<p>If your local sidereal time is 05h 55m 10.30536s, then Betelgeuse is on the meridian. The local sidereal time is always equal to the right ascension of a point on the meridian.</p>

CC BY-SA 4.0
2023-02-28T05:35:59.343Z
2023-02-28T05:35:59.343Z
Pierre Paquette
<p>If I'd like to watch star like Betelgeuse that has coordinates - right ascension 05h 55m 10.30536s and declination +07° 24′ 25.4304″.</p>
<ul>
<li><p>If my local sidereal time is 05h 55m 10.30536s does it mean that Betelgeuse crossed my meridian?</p>
</li>
<li><p>And if I want to track it with right ascension on the telescope I can define it as <code>LST - RA of a star</code> take this number and put it on the RA axis of a telescope and see a star?</p>
</li>
</ul>

CC BY-SA 4.0
2023-02-28T14:13:24.290Z
LST - RA is better known as the "Hour Angle" of an object. It is 0 when the object is on the meridian, and increases for every hour of RA past that time.  https://en.wikipedia.org/wiki/Hour_angle
Greg Miller
<observational-astronomy><telescope><amateur-observing>
Right ascension of a star and local sidereal time
pacman
# Right ascension of a star and local sidereal time

(Asked by: username_0 on 2023-02-28)

If I'd like to watch star like Betelgeuse that has coordinates - right ascension 05h 55m 10.30536s and declination +07° 24′ 25.4304″.

* If my local sidereal time is 05h 55m 10.30536s does it mean that Betelgeuse crossed my meridian?
* And if I want to track it with right ascension on the telescope I can define it as `LST - RA of a star` take this number and put it on the RA axis of a telescope and see a star?

**Tags:** observational-astronomy, telescope, amateur-observing
> **Comments:**
> **username_1**: LST - RA is better known as the "Hour Angle" of an object. It is 0 when the object is on the meridian, and increases for every hour of RA past that time.  https://en.wikipedia.org/wiki/Hour_angle  

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## 1 answers

### Answer by username_2 on 2023-02-28. Score: 3 | Accepted answer

If your local sidereal time is 05h 55m 10.30536s, then Betelgeuse is on the meridian. The local sidereal time is always equal to the right ascension of a point on the meridian.


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