How to use PlanAstro

A complete walk-through of every part of the app — planning a night, finding targets, saving your gear, and reading the charts.

1. Getting started and your account

PlanAstro opens on one screen: a live all-sky chart with small buttons around it. The icons on the left open panels over the chart, the clock sits bottom-right, and Search sits on the right.

• Create an account or sign in at the start, or later from Menu → My Profile. Your account keeps your Favorites and Imaged targets private to you and available on every device you sign in on. You can sign out again from My Profile at any time.
• Set your location — Menu → Location settings. Use your device location or type latitude and longitude. Everything else — darkness times, altitudes, pointing windows, weather — depends on it. Your signed-in location is restored before planning starts. A recent forecast saved for those coordinates appears immediately, then refreshes quietly in the background.
• Time control opens as a small panel attached to the clock in the bottom-right corner, and steps forwards and backwards through the night or jumps back to Now. Every chart, altitude graph and pointing window follows the time you pick.
• Display controls what appears on the chart: sky survey imagery, labels, constellation art, lines and boundaries, degree-labelled grids, the horizon, and the chart symbol key.
• The Menu stays open when you close a panel you opened from it, so you can move between My Profile, Location settings, My Archive, ISS Tracker and About Us; close it with the X or by tapping the sky.
• Panels that float over the chart are gently see-through, so you keep a sense of the sky behind them.
• On phones, PlanAstro reads the live screen size and safe margins. Search, Browse, Favorites, Display, object-card actions and the atlas resize and wrap so controls are not cut off, including on narrow and landscape screens.

2. The sky chart

The chart shows the whole celestial sphere from your location and time.

• Drag to pan, pinch or scroll to zoom. Panning is unlimited across the whole celestial sphere, so you can look at objects that are below your horizon or not yet risen.
• Below-horizon sky is shaded slightly and the ground is tinted, but objects there still draw, label and select normally.
• Tap the compass to steer the chart smoothly through the full north, east, south and west range with your phone's motion. Tap it again to switch motion off.
• The meridian line marks where objects reach their highest point. Transit times are shown on each object card.
• The centre control returns the chart to its default 101° field of view. You can still zoom out manually to 180°.
• Survey imagery offers NASA 2MASS J (the default), 2MASS K, WISE W1, and Pan-STARRS1 + SkyMapper true colour. The Sky Survey switch turns all imagery on or off without hiding the drawn chart.
• The shared Constellation art control changes the brightness of the artwork, official IAU boundaries and figure lines together. Its new-session default is 10%; Star size starts at 1.40×.
• Equatorial and Alt-az grids carry degree labels so you can read positions directly from the chart.
• The chart symbol key in Display is a dropdown: tap a type to show only that type of object on the chart and in the lists.

3. Finding targets

Open Search and type a name, catalogue number or common name — M31, NGC 7000, Sh2-155, "Veil". The index covers over 22,000 deep sky objects and results narrow as you type.

• Browse groups objects by catalogue and type so you can explore rather than search.
• Search Filters is one dropdown above the results holding the object-type key, Tonight's best for my rig and Sort, so the panel reads: search box, filters, results.
• The object type key lives inside Search Filters and in the Display panel. Tap any type — emission nebula, reflection nebula, planetary nebula, supernova remnant, galaxy, open cluster, globular cluster — to show only that type. Both keys stay in sync.
• Target finder suggests what is well placed right now for your location, gear and sky.
• Favorites and Imaged are full card lists. Favorites is a saved list rather than a search surface: no search box or type key, just Tonight's best for my rig and Sort. Starring from a card shows up there straight away, even for objects in catalogues that were not loaded yet. Signed-in lists are private and synchronized with your account.

4. Object cards

Tap any object to open its card. Expanded, a card shows:

• Coordinates, type, size, magnitude and surface brightness.
• An altitude timeline for the night, with your usable pointing window shaded and the meridian crossing marked. It spans the width of the card content.
• Tonight and Point your rig lines that spell out the usable window in plain words, wrapping onto as many lines as they need.
• Locate on sky chart to centre the chart on it, and Set as target directly below to add it to tonight's list.
• FOV Frame, Sky Atlas and SIMBAD-VizieR sit together above the picture. The Sky Atlas (Aladin Lite) and the SIMBAD-VizieR reference replace that picture inside the card, rather than opening over Search.
• Buttons to add the object to Favorites or mark it Imaged.
• A Position approximate note if the catalogue position could not be confirmed against SIMBAD.

5. Planets and the Moon

Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune are drawn on the chart along with the Moon, each with its own symbol and label. Tap one to open a card just like a deep sky object: current position, altitude through the night, transit time and a picture of the body. The Moon also drives the moon-interference advice in Conditions, so you can see at a glance whether it will sit in your way. The Sun is used for twilight and darkness calculations but is not a chart target.

