Astronomy Cafe – Jan 17, 2022

Posted by as Astro Cafe

Transcript video of the meeting

Meeting notes

  • A Woman of Astronomy – Marji Welchframe
    • Urania, Muse of Astronomy
    • Seal of the RASC – “Quo Ducit Urania” (i.e. where Urania leads, we follow)
    • Urania is 1 of 9 Muses of the Arts in Greek Mythology
    • Uranometria star atlas by Johann Bayer (1603) – published and sold by Sky & Telescope (Willman Bell section)
  • Early computer memories
    • LGP-30 tube-based computer used at the University of Alberta in Edmonton by John McDonald in 1958
    • Reminisces from various members about early computers, calculators, slide rules, and other computing devices and programming languages they used decades ago.
  • Lunar Puzzles – Randy Enkin
    • 100-piece from NASA
    • 1000+ piece from Cobble Hill
    • 1000 piece from Four Point
    • 3-D printed Moon puzzle – Randy and his daughter assembled it
  • Reports  from Lauri Roche
    • 2022 RASC Calendars have still not arrived
    • Sky Cultures of the World: RASC World Asterisms Program – Charles Ennis, 1st VP with RASC National – FDAO Star Party – this Sat, Jan 22nd 7-9PM – available on Zoom and Youtube
    • Eclipses for 2023 and 2024 – Education & Public Outreach Committee task force headed by Randy Attwood. Thousands of eclipse glasses will be available and sent to RASC Centres. Members can participate on the committee – contact Lauri.
  • JWST Update – Chris Gainor
    • Mirror Segment Deployment Tracker – activating the actuators behind the mirror segments
    • JWST enters a halo orbit around L2 position this Sunday, Jan 23rd
  • Astro Cafe next week – Jan 24, 2022
    • Dr. Tanya Harrison, “a professional Martian” – our Astro Cafe speaker next week
    • David Lee will be hosting
  • Scarlett Caterpillar Club – a parasitic fungus Bill Weir found near the observatory at Pearson College

Extras

  • NASA 3D Resources – 3D models of equipment, models of celestial and solar system objects, space missions (like JWST). Various media for download: fly-throughs, interactive visualizations, 3D printer files, stereo images.

Astronomy Cafe – Dec 6, 2021

Posted by as Astro Cafe

Transcript video of the meeting

  • Review next week’s presentation by Dr. Robert Thirsk – Chris Purse
    • Connection to meeting will be through a waiting room
    • Jeff Pivnick will host
    • Link for this meeting will be unique, and emailed to all RASC Victoria members
    • Maximum of 100 attendees
  • Total Solar Eclipse from Antarctica – Joe Carr
  • Astro Compass – Randy Enkin & Peter Kabel
    • Frank Younger’s estate donated the Compass Astro to Victoria Centre
    • Used in aircraft when they are flying a long way north, where the magnetic field isn’t reliable
    • “It’s a sundial in reverse”
    • Need to know your position and time, sighting on a celestial object with known Right Ascension & Declination. North will be indicated accurate to within about 1º.
  • Edmonton Astrophotos – Dave Robinson
    • Photo of Comet C/2001 A1 Leonard near M3 cluster – Arnold Rivera
    • Sketch of Comet C/2001 A1 Leonard with observing narrative – Berta Beltran
    • Rosette Nebula photo – Arnold Rivera
  • Chris Gainor
    • James Web Space Telescope update
      • Completed fuelling operations for the JWST itself
      • To be mounted onto the Ariane 5 rocket next
      • Dec 22nd launch date
      • Launch website
    • Not Yet Imagined – Chris’ new book about Hubble Space Telescope’s history. Book should be available for sale in awhile through RASC’s e-store and FDAO’s e-store locally. Electronic versions from NASA
  • Comet C/2001 A1 Leonard – observing report by David Lee
    • Observed and photographed through some clear spots over the last few days
    • Poor conditions for photography, but managed to get a good wide field image of the comet using a dSLR and tracking mount
    • Virtual Telescope broadcast – tomorrow 8PM PST
  • Lauri Roche
    • 2022 RASC Calendars
      • Send any more requests for calendars to Lauri
      • Should be $16 each
    • FDAO e-store – astronomy and space themed fun items available for sale. Free local delivery or shipped by mail (extra cost).

