The moon will be in waning gibbous phase for the next few nights. This is the view tonight with the two most prominent rayed crated Copernicus and Tycho marked. Both can be seen with the naked eye if you look closely. Binoculars make them easy catches. Credit: Patrick Chevalley, Christian Legrand / Virtual Moon Atlas
Hope you had a great look at the Harvest Moon this week. Tonight it will rise big and bright but not so round. You’ll notice a sliver missing along its western side marking the moon’s transition from full phase to waning gibbous.
The photo-map at left is a screen grab from Christian Legrand and Patrick Chevalley’s Virtual Moon Atlas, a fantastic free program for Mac and Windows.
Harvest Moon photographed on Sept. 19 from the San Luis Reservoir, Pacheco State Park in California. Credit: Kirk Bender
The atlas shows a very realistic moon with exact phase for your location, libration angle and lots of labeled features with in-depth descriptive information. The authors also offer a crazy variety of downloadable databases (Lunar Orbiter, Chinese Chang’e 2 moon data, etc.), picture libraries and different landscape textures available as add-ons. To get started, download the atlas HERE.
Prefer an atlas for your iPhone or Android? No problem. Check this list of lunar apps to find something you like.
I received several Harvest Moon photos in my e-mail the past few days. Thank you everyone who sent one! We were mostly cloudy here in Duluth, Minn. except for a short spell late last night when the sky cleared to reveal a brilliant white moon riding high in the southern sky.
Two views of the Harvest Moon from two very different locations. At left, Victor Pinheiro photographed the moon from the city of Espargos on the island of Sal, one of the Cape Verde Islands west of Senegal, Africa. The other was taken from Lynn, Mass. U.S. by Jimmy Peguero.
Twenty minutes later clouds returned, but rather than detracting from the scene, they diffracted moonlight into a set of pretty red and blue rings called a corona. Further west I was able to grab a look at the nova in Delphinus the Dolphin.
Remember the nova? It was caught in eruption on Aug. 14 and reached naked eye brightness before slowly fading to its current magnitude of 7.8-8.0. Like every nova, it’s now received a formal name – V339 Delphini, the 339th variable star discovered in the constellation Delphinus.
You can use this chart and a pair of 40-50mm binoculars to spot Nova Delphini (=V339 Del) now near 8th magnitude. That’s nearly the same brightness as the star it sits right next to. Click map for a larger version. Created with Stellarium
Bright moonlight made it difficult to get a good fix on the nova last night, so I toted out the 10-inch scope for a look. Wow! While many of you, myself included, have noticed its pink or reddish color, I’m here to report that this star is now a striking red.
Updated pic of the nova taken Fri. evening Sept. 20, 2013. Details: 100mm lens, f/2.8, ISO 400 on a tracking mount. Credit: Bob King
It reminded me of a shimmering ruby and was a close match for Hind’s Crimson Star, an amateur astronomer favorite and one of the reddest stars (if not THE reddest) in the sky.
An AAVSO chart you can use with a small telescope to follow the nova as it fades. Click for a larger version or click the link at right and download a chart. Credit and copyright: AAVSO
The color comes from the release of what’s called hydrogen alpha light. Energy from the nova explosion gets absorbed by hydrogen gas surrounding the star. Hydrogen atoms then release that energy as red light when they return to their original rest state.
Additional red light comes from dust in the star’s vicinity absorbing shorter wavelengths of light and allowing only warmer colors to pass, much like a sunset. Seeing red means seeing energy transferring hands.
While the nova was too faint to detect color in binoculars a small scope will show it well. I’ve included a brand new map you can use as well as a smaller version of a deeper map from the American Association of Variable Star Observers (AAVSO) so you can follow the star as it fades below 8th magnitude. I’d love to hear of your impressions of its color. Please take a look and let us know what you see.
The “waning” Harvest Moon and its reflection from Trieste, Italy this morning Sept. 20. Credit: Giorgio Rizzarelli
