What is new in SkyGrade?

The Bortle scale divides the sky into nine steps – fine as a rough guide, too coarse to compare two dark sites: class 4 spans 20.5 to 21.7 mag/arcsec², more than a full magnitude. In the Westhavelland dark-sky reserve every observing site falls into that single class, although there are noticeable differences between the brightest and the darkest of them.

SkyGrade therefore keeps working with the measured value instead of rounding it to a class. The effect is strongest in the Astrophoto Planner, where sky brightness feeds directly into contrast. And “Where tonight?” now picks the genuinely darkest among the reachable sites – previously a closer but brighter place could crowd out the better one.

A site of average brightness for its class keeps its previous value. Darker places gain a few points, brighter ones lose a few – so the numbers do not get better or worse, they get more accurate.

The deep-sky score answers whether the night is worth it – but not where the sky opens up. That is what the new cloud cover map shows: cloud cover within roughly 60 kilometres, hour by hour through your observing window. Wherever green shows through, the sky is clear. It also names the clearest direction – so when your own location clouds over, you can see at a glance whether half an hour towards the south-east would pay off.

The map uses the same forecast as the score, so the two cannot contradict each other. It is drawn in your browser from the weather data itself – coastlines, rivers and place names are served by SkyGrade. Viewing it therefore creates no connection to any map service.

The observing tips on the “Visual observing” page depended only on the object type. Anyone who had picked a telescope still read “most beautiful in binoculars”. The chosen equipment now counts, and the object’s size is weighed against the respective field of view – a cluster wider than the field needs different advice than a tiny planetary nebula.

On the aurora page, the same note appeared below the three German zones regardless of the situation – even when all zones showed “very low”. It now follows the actual forecast: with no chance it states the required Kp value, otherwise it names the regions where something is genuinely possible.

The new Astrophoto Planner answers how well a deep-sky object can be photographed at your location tonight – and how much usable exposure time is left for it. At its core is an object-based contrast score: the object’s surface brightness against the real sky (Bortle, moon, filter). It adds a per-object filter recommendation and an imaging-time calculator that estimates the expected integration and the number of lights from the visibility window, weather and your capture system.

Beginners simply pick their capture system (from smart telescope to cooled astro camera) – SkyGrade uses sensible defaults. Without a chosen target you get the best targets tonight as a shortlist, per object type and ranked by feasibility. Note: the astrophoto score measures per-frame contrast suitability – a low value is compensated in astrophotography through integration time.

The new “Where tonight?” tool answers whether it is worth driving to a darker site tonight – and if so, where. SkyGrade compares curated, freely accessible observing sites by real driving time and the same realistic deep-sky assessment as the deep-sky tool. For each site you see the driving time, the deep-sky score with the gain over your starting location, the best observing window and the Bortle class; a map can be shown or hidden optionally.

The list of sites keeps growing and already covers Germany, Austria, Switzerland and France. Know a good, freely accessible spot? Send it to kontakt@skygrade.de. All information is non-binding – please check on site.

On the planets page SkyGrade now automatically detects close planetary encounters of the night: when two planets stand close together you see their angular separation, whether they fit into the same binoculars or telescope view, the shared visibility window and the best observing time – plus “up to N planets visible at the same time”.

For meteor showers, SkyGrade translates the often-misunderstood ZHR into a realistic expected range for your location. The ZHR only applies to a perfectly dark sky with the radiant high overhead; in reality the number depends on radiant altitude, light pollution, the Moon and the weather. The highlights page and the meteor video now show an honest range instead of a wishful figure.

The light-pollution map previously did not reach the Atlantic islands. SkyGrade now also provides an automatic Bortle-class estimate for the Canary Islands, Madeira and the Azores – matching the Europe-wide location search. If a location lies entirely outside the map, SkyGrade now points this out discreetly instead of silently assuming a default value.

The Deep-Sky score now shows the realistic Deep-Sky suitability at your location: light pollution is weighted more heavily because it determines which objects are reachable at all. At bright city locations the value is therefore lower – and more honest – than before.

