September 17 2018: 21P Comet Giacobini-Zinner

Posted by as Observing Highlights

From an email post to RASC Victoria on September 17 2018: 21P Comet Giacobini-Zinner

It was clear enough last night to get a quick snapshot of the comet from the driveway. I had to get the light stand out with a large sheet of black foamcore to block the streetlight nearby. Light pollution was a challenge but I was able to collect 16 one minute images and do a simple stack in Maxim DL. It’s nicely framed by the open cluster M35 just underneath Auriga, IC443 a supernova remnant in Gemini and NGC2174 a HII emission nebula in Orion. Hopefully I’ll be able to get a better shot from darker skies this week :-)

David Lee

A response from Bill Weir:

That’s really nice David. In the early morning when the comet was within M35 I took the chance and drove to the cricket pitch in Metchosin even though 90% of the sky was cloud. This is my write up of the event.

Well that was fun and reconfirmed to me the value of being prepared. Around 0030hrs PDT I was putting the dogs out and looked up and saw a clear patch of sky heading to the east. I grabbed my eyepiece case, jumped in the car and headed to the cricket pitch as the 6 inch dob had already been in the car for days. It took over an hour for the clearish patches to make their way across the sky but that was OK as it gave me a chance to collimate the scope and check out various deep sky objects along the way. Eventually the left toe of Gemini (their toe) peaked through the clouds and I was able to pick out M35 with the 15X70 binos. No comet was visible so I panned about but couldn’t make out anything. Through the scope at 38X with a 31N it was a beautiful view of M35 and NGC 2158 but no comet was visible in the area. I upped the power to 60X and focused on M35 still nothing until I began to notice a fuzziness within the eastern side of the cluster to the SE(?) of a beautiful curving chain of stars. As I advanced though 120x and then finally to 200X it became apparent this was the comet fully within this beautiful cluster! It was similar to this image except move the comet a bit down and to the left.

http://spaceweathergallery.com/indiv_upload.php?upload_id=148036&PHPSESSID=mkimbs7bfvk4n5pikdrfkqtpk3

In the end it reminded me in a way of the planetary nebula NGC 2438.

Shortly after drinking in the view clouds moved in and the show was over. It wasn’t my best comet observation by far due to low altitude in the sky and being over Victoria to the south east. That was OK though because my feet were freezing as good footwear was the one thing I neglected as I raced out the door. Drove off the field at 0215 PDT and was soon tucked in bed. Many like the phrase “make hay when you can” but I prefer,”you can’t dance at the party if you don’t show up”. This means go out even if the weather doesn’t seem optimal or you won’t see things at all.

Bill in Metchosin

President’s Message – September 2018

Posted by as President's Message, Uncategorized

I hope everyone had an enjoyable summer and had many opportunities to enjoy the night sky.

I am pleased to announce that our very own Dr. Chris Gainor was elected president of the Royal Astronomical Society of Canada at the General Assembly in Calgary. It has been 40 years since another Victoria Centre member, Dr. Alan Batten, was the national president. Please join me in congratulating Chris on his election.

The Victoria Centre had a great summer of outreach events in 2018. Thank you to all everyone who organized and participated. We had another successful season of summer star parties at the Dominion Astrophysical Observatory; there were a total of 19 well-attended Saturday evenings offered. A group of RASCals were at the Saanich Strawberry Festival with solar viewing in July. For the second year, members had their telescopes at the Fort Rodd Hill Star Gaze in August. There was an event on Pender Island on the same evening. And, there was the annual participation at the Saanich Fair over the Labour Day weekend. Some members also participated in a number of special events such as instruction and observing offered to guides and cadets. It was a busy and rewarding summer!

It was unfortunate that the Fort Rodd and Pender Island events coincided with the worst viewing conditions that I have experienced. In looking at Saturn, it was a fuzzy football-shaped object instead of its normally stunning planet with a fabulous ring. As I recall, that was one of the first evenings when forest fire smoke was in the skies above us. That really had a major impact and I am concerned that an increase in the severity of our forest fire seasons will make smoke a regular part of our summer.

With the arrival of September, we return to our normal schedule of weekly Astro Cafés starting on Monday, September 10 and monthly meetings resuming on Wednesday, September 12. As a reminder, we will be voting on our revised bylaws at the September 12 meeting.

We have another major event in September this year and that is our annual star party. It is taking place at our new venue on the grounds of St. Stephen’s Church in Central Saanich. That takes place September 7 to 9 and I hope many members are able to attend. Please see the website for the schedule.

Save the date for our Annual General Meeting on the evening of Saturday, November 17. Evening festivities include a dinner, speaker, annual awards, and election of council. We will be posting information about the meal options and cost once that is finalized.

We are now accepting nominations for the annual awards. In particular, we are seeking nominations for the Newton-Ball Award. Please see the website for details of the award and how to nominate a member to receive the award.

