Comparison

Mars Book vs Solar System&Celestial Objects

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

Head to head

Solar System&Celestial Objects

Solar System Stars Flashcard

Free

📚 Education

No ratingsView app →

About

Mars Book

Read full description

The Mars Book is an app that is dedicated for observing Mars which will make close approach in summer 2020. Mars will come close to Earth from September 2020 through October 2020. Closest approach will take place on October 6, 2020. Mars Book is a highly useful Mars observing app which will indicate the location of Mars visible in the sky. It shows you why Mars Close Approach will take place, and it is explained readily using animated illustrations and star charts at a viewpoint from outer Space. Mars Close Approaches taking place 23 times from the year 2003 through 2050 will be displayed and apparent retrograde motion of Mars will be displayed. Enjoy Mars Close Approach this summer with the Mars Book app!

About

Solar System&Celestial Objects

Features

Read full description

Easy learning about solar system, stars, celestial objects, constellations, spacecraft with pictures ,sounds and quiz games. If you who always search and learn a quiz app like these, this app is for you ① Solar system Flash card app. ② Stars Quiz app. ③ Celestial objects quiz app. ④ Stars history and information app. ⑤ Constellations name cards. ⑥ Guess solar system app. Features: - You can learn many kinds of stars. - You can play solar system quiz. - Many information related to solar system, stars, celestial objects, constellations, spacecraft - Support Quiz feature. - Support 5 languages: English, Japanese, Korean, Chinese, Vietnamese

Screenshots

Mars Book3 screens

Solar System&Celestial Objects4 screens

Verdict

The call

The clearest difference is ads: Mars Book at none against Solar System&Celestial Objects's shown. Mars Book also leads on iOS requirement (9.0 vs 12.0). Solar System&Celestial Objects's advantage is update cadence (every 6 weeks vs every 13 months). On price, in-app purchases and device support there is nothing between them.

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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Mars Book ships an update every 13 months, Solar System&Celestial Objects every 6 weeks. The most recent releases landed on September 10, 2026 and May 16, 2026 respectively.

Scorecard3 real differences · 3 level

Mars Book versus Solar System&Celestial Objects: the parameters behind the verdict, then further details
Parameter	Mars Book	Solar System&Celestial Objects
Price	Free	Free
Update frequency	Every 13 months	Every 6 weeks — better
Ads	No — better	Yes
In-app purchases	No	No
Devices	iPhone, iPad, iPod	iPhone, iPad, iPod
Requires iOS	9.0 — better	12.0
Further details — not scored
Size	14 MB	62 MB
Age rating	4+	4+
Developer	Vixen Co.,Ltd.	NIKI TECH

In-app purchases

None

Mars Book

No in-app purchases

None

Solar System&Celestial Objects

No in-app purchases

Questions

Is Mars Book free?

Mars Book is free to download, with no in-app purchases.

Is Solar System&Celestial Objects free?

Solar System&Celestial Objects is free to download, with no in-app purchases.

Do Mars Book or Solar System&Celestial Objects have ads?

Solar System&Celestial Objects shows ads; Mars Book does not.

Which is updated more often, Mars Book or Solar System&Celestial Objects?

Mars Book ships an update every 13 months, and Solar System&Celestial Objects every 6 weeks. Most recently, Mars Book was updated on September 10, 2026 and Solar System&Celestial Objects on May 16, 2026.