I have a question about market charts.?

While following a chart for the June S&P 500 emini ESM9 chart this morning (3-23-09) I noticed that on intraday charts of 5-10 minutes, the market showed an opening at around 783.50 or 783.25. However, when looking at a daily chart, the opening was indicated at 766.75–quite a difference. As of about 10:15 am the daily chart indicated a trade as low as 765.50 but none of the intraday charts had moved lower than 778.50. I checked several different charting sources and they all show the same thing. What accounts for this discrepancy and how can you get an accurate indication of the market open?

yeah, that’s why you shouldn’t look for actual values by reading charts.

charts can tell you direction and movement, but the actual values are often corrupted a bit in order to draw a line a bit easier.

just check any regular data table – "Open" is a universal stat.