Market Open Scan Limitations

[TPTrades]

Good Evening,

I wanted to start a discussions on scanning for longer time frame candles at market open from the transition when markets opens from the pre market. I’m using a scanner that spots trend reversals right at market open. I have been noticing that my scanner is not picking up the first candle right at the trend reversal of market open but will pick up the second candle with the trend reversal at the market open. My question is are their limitations for using aggregates using the non extended to the extended hours right at market open or is their a way to remove these limitations. Has anyone experienced this?

 

[Joshua]

scanning for longer time frame candles at market open

Most likely, you're using a time frame larger than what divides evenly into market hours. I am not sure which, so take the Hourly time frame for example: The first hourly candle will open at 9:00. Thinkscript doesn't really recognize time. There's just the 9:00 bar and then the 10:00 bar, etc.

The script you're using is probably looking for the time to be greater than or equal to 9:30. This condition won't be true until the 10:00 bar, which is why it perceives the second bar as the open.

It will still do this even with extended hours off due to there being 30 minutes out of place. The "start aggregations at market open" setting isn't available in scans, that only works on charts.

There are potential work arounds, like using every 2nd 30 minute bar to recreate an Hourly scan, but it's highly situational as to whether that would be practical or not.