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15
Jan

Betelgeuse is Fading

There has been a lot of buzz on the net about the star, Betelgeuse, Alpha Ori… the red supergiant in Orion’s shoulder (or armpit as people might prefer). It is a well known, bright red, supergiant, and it is a well known variable with a long period. Of late, it has been fading rather unusually for its regular patterns of ups and downs in brightness. This fading has everyone charged up…. you see, the star is old, near the end of its life. Stars of this high mass are supposed to supernova… BOOM! The trick is to know when. We have little idea on that, so any changes seen in stars like this make us get realllllly focused. Below is a snap of the latest observations of Betelgeuse’s brightness in V taken from the AAVSO. You can go see this data for yourself at www.aavso.org, and entering “Alfa Ori” sans quotes into the “Pick a star” field on the lower right of the page. Select plot light curve after that.

AAVSO V filter light curve of Betelgeuse

AAVSO V filter light curve of Betelgeuse

Where is Betelgeuse located? Here’s a chart as seen from mid northern latitudes tonight at 9:00pm

Orion

Orion with Betelgeuse as it would appear at 9:00pm from mid-northern latitudes tonight (January 15)

4
Dec

How to Observe a Meteor Shower

Whenever the major yearly meteor showers show up on our calendar, I am often asked:

  • How do I observe a meteor shower?
  • What’s the best place to go?
  • What is the best time to observe?
  • Do I need a telescope: also, is your observatory open?

Here is some helpful information to help you plan out your meteor shower observing event.

Best Methods:

Look up!  That is all there is to it for the vast majority of meteor showers. You need to lie down and look up! Keep your field of vision away from obstructions (trees, houses, etc). At a minimum keep your vision aimed at 45 to 60 degrees above the horizon.

I recommend bringing a blanket, a sleeping bag, some snacks and warm drinks to help you stay safe, comfortable and awake. A lawn chair helps to keep you off the moist ground.

You do not need any optical instruments. Meteors streak across the sky as the small particles disintegrate in our atmosphere. These quick streaks of light will cover some 10 degrees or much more. Now, there are some telescopic meteor showers. There is a lot to be said about doing science with the use of a wide field instrument like a pair of binoculars or a rich field telescope. My recommendation is that if you are new to observing showers, then keep the telescopic meteor showers in your back pocket until you have some experience with what to expect and some of the science behind it all.  More info about this can be found here: Telescopic meteor observing (external link to Society for Popular Astronomy).

Location:

The very best piece of advice is this: go to a place that is far away from city and town lights. Nothing (except the weather) causes more interference to meteor shower observing than lights. Stay away from them. Period.  This includes your own lights that you might bring with you: Flash lights? No. Cell phones? No. Candles, lanterns? No. This also includes lights you cannot control: the moon, aurora or zodiacal light.

During the summer, avoid low lying areas that get foggy in the late hours (near swamps, rivers, etc). This also helps reduce your being bothered by mosquitoes.  Bring and use DEET. During the winter be sure you can get to a place of safety and warmth when you are done. Make sure that your car battery works well before driving to a remote site! You don’t want to get stuck some place in the cold and typically away from good cell phone reception.

If your observing takes you to some place unknown: scope it out first. If it’s on private property, get written permission to observe from that location.  Tell people where you are going.

Best sites are fields away from trees which block some of your view.

Time:

Meteor showers happen when the planet Earth orbits through debris left behind by comets and asteroids in their orbits around the Sun.  The side of the Earth that faces the same direction as our orbital path is on the morning side of the planet…. so the best time is very typically after local midnight until the morning dawn. This makes showers tricky for little kids and those who have to get to work the next day!

Other Thoughts:

Do you wear bifocals or multifocal glasses? Change them out for distance-only glasses if you can. All the stars in your entire field of vision should be in focus at once.

Bring a friend or two: that way you can see more of the sky and share the event. It also allows you to keep each other awake! Start with a pot-luck supper and turn it into an event.

Keep reasonable expectations: Not all showers have huge cataclysmic appearances… in fact those huge shower events are rare. Astronomy enthusiast calendars will post a tidbit of information for you: the Zenithal Hourly Rate. This ZHR is an estimation of how many meteors you could expect to see from the shower on the night of the shower’s peak under perfect observing conditions. Rarely will you see anything close to that value.

Geminid Meteors

An outburst of Geminid Meteors in 2009 taken with a wide field lens in a time exposure (Credit NASA/JPL).