So you can see what a mediocre rating is down to, there is a second value “Conditions tonight” – the same night without light pollution, i.e. the pure weather and Moon quality. A short verdict also tells you what the night is suited for (e.g. bright star clusters yes, faint galaxies rather not).

The automatic light-pollution estimate (Bortle class) for your location is now based on an up-to-date sky-brightness map from 2024 (David Lorenz) instead of the previous 2015 data. Since light pollution increases year by year, the old map tended to be too optimistic – the new one reflects today's sky more realistically.

Resolution (~1 km) and usage stay the same: the value remains an adjustable suggestion you can override manually at any time. The Bortle classification is our own approximation. The night-time lights data comes from the Earth Observing Group at the Colorado School of Mines.

The aurora page is now far more resilient: the Kp index (current value and forecast) comes from the GFZ Helmholtz Centre for Geosciences, Potsdam – the official producer of the Kp index and independent of NOAA. If NOAA is unavailable (as happened recently), the aurora chance including Kp stays available.

When individual real-time values such as the Bz magnetic field or the solar-wind speed are temporarily unavailable, the page now shows this honestly with a note instead of leaving them blank – and brings them back automatically once the data returns.

On the Visual observing page you can now switch between Deep-sky and Planets. The two have very different demands: deep-sky thrives on a dark, moon-free sky, while planets depend mainly on steady air (seeing). SkyGrade now weights the factors to match the chosen target and shows a headline card with the target score plus the matching object list – switching recomputes instantly.

SkyGrade also rates moon interference more realistically. Previously a low Moon was discounted too strongly by altitude – so a bright, low Moon could wrongly appear barely disruptive (“green”). Now its scattered light counts as long as it is above the horizon, with altitude entering via a flattened curve. Dark sites under a high Moon stay practically unchanged, while low bright Moons are correctly rated more strictly.

The sky-highlight calendar now also shows eclipses: solar and lunar eclipses visible from Germany. Lunar eclipses are computed dynamically, solar eclipses are listed through 2039 – including the partial solar eclipse on 12 Aug 2026. The meteor-shower calendar now covers 14 showers with rate, radiant, speed and parent comet.

For observing targets, the recommended equipment now follows the surface brightness rather than the integrated magnitude alone – so extended objects like the North America Nebula are no longer wrongly labelled “naked eye”. There are also German object names and a “dark sky needed” hint.

The deep-sky score now accounts for two practical factors that were previously shown only as a hint: dew risk (a small gap between temperature and dew point fogs up the optics and lowers transparency) and strong gusts (shake during long exposures). Both are weighted deliberately conservatively – a good night stays good, the value only dips slightly when there is real dew or wind risk.

Planetary and visual scores stay unchanged. In addition SkyGrade now shows the strongest gusts of the night and recommends a dew heater or heater strap when there is dew risk.

Until now the Moon was only a nuisance for deep-sky at SkyGrade. Now it is a full observing target: around the quarters the low Sun casts long shadows along the terminator, and craters and mountains stand out beautifully. The new page rates exactly that and shows the right targets for your instrument.

The clever part: it works even in the city and under a bright Moon – precisely when deep-sky is out. Targets are selected day-precisely from the selenographic colongitude (the position of the terminator), including events like the Golden Handle.

The moon calendar now shows more honestly when it is truly dark at your location. The darkness threshold lets you choose how strict “dark enough” means: −18° (true astronomical night), −15° (a compromise) or −12° (nautical). In midsummer the Sun often never reaches −18° here – it then honestly shows “no real darkness”, and a looser threshold reveals usable windows again.

Alongside this, smaller readability improvements: clearly labelled columns, concrete times even for fully moon-free nights, a short explainer, and a tidy layout on mobile.

The navigation had grown crowded with many individual links. All pages are now grouped into four clear areas – on desktop as dropdown menus with an icon and a short description, so you find what you need faster.

On mobile there is now a fixed bar at the bottom (like in an app): a tap opens the respective area. The language switch now sits directly at the top right, without having to open the menu first.

The sky highlights calendar now also shows close encounters: when two planets – or the Moon and a planet – appear especially close together in the sky. For each encounter you see the angular separation and whether the pair fits into binoculars or even a telescope.

It shows the date of closest approach (smallest separation) – all computed, so it stays up to date with no maintenance.

