In Slay the Spire, relics are game-changing items that shape each run, and among them, Astrolabe stands out as one of the more intriguing and versatile boss relics. Appearing as a post-act boss reward, Astrolabe offers the player a chance to transform and upgrade cards from their deck. This seemingly simple effect can open up creative strategies, solve deckbuilding problems, and even swing a run toward victory with the right luck. Understanding how and when to choose Astrolabe is key to mastering its potential and incorporating it into a successful climb through the Spire.
What Is Astrolabe?
Astrolabe is a rare boss relic offered at the end of Act 1 or Act 2 in Slay the Spire. Its effect reads: Upon pickup, choose and transform 3 cards, then upgrade them. This means that three cards from your current deck are removed, and in their place, three new, randomly chosen cards appear, each starting upgraded.
Relic Overview
- Rarity: Boss Relic
- Effect: Transform 3 cards upon acquisition, and those cards are automatically upgraded
- Appears: At the end of Act 1 or 2 (replacing your relic reward if chosen)
Unlike relics that passively improve your stats or economy, Astrolabe gives immediate deck manipulation. It encourages strategic planning and risk-taking, rewarding those who know how to manage their deck’s synergy and size.
How Astrolabe Works
When you select Astrolabe, you’re prompted to choose three cards from your deck. These can be any cards you own, whether they’re basic strikes and defends or rare and unupgraded picks from earlier encounters. Once chosen, each selected card is permanently removed and replaced with a random card appropriate to your character class each one fully upgraded.
Card Pool and Transformation
- The new cards are drawn from the current run’s pool of available class-specific cards
- Transformed cards inherit upgrade status immediately
- Basic cards (like Strike or Defend) can be good candidates to remove
Because the new cards are fully upgraded, they can often outperform most early-game options, especially if you’re still running unupgraded or filler cards. However, the result is random, so there is always a gamble involved when using Astrolabe.
When to Choose Astrolabe
Picking Astrolabe is not always a straightforward decision. It’s most effective when your deck needs a shake-up or when you’re looking to remove weak cards and possibly gain powerful synergies. Astrolabe shines in runs where flexibility and deck thinning are valuable assets.
Ideal Scenarios for Astrolabe
- You have three or more undesirable cards (e.g., Strikes, Curses, poor event rewards)
- You’re lacking synergy and need new options to power your strategy
- You’ve already upgraded your core cards and want to expand with strong upgrades
- You’re transitioning between archetypes and need replacement tools
Astrolabe is especially valuable for players who understand the character’s card pool well, as recognizing high-impact cards during transformation allows them to capitalize quickly on strong combos.
Astrolabe by Character
Each of the four playable characters in Slay the Spire interacts with Astrolabe in different ways due to their unique card pools and deckbuilding needs. Knowing how to use it effectively based on your chosen character can greatly influence your success.
The Ironclad
For Ironclad, Astrolabe is a strong option for replacing basic Strikes or unwanted skill cards. The Ironclad has access to many high-impact upgraded cards like Bludgeon+, Offering+, and Demon Form+, which can transform a basic deck into a powerful one.
- Use Astrolabe to pivot into strength-based builds or Exhaust archetypes
- Works well when you’re low on scaling or lack damage options
The Silent
The Silent can use Astrolabe to find elusive synergies, such as those tied to poison, shivs, or discard mechanics. The character’s deck often benefits from variety, and getting cards like Catalyst+, After Image+, or Wraith Form+ can be game-changing.
- Ideal for refining your deck early and moving toward specialized builds
- Consider using it if your early card rewards were weak or unfocused
The Defect
Astrolabe for the Defect can be more volatile due to the synergy-dependent nature of the class. However, it can still be valuable for replacing cards that don’t fit your current orb setup. Upgraded powers or zero-cost skills like Loop+ or Cold Snap+ are big boons.
- Can help refine a deck into frost, lightning, or claw archetypes
- Risky if you don’t already have a stable orb engine
The Watcher
Watcher gains high value from upgraded cards due to her stance system. Transforming into cards like Talk to the Hand+, Ragnarok+, or Deus Ex Machina+ can dramatically enhance consistency and damage output.
- Excellent option to remove Wrath-risky cards or duplicate low-impact skills
- Helps support stance control by adding upgraded Calm/Wrath entries
Strategic Tips for Using Astrolabe
While Astrolabe is tempting for its instant upgrade effect, using it wisely requires consideration of deck size, synergy, and risk. The randomness of the transformed cards means you can’t always plan for specific results, but you can prepare to make the best of whatever you get.
General Tips
- Prioritize transforming basic cards when they no longer serve your deck’s goals
- Time your choice of Astrolabe when you’re confident your deck needs flexibility
- Be ready to adapt your strategy based on the transformed results
- Consider synergy with relics that benefit from upgraded cards
Astrolabe can act as a pivot point. If you’re stuck in a weak or overly large deck, trimming it down while adding powerful tools is often worth the gamble especially if you’re an experienced player.
Strengths and Weaknesses of Astrolabe
Like many relics in Slay the Spire, Astrolabe isn’t universally strong or weak it depends heavily on context. Understanding both its benefits and limitations helps players decide when it’s worth choosing over other powerful relics.
Strengths
- Deck refinement through card removal
- Powerful instant upgrades of new cards
- Supports synergy discovery and archetype transition
- Ideal for reducing dead draws or filler cards
Weaknesses
- Completely random results with no reroll option
- Can disrupt synergy if the new cards don’t align with your current build
- Requires player adaptability and strong card knowledge
Astrolabe is a relic that rewards knowledge and flexibility. It’s not for the faint of heart, but it can turn a struggling run into a dominant one with a bit of luck and smart decision-making.
Astrolabe in Slay the Spire represents the core gameplay philosophy of risk versus reward. Offering the chance to remove undesirable cards while gaining powerful upgraded replacements, it can dramatically reshape a deck’s future. Its randomness makes it unpredictable, but for players who understand their build, character strengths, and card synergies, it’s a relic that can unlock hidden potential and create winning combinations.
Whether you’re clearing your deck of weak basics or seeking a surprise power boost, Astrolabe provides an exciting opportunity to refresh your strategy and climb higher in the Spire with renewed purpose.