* Supermoon lunar eclipses are uncommon. * The visible difference can be up to ~14%, and its significantly brighter too.
But viewing the moon on the horizon will get you a bigger apparent size difference, no supermoon needed.
Let's coin 'superdupermoon' for the 1% case.
And ... so what? As http://science.nasa.gov/science-news/science-at-nasa/2011/16... points out:
> Okay, the Moon is 14% bigger than usual, but can you really tell the difference? It's tricky. There are no rulers floating in the sky to measure lunar diameters. Hanging high overhead with no reference points to provide a sense of scale, one full Moon can seem much like any other.
About once a year Jupiter is in opposition. Should we call that a "super Jupiter"?
Within 90% of perigee, yes.
> it happens for about 10% of all eclipses.
Hayley's comet is visible for 100% of its orbits. It's passing is still a rare event because it happens typically once in a lifetime. A supermoon lunar eclipse will happen maybe half a dozen times in yours. It's an uncommon event.
> And ... so what?
If you're not interested, you're not interested. I don't like the term supermoon either. But it's interesting to me that the difference is measurable. Photographing the full moon at perigee and apogee and measuring the difference is my kind of fun.
Again, remember that you were being a devil's advocate. My "so what?" comment was mean to highlight the weakness of your counter-argument. It's not actually significantly naked-eye brighter but requires instruments to measure. Now you've jumped to something outside of the role that you've assigned yourself, because you switched to talking about 'your kind of fun' and using instruments to help with your fun. That's a very different topic than what you started with.
Saying "X is an uncommon event" does not, on its own, justify or explain anything. There are millions of rare events every day. Should we celebrate when Jupiter is at perihelion? That's only once every 11.86 years. What about when Mars is in aphelion? 67P/Churyumov-Gerasimenko was at perihelion on 13 August 2015 - did you celebrate?
Here's an example I shot two full moons ago: https://www.flickr.com/photos/aaronbrethorst/20189872605/in/...
The moon looks absolutely monstrous here, but, I expect that if I had measured it when it was high up in the sky, the actual apparent size wouldn't have been any different.
>A simple way of demonstrating that the effect is an illusion is to hold a small object (say, 1/4 inch wide) at arm's length (25 inches) with one eye closed, positioning it next to the seemingly large Moon. When the Moon is higher in the sky, positioning the same object near the Moon reveals that there is no change in size.