We will be looking for members to join the council this year. It has been a great experience for me to become part of the council and I encourage everyone, even if you’ve just joined, to consider putting your name forward. Sherry, our past president, will be coordinating the nomination process so please contact her at pastpres@victoria.rasc.ca if you would like more information and to put your name forward.

Mars Opposition 2018

Posted by as Observing Highlights

On Friday July 27th 2018 Mars will make it’s closet approach to Earth in 15 years.

RASC Victoria Centre: David Lee &emdash; The Planets at Cattle Point
Planets visible from Cattle Point – by David Lee

This occurs when Mars, Earth and the Sun are aligned with Mars located on the opposite side of Earth from the Sun. Mars will slowly rise on the eastern horizon late that evening … not the best viewing situation. A major dust storm developed on May 31st and has obscured details of the Martian surface. (see image below) Surface details will gradually re-emerge later this Summer as the dust storm subsides.

The viewing characteristics of Mars as seen from the Victoria area are tabulated below for the remaining DAO Saturday Night Summer Star Parties of the season.

Notice that the appearance of Mars (angular diameter) will decrease very slowly after the opposition. One week following opposition the angular diameter will only be 0.5% smaller but Mars will rise earlier and surface features may start to re-emerge.

Evening viewing conditions of Mars therefore will be more favourable and convenient in August.
Consider attending a DAO Saturday Night Star Party this August.
Volunteers of RASC will be there to share the night sky with their telescopes.
Click here to obtain free Star Party tickets. Note: No Star Party on July 28th.

In the Victoria area the best evening views of Mars are obtained with an unobstructed view of the southeast such as: Cattle Point Urban Dark Sky Park, Clover Point, Island View Beach, and Mount Tolmie. In the late evening Mars will appear fairly low in the southeast as an exceptionally bright red dot. It is hard to miss. Check it out.

Click here to learn more about the Mars 2018 Opposition and observing hints.
Click here to see images of the 2018 Martian Dust Storm.

 

The Surface of Mars Before and After the Martian Dust Storm (from NASA Mars Reconnaissance Orbiter)

Inaugural Transboundary Fireworks Festival

Posted by as Observing Highlights

By Reg Dunkley

On a mild July 4th evening about 10 RASCals assembled at Cattle Point Urban Dark Sky Park for the Inaugural Transboundary Fireworks Festival. Attendees were rewarded with spectacular views of two July Forth Fireworks shows. Between 10 PM and 10:15 PM Friday Harbour on San Juan Island took the stage. Terrain blocked some of the low level displays but the airborne clusters filled the field of view of most scopes. The main event occurred between 10:30 PM and 10:50 PM when Fisherman Bay on Lopez Island launched their salvo. Although slightly farther away we enjoyed an unobstructed view of the Lopez conflagration.

A variety of scopes were deployed including refractors, newtonian reflectors, spotting scopes, binoculars as well as an 8 inch Schmidt Cassegrain. In order to squeeze in the view RASCals resorted to lower magnifications. This confirmed that you do not need a big scope to enjoy the show.

It took about one minute 20 seconds for the muffled booms to arrive on the scene. This soundscape combined by the spontaneous whoops and ah’s from the RASCals added to the party atmosphere. It would have been nice if we were able to transition from the fireworks to star gazing … but clouds intervened.

Should we try again next year? Randy Atwood’s attached photo captured Chris Aesoph giving it two thumbs up! So I reckon that is a yes. It was a RASCal Worthy event.

The attention the photons received was well deserved.

Thanks to all the attendees.

President’s Message – June 2018

Posted by as President's Message

This month, I am starting with thanks for contributions to our centre.

My first thanks go to the Astro Café hosting team, Reg Dunkley, Barbara Lane, Kurt Lane, and John McDonald. Their efforts to get the room set up, coordinate presentations, and keep us fed with coffee and cookies are appreciated. Attendance at Astro Café has remained high throughout the year and I attribute that to the work of this team. In addition, I would like to thank everyone who has presented at Astro Café this year. It is impressive to have our youngest member making presentations as well as a number of new members. Well done everyone and I look forward to the resumption of Astro Café on Monday, September 10.

Nelson Walker also deserves thanks for two contributions. Nelson has taken on the modernization of our centre by-laws required by amendments to the BC legislation that governs societies. He has worked tirelessly on this document and we will be distributing the draft to members for discussion and feedback soon. Our plan is to hold a vote on adopting the new by-laws at the monthly meeting on Wednesday, September 12. In addition, Nelson brought a number of his surplus items to sell at Astro Café on May 28. He donated the proceeds to the centre’s public outreach fund. He had a great selection of gear and sold most of it. Over $400 was raised via his generosity. Thank you for those contributions, Nelson, they are greatly appreciated!