More Information (links to external sites):

3
Dec
2019 Geminid Shower

2019 Geminid Meteor Shower

One of the best meteor showers of the year is rapidly approaching. Peaking on the night of December 13/14, the Geminids put on a good show with peaks averaging at 120 meteors per hour. Now, with the moon being just past full that night, many of the fainter meteors will be drowned out by moonlight. Don’t be discouraged, though: we still expect to see some 30 meteors per hour. The best time to watch? After midnight, usually around 2:00am is best, but you can start seeing them after 10pm easily enough. Gemini will be high in the sky, and the night time side of Earth will be heading into the meteor stream.

The source of these meteors is from asteroid 3200 Phaethon, named after the son of Helios… Phaeton swings very close to the Sun in its orbit, being one of the Apollo asteroid members. Does it pose a threat to Earth? Not for the next 400 years or so, which is as far as our high-level orbital analysis shows. The asteroid has a 30 year orbit… so maybe in the distant future we might have to worry about this one.

2019 Geminid Shower

Looking east at about 9pm local time, the constellations Orion and Gemini will be well above the horizon. Alas, the moon will also be in Gemini and just past full phase. Rather than looking at the moon-lit Gemini, look straight up and all around in the sky for the Geminid meteors.

9
Nov

Safe Solar Observing

Looking at the Sun directly is dangerous: it will damage your eyes. You need to use approved optical systems to view the Sun, both with and without telescopes or binoculars. I highly recommend that you work with a local astronomer or a local astronomy club to get set up with the equipment you need in order to do the kind of observing you wish.

In brief, all optical systems, like telescopes, binoculars, monoculars, spotting scopes, and the like, require that you place a solar filter in FRONT of the system’s light collecting opening (the objective). You do not want unfiltered sunlight to enter your optics, as this will likely damage your optics as well as your eyes. Some small refractor telescopes can be used to project unfiltered sunlight onto a white board. DO not do this with large telescopes or with reflector telescopes or catadioptrics.

DO: 

  • Use certified solar filters. Companies like Baader (https://www.baader-planetarium.com/en/solar-observation.html) make excellent solar film for covering telescope optics.
  • Make sure that the filters cover the front of your telescope’s system, the opening where the light goes in.
  • Make sure that the filters cannot come loose and fall off the telescope when in use. Tape the filters on for protection!
  • Ask for help from someone who has done this before. Better safe than blind.
    Project the sun’s image onto white paper or board, but only with a SMALL refractor. This can damage larger telescopes, like SCTs and such. When in doubt – don’t.
  • Use Welders Filters shades 13 or 14. While #12 is also safe, it is not too comfortable. These can be placed in front of your eyes when looking directly at the sun. These are not for use with a telescope or other optical aids.

and….

  • DO NOT Use random glass filters or lenses that have been marked as solar filters. Many are not safe! This includes stacking old exposed film.
  • DO NOT Place filters at the eyepiece of the optical system: they will burn and break!
  • DO NOT Expect solar glasses to protect you from harm when using them with binoculars. They will burn and you will be hurt!
  • DO NOT Use skin sunscreen in your eyes. This does not work. Yes, people have done this. Don’t.

Other links:

Sky & Telescope Safe Solar Observing
https://www.skyandtelescope.com/observing/celestial-objects-to-watch/safe-solar-observing/

1
Aug

The 2019 Perseid Meteor Shower is Here!

The Annual Perseid Meteor Shower

Each August, the Earth passes through a stream of comet debris from Comet 109P/Swift-Tuttle.  The comet will not be back our way until 2126… so… I wouldn’t wait up for that one.  Along the orbital path, the comet has left behind small bits and pieces, most no bigger than a grain of sand. These run into our planet’s atmosphere and burn up due to friction. The result of this friction-filled reentry is a meteor, a rapid streak of light through the sky.  This shower usually gives us about 60 meteors per hour at peak, and many fireballs: bright meteors that can even be bright enough to cast a shadow.  How to see it?

  • Pick a clear night closest to the peak, which is on August 11th/12th/13th.
  • Go to a dark sky site: avoid lights and cities. The darker, the better.
  • Bring something comfortable to lie down on: sleeping bags are good.
  • Bring food, drink, and bug spray if needed for your location.
  • Spend the night time hours looking up at the sky! No optics required other than your eyeballs.
  • Avoid lights!  No cell phones. No flashlights. Your eyes take between 30-60 minutes to become dark adapted, and you lose that dark adaptation instantly if you see a light. Avoid lights!
  • The shower appears to come from a spot in the sky in the constellation Perseus. This rises just before midnight, so best observing will be after that, into the morning hours.
  • Have fun!