The new Sky highlights page collects the upcoming notable events in the sky: meteor showers with peak, rate and radiant, plus planetary oppositions – sorted chronologically, with a countdown to the next highlight.

Each event shows a moon outlook (how much moonlight interferes at the peak). With a location, events within the next seven days also get the familiar SkyGrade weather rating.

The dates keep themselves up to date: meteor peaks are computed each year from the shower's solar longitude, planetary oppositions directly from orbital data. On the home page a teaser points to the next highlight.

The aurora page no longer only answers „Can I see aurora tonight?" – it now gives a compact overview of current solar activity: the Sun's status, recent solar flares, a possibly Earth-directed CME with estimated arrival, and the geomagnetic storm level.

New are small 24-hour trends under Kp, Bz and solar wind, an overview of the aurora chance for northern, central and southern Germany, the current SDO Sun image, and a clear explanation of why the magnetic field Bz matters so much.

All data (NOAA SWPC, NASA DONKI, SDO) is fetched and cached server-side at regular intervals – the browser only receives finished values. The page stays true to its style: a few clear metrics instead of a flood of raw data.

A new collapsible temperature and dew-point curve for the selected night is now available on the deep-sky and the planets page. Two lines show how temperature and dew point develop through the night.

What matters is the gap between them: when the two lines converge, optics fog up. The affected hours are marked in red as dew risk – so you can see in advance when a dew shield or heater is worthwhile. This complements the existing dew-point warning with the time course. The data comes from the weather forecast that is fetched anyway.

In addition to the 7-night forecast, the deep-sky page now has a collapsible hour-by-hour weekly overview: a heatmap with the 7 nights as rows and the hours from 18:00 to 06:00 as columns. Each cell is coloured by the deep-sky score for that hour – so you can spot the best window of the week at a glance (it is also highlighted).

A toggle switches the colouring between score and cloud cover. Hours when the Sun is above the horizon are dimmed – so in winter the grid fills up almost completely, while in summer it is limited to the short dark hours. Tapping a cell shows date, time, score and cloud cover.

The planets page now has a collapsible, interactive solar system view with two switchable perspectives: the heliocentric top-down view (looking down on the orbits – shows when and why a planet is well placed: evening/morning sky, opposition, greatest elongation) and the geocentric sky view (altitude above the horizon and compass direction – exactly what drives the score).

A time slider with a play function animates the planets: over about a year in the top-down view, over 24 hours in the sky view. Plus a table with distance to the Sun (in AU), angle to the Sun (elongation) and visibility at your location – along with curated highlights.

Everything is computed purely from the orbital elements (no weather) and is labelled as schematic, not to scale. Without JavaScript a static table remains visible.

The new overview page Tonight lets you enter just your location and see at a glance whether the night is worth it. It brings together what is otherwise spread across several pages – the object of the evening, the top 10 targets, „Why tonight?" with ✔/✖ factors and the bottleneck (the currently weakest factor), the best hour of the night, and a star rating of what the night is currently good for.

A highlight is the „How exceptional?" rating: SkyGrade compares the current night with the last 30 nights at your location and tells you whether tonight is an above-average night. This history is collected over time; until enough nights are available, the preview of the coming week serves as a stopgap.

The page doesn't recompute anything – it bundles the existing assessments (weather, seeing, moon, light pollution) into a quick overview and links to the individual tools for details.

SkyGrade gains a major new page: Visual observing. Instead of only rating conditions, it recommends the currently best targets for your location, date and gear (naked eye, binoculars or telescope) – planets, star clusters, nebulae and galaxies – sorted by the SkyGrade score.

The key novelty is expectation management: for every object you see not just a number, but the difficulty (beginner/intermediate/expert), the recommended instrument and a practical sentence about what you will actually see – so the colourful photo you saw online doesn't turn into a disappointed look through the eyepiece. A location-based hint also tells you whether an object is visible to the naked eye at your light pollution (Bortle class).

The object selection is based on a local catalogue of Messier and bright NGC/IC objects (data source: OpenNGC). Planets are computed live as usual. A collapsible section on the page briefly explains the score, magnitude, difficulty and Bortle.

