Astronomy with MicroStation Local Coordinate Frame

By | November 22, 2019

Here we are going to learn about one of the simplest coordinate frames in observational astronomy and as any observation process involves
it has two components the observer which we can see here and the observed which will be presented to the observer on a screen and that screen is going to be a sphere at the center of which the observer stands so everything in the universe the stars, galaxies, planets, nebulae … everything would be projected onto the screen so
the observer can see them this is called as a celestial sphere and
we’ll be presenting it with this circle now at no point of time the observer can see the whole celestial sphere He or she can see only half of it and that is limited by the horizon in the best possible conditions
everything above the horizon will be seen but nothing below the horizon will be observable then we are going to established a few
points the first point is called zenith. It is right above the observer on the celestial sphere and then let’s establish north maybe we know how to find north using pole star or maybe we have a GPS or a compass or we ask the next person and once we know north we can also put down where is south, west and east then we are going to look at a star but as you know we’re not going to look at
the start directly but we are going to look at the projection of that star on our screen so here is the protection of the star as it appears on the celestial sphere and on the sphere we are going to draw an arc which will start at the zenith pass through the star and we will continue that till it meets the horizon so this is the arc over here and this arc is going to subtend an angle so this angle will be measured from the horizon to the star so this angle called as altitude represents how far up the star is in the sky but that alone is not sufficient to know the position of the star because there are going to be many celestial objects which are at the same height for example everthing on this circle will have the same angle of altitude and therefore to nail it down we need
something more so let us have another angle here which will be measured from the north in the eastward direction till we hit this plane this is called as the azimuthal angle let us label it and these two angles together will be able to specify pinpoint anything in the sky so this is the local coordinate frame and it uses two angles – azimuth an angle measured from north towards the east til we hit the plane of the star and then we go up through the angle of altitude and we see the image of the star Let’s recap the whole thing but this time in color So we start with the observer who is surrounded by the celestial sphere which is divided into two halves by the
horizon. Only the upper half is seen In the upper half we have we have the highest point called as the zenith Then the north point is established from which east, west and south can be figured out and we start observing a star To do that we draw an arc passing through the zenith the star till it meets the horizon and then we measure the angle of altitude which represents how far up the sky is the star and then we measure another angle to pin it down which is major from north in the easterly direction till we hit the plane of the angle of altitude this is called as the azimuthal angle So together azimuth and altitude can pinpoint any location in the sky This is the local coordinate frame.

46 thoughts on “Astronomy with MicroStation Local Coordinate Frame

  1. Ashutosh kothiwala Post author

    Sir, your teaching fabulous… Each clg n school teacher should teach like this…

  2. AurorasDawn Post author

    This is absolutely wonderful. Very clear and coherent. Thank you.

  3. Ujjwal Suryakant Rane Post author

    @AurorasDawn The whole observational framework and their effects are so beautifully geometric and visual, that it was a pleasure to turn them into this clip. Glad you liked it and thanks for the feedback!

  4. Ujjwal Suryakant Rane Post author

    @gjmsbg So good to hear that! Thanks for extending this to your students. Yes, the duration is deliberate 🙂 I try to keep it 'byte sized' for easy consumption.
    Also, please let me know of topics you might like to see on this channel. If I know enough about it, I can create some clips for your class.
    Once again thank you for stopping by and sharing this with your class.
    – Ujjwal

  5. Ujjwal Suryakant Rane Post author

    @Dominic Borg Thank you! 🙂

  6. Ujjwal Suryakant Rane Post author

    @LubieKanapke Glad you liked it. Thanks for watching!

  7. Phillip Bassignani Post author

    Very well done. Thanks for clearing up how azimuth plays into pin pointing the celestial object. Do you always measure azimuth from north towards east?

  8. Ujjwal Suryakant Rane Post author

    @Phillip Bassignani North is more common reference direction, but other directions (among them south being more common) and other direction of measurement (CW or CCW) are also used. The provision for all these possible choices is in MicroStation too. So some of the Engineering applications must be using these variations.

  9. Ujjwal Suryakant Rane Post author

    @Tanzim Kawnine Thank you for watching and sending in the feedback! Glad you liked it.

  10. engman6 Post author

    Thank you for the very informative explanation.

  11. Roger Mori Post author

    I have downloaded MicroStation to learn Astronomy modeling but found mostly Civil/Mechanical engineering material.  Could you recommend a learning path to draw astronomical diagrams with MicroStation?

  12. Daniel Holley Post author

    Very good video! I used it explain some fundamentals of auditory localization to a classmate.

  13. Khalil Parkar Post author

    thank you for making the concept clear…well done Sir

  14. Quantumme Post author

    Thank you very much for making this video. Can you plz make one about Sidereal time with examples?! Thank you.

  15. Ravi Sharma Post author

    How can i calculate my Lat Long using Trilateration method and without using GPS device??
    how can i know coordinates of satellites?

  16. Ravi Sharma Post author

    can we find the coordinates of a satellite using this method?

  17. PRATEEK GARG Post author

    Sir your way of explaining things is very good.Please also explain Theory of Relativity in such a good manner.

  18. Rahul Gopi Post author

    Its really good sir, can I ask you to upload a video on the complete Solar Radiation Geometry.



  20. Architeuthis Dux Post author

    I was just looking at some Azimuth watches to buy, but curiosity took me here. Glad I learnt something interesting today. Thanks for a comprehensive and well presented video.

  21. Neelim Barman Post author

    Sir plzz inform us 'bout the application you're using in pc?

  22. Aditya Post author

    Thanks a lot sir. I have Semester exams of Survey 2 in 5 hours ahah just studying this theory chapter which has Azimuth Zenith, Celestial Stars, Gis, GPS, remote sensing..

  23. Rutuja Koli Post author

    A tedious thing explained in such word, thank u so much! That was really helpful.

  24. Prasanna Post author

    Hi Mr Ujjwal, how beautifully you explain the concepts! Hats off sir!

  25. That Guy Post author

    So, the earth is flat. Got it. How does a person stand inside the "molten iron core" to make these plane Euclidean geometry illustrated?
    Flat plane geometry =flat plane earth. Spherical sky. Celestial sphere.

  26. That Guy Post author

    North is ALWAYS 0°. South is ALWAYS 180° from north. Always.
    That means no south pole.

    If there were a South pole, upon crossing the equator into the southern hemisphere, south would become 0° and north 180°. For the same reasons North is 0 in southeast 180 in the northern hemisphere of a globe.

    To be oblivious of this fact while describing it is a testament to the brainwashing and cognitive dissonance. Sorry. . . not sorry.


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