If it wasn’t for the bright moon, you’d be able to see the new nova with the naked eye even from the suburbs. But who knows? By tonight it could bust that barrier.
Last night Nova Delphini was magnitude 4.8 and still brightening. Richard Keen of Colorado saw it shortly before 2 a.m. this morning at 4.4. Already it’s some 10 times brighter than only two days ago at the time of its discovery. That puts it in the top 35 in recorded history!
I took a photo of Delphinus and the nova last night and annotated it with additional star magnitudes so you can watch it fluctuate in brightness in the coming nights. The smaller the number, the brighter the star.
Astronomers use the magnitude scale to measure star and planet brightness. Each magnitude is 2.5 times brighter than the one below it. Deneb in the Northern Cross, which shines at 1st magnitude, is 2.5 times brighter than a 2nd magnitude star like the North Star, which in turn is 2.5 times brighter than a 3rd magnitude star and so on. A first magnitude star is 2.5 x 2.5 x 2.5 x 2.5 x 2.5 (about 100) times brighter than a 6th magnitude star, the typical naked eye limit under dark skies.
The larger the magnitude, the fainter the star. If something is very bright, its magnitude is a negative number. Vega shines at 0 mag. while Sirius, the brightest star, sparkles at -1.4 mag. Venus is brighter yet at -4.4. Click HERE for more information about star magnitudes.
Keep an eye on the nova’s color. Right now it’s still in its explosive fireball phase and appears yellow through a telescope. That could change over the coming weeks as it either brightens or fades. Some novae turn a lovely pink. No matter what’s in store, you’ve got a front row seat as long as you have a good pair of binoculars and star chart. Go for it!
If you want the latest estimates of Nova Delphini’s brightness, go to aavso.org and type in N Del 2013 in the Star finder box, then click “Check reecent observations”.