SkyGrade gains a new category: Aurora. Enter a location and you immediately see the chances of aurora where you are – with a traffic light from “low” to “high”.

It rates the three decisive space-weather quantities: the Kp index (geomagnetic activity), the magnetic field Bz (a southward direction is the trigger) and the solar-wind speed. The data comes in near real time from NOAA SWPC. Because the Kp needed depends on latitude, SkyGrade puts it in context for your location – the further north, the weaker the storm required.

A short tonight preview from the 3-day Kp forecast also shows whether things could get interesting “tonight”. The aurora panel is deliberately decoupled from the score – it is its own look at the sky, not part of the deep-sky rating.

SkyGrade gets a new home page: instead of starting straight with the deep-sky form, you first pick your category at the top – deep-sky, planets, visual observation or the moon calendar. You then enter location and date on the respective page. The familiar deep-sky tool now lives at /deepsky; all features stay exactly the same.

Also new is the clear-window hint: after a cold front passes, the sky is often especially clear and steady. SkyGrade now detects these phases automatically from the hourly data (cloud cover, high cloud, dew point, precipitation and air pressure) and shows you the clear window with a concrete time span – both in the deep-sky and the planet tool.

If a warm front with high cloud moves in shortly after, an amber note points out that the window is only open briefly – so you can make use of the best time early enough. The relevant hours are also highlighted directly in the hourly view. The hint appears only when there really is a window between worse spells – on a night that stays clear or overcast throughout, it stays hidden.

The SkyGrade blog is now fully bilingual: every article is also available in English at /en/blog – including dedicated English infographics. Use the language switcher at the top right to switch between German and English as usual.

SkyGrade can now be placed on your home screen like an app – on iPhone via "Add to Home Screen", on Android via "Install app". It then starts with its own icon in full screen, without any browser bar.

It stays a lightweight web app on purpose: an internet connection is still required (no offline mode) – in return there is nothing to update, you always have the latest version.

When the seeing forecast (7Timer) is temporarily unavailable, SkyGrade keeps calculating with default assumptions – this is now shown openly: the badge on the result switches from "Live data" to "Partly estimated", the seeing value is marked as "estimated", and the affected nights in the 7-night preview get a note – instead of showing a seemingly exact score.

If the location search is temporarily unreachable, an honest message now appears instead of "Location not found". The score itself is unaffected – this is purely about transparency.

The moon interference is now coupled to the light pollution at your location: because sky brightnesses add up, the same moon raises a dark rural sky strongly, but an already bright city sky hardly at all. Under a dark sky the moon therefore acts in full, in the bright city only partially.

The factors are derived from an additive brightness model (based on Krisciunas & Schaefer 1991) – traceable instead of guessed. Compared to the previous calculation, dark sites stay practically unchanged (the moon always acted in full there); in brighter areas the previously too strict moon penalty is realistically reduced.

There is a new FAQ page (linked in the footer): short, honest answers about SkyGrade, the score and the data – collapsible by topic. The moon calendar has also moved into the header menu to keep the navigation tidy.

Until now only the total cloud cover counted – 30% high cirrus was treated like 30% dense low cloud. SkyGrade now distinguishes the three altitude layers (low / mid / high): low clouds still block hard, while thin high cirrus no longer "closes" the night completely.

Instead, cirrus specifically lowers the deep-sky contrast, while bright planets are barely affected. The layer weights are based on measured optical depths of the cloud types. Thanks to the Astrotreff community for the nudge!

New is the moon calendar (linked in the footer): it shows the coming weeks with the moon phase and highlights the moon-free nights – ideal for deep-sky planning around new moon. If you enter a location, SkyGrade also computes the actual moon-free dark window for each night – after all, a bright moon that sets early still leaves a dark night.

In addition, two new notices in the raw data point out dew risk (fogged optics) and strong wind (shaky mount). And the three ratings are now labelled more clearly: "Deep-sky" and "Planets" refer to imaging, "Visual" to observing at the eyepiece or binoculars. Many thanks for all the feedback from the forum!

