May 23, 2017

Astro-Vid of the Week: An Amazing Grazing Occultation

Going, going…

Credit Stellarium

What a difference a few 100 meters can make. On the night of March 5th, 2017, the waxing crescent Moon occulted the bright star Aldebaran. This event was well placed for North American viewers… heck, it even occurred over the weekend on a Saturday night, to boot. We even managed to dodge social obligations to briefly duck outside with our trusty 15x 45 image-stablized binoculars to watch Aldebaran wink out behind the dark limb of the Moon. [Read more...]

Astronomy Video Of the Week: An Occultation Weekend

 

Beta Capricorni (arrowed, click to enlarge) moments before it was occulted by the Moon on October 12th, 2013. (Photo by Author).

After a rainy Florida summer, our astronomical fortunes finally changed this past weekend. Two fine bright star occultations graced our skies on Friday night and Saturday evening. These are always fun “now-you-see-it, now-you-don’t” kinds of events to witness, as the Moon abruptly covers a distant star. Grazing events can be especially dramatic, as starlight can be seen winking in and out along the valleys along the lunar limb in a dramatic fashion. And some real science can be gathered by such events as well, as close double star companions can reveal themselves as the star lingers and winks out in a step-wise fashion. [Read more...]

AstroEvent: See Mercury at its 2011 Morning Best.

Never seen the planet Mercury before? This coming week offers a good time to try, as the inner-most world undergoes its best morning apparition for northern hemisphere viewers. The tiny world reaches a greatest elongation of 18.1° degrees west of the Sun on September 3rd at a brightness ranging from about -1 magnitude to 0.0 on the dime. [Read more...]

Astro-Event: Will the 2011 Perseids Perform?

A classic summer astronomical standby may be in trouble this year, but that shouldn’t stop you from looking. That’s right, we’re talking about the Perseids, the “old faithful” of meteor showers that gets northern hemisphere residents bundled up and out under the summer stars every mid-August.

[Read more...]

AstroEvent(s): Of Occultations & Daytime Stars.

Mekbuda Occultation from Tampa, Florida. (Created by Author in Starry Night). 

This week brings with it an interesting double-double header. First up is a challenge that comes to us via the Royal Astronomical Society of Canada … sure, you’ve seen Venus near the daytime Moon, and perhaps you’ve caught Jupiter low at opposition just prior to the setting of the Sun… but did you know that it’s possible to catch some of the brightest stars while the Sun is still above the horizon? Right around the first full week of April is a good time to give this a try; your assigned quarry is Sirius in the pre-dusk, and Vega in the post-dawn. Both of these stars are in the negative magnitude range and might just be visible from a pristine site with good seeing. In the case of Vega, a fun project would be to acquire it before sunrise and follow it into the daytime skies either visually or with an equatorial tracking telescope. Sirius, although brighter at magnitude -1.5 may be tougher; in this instance, finding the star in relation to a nearby landmark a day prior at dusk and then trying to acquire it before local sunset may work. I once successfully caught Jupiter in the daytime in this fashion, near opposition from the arming-end of runaway in Kuwait back in 1998. Good luck, and we’ll be attempting this feat of visual athletics right along with you!

But wait, there’s more… this week also sees the waxing crescent Moon pass through some interesting star fields in the constellations Taurus and Gemini. The result is a series of interesting stellar occultations; 1st, on the evening of April 7th, the Moon skims the Hyades cluster and occults Upsilon and Kappa Tauri for viewers in western North America. Kappa is of particular interest as it is a very close (0.1”) double. Even if you aren’t in the target zone, the crescent Moon+Hyades= a good photo op. Three days later, we US east coasters get a shot with an occultation of Zeta Geminorum, otherwise known as Mekbuda. This is another bright star around magnitude +4.0. Mekbuda is also a Cepheid variable with a period of 10.2 days, one of the brightest in the sky. Watching this star wink out and then reappear should be a good replay of last month’s Mu Geminorum occultation… the action for the US East Coast centers around ingress at 9:21 PM EDT and an egress of 10:35PM. The occultation extends up to a graze line cutting across the Canadian Maritimes… good luck, and watch this space for a video after-action clip if successful!      

The astro-term for this week is Transparency. In terms of astronomy, transparency is the ability for light to pass unhindered through the atmosphere. Pollution, dust, and aerosols all act to scatter light and dim objects. You can have clear skies, but poor, washed out transparency. Generally, the higher and drier you are, the better transparency will be, as evidenced by a deep blue daytime sky and an inky black nighttime sky. This is also an all important factor in success in daytime star-spotting as discussed above.  Transparency is rated 1 to 10, with 10 being the absolute best, and is closely tied with seeing, or the resolution ability based on atmospheric turbulence. I’ve had clear skies and decent transparency after a storm front, only to have poor seeing as the convective cells rolled before my eyepiece!   

20.03.11: An Occultation Update.

Mu Geminorum ingress…(Photo by Author).

This Super-moon Sunday, we’d just like to give a brief self promotional shout-out to an astronomical success we had last weekend. Last Sunday we managed to catch the occultation of the 4th magnitude star Mu Geminorum by the waxing gibbous moon from Astroguyz HQ here in Hudson, Florida; [Read more...]

AstroEvent: A Lunar Occultation.

Path of Sunday night’s lunar occultation. (Created by the author Using Google Earth & Paint).

Lunar occultations can be fun events to observe. As the moon continues its 27+ day long path around our planet, it sweeps out a 0.5 degree wide path and occasionally covers up a distant background star or planet. Such occasions can be fun events to observe, as the star winks out and later seems to pop back into existence from behind the lunar limb. Such an event occurs this Sunday, the night of March the 13-14th, as the waxing crescent Moon occults the semi-bright star Mu (µ) Geminorum.  [Read more...]