# 天文ガイド vs Mars Book

The clearest difference is in-app purchases: Mars Book at none against 天文ガイド's 39. Mars Book also leads on ads (none vs shown) and iOS requirement (9.0 vs 13.0). On price, update cadence and device support there is nothing between them.

Both are free to download. 天文ガイド sells 39 in-app purchases, starting at $6.99 per month. Mars Book asks for nothing beyond the download.

天文ガイド ships an update every 14 months, Mars Book every 13 months. The most recent releases landed on September 20, 2026 and September 10, 2026 respectively.

## The numbers

| Metric | 天文ガイド | Mars Book |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 20.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Every 14 months | **Every 13 months** |
| Size | 41 MB | 14 MB |
| Requires iOS | 13.0 | **9.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Seibundo Shinkosha Publishing Co., Ltd.](https://appshunter.io/developer/513602721) | [Vixen Co.,Ltd.](https://appshunter.io/developer/536188843) |

## What reviewers say

### 天文ガイド

[App page](https://appshunter.io/ios/app/id987344209)

**In-app purchases (39)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 天文ガイド | $6.99 | per month |
| 天文ガイド | $39.99 | per 6 months |
| 天文ガイド | $79.99 | per year |
| 天文ガイド2016年11月号 | $5.99 | one-time |
| 天文ガイド2016年12月号 | $5.99 | one-time |
| 天文ガイド2019年2月号 | $5.99 | one-time |
| 天文ガイド2019年4月号 | $5.99 | one-time |
| 天文ガイド2019年10月号 | $5.99 | one-time |
| tenmonguide202606 | $6.99 | one-time |
| tenmonguide202607 | $6.99 | one-time |
| tenmonguide202602 | $6.99 | one-time |
| tenmonguide202603 | $6.99 | one-time |
| tenmonguide202601 | $6.99 | one-time |
| tenmonguide202511 | $6.99 | one-time |
| tenmonguide202512 | $6.99 | one-time |
| tenmonguide202510 | $6.99 | one-time |
| tenmonguide202509 | $6.99 | one-time |
| tenmonguide202508 | $6.99 | one-time |
| tenmonguide202507 | $6.99 | one-time |
| tenmonguide202506 | $6.99 | one-time |
| tenmonguide202504 | $6.99 | one-time |
| tenmonguide202505 | $6.99 | one-time |
| 天文ガイド2025年3月号 | $6.99 | one-time |
| 天文ガイド2025年2月号 | $6.99 | one-time |
| 天文ガイド2025年1月号 | $6.99 | one-time |
| 天文ガイド2024年11月号 | $6.99 | one-time |
| 天文ガイド2024年12月号 | $6.99 | one-time |
| 天文ガイド2023年10月号 | $7.99 | one-time |
| 天文ガイド2023年11月号 | $7.99 | one-time |
| 天文ガイド2023年12月号 | $7.99 | one-time |
| 天文ガイド2024年1月号 | $7.99 | one-time |
| 天文ガイド2024年3月号 | $7.99 | one-time |
| 天文ガイド2024年4月号 | $7.99 | one-time |
| 天文ガイド2024年10月号 | $7.99 | one-time |
| 天文ガイド2024年9月号 | $7.99 | one-time |
| 天文ガイド2024年8月号 | $7.99 | one-time |
| 天文ガイド2024年7月号 | $7.99 | one-time |
| 天文ガイド2024年5月号 | $7.99 | one-time |
| 天文ガイド2024年6月号 | $7.99 | one-time |


### Mars Book

[App page](https://appshunter.io/ios/app/mars-book/id1342509724)

**In-app purchases:** none


## Frequently asked questions

### Is 天文ガイド free?

天文ガイド is free to download, with in-app purchases available.

### Is Mars Book free?

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

### Do 天文ガイド or Mars Book have ads?

天文ガイド shows ads; Mars Book does not.

### Which is updated more often, 天文ガイド or Mars Book?

天文ガイド ships an update every 14 months, and Mars Book every 13 months. Most recently, 天文ガイド was updated on September 20, 2026 and Mars Book on September 10, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*