space.observe

Compute where any asteroid or comet is in the sky and whether you can see it. Give a body (designation/number/name, e.g. "433 Eros", "Ceres", "2024 YR4") and optionally your lat/lon and a time (ISO, default now). Returns the body's identity (NEO/PHA flags, orbit class, absolute magnitude H), its geocentric right ascension + declination, the constellation it's in, geocentric + heliocentric distance (AU), solar phase angle, and its apparent visual magnitude (IAU H-G model — how bright it appears now). With lat/lon it adds altitude/azimuth, whether it's above your horizon, a visible-now flag (up AND sky dark), and the best viewing window in the next 24 hours (when it's highest during darkness). Orbital position is computed locally from JPL elements — VALIDATED against JPL Horizons to <0.1 arcminute. Stargazing, astrophotography planning, occultation/observation prep. For the body's static physical + orbital params see /api/space/body.

price
$0.0029 USDC per call
method
GET/api/space/observe
payment
x402 v2 · USDC on Base (EIP-3009) or Solana (SPL transfer)
auth
None. Sign the payment, retry with PAYMENT-SIGNATURE.
tier
Tier 0 — no paid upstream

Parameters

NameTypeDescription
bodyrequiredstring
min 1 chars · max 60 chars
latnumber
min -90 · max 90
lonnumber
min -180 · max 180
altKmnumber
min -0.5 · max 9
atstring
date-time

Code samples

cURLbash
# 1. Probe with no auth → 402 envelope with PaymentRequirements
curl -sS 'https://2s.io/api/space/observe?body=example&lat=-90&lon=-180&altKm=-0.5&at=example'

# 2. Sign + retry with PAYMENT-SIGNATURE:
curl -sS 'https://2s.io/api/space/observe?body=example&lat=-90&lon=-180&altKm=-0.5&at=example' \
  -H 'PAYMENT-SIGNATURE: <base64-json-payload>'

# Or use the canonical runner (handles probe → sign → retry):
#   EVM_PRIVATE_KEY=0x... node --env-file=.env.local \
#     --experimental-strip-types scripts/x402-pay.ts \
#     'https://2s.io/api/space/observe?body=example&lat=-90&lon=-180&altKm=-0.5&at=example'
TypeScript / Node — @2sio/sdktypescript
import { TwoS } from '@2sio/sdk'

const client = new TwoS({
  privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})

const result = await client.space.observe({
  "body": "example",
  "lat": -90,
  "lon": -180,
  "altKm": -0.5,
  "at": "example"
})

console.log('endpoint:', result.endpoint)
console.log('cost:', result.costUsd, 'USDC')
console.log('tx:', result.settlement?.txHash)
console.log('data:', result.data)
Python — 2siopython
import os
from twosio import TwoS

client = TwoS(private_key=os.environ["EVM_PRIVATE_KEY"])

result = client.space.observe(body="example", lat=-90, lon=-180, altKm=-0.5, at="example")

print("endpoint:", result.endpoint)
print("cost:", result.cost_usd, "USDC")
print("tx:", (result.settlement or {}).get("tx_hash"))
print("data:", result.data)
MCP — Claude Desktop / AgentKit / any MCP hostjson
// 1. Add @2sio/mcp to your MCP host config (Claude Desktop example below).
//    EVM_PRIVATE_KEY funds x402 payments per call.

// claude_desktop_config.json
{
  "mcpServers": {
    "2sio": {
      "command": "npx",
      "args": ["-y", "@2sio/mcp"],
      "env": { "EVM_PRIVATE_KEY": "0x..." }
    }
  }
}

// 2. Once the server is running, agents call this tool via standard MCP:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "space.observe",
    "arguments": {
      "body": "example",
      "lat": -90,
      "lon": -180,
      "altKm": -0.5,
      "at": "example"
    }
  }
}

Response

FieldTypeDescription
bodyobject
atstring
positionobject
observerobject
sourceobject
Example response datajson
{
  "body": {
    "fullName": "example",
    "neo": false,
    "pha": false,
    "orbitClass": "example",
    "absoluteMagnitudeH": 1
  },
  "at": "example",
  "position": {
    "rightAscensionHours": 1,
    "declinationDeg": 1,
    "constellation": "example",
    "geocentricDistanceAu": 1,
    "heliocentricDistanceAu": 1,
    "phaseAngleDeg": 1,
    "apparentMagnitude": 1
  },
  "observer": {
    "altitudeDeg": 1,
    "azimuthDeg": 1,
    "aboveHorizon": false,
    "visibleNow": false,
    "bestViewing": {
      "at": "example",
      "altitudeDeg": 1
    }
  },
  "source": {
    "provider": "example",
    "url": "example",
    "license": "example"
  }
}

Discovery

2s.io is x402-native. Every call is paid per-request from a USDC-funded EVM wallet on Base — no signup, no API keys, no monthly fees. Source code: github.com/2s-io/sdk.