off to compare with geometric (airless) tables

A list of keyboard shortcuts is shown on this tab; see also Keyboard shortcuts.

Data

The data manager lists the catalogues, orbit files and ephemerides you can download. Nothing is downloaded until you ask.

Column	Meaning
☐	Tick the datasets to download or remove
Dataset	Name
Description	What the dataset adds
Size	Approximate download size
Status	Installed (with date) or not installed
License	The dataset's licence

Button	Action
Download selected	Downloads and installs the ticked datasets, then loads them
Update installed	Downloads fresh copies of everything already installed. Do this every week or two for comets and asteroids
Stop	Ends a download. A dataset that was not completely downloaded is not kept
Remove selected	Deletes the ticked datasets. Sidralune falls back to its built-in data
Open data folder	Opens %LOCALAPPDATA%\Sidralune\Data in Explorer
Reload catalogs	Reloads every catalogue from disk, for example after copying files in by hand

The status line shows which ephemeris and catalogues are loaded. See Data and catalogues for details of each dataset.

If you have no internet access at the telescope, download the data at home; everything works offline afterwards. You can also copy the Data folder from another computer.

About

Shows the version, the copyright, the main algorithms Sidralune uses, the data credits and the folder where settings and data are stored.