I wonder how Daylight Savings Time affects the casting natal charts.

Based on my understanding, anyone born after DST has been applied will have to subtract one hour to align their view of the stars, and anyone born after DST has been readjusted will have to add one hour.

For example if standard/solar time 2h = sidereal time 2h, and DST gets applied, then standard/solar time 3h = sidereal time 2h. All hours after that will have one hour discrepancy, so we cannot cast charts by the previous model anymore. We need to use the 3h st = 2h sid model now.

Larxene wrote:I wonder how Daylight Savings Time affects the casting natal charts.

Based on my understanding, anyone born after DST has been applied will have to subtract one hour to align their view of the stars, and anyone born after DST has been readjusted will have to add one hour.

For example if standard/solar time 2h = sidereal time 2h, and DST gets applied, then standard/solar time 3h = sidereal time 2h. All hours after that will have one hour discrepancy, so we cannot cast charts by the previous model anymore. We need to use the 3h st = 2h sid model now.

Of course the DST has to be considered in a chart calculation - and it is.

This is why it is so important to know, whether a given time, a birth time for example, is with or without DST, otherwise you would indeed get a wrong chart.

DST is changing the time shown on the clock - but not the time zone.
The time zone remains the same whereas only the time is changed within the same time zone.

because sidereal time is local for that place whereas standard time or DST applies to a much wider area.

http://www.skyandtelescope.com/howto/ba ... 04611.html

PD