6. Tonight's plan

The planning view sequences your chosen targets across the night: when each one clears your minimum altitude, when it transits, and when it drops or the sky brightens. Use it to decide the order to shoot in and how much time each target really has.

• Targets you set from a card are collected here in time order, with their shaded windows side by side.
• Blocked directions, the meridian flip and your lowest usable altitude are all taken into account, so the plan matches what your mount can actually do.
• Change the time with the clock and the whole plan re-reads for that moment.

7. My Gear

Save your real equipment once and PlanAstro tailors framing and pointing windows to it. You can keep up to three rigs and switch between them.

• Telescope — tap the field and a searchable list drops down with popular models; typing narrows it. Selecting one fills aperture, focal length and f-ratio, all still editable. Not listed? Enter your own and submit it for the community list.
• Camera — sensor size and pixel size drive field of view and arcsec/pixel.
• Barlow / reducer — enter the multiplier (e.g. 0.8 or 2.0). Effective focal length, f-ratio, field of view and image scale all update, while your telescope's native specs are kept.
• Mount / tracking — same searchable list. Mount type and tracking style feed the pointing window and meridian handling; strain-wave mounts skip the flip.
• Number fields for coordinates, focal length and sensor size are wide enough that long values never hide behind the little up/down arrows.
• Minimum altitude and blocked directions — tell PlanAstro about trees, houses and hills so the shaded pointing window is honest.
• Connect to mount (live GoTo) is shown as disabled — live control is planned for a later release.

8. Framing and image scale

Once a rig is saved, the chart draws your camera's field of view as a frame you can rotate over any target, and shows arcsec/pixel so you can judge sampling. The framing sliders have large finger-friendly touch areas. Use it to check whether a large nebula fits, or whether you need a mosaic.

Framing Assistance adapts to the picture mode. Sky Atlas provides Survey Zoom, camera Rotate, Frame Zoom, Shift X and Shift Y; the footprint updates live inside Aladin Lite. The regular FOV Frame uses the same framing controls without a separate Rotate sky slider. On every screen size the assistant sits below the atlas, leaving the live sky view wider, taller and easier to close.

9. Conditions, darkness and filters

The Conditions pill opens the night at a glance, and each tile opens a fuller card.

• Weather — cloud cover, transparency, seeing, temperature and humidity hour by hour. It loads by itself once your location is set, retries quietly if the network hiccups, and tells you when it is loading rather than waiting for a tap. A recent forecast is saved against its coordinates so it can return immediately after sign-in while fresh data loads.
• Sky darkness (Bortle) — set how dark your site is; it feeds target recommendations and realistic expectations for faint broadband objects.
• Sky state — daylight, civil, nautical or astronomical twilight, or true dark, for the time you are looking at.
• Tonight's darkness — how many hours the sun stays below −18°, so you know when to do calibration, focusing and framing.
• Moon — phase, rise and set, and how much of the darkness the moon actually spoils, ending in a plain verdict: a broadband night for galaxies and dust, or a narrowband night.
• Filter kit — tick the filters you own, add your own names, and PlanAstro recommends which to use for the night and target in front of you.

10. Sky Atlas and SIMBAD-VizieR

Sky Atlas opens from the button beside FOV Frame on any object card and aims at the object in that card every time, even after you have opened a different target. It replaces the survey preview with a larger, live Aladin Lite view that starts on DSS2 colour. Pan and zoom freely, or tap Close atlas to return.

• Your camera footprint is one true sky-coordinate rectangle inside the atlas. It scales with Survey Zoom and moves with the sky when you pan, so there is no second fixed frame in the centre.
• Framing Assistance sits below the atlas. Survey Zoom changes the atlas field; Rotate, Frame Zoom and Shift X/Y update the live camera footprint. The regular FOV Frame uses the same framing controls without Rotate sky.
• The survey image credit is bottom-centred so the ICRS coordinate readout remains clear. Aladin Lite's own logo and credit links stay visible and unchanged.
• SIMBAD-VizieR opens the professional SIMBAD reference in the same card area, with an Open fallback when the browser restricts the embedded page.
• The same atlas is available in Search → Sky Atlas, where Go to my target, Use this view in PlanAstro and Show my favourites link it back to the chart.

Credits: PlanAstro uses an iFrame in the framing assistance panel via Aladin Lite, developed and maintained by the Centre de Données astronomiques de Strasbourg (CDS), Strasbourg Astronomical Observatory, France. Image Credit: CDS Aladin Sky Atlas / the survey selected in the view.

