From Elite Wiki
Market Observer


This oxp enhances the market screen with valuable data. To keep this enhancement free, ads from various advertisers are shown in the market screen.

  • The Vanilla game's F8 screen merely shows 5 columns: commodity name, the price, amount for sale & amount in your hold, and the legality for each commodity.
  • This oxp adds another 4 columns:
  • the galaxial average price (for comparison)
  • the difference between the station price and the galactic average
  • the % difference
  • the price(s) at which you previously bought the commodities already in your hold.
  • You now have all the important information on the screen in front of you when deciding to buy or sell.

Core Features

1. Market Reference Gatherer Engine

This feature monitors the prices of system markets and keeps a list of average prices. This data is printed to the market screen.

2. System Price Difference Viewer

This feature prints the difference of station prices compared to the averages as absolute and percentage value to the market screen. Gives a quick overview of what is cheap and what expensive.

3. Purchase Log

Purchase log is collected from purchases at the standard market. Helps to determine if it's worth while to sell or not.

  • Complete details of multiple purchases is available in the detailed commodity view (f8-f8).
  • When selling, the log is purged starting from the most expensive purchases. The most expensive purchase is printed to the market screen.
  • Lost cargo is purged from the log when docking at any station.

4. Ads From YAH / Now separated to a Market Ads OXP

  • Various ads from Your Ad Here! OXP are shown in the bottom of the market screen.
  • Note that these ads can be useful! They often give information about Oolite options. And some are jolly funny to boot!
  • Market Ads OXP has an api for adding even more ads to the mix: Simply call worldScripts["market_ads_service"]._setHorzAd('filename_of_your_horizontal_ad') in startUp and that's it. Ads need to be in 256x128 resolution.

5. Trader's Rating

Market Observer monitors the profit you gain from buying and selling at the standard market and gives you a rating. Profit is calculated when selling a commodity whose purchase has been logged. No profit is calculated from salvaging or contracting etc, unless some purchased cargo is lost. Player is given a Trader's Rating based on profit made. Rating is shown on the (F5) ship manifest and, if Market Ads is installed, on the (F8) market screen.

  • First rank at 1,500₢. Highest rank at 1,000,000₢.


  • Oolite version 1.82 or higher.


  • All ads are selected and cropped from Your Ad Here! oxp and Your Ad Here! forum thread. Ads are made by different Oolite players.


  • Download the latest version (for Oolite 1.82) from the expansion manager. Market Observer for the statistical functionality and Market Ads for, eh, ads.
  • Download version 2.3.2 (for Oolite 1.79) from the expansion manager. Oxz version includes the trader's rating addon.
  • Download version 2.2.3 (for Oolite 1.77) from the box.
  • Only for the version 2.2.3. Download an update (1.2) to the Commodity Markets OXP addon from the box. This update preserves buy/sell prices over saves. Update by laxori666.


Install the OXP by copying marketObserver.oxp to your AddOns-folder.


You may care to consult How to tweak OXZ's

Tab Stops

Switeck's tab-stop tweak prevents some larger numbers overlapping:

I didn't like how when I had a mad number of cargo contracts going that the amounts for Gold/Platinum/Gems could almost overlap with the for sale amount.

So I edited Market Observer's Tab stops for displaying that page...
It's in the gui-settings.plist file inside Config folder. (Have to unzip the OXZ first to access this!)

I changed from:
"market_tabs" = (0,101,227,307,326,431);

"market_tabs" = (0,101,227,287,326,421); 

Market Aide

Here is a 2008 description from the Dark Ages before Spara's Market Observer. Spara first wrote MarketAide OXP in 2012 which merely posted the minimum, average & maximum prices for each commodity (taken from the OoliteRS sheet which came with your original game download). He then developed Market Observer the next year which creates the min/avg/max prices dynamically based on the markets you have personally visited. There was also a brief flirtation with a Troomp.oxp (see SothisTC for details)!

Quick Facts

Version Released License Features Category Author(s) Feedback
3.7 2020-10-12 CC BY-NC-SA 4.0 Statistics Equipment OXPs Spara Oolite BB

Gameplay and Balance indicator


No difference to combat or that sort of thing, but goodness... this little OXP unlocks the markets and trading for you. Unbelievably helpful and informative. A "must" for every new player.