On nights that do not get fully dark (for example in Berlin in summer), the twilight was previously classified one stage too bright and shown as "nautical twilight", even though the sun had already reached astronomical twilight. This is fixed: astronomical twilight is now its own stage with a fitting, milder penalty – the deep-sky score of such nights comes out somewhat higher and more realistic.

In addition, SkyGrade now discreetly points out when the actually dark window is very short (under 1.5 hours). Thanks to an attentive user from the forum for the hint.

Until now the main rating was cached for up to six hours – which could make the values seem unchanged over the day. From now on the cache shortens automatically towards the evening: a few hours in the afternoon, only one hour from 6 pm. That way SkyGrade shows the most up-to-date state of the weather models shortly before observing starts. Thanks to an attentive user from the forum for the hint.

SkyGrade now remembers the location you last entered and fills it into the search field automatically on your next visit. So a single click on "Calculate" is enough to see right away whether the evening is worth it – ideal if you always check the same observing site.

SkyGrade stays true to its data-minimal approach: the location is stored only locally in the browser, never sent to the server, and it is not a cookie – so it needs neither consent nor a banner. Thanks to an attentive user from the forum for the suggestion.

SkyGrade now also speaks English: using the language switcher at the top right you can switch between German and the new English version at skygrade.de/en/. Everything has been translated – from the home page through the complete rating result including the score explanation to the info pages. German of course remains the default language.

Technically this was the biggest step so far: both languages are served cleanly separated, are correctly declared as language variants for search engines (hreflang) and can be maintained centrally. That is why SkyGrade jumps to version 2.0 with this update.

SkyGrade schätzt die Lichtverschmutzung (Bortle-Klasse) jetzt automatisch aus deinem Beobachtungsort – du musst sie nicht mehr selbst kennen. Grundlage ist der „World Atlas of Artificial Night Sky Brightness" (2015). Die geschätzte Klasse wird direkt unter der Standortwahl angezeigt. Es ist ein Modellwert, der lokale Gegebenheiten nicht kennt – deshalb kannst du ihn jederzeit manuell überschreiben, wenn du deinen Himmel besser einschätzt.

Außerdem lässt sich der Standort jetzt direkt als GPS-Koordinaten eingeben – im Format Breite, Länge (Dezimalgrad), zum Beispiel 47.07, 15.44. So sind auch abgelegene Beobachtungsplätze ohne Ortsnamen punktgenau bewertbar.

Der angezeigte Mondaufgang gehörte bisher zum Vortag – bei Eingabe des 1. Juli erschien beispielsweise der Aufgang des 30. Juni. Ursache war das Abtastfenster der Berechnung, das bereits am Vorabend begann und dadurch den falschen Aufgang erfasste. Die Berechnung ist nun auf den Kalendertag begrenzt und liefert Mondauf- und -untergang exakt für das gewählte Datum. Vielen Dank an einen aufmerksamen Nutzer für den Hinweis.

Zusätzlich zeigt SkyGrade unter der besten Beobachtungszeit jetzt auch die Dauer der nutzbaren Dunkelheit an – also die Länge der astronomischen Nacht (bzw. der nautischen oder bürgerlichen Dunkelphase in kurzen Sommernächten). So ist auf einen Blick erkennbar, wie viel Zeit tatsächlich zum Beobachten bleibt.

Wird es in kurzen Sommernächten oder in nördlichen Breiten nicht vollständig dunkel, bleibt der Himmel aufgehellt – schwache Deep-Sky-Objekte verlieren dann deutlich an Kontrast. SkyGrade berücksichtigt das jetzt direkt im Score: Bei nautischer und bürgerlicher Dämmerung wird der Deep-Sky-Score abgestuft reduziert, bei „Mitternachtssonne" praktisch auf null. Helle Ziele wie Planeten, die auch in der Dämmerung gut sichtbar sind, werden kaum oder gar nicht abgewertet.

Nutzer können SkyGrade jetzt mit 1 bis 5 Sternen bewerten und einen kurzen Kommentar hinterlassen – komplett anonym, ohne Anmeldung und ohne Cookies. Ein Nickname reicht. Alle Bewertungen werden vor der Veröffentlichung kurz geprüft.

