For those of you that don't like reading math, please feel free to skip to the bottom for my TL:DR version of the post.
Ok, How will Eclipse affect my DPS?
Please Note: Most of the assumptions I made in part one will apply to this post as well. The one exception is to my 5th assumption. For this section I am assuming that you have the [Idol of the Shooting Star] equipped when casting both Starfire and Wrath to maximize the Starfire Eclipse buff.
It is difficult to assign Eclipse a concrete value. Given it's random nature it is impossible to nail down an exact DPS rotation to measure it, and when it does proc the buff might be wasted due to fight mechanics. So, the number I am presenting in this section are kind of a best case scenario.
There are 5 steps to providing a value to eclipse.
1. We need to determine how long our Precasting period will be and how much damage we will do during it. We can determine the average number of Wrath casts it is going to take to proc the Starfire Eclipse using the following formula:
# of Casts to proc = 1 / (proc rate * crit rate) orSince it is highly unlikely that you will see the buff proc before your casting your next spell I will assume a 1 spell cast buffer. This will increase the number of Wrath's cast by 1 and reduce the Buff period by Wrath's casting speed.
# of Casts to proc = 1 / (0.60* 0.35) = 4.7619 Casts
So our Casting Time and Damage for the Precasting period looks like this:
Avg # of Wrath's = 4.7619 +1 = 5.7619
Avg Wrath Cast time = (((1.5/1.17) * (1 - 0.35)) + 0.35) = 1.1833 seconds
Avg Wrath Damage = ((((588 + (2000 * 0.6714)) * 1.13)*1.0712)*(1-0.35))+((((588 + (2000 * 0.6714)) * 1.13)*1.0712)*2.09 * 0.35) = 3228.77 damage
Precasting period cast time = 5.7619 * 1.1833 = 6.8181 seconds
Precasting period damage = 5.7619 * 3228.77 = 18603.85
2. Now we need to determine how long our Buffed period will be and how much damage we will do during it. The Duration of the eclipse buff is 15 seconds, but I am assuming that we will cast one Wrath before we recognize that we have the buff. So the buff's duration is reduced by Wrath's cast time of 1.1833 seconds. Also remember that Damage is calculated at the end of spells cast. Therefore I will ignore any partial casts and round down to the nearest number of whole Starfire casts.
So the numbers for the Buffed period look like this:
Avg SF Cast time = (3 - (0.5 * 0.68)) / 1.17 = 2.2735 seconds
Avg # of Buffed SF casts = (15 - 1.1833) / 2.2735 = 6.077, rounded down to 6 casts.
Avg SF Damage = ((((1285 + (2000 * 1.2)) * 1.1)*1.0712)*(1-0.68))+((((1285 + (2000 * 1.2)) * 1.1)*1.0712)*2.09 * 0.68) = 7560.48 damage
Buffed period cast time = 6 * 2.2735 = 13.641 seconds
Buffed period damage = 6 * 7560.48= 45362.88
3. The combination of the Precasting period and the Buffed period are what I call the Eclipse Rotation. So lets combine the values from the previous two steps.
Eclipse Rotation cast time = 6.8181 + 13.641 = 20.4591 seconds4. Now that we have the DPS of the Eclipse rotation we need to compare it to what we would be casting otherwise. Once again I am ignoring DoTs and assuming that they don't need to be refreshed. Therefore, the only other DPS options are Wrath Spam or Starfire Spam.
Eclipse Rotation damage = 18603.85 + 45362.88 = 63966.73 damage
Eclipse Rotation DPS = 63966.73 / 20.4591 = 3126.57 DPS
The average DPS of Wrath Spam can determined using information from step 1 above and the average normal Starfire DPS is also listed above.
Avg Normal Wrath DPS = 18603.85 / 6.8181 = 2728.60 DPSTherefore, the Eclipse rotation increases DPS by:
Avg Normal SF DPS = 2556.78 DPS
Value of Eclipse Rotation (Comp w/ Wrath) = (3126.57 - 2728.60 ) / 2728.60 = 14.59% DPS increase5. The above numbers ignore the cooldown, so we need to determine what portion of our total casting rotation is taken up by the Eclipse rotation. We already know that the Eclipse rotation will last 20.4591 seconds on average. The total casting rotation is the sum of the precasting period minus the buffer cast, plus the 30 second cooldown.
Value of Eclipse Rotation (Comp w/ SF) = (3126.57 - 2556.78 ) / 2556.78 = 22.29% DPS increase
Total Casting Rotation Duration = 30 + (4.7619 * 1.1833) = 35.6348 secondsSo,
Eclipse Rotation "Up Time" = 20.4591 / 35.6348 = 57.41%
Value of Eclipse (Comp w/ Wrath) = 14.59% * 0.5741 = 8.38% DPS increaseAs I said before these numbers are a best case scenario. In actuality the will be significantly smaller. This is because you will have to refresh dots and you will miss some of the buffs due to movement and such. However, even if the benefit is cut in half you're still talking about a 4% to 5% increase in DPS from 3 points in Eclipse.
Value of Eclipse (Comp w/ SF) = 22.29% * 0.5741 = 12.79% DPS increase
Edit: Down Ranking Eclipse A couple of people have asked in the comments that I value Eclipse point for point. I won't detail the math because it is really just repeat of the math above with a change in a variable. However, please know that I have used the same approach to come up with these numbers.
In the math above I showed that an Eclipse rotation is a 12.75% DPS increase over a normal Starfire rotation and a 8.45% increase over a normal Wrath rotation if you put a full three points into Eclipse. Please remember that these numbers were calculated under ideal circumstances.
If you put just one point in Eclipse it will increase your DPS by 11.27% over Starfire and 6.42% over Wrath. With two points in Eclipse it will increase your DPS by 12.31% over Starfire and 7.83% over Wrath.
This means that mathimatically you can receive 75% to 90% of the benefit of Eclipse from just 1 point. This is because of the 30 second cooldown. It has a greater impact on determining when Eclipse procs then your Crit chance.
Personally, I will proably still put 3 points into Eclipse, eventhough those last couple of points will have a much smaller impact then the first point. I will do this for two reasons. First, there isn't a great talent to put the points into. I would love to pick up Gale Winds but It is hardly necessary. Second, I want to cut down on the randomness. Eclipse is already very dependent on the RNG and I want to reduce some of that impact.
The Eclipse buff is very powerful buff. In an ideal situation it can improve your DPS by up to 12%. However the ideal situation is near impossible to achieve, but even if you miss half the buff your still increasing your DPS by close to 6% for a 3 point investment.
This indicates that Eclipse is a must have talent for raiders. However, you don't have to invest a full three points into the talent. You can receive a majority of Eclipse's value by spending just one point on the talent. However, Eclipse is already a very random talent, and for that reason I recommend investing 3 points to reduce that randomness.