Astronomy Cafe – May 31, 2021

Posted by as Astro Cafe

Video transcript of the meeting

  • CRD lighting of Galloping Goose Trail from Selkirk Water to Lochside/Borden and Spectrum School – Chris Purse & Dave Robinson
    • Dave has given CRD feedback – dark adaption is adequate, so opposed
    • Members should give CRD feedback through the online survey
  • Moving and installing Bill Almond’s observatory – Cameron Burton & Lisa Meister
    • Disassembly
    • Moving from Bill & Janet’s home
    • Installation at Cameron and Lisa’s home
    • Victoria Centre’s history with Bill Almond and reminisces from members
  • Total Lunar Eclipse – Randy Enkin 
    • Review of online photos (since we were clouded out)
    • Diameter of the Earth’s shadow is larger than expected – more to come
  • Edmonton photos – Dave Robinson
    • NGC 6946 Fireworks Galaxy – Tom Owen
    • Moon over Edmonton – Alister Ling
    • Sunspots – Arnold Rivera
  • Edmonton Centre’s new observatory – Dave Robinson
  • SIGs – David Lee

Total Lunar Eclipse – Jan 31, 2018

Posted by as Observing Highlights

Total Lunar Eclipse on Sep 27, 2015 from Victoria
Total Lunar Eclipse on Sep 27, 2015 from Victoria – photo by Joe Carr

On Wednesday, January 31st, weather willing, we will be able to view a total eclipse of the Moon. The Moon will move into full eclipse in the early hours of the morning and will be in partial phase in the western sky as the Sun rises. The Total Lunar Eclipse will develop over the course of about 3 hours. It’s a perfect opportunity to capture some snapshots of the event. Read further to find out what happens during the eclipse and how to capture it photographically.

 

 E C L I P S E   T I M E L I N E
Moon below the horizon Moon’s eastern limb enters the penumbra 2:51 am PST
Partial eclipse begins – 1st Contact Moon’s eastern limb enters the umbra 3:48 am PST
Total eclipse starts – 2nd Contact Moon entirely in the umbra;
deep orange red
4:52 am PST
Totality 5:30 am PST
Total eclipse ends – 3rd Contact 6:08 am PST
Partial eclipse ends – 4th Contact Moon’s western limb leaves the umbra 7:11 am PST
Sunrise 7:48 am PST – approximate
Eclipse ends Moon leaves the penumbra 8:09 am PST

 

What’s Happening

A total lunar eclipse occurs when the Earth comes between the Sun and the Moon. During a lunar eclipse the Moon’s position traverses the Earth’s shadow. The Moon’s first contact with the Earth’s shadow is at the outer band of the shadow called the penumbra. The light falling on the Moon is progressively blocked until at the moment of total eclipse the Moon is completely in the darkest central area of the Earth’s shadow called the umbra. At the point of total eclipse the process starts to reverse itself until the Moon is totally out of the Earth’s shadow.


Glossary

  • limb – the outer edge of the Moon
  • penumbra – the outer band of the Earth’s shadow
  • umbra – the darker central area of the Earth’s shadow
  • partial eclipse – the Moon is positioned within the penumbra
  • total eclipse – the Moon is positioned totally within the umbra
Above Eclipse times are for Pacific Standard Time (PST) for the west coast of North America, and are calculated from UT as presented in the Observers Handbook 2018, pages 126-27.

Observing Tips

What do you need?

Everything from your eyes, binoculars and telescope are suitable. Bear in mind this is a long process and at this time of year dress warmly and bring a chair if you want to be comfortable.

Find yourself a location that has a clear horizon view of the west especially if you wish to view during the late stages.

Keep a log of what you see and note the time. Pay attention to how much of the light on the moon is obscured and if there are any colouration changes. During the total eclipse the Moon will take on a deep orange-red colour. The colour of the Moon is a function of contaminants in the atmosphere and varies from year to year.


Photographic Tips

Equipment
Any camera with the capability of setting shutter speeds and aperture settings manually will do fine. The ability to use interchangeable lenses will be an advantage for more detailed images of the Moon. For the darker parts of the eclipse, eg. totality you should use a tripod support for best results. If you have access to a telescope you can try capturing the event using prime focus techniques through the telescope optics.

Settings
Today’s digital cameras are very sensitive to light reflected by the Moon. Use ISO 400 to ISO 800 and a long telephoto lens or zoom setting. Smartphones and point-and-shoot digital cameras will not produce rewarding photos of the eclipsed Moon, but can be useful for taking panoramic shots of your surroundings which include the eclipsed Moon.

Technique
The simplest eclipse pictures can be taken with manual settings on your camera and a normal lens, preferably supported by a tripod. For best results use a cable release to minimize vibration. Images taken in this fashion result in a small lunar image. This is why it is preferable to use a telephoto lens to photograph the Moon. For a 35mm camera try a 200mm lens or something close to this, even better a 500mm lens or higher. You may also use teleconvertors to increase magnification, these typically come in 1.4x and 2x strengths. Their downside is they reduce the effective aperture of your optical system. A 1.4x teleconvertor will decrease your effective exposure by 1 stop, a 2x teleconvertor will decrease your effective exposure by 2 stops. Work out your effective aperture of your optical system ahead of time so you don’t have to think about it on the night of the eclipse.

