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Could anyone tell me what the names of the Greek letters in the screenshot are? Is the first one alpha? They are used in calculating ICRF rotations. Wikipedia uses a different font for their list of characters, so it's hard to tell.

enter image description here

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    $\begingroup$ Orientation models use three Euler angles to describe body orientation. The first two angles are the right ascension and declination of the north pole of a body as a function of time. The third angle is the prime meridian location (represented by "W"), which is expressed as a rotation about the north pole, and is also a function of time. $\endgroup$ – Mick Sep 21 '18 at 8:23
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    $\begingroup$ …and yes, those letters are an alpha ($\alpha$) and a delta ($\delta$). $\endgroup$ – pela Sep 21 '18 at 8:24
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    $\begingroup$ Do you want the names of the Greek letters or the quantity it stands for? $\endgroup$ – user1569 Sep 21 '18 at 9:18
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    $\begingroup$ This is a reminder to everyone involved to be polite when correcting each other. $\endgroup$ – called2voyage Sep 21 '18 at 12:37
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    $\begingroup$ I'm voting to close this question as off-topic - it really does just look like a request for the greek alphabet. $\endgroup$ – Rory Alsop Sep 24 '18 at 14:26
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The first one is alpha (α); the second one is delta (δ). You can study the shapes of the letters here:

https://en.wikipedia.org/wiki/Greek_alphabet

Here's what they mean (information from a comment to your question):

Orientation models use three Euler angles to describe body orientation. The first two angles are the right ascension and declination of the north pole of a body as a function of time. The third angle is the prime meridian location (represented by "W"), which is expressed as a rotation about the north pole, and is also a function of time.

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    $\begingroup$ Thanks. The Wikipedia article is the first place I looked. But they use a sans serif font in that article instead of the serif font used in the screenshot I posted as well as here on SE. Delta looks very different, for instance. $\endgroup$ – posfan12 Sep 25 '18 at 1:26
  • $\begingroup$ @posfan12 Sure thing. $\endgroup$ – Alphecca Sep 25 '18 at 1:45

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