Comparison

OptiUniverse vs Sideris

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

OptiUniverse

Features
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Explore the Solar System in 3D on your iPhone. Get close to Saturn's rings, discover Jupiter's cloud bands, inspect Earth, and choose a space mission to replay. OptiUniverse brings planets, moons, and spacecraft journeys together in an interactive universe built for curiosity. Browse celestial destinations, move freely around each world, and learn through detailed visuals and concise science facts. EXPLORE PLANETS AND ORBITS - Discover planets, moons, and distant worlds with detailed 3D materials, atmospheres, and rings. - Pan, pinch, and rotate to find your own perspective, or follow a celestial object. - Inspect object facts and visualize orbital paths and supported transfer routes. - Explore a solar-system simulation synchronized to the current date using offline planetary ephemerides. REPLAY SPACE MISSIONS - Follow Voyager 1 from launch through its Jupiter and Saturn flybys to its journey beyond the heliosphere. - Watch Crew 13 travel from Earth to docking with the International Space Station. - Explore Artemis II's Earth-Moon-Earth journey and Starship Flight 14's launch, deployment, and return. - Choose missions from the home-screen carousel, ordered by launch date. Mission replays are compressed, illustrative visualizations. Spacecraft sizes, trajectories, and timing are adapted for clarity; they are not live spacecraft tracking or telemetry reconstructions. From a quick look at a favorite planet to a journey through spaceflight history, OptiUniverse makes space something you can explore.

About

Sideris

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Sideris is a plate solver for astrophotography with simple gear: a camera, a lens or a telescope, and a star tracker without go-to functionality. You aim at a galaxy and take a test shot, but the camera's screen only shows stars. Is your target in the frame, or just outside it? Take a photo of the screen with your phone (or tablet), and Sideris tells you exactly where your camera is pointing. Your shot appears on the interactive sky map, next to the target you are aiming for, so you know which way to move. No go-to mount, no laptop and no internet needed at your dark site. HOW IT WORKS 1. Take a test shot with your camera. 2. Photograph the camera's screen with your phone, or import the photo itself. 3. Crop it, and Sideris solves it in seconds, right on your device. 4. See your photo on the sky map, and how far you are from your target. PLATE SOLVING, FULLY OFFLINE • Solving runs on your phone, so it works where there is no signal. • Most photos solve with nothing but the picture. If one struggles, add your sensor size, focal length or target to help it. • From camera lenses to telescopes of about 1,200 mm on a full-frame camera. • A solve that fails does not use up a free solve. FRAME YOUR SHOT Add your cameras and your lenses or telescopes, and the framing tool shows your exact field of view on the sky map. Turn the frame to match your camera and plan the composition before you shoot. MORE THAN 21,000 DEEP-SKY OBJECTS • Messier, Caldwell, Herschel 400, NGC and IC, plus Sharpless, Barnard and Lynds nebulae, planetary nebulae, supernova remnants, star clusters and galaxy groups. • Show the 500 best known, the 2,500 within reach of a camera lens, or all of them. • Search any object by name or number, filter by type, catalog, magnitude, size or altitude, and sort the list by what matters tonight. • Every object has an altitude curve for the night, and the 110 Messier objects have NASA and ESA photographs. AN INTERACTIVE SKY MAP • 364,000 stars, the planets, and the Moon in its real phase. • Point your phone at the sky and the map follows. Select an object, and arrows guide you to it. • Constellation lines, an equatorial or azimuthal grid, and the sky at any date and time. TOOLS FOR THE FIELD • Polar scope: a Polaris reticle for the polar alignment of your star tracker. • Night mode: turns on at sunset to protect your night vision, with an all-red option for the darkest sites. • Moon phase calendar: phase, illumination, moonrise and moonset for every night. • White screen: a dimmable panel for flat frames. • Location from the GPS, or chosen on an offline world map. LEARN IT ON REAL PHOTOS A guided tutorial walks you through two real solves on example photos, with an animation of the whole process. ONE PURCHASE, NO SUBSCRIPTION Your first 10 solves are free. After that, a single one-time purchase unlocks unlimited plate solving on all your devices. No subscription, no ads, no account. I built Sideris for my own nights under the stars, after spending too many hours trying to find my targets. I hope it can help you take beautiful photos as well. Clear skies!

Screenshots

OptiUniverse4 screens
Sideris4 screens

Verdict

The call

The clearest difference is in-app purchases: OptiUniverse at none against Sideris's 1. Sideris's advantage is device support (3 vs 1) and iOS requirement (15.0 vs 26.0). On price, update cadence and ads there is nothing between them.

Scored on Price Ā· Rating Ā· Positive reviews Ā· Number of ratings Ā· Update frequency Ā· Ads Ā· In-app purchases Ā· Monetization Ā· Best chart rank Ā· Devices Ā· Requires iOS

CostPrice Ā· In-app purchases Ā· Ads Ā· Monetization

Both are free to download. Sideris sells 1 one-off in-app purchase. OptiUniverse asks for nothing beyond the download.

UpkeepUpdate frequency

OptiUniverse ships an update every 10 days, Sideris every 2 weeks. The most recent releases landed on October 24, 2026 and October 31, 2026 respectively.

Scorecard3 real differences Ā· 3 level
OptiUniverse versus Sideris: the parameters behind the verdict, then further details
ParameterOptiUniverseSideris
PriceFreeFree
Update frequencyEvery 10 days — betterEvery 2 weeks
AdsNoNo
In-app purchasesNo — betterYes
DevicesiPhoneiPhone, iPad, iPod — better
Requires iOS26.015.0 — better
Further details — not scored
Size421 MB137 MB
Age rating4+4+
DeveloperMaksim DoroshenkoLoris BERT

In-app purchases

None

OptiUniverse

No in-app purchases

1 purchases

Sideris

One-time1
  • Unlimited Plate Solving$9.99

Questions

Is OptiUniverse free?
OptiUniverse is free to download, with no in-app purchases.
Is Sideris free?
Sideris is free to download, with in-app purchases available.
Do OptiUniverse or Sideris have ads?
Neither OptiUniverse nor Sideris shows ads.
Which is updated more often, OptiUniverse or Sideris?
OptiUniverse ships an update every 10 days, and Sideris every 2 weeks. Most recently, OptiUniverse was updated on October 24, 2026 and Sideris on October 31, 2026.

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