Another piece of good news is that the remaining items from the VCO have been sold. Thank you to the team members who worked on that project. I am sure the new owners will put that equipment to good use.

Later this year, we will be seeking nominations for positions on the council. Although that is some time in the future, I want to highlight this now as being on council is a great opportunity to become more involved in the centre and its operation. We rely on members who are willing to devote some of their time to the administration tasks. As you will see in the by-laws, there are some defined positions augmented by members who assist with specific tasks. The time commitment is not too onerous; the adage many hands make light work is true. In addition to the centre activities in which you normally participate, there are council meetings every second month, some duties specific to the role that need to be done on a regular basis, and occasional emails needing a response. I hope that some of members who have not previously served on council will consider it this year.

Finally, please remember that our June monthly meeting is in a different room. We will meet in the Engineering and Computer Science building room 124 for our Wednesday, June 13 meeting. As we do not have monthly meetings in July and August, our next monthly meeting will be on Wednesday, September 12.

Have an enjoyable summer!

President’s Message – May 2018

Posted by as President's Message

May has started with an incredible celebration. The Plaskett Telescope turns 100 this month and the plaque designating the DAO as a National Historic Site of Canada has been unveiled. I was asked to speak on behalf of the Centre at this event. Here is a summary of the speech I made.

In addition to the centenary of the Dominion Astrophysical Observatory, 2018 marks the sesquicentennial of the Royal Astronomical Society of Canada or RASC. Founded in Toronto by a group of astronomy enthusiasts, RASC has grown to be a national, coast to coast organization. With the addition of the Yukon Centre in 2016, the society is moving toward becoming truly coast to coast to coast.

The Victoria Centre joined the Royal Astronomical Society of Canada in 1914. Centre historians have discovered that the 1914 founding was not the first attempt by astronomy enthusiasts in Victoria to join RASC. In 1909, efforts were made to start a centre here which were unsuccessful.  However, just five years later, the effort was successful. Why was that?

I think a critical piece that was missing in Victoria of 1909 was an anchor for an astronomy group.  In the pre-information age, the success of societies such as RASC was greatly increased when there were locally available, high quality resources to support the efforts of the amateur members. Typically, this would be a research university. A university would provide faculty and staff members who might have expertise in astronomy, current publications in the library, and, perhaps most importantly, access to high quality equipment. By 1914, what had been missing in Victoria was starting to take shape.

The selection of Victoria as the home of the Dominion Astrophysical Observatory meant that Victoria became the centre of astronomy in Canada. Having a top notch research institution is the best possible support a RASC centre could hope for. Just look at the telescope that came with this observatory! No one else had anything like that. As a result, the location of the DAO in Victoria was instrumental in the founding and success of the Victoria Centre. It is likely that Victoria would not have a 104 year old RASC centre had this observatory been built somewhere else.

A particular strength of the DAO continues to be public outreach. From the very early days, the public were welcomed to look through the telescope. A centre member studying its history discovered that the DAO was a leading tourist attraction in Victoria of the 1920s; records show that more than 30,000 visitors per year came to the hill. If you ask almost anyone who grew up in Victoria, they can describe a visit to the observatory so this facility certainly made an impression. For 100 years, it has been part of the fabric that makes Victoria an outstanding place to live.

Our centre benefits greatly from our relationship with the Dominion Astrophysical Observatory. From the employees who are active RASC members to the many who volunteer to speak at our monthly meetings, we are a stronger centre because of the Dominion Astrophysical Observatory. In addition, the Victoria Centre has a larger membership that many other centres in Canada that have greater surrounding populations. I attribute some of that to the interest in astronomy that is generated by the presence of the Dominion Astrophysical Observatory.

President’s Message – April 2018

Posted by as President's Message

Our tech committee has made further progress with the upgrade to the Victoria Centre Observatory telescope. More equipment has arrived and has necessitated the installation of some different wiring in the mount. Recently, members of the committee held a work party at the VCO to make the changes.

The committee has also prepared the surplus equipment for sale. Please see victoria.rasc.ca/for-sale-observatory-equipment/ for the details of the items for sale and how to make an offer to purchase. The sale is open for the month of April. This is another step forward in the project as realized funds will be used for further purchases of equipment for the VCO.

Late last month, a few of the council members received emails from what appeared to be the president’s address. These emails asked the recipient to make an urgent payment on behalf of the centre using personal funds; a promise was made that these funds would be reimbursed by the centre within short order. This was a scam. It does go to show that the criminal element is out there looking for opportunities to defraud anyone. I mention this as a reminder to all of us to remain vigilant any time we are asked for money by email.

Here are some announcements:

RASC members may register to attend the CASCA 2018 conference that takes place May 22 – 26. See casca2018.ca/ for more information.

