Happy New Year to all. Observed a "monster" flare of Iridium 30 at 22:40:51 UT on Jan 1. Iridflar predicted mag -8.2. The event was spectacular to say the least. I now will search for the "perfect flare". Criteria include: 1. Dark sky - no moon. Need I mention a clear sky? Sun at least -10 deg elevation. 2. Minimum distance to Iridium. Needing a zeneth pass at perigee. Although the orbits are nearly circular, the 15 km should make a few tenths of magnitude difference. Last night's Iridium 30 flare came close. There was a cresent moon low in south-west, but the sun was -18 deg, and sky clear. The max flare was at elevation of 49 deg, this put the distance at 995 km. This makes consideration of perigee/apogee unimportant. I was predicted to have a flare angle of only 0.02 deg. Centerline would have put me in dense forest! My questions are: 1. What is the consensus opinion on trying to move to better location (ie flare angle 0.00) My understanding is that attitude constraints of the sat are such that anything less than flare angle 0.05 is acceptable, and within the "error window" of actually being perfect. 2. Can someone calculate the effect on magnitude of a 15 km difference in distance? In fact examination of a list of Iridium elsets (Dec 31) indicates the following: 1. Iridium 21 has the highest eccentricity at 0.0013. Perigee 628 km, apogee 647 km. 2. Almost all the so far launched Iridiums have perigees in the 770's (km). There ARE a few exceptions. Specifically: Ir 21 628 Ir 27 554 Ir 45-49 665-669 range Now, this is far more variation than the typical 4-5 km per/apo range of the sats with almost circular orbits. Therefore flares of Irid 21, 27 and the 45-49 group have the greatest potential magnitude. Let us therefore calculate the difference of, say, Ir 27 vs a typical Ir both at perigee. Brightness wil vary with inverse square of distance. I calculate a 1.97 difference!! If the absolutely typical Ir 30 can produce a -8.2 at 995 km range then Ir 27 should produce, for an optimal pass, the distance difference produces a brightness difference of 3.25. Given the brightness difference for a one magnitude change is 2.5, then the flare be in the -9.5 range. It would seem that observing the right satellite, rather than peri/ apo considerations is most important! I wonder why those Iridiums have different orbital parameters than the rest of the fleet? Finally, there has been some discussison on how to accurately measure the magnitude of the monster flares. The eye fails, it has no standard of reference with which to compare. Perhaps a CCD camera could do the job. I know that variable star observers can get extremely accurate magnitudes using these devices. In closing, and I apologize for the length of this post, my son's comments on seeing the flare last night were comical. "Wow, what is that?- an anti-vampire weapon? Steve Bolton Lat 45.432 N Long 65.976 W