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Re: APOD: Moonbow Beach (2014 Sep 06)

Posted: Wed Sep 10, 2014 1:31 am
by Rogelio Bernal
After double-checking my files, I can confirm that the time I took the picture was not around 3am but midnight. I relied on the EXIF data of the image files, and only yesterday figured that the time in the camera was still PDT (where I live). This means that back in June, if the EXIF says 3am, local Hawaiian time was three hours earlier. This puts the Moon near 30 degress above the horizon (looks about right in the 360 panorama image I posted the other day), and the stars are where they're supposed to. Apologies for any confusion my oversight may have caused.

In retrospect....It's very easy to lose track of time at a beach in Molokai after midnight :ssmile:

Re: APOD: Moonbow Beach (2014 Sep 06)

Posted: Wed Sep 10, 2014 2:08 am
by geckzilla
Antony can give himself a pat on the back, now. :wink:

Re: APOD: Moonbow Beach (2014 Sep 06)

Posted: Wed Sep 10, 2014 2:49 am
by Nitpicker
In the first few minutes of 17-June-2014, in Hawaii (UT-10.0), the waning gibbous Moon (~75% illuminated, 4 days past full) was below 20° elevation, having been up for less than an hour and a half. The Moon would have been around 30° elevation at 1 am. (Note that Hawaii doesn't observe daylight saving.)

Edit: But the difference between PDT and HAST is indeed 3 hours. And based on the elevation of the visible stars in Leo, the local time must have been midnight.

Re: APOD: Moonbow Beach (2014 Sep 06)

Posted: Sat Sep 20, 2014 5:28 am
by abhagwat
Would like to show you a photo of a sun-bow!

All of us have seen rainbow, moon-bow, glory, etc. But a sun-bow? This photo was taken by my friend Saee Nair in Melbourne on a cold July 2014 morning.

Interesting, is it not?

I hope APOD will display this photo soon on the NASA APOD website.

Thanks!

Anuradha Bhagwat

Re: APOD: Moonbow Beach (2014 Sep 06)

Posted: Sat Sep 20, 2014 6:05 am
by alter-ego
abhagwat wrote: All of us have seen rainbow, moon-bow, glory, etc. But a sun-bow? This photo was taken by my friend Saee Nair in Melbourne on a cold July 2014 morning.
My experience is that a moon bow is a much less common event than what you've photographed, which appears to be a fairly common 22° halo. It's not a "bow" as in a rainbow or moon bow because they are seen when the light source is 180° from the arc's center (i.e. back lit wrt to the observer). A halo is viewed with the source in front of the observer at 0°, or at the center of the arc/circle.

Atmospheric Optics is a great website for all kinds of atmospheric phenomena. They have picture of the day too. A good halo picture might land there more so than here.

Edit:
I thought I'd add a bit more information about "sunbow". Wiki describes the sunbow as a circumzenithal arc (CZA). Atmospheric Optics also has nice pictures and discussion of the CZA. Although rare, the "sunbow" occurs near the zenith, but never completes a full circle and always when the sun is low in sky, i.e. never centered on the sun. A sunbow appears as an upsidedown rainbow.

Halos appear as circles around the sources, e.g. Sun and Moon. Their colors typically are red to pastel, but do not contain reds greens or blues (unlike the CZA which shows all colors). The reddish color is in the inside (sharp edge towards the sun) as your picture also shows.

Your picture shows all the attributes of a standard halo and It appears to be of the 22° type. Unfortunately, you have not captured a "sunbow" (CZA) but a nice picture for sure.