Example:

 

 Focal Length  Aperture Effective Focal Length
with 2x teleconvertor
Effective Aperture
with 2x teleconvertor
 180mm  2.8  360mm  5.6
 480mm  6.8  960mm  13.6

 

To achieve any higher magnification than what is stated above you will have to use a telescope at prime focus. For this your manual camera does need to have the capability of using interchangeable lenses. For prime focus you will use the telescope optics as your interchangeable lens. To attach your camera to your telescope you will need two things a T-adapter that fits your camera and a telescope camera adapter that fits your telescope. The telescope camera adapter is designed to fit in the focusing tube of your telescope and is threaded to accept the T-adapter of your camera. With the magnification involved with telescopic optics it is likely that you will need to use a tracking mount. Preferably the mount should be able to track at lunar speed as opposed to sidereal but if the shutter speeds chosen are shorter than 1 or 2 minutes this is not critical.

Exposure times are the next consideration. The following exposure times are based on a medium speed film and an effective aperture that would be common with a long telephoto and teleconverter combination. Exposures may vary with your equipment based on ISO speed of film used and effective aperture. The Danjon Lunar Eclipse Luminosity Scale has been included to provide better guesstimates for totality.

 

Exposure Times: based on ISO 400
Full Moon  1/250 second at f/16
1st Contact 1/125 second at f/16 see note 1.
2nd Contact 2 seconds at f/16 see note 2.
Totality
*see table below
L = 4 : 8 seconds at f16
L = 3: 30 seconds at f16
L = 2: 2 minutes at f16
L = 1: 8 minutes at f16
3rd Contact 2 seconds at f/16 see note 2.
4th Contact 1/125 second at f/16 see note 1.
* Danjon Lunar Eclipse Luminosity Scale
 L = 1 dark eclipse; lunar surface details distinguishable only with difficultly
 L = 2 deep red or rust coloured eclipse; central part of the umbra dark but outer rim relatively bright
 L = 3 brick-red eclipse; usually with a brighter (frequently yellow) rim to the umbra
 L = 4 very bright copper-red or orange eclipse, with a bluish, very bright umbral rim

 

Note 1. 1st and 4th contact times given for the partial phases are biased for the light part of the Moon. Remember you are dealing with vastly different exposures between the light and dark parts of the Moon during eclipse. The bias of about 1 stop minus avoids overexposure of the dominant bright area of the Moon.

Note 2. 2nd and 3rd contact times given for the partial phases are biased for the dark part of the Moon. The bias of about 1 stop plus is a good strategy for negative film not quite so good for slides and digital capture given they don’t tolerate overexposure well.

The exposure times are only recommendations. Remember the cardinal rule about photography … bracket. Always try exposures plus and minus your chosen exposure. This gives you a better chance at getting usable results. Let’s all hope for clear weather. If you have any questions please send email to David Lee at davidflee7331@gmail.com.


David Lee – original image and text
Joe Carr – updated for 2018
Brenda Stuart – illustrations

Total Solar Eclipse – August 21, 2017

Posted by as Observing Highlights

2012 Total Solar Eclipse aboard the Paul Gauguin cruise ship, on the totality track south of New Caledonia Nov 14, 2012 200km south of New Caledonia in the Coral Sea
2012 Total Solar Eclipse

A Total Solar Eclipse is a rare astronomical event, and it is even rarer for one to occur close to where you live. Those of us who live in the Pacific Northwest of North America will be favoured with such an event happening near us on August 21, 2017. In fact, everyone in North America is within striking distance of being able to observe this amazing event, where the Moon slides in front of the Sun for a few brief minutes, suddenly and totally obscuring the Sun.

If you haven’t observed a Total Solar Eclipse, this is your chance!

Location

The eclipse tracks across Oregon and Idaho, making it easy to get to the eclipse totality track from Victoria, British Columbia with one day’s drive. The major cities of Portland and Eugene in Oregon are obvious targets for those of us who are eclipse chasers. I-5, an Interstate highway, crosses the eclipse centreline at the city of Salem, Oregon as the eclipse tracks eastward across the U.S.A. So you might decide to stay in Portland or Eugene, but you will have to drive to the centreline, otherwise you will miss the eclipse!

NASA’s Eclipse website gives all the facts and figures required to find and enjoy the eclipse, including an interactive zoomable map showing the eclipse track.

