<p>You'll need to convert local sidereal time to local time on the specific date, using the longitude of your location. This can be done with the formula described <a href="https://astronomy.stackexchange.com/q/20296/7472">here</a>:</p>

<blockquote>
  <p>$$
UT = \frac{LST - \frac{L}{15} - 6.697374558 - 2400.051336*T - 0.000025862*T^2)}{1.0027379093}
$$</p>
  
  <p>where $UT$ is the time in Universal Coordinated Time, $LST$ is the Local Sidereal Time, $L$ is the longitude, and $T$ is:</p>
  
  <p>$$
T = \frac{JD-2451545.0}{36525.0}
$$
  where JD is the Julian Date at noon UTC.  Once I've calculated the time in UT, I then add or subtract 24 until the result is within 0 - 24 hours.  Then I can convert from UT to local time.</p>
</blockquote>

CC BY-SA 4.0
2018-07-22T20:36:00.903Z
2018-07-22T20:36:00.903Z
Glorfindel
<p>Given the local sidereal time (LST) of a star when it rises, how can I find out the time when it will rise (according to my watch) on a specific date? </p>

<amateur-observing><coordinate><time>
Rising & Setting time of a star on a specific date
Arnab Chowdhury
# Rising & Setting time of a star on a specific date

(Asked by: username_0 on 2018-07-22)

Given the local sidereal time (LST) of a star when it rises, how can I find out the time when it will rise (according to my watch) on a specific date?

**Tags:** amateur-observing, coordinate, time


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## 1 answers

### Answer by username_1 on 2018-07-22. Score: 1 | Accepted answer

You'll need to convert local sidereal time to local time on the specific date, using the longitude of your location. This can be done with the formula described [here](https://astronomy.stackexchange.com/q/20296/7472):

> $$
> UT = \frac{LST - \frac{L}{15} - 6.697374558 - 2400.051336\*T - 0.000025862\*T^2)}{1.0027379093}
> $$
>
> where $UT$ is the time in Universal Coordinated Time, $LST$ is the Local Sidereal Time, $L$ is the longitude, and $T$ is:
>
> $$
> T = \frac{JD-2451545.0}{36525.0}
> $$
> where JD is the Julian Date at noon UTC. Once I've calculated the time in UT, I then add or subtract 24 until the result is within 0 - 24 hours. Then I can convert from UT to local time.


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