Nach dem Ergebnis zeigt SkyGrade jetzt einen stündlichen Verlauf des Deep-Sky-Scores für die gesamte Beobachtungsnacht – inklusive je einer Stunde vor und nach dem eigentlichen Dunkelheitsfenster. So ist auf einen Blick erkennbar, ob die Bedingungen im Laufe der Nacht besser oder schlechter werden. Der Mondstand wird dabei für jede Stunde individuell berechnet.

Direkt unter der Beobachtungszeit gibt es jetzt einen ausklappbaren Abschnitt „Wie wird der Score berechnet?". Er erklärt in einfachen Worten, welche sechs Faktoren in den Score einfließen, wie sie gewichtet werden – und warum der Score immer nur für das angezeigte Beobachtungsfenster gilt.

Die 7-Nächte-Vorschau berechnete die Wetterwerte bisher über ein pauschales Fenster von 21:00 bis 05:00 Uhr. Dadurch wichen die Vorschau-Scores teilweise erheblich vom Hauptergebnis ab – etwa wenn der Abend noch bewölkt, die eigentliche Nacht aber klar ist. Ab sofort verwendet die Vorschau für jeden der sieben Tage das exakt berechnete astronomische Dunkelheitsfenster, genau wie das Hauptergebnis.

Eine neue Seite dokumentiert alle Datenquellen und Dienste, die SkyGrade verwendet – von Wetterdaten über Seeing-Prognosen bis hin zur Kartendarstellung. Jeder Dienst ist mit Quelle und Lizenzhinweis aufgeführt.

Jeder Versions-Eintrag zeigt jetzt auf einen Blick, was sich geändert hat: ein farbiger Tag nennt die Art der Änderung, darunter stehen die wichtigsten Punkte als kurze Liste. Das genaue Veröffentlichungsdatum steht direkt neben der Versionsnummer.

Die atmosphärische Durchsicht – also wie klar und staubfrei die Luft ist – wird beim Deep-Sky-Score jetzt stärker berücksichtigt. Dunst, Saharastaub oder Aerosole in der Luft können schwache Galaxien und Nebel deutlich abschwächen, selbst wenn der Himmel wolkenlos ist. Diese Anpassung spiegelt das realistischer wider.

Die Grenzen für die Bewertungsstufen wurden angepasst. "Exzellent" beginnt jetzt erst ab 92 Punkten, "Sehr gut" ab 81, "Gut" ab 67 und "Mittel" ab 50 Punkten. Die alten Grenzen waren zu großzügig – eine wirklich exzellente Nacht ist selten und soll das auch im Score zeigen.

Bei mehr als 80 % Bewölkung sinkt der Gesamtscore jetzt deutlich stärker ab – bei vollständig bedecktem Himmel (100 %) ist der Score 0. Vorher konnte ein guter Seeing-Wert oder eine niedrige Bortle-Klasse den Score noch künstlich hochhalten, obwohl man durch die Wolken ohnehin nichts sieht. Das war irreführend und ist jetzt korrigiert.

Die Infografiken in den Blog-Artikeln zu Seeing, Bortle-Skala und astronomischer Dämmerung waren auf dem Smartphone kaum lesbar. Auf kleinen Bildschirmen wird jetzt automatisch eine kompakte vertikale Version angezeigt, auf dem Desktop die klassische Ansicht mit mehr Platz.

Neben der Texteingabe kann der Standort jetzt auch per Klick auf eine interaktive Karte gewählt werden. Ein "Meinen Standort verwenden"-Button ermöglicht die direkte GPS-Ortung über den Browser. Das Kartenthema wurde auf eine ausgewogene, gut lesbare Darstellung umgestellt.

Favicons für verschiedene Gerätegrößen ergänzt. HTTPS wird jetzt serverseitig erzwungen. Cache-Header für schnellere Ladezeiten gesetzt. Hamburger-Menü für die mobile Navigation eingebaut.

Der erste öffentliche Launch von SkyGrade. Deep-Sky-Score, Planeten-Score und Visuell-Score auf Basis von Open-Meteo und 7Timer. Standortsuche per Ortsname oder Postleitzahl, 7-Nächte-Vorschau, astronomisches Beobachtungsfenster.