Total Solar Eclipse 2017 track across Oregon and Idaho
Total Solar Eclipse 2017 track across Oregon and Idaho

At the intersection of I-5 and the eclipse path near Salem, Oregon, these are the characteristics of the eclipse:

Lat.: 44.803° N
Long.: 123.0318° W

Duration of Totality: 2 minutes 0 seconds

  • Start of partial eclipse (C1) : 09:05:18AM  Altitude=27.8° Azimuth=101.2°
  • Start of total eclipse (C2) : 10:17:13.0AM  Altitude=39.8°  Azimuth=116.8°
  • Maximum eclipse : 10:18:13AM  Altitude=40.0° Azimuth=117.0°
  • End of total eclipse (C3) : 10:19:13AM  Altitude=40.1° Azimuth=117.3°
  • End of partial eclipse (C4) : 11:37:50AM  Altitude=51.0° Azimuth=140.1°

Why this location? Well, if you look at the weather predictions and the track maps, you will see this location is easiest to get to from Victoria, and offers a decent chance of clear skies. Simply take a ferry to the mainland, and drive down I-5 to Oregon. This location is away from the coastal clouds, even though there is better weather available if you drive eastward through Oregon and possibly into southern Idaho. You can also seek out more scenic locales such as Wyoming, however now you will be traveling much further.

What if you can’t travel to the track of totality?

You can still see a partial solar eclipse from anywhere in North America. Use NASA’s Interactive Eclipse Map to get the calculated timing for the eclipse in the area you plan to observe from. Click and zoom to your area, then click on your observing spot to see a popup telling you how long the eclipse will last and what you will see.

Eclipse observing events in Victoria, BC, Canada – 90% coverage in Victoria

Weather map for the Total Solar Eclipse 2017 in Oregon
Weather map for the Total Solar Eclipse 2017 in Oregon

Weather

Weather always plays a big part in any solar eclipse, so being mobile is key to improving the odds of actually seeing the event should clouds threaten to obscure the Sun at the critical moment. Our very own Jay Anderson (former RASC Journal editor) is a weather expert, and specializes in forecasting weather for solar eclipses. His Eclipse website offers sage advice backed up with maps and charts depicting weather prospects for each eclipse happening in the world for the next several years. Read Jay’s analysis of the area you propose to observe from, so you understand how the weather might behave on eclipse day. Topography, elevation changes and local factors play into how the weather evolves throughout the day for a particular locale. Become a local weather expert, and you increase your chances for success!

Observing

Observing a Total Solar Eclipse is pretty easy, however that said, if you haven’t done it before, it’s nice to have experienced eclipse observers around to guide you through the process. Obviously the time of total eclipse is the main event, however other things happen beforehand, afterwards, and during an eclipse that are worthwhile.

You should try out any gear you propose to take with you before you leave. Make sure you have proper solar eclipse filters for any binoculars, camera lenses and telescopes you are bringing along. Take test photos of the Sun weeks before you leave, so you know your photo gear will work as expected. Always have a backup plan for when (not if) gear breaks, or you simply can’t get it to work properly. Remember, you only have a couple of minutes to see this event!

Finally, relax and enjoy the day. Arrive early. Try to manage your stress level. Just sit back in a reclining chair, have your solar glasses handy, and enjoy!

Safely observing a solar eclipse – read about how to safely observe a solar eclipse

DIY Box Pinhole Projector – to safely observe the eclipse with only a box and some aluminum foil!

Help!

If this will be your first time observing a total solar eclipse, no doubt you have many questions and concerns, and don’t know where to start. The resources presented here may be overwhelming. Please ask any questions you might have about eclipses at Astronomy Cafe, held each Monday evening. Your fellow RASC members have observed solar eclipses before…they can help!

Perhaps you prefer to leave it to someone else to organize for you, and take a tour. Tour organizers will ensure you are on the centreline for the event, will do their very best to seek clear skies (no guarantees though!), and will supply you with eclipse glasses and ensure you are as comfortable as possible throughout the event. Some suggestions:

  • RASC Eclipse 2017 – a scenic holiday to the midwest USA, a solar eclipse, and sponsored by RASC!
  • Sky & Telescope – overland to Nashville, seeing rockets and observatories along the way…and the eclipse
  • Travelquest – a tour company specializing in eclipses who are offering five different experiences for the 2017 eclipse

Resources

  • NASA’s Eclipse – a great starting point for information gathering and predictions
  • Eclipsophile – Jay Anderson’s weather predictions are a must to select a location that will likely have clear weather
  • Great American Eclipse – comprehensive information about this specific eclipse – where to go and what you will see
  • Eclipse 2017 – lots of home-grown advice about where to be and what to do
  • America’s 2017 Solar Eclipse – Sky & Telescope’s online resources for planning your eclipse adventure
  • MrEclipse – Fred Espenak’s guide to successfully experiencing and photographing an eclipse
  • Mr. Eclipse says west may be best… – Fred’s eclipse predictions to the Seattle Astronomical Society
  • Kendrick Astro – a Canadian astronomy dealer who sells solar filters for visual and photographic use