Good day to you all, I could be asking too much here. I’m someone who prefers to understand formulas by deriving them from own made scenarios. In this case I was trying to derive the time dilation Lorentz formula using my own made up example and I wanted to know if I'm on the right track here. Here’s my scenario: Observer A, Observer B and a photon are all standing in the same position. Right at t = 0, Observer B moves with a velocity vB and the photon with velocity c, both in the same direction. Observer A stands still. From this scenario I wanted to show that after a Δt, both Observer A and Observer B would calculate the speed of the photon as c. I’ve done this by starting like this: From Observer A’s perspective, he would calculate the velocity of Observer B as in which DB is the distance made by Observer B with respect to A and tA is the Δt for Observer A at which he calculates the speed of Observer B. Also from Observer’s A’s perspective, he would calculate the velocity of the photon as in which the DcA is the distance made by the photon with respect to A and again, tA is Δt for Observer A at which he calculates the speed of the photon. Also, Observer A would calculate the speed of the photon with respect to Observer B as: However, Observer B would still calculate the speed of the photon as c by using: In which DcB is the distance made by the photon with respect to Observer B and tB is the Δt at which Observer B calculates the speed of the photon. Before I’m continuing this, I’d really like to know if this example is even suitable at all for deriving the Lorentz formula regarding time dilation and if so, am I going the right way with this or not?