11. My Archive

Menu → My Archive turns the frames you have already captured into a picture of what you have really imaged. PlanAstro reads only the header of each light frame (FITS or XISF) to learn the target, date, exposure, filter and equipment — your image data never leaves your device, and your original files are never changed.

• Connect a source — Local files or a folder from your computer, or Google Drive, Dropbox or OneDrive. Connected folders can be re-scanned at any time with Refresh sources.
• Auto-refresh daily — switch it on and pick a time (03:00 by default) and new frames are indexed without you doing anything.
• Cancel an upload mid-way; anything already indexed stays, and nothing is removed from your originals.
• Target cards show total integration time, number of sessions, filters used, imaging dates and a preview thumbnail.
• Search and sort by most integration, newest or oldest imaging date, recently or first uploaded, name, or most sessions; filter by object type and by progress.
• Progress — mark a target In progress, Review or Complete and see the badge on its card.
• Rename any target with a label of your own; the custom name is used in cards, search and Locate, and resets to the catalogue name whenever you want.
• Duplicate designations are merged — the same object uploaded as Sh2-155 and as C9 lands in one target folder, keeping both names.
• An archived target that has coordinates but no catalogue match is still marked on the sky chart so you can find it again.

12. ISS Tracker

Menu → ISS Tracker follows the International Space Station live and finds the moments worth photographing.

• A 3D globe shows the station's current position, its ground track from 30 minutes back to 90 minutes ahead, day/night shading, altitude and speed. Drag to rotate, scroll or pinch to zoom, double-tap to recentre, and use Auto-follow to keep the station in view.
• Find ISS passes · next 5 nights lists every visible pass for your location, with times, direction, maximum altitude and brightness. Tap a pass to draw it on the globe; the refresh button pulls fresh orbital data.
• Solar and lunar transits — close approaches of the station to the Sun or Moon are flagged. These last under a second: shoot high-speed video (60fps or more) starting 30 seconds early at 1/1000s or faster, and confirm the centre-line on a dedicated transit finder a day ahead.
• Pass imaging — a wide lens on a fixed tripod with 10–30 second exposures gives a clean streak; tracking it manually at long focal length can show structure.

Solar transits require a certified solar filter over the front of the optic at all times. Never point an unfiltered camera or telescope at the Sun.

13. Favorites, Imaged and exporting

• Favorites — star objects you want to revisit. Signed-in favorites are private and follow your account across browsers and devices.
• Imaged — mark a completed object from its card, then see it in Search → Imaged. This list is also private and account-synced.
• My Archive — the detailed record of light frames, integration totals and progress, described above.
• High-resolution export — save the current chart, exactly as you have set it up, as a large image for sharing or printing.
• This guide can be shared, printed or downloaded as a PDF from the buttons at the top of the guide window.

14. Comfort, gestures and installing

• Night vision — a red screen mode in Display that protects your dark adaptation at the telescope.
• High contrast and text size controls sit beside it, so the app stays readable in the dark or in daylight.
• Gestures — pull a panel down from its top edge, or swipe it sideways, to close it. The X button, Escape and tapping the sky all work too.
• Install it — add PlanAstro to your home screen for a full-screen app that keeps working when the signal at your site does not.

15. Help and support

Menu → About Us holds the story behind PlanAstro, this guide, the full image credits list, and Contact support. Sign in and you can message the team from inside the app: pick a topic — question, concern, suggestion, bug report or other — and the whole conversation, including every reply, stays in the app tied to your account. No email needed.

16. How accurate is it?

NGC and IC objects come from OpenNGC; other catalogues use their published tables. Chart positions use validated J2000/ICRS degrees. Every identifier that resolves is reconciled against SIMBAD, the professional astronomical database, and its coordinates are used. Objects that could not be confirmed keep their source position and are flagged "Position approximate" on the card. Rise, transit, set, twilight and moon calculations use standard astronomical algorithms for your exact coordinates and time.

The owner-only catalogue editor can search NGC, IC, Abell, Arp and Sh2 entries, compare original and active values, correct coordinates and brightness, update type or constellation, and set the verified flag. These controls and the changelog remain hidden from ordinary accounts.

In the owner support inbox, opening or replying to a ticket marks it read. Individual messages or a whole ticket can be deleted after confirmation.

17. Tips

• Set your minimum altitude honestly — 30° gives far better data than 15°.
• Plan around the meridian: the hour either side of transit is the cleanest part of the night.
• Use the moon times, not just the phase — a bright moon that sets at 01:00 still leaves a good night.
• Point My Archive at your imaging folder once and let the daily refresh keep your integration totals honest.
• Add the app to your home screen for a full-screen, offline-capable experience.

Clear skies. — PlanAstro