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Posts from the ‘Astronomy’ Category

11
Jul

Comet C/2020 F3 NEOWISE the July 2020 Surprise

This has been quite a year. Now, add to this a bright new comet, and it gets a little better, yes? Comet C/2020 F3 NEOWISE: Named after the Wide Field Infrared Survey Explorer’s asteroid hunting mission [https://neowise.ipac.caltech.edu/], this comet has become visible to the unaided eye, and, for now, is a morning object rising just before the Sun in the northeast sky. By the week of July 13th, the comet will be more of an early evening object, and it should also be getting fainter as it heads both away from Earth and the Sun.

Weather here in New Hampshire is not forgiving to astronomers. In July we typically have high humidity and heat. Add to that some vertical temperature instability, and thunderstorms will be the rule followed by wet foggy mornings once dew point is reached. We did have one clear morning this week, and that allowed for some quick imaging of comet NEOWISE. Be sure to click on the images to see in larger format.

Equipment used:

  • Nikon D-810a with 28-300mm zoom lens at 150mm at f/3.5 and Optolong L-Pro light pollution reduction filter.
  • Nikon D-810 with 300mm telephoto at f/4.
  • Tripods with slow motion controls: untracked.

Those looking to spot the comet should bring with them a pair of binoculars and the information provided in this article from Sky & Telescope. Be sure to find a viewing location away from ground fog, and with a low horizon.  A Bright New Visitor: How to Spot Comet NEOWISE [https://skyandtelescope.org/press-releases/new-bright-visitor-comet-neowise/]

Comet C/2020 F3 NEOWISE Comet C/2020 F3 NEOWISE Comet C/2020 F3 NEOWISE Comet C/2020 F3 NEOWISE Comet C/2020 F3 NEOWISE Comet C/2020 F3 NEOWISE

12
Mar

A 360 Degree Tour of the 0.7m Dome

The new 0.7m telescope dome is up and running at Phillips Exeter Academy. There is still some serious testing to do in order to prove out the various bits and pieces that all have to integrate together: mount control, focus control, heaters, fans, pointing models, dome control, linking dome to the telescope, imager and filter wheel control. We’ve had a couple of clear nights, and thus far everything seems to be working. Below are two 360 degree tours of the building. One is a view from the control room. The other is from the dome. Be sure to use your mouse to look around the images by clicking and dragging. You can also zoom in and out. Enjoy!

18
Jan

A Wide Field Orion Taking on Taurus

Winter is the Orion time…. time to get a wide field camera taking snaps of the winter sky. Here is a wide field frame of Orion with his nemesis, Taurus the Bull. This was a process-image of seven 15-second exposures at f/3.5 28mm, ISO10000, with automatic dark frame subtraction using a Nikon D810a on a tracking mount. Post processing was done in PixInsight to stack the images using median combine, flatten the background, correct color, then crop and save off as a JPG with the correct histogram. Some graininess was removed in Photoshop in the end.

This shows Orion with its definitely-fading Betelgeuse (upper left shoulder), the Orion Nebula, The Barnard Loop, The Rosette Nebula, Sh2-264 (Lamda Orionis Ring) and NGC2175 (upper left).   Click on the image for full size.

Wide field view of Orion and Taurus 2020-01-18

Wide field view of Orion and Taurus 2020-01-18

An annotated image is below. Once again, click on this to see full scale.

Orion annotated

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):