The Friends of the Dominion Astrophysical Observatory has launched a new website. The new URL is www.thecentreoftheuniverse.net. This is where the information about the Summer Star Parties will be posted.

The Vancouver Island Regional Science Fair is taking place on April 8 and 9 in the Elliott Building Lecture Wing at the University of Victoria. See web.uvic.ca/~virsf/index.php for more information.

Our monthly meeting on Wednesday, April 11 at 7:30 p.m. will be in the Elliott Building, room 167, as our regular room is being used for an exam.

The Science and Technology Awareness Network (STAN) helps promote science and technology education. This year, their conference is on Wednesday, April 11 in Vancouver. The conference web page provides registration and all other details, www.stanrsst.ca/stan-conference. By the way, STAN membership is free; you may be interested in joining STAN especially if you have an interest in science and technology education.

Astronomy Day will take place on Saturday, April 21. The daytime portion will be at the Royal BC Museum and the evening will be the first of the summer star parties at the DAO.  If you are not already on the list to volunteer at those events please let Ken, our outreach coordinator, know that you are available. He may be contacted at outreach@victoria.rasc.ca.

President’s Message – March 2018

Posted by as President's Message

As the spring and summer approaches, planning is underway for our annual season of outreach events. The first event of the season is Astronomy Day on Saturday, April 21 at the Royal BC Museum. We will require volunteers to help with this event including people for the information table, people to do a show and tell with telescopes and their astrophotography, and some solar viewing as well if the skies cooperate. If you have not already been contacted and wish to help out, please contact Ken (outreach@victoria.rasc.ca) to put your name on the list as an outreach volunteer.

We will be holding another season of Star Parties at the Dominion Astrophysical Observatory on Saturday evenings. The first of these evenings will be on Astronomy Day. The season will continue until Saturday, September 1 for a total of twenty evenings. Planning is underway for some special evenings including Saturday, May 5 to coincide with the 100th anniversary of first light of the Plaskett Telescope that was on May 6, 1918. Again we will need people to be on hand to direct the visitors, provide views of the sky with telescopes, and other duties. We have a contact list of volunteers but if you are not on the list already and would like to be added please contact Chris (president@victoria.rasc.ca).

The annual general meeting of the Canadian Astronomical Society (CASCA) is taking place in Victoria this year. The conference title is A New Century for Canadian Astrophysics and it will be at the convention centre from May 22 to 26. Through a special arrangement with the organizing committee, members of RASC may register to attend. The options for RASC members are a one day rate or four day rate; the early bird rates are in effect until April 6. Complete details about the meeting, including a list of invited, centenary, and education and public outreach speakers, an outline of the graduate student workshop program, and special events, can be found on the CASCA 2018 website. One of the speakers, former RASC president R. Peter Broughton, is the author of new book about John Stanley Plaskett founder of the Dominion Astrophysical Observatory. Entitled Northern Star J.S. Plaskett, it is now available from the RASC store.

President’s Message – February 2018

Posted by as President's Message

I find it fascinating that we have developed a sensationalized vocabulary about naturally occurring events. Perhaps it is the result of reality television becoming so prevalent that everything must be a challenge, a contest, the best, the brightest, the most shocking, etc. Having the recent lunar eclipse labelled with 3 different descriptors, super moon, blue moon, and blood moon, made for some interesting headlines. Are these events really deserving of these labels?

The distance between the moon and the earth does change throughout the month due to the moon’s elliptical orbit. For a viewer on earth, the apparent change in the moon’s diameter between apogee and perigee is about 13%. That does make a full moon around the perigee appear larger thus potentially brighter. But do most of us really notice without being told? Probably not. As the earth has a greatly varying atmosphere, which has a significant influence on light transmission, the amount of light from a full moon is not a reliable indicator. How many of us can recognize that a full moon is larger, or smaller, than the previous time we saw it? Photographs will show a difference but most of us do not have that sort of visual memory. Is a moon that appears to be 13% larger than at its smallest apparent diameter a difference worthy of being called a super moon? I lean toward describing it as a full moon near the perigee.

According to sources I have found, the term blue moon, when used to count full moons in a certain time period, was originally used for seasons. Most seasons have three full moons but every tenth season or so has a fourth full moon. The blue moon was the label given to the third full moon of a season with four full moons. Along the way, blue moon has become an accepted expression for the second full moon in a single calendar month. Is having an extra full moon in a month or a season, both of which are arbitrary, human-designated periods of time, significant? Why not just refer to it as the second full moon of January? By the way, March 2018 also has 2 full moons so we will have a second blue moon this year.

The term blood moon is used to describe the red-coloured moon that we see during a lunar eclipse. During the eclipse, the sun’s light is blocked from reaching the moon’s surface directly. The earth’s atmosphere scatters light, particularly in the blue-violet end of the spectrum. This means that light that has passed through the earth’s atmosphere and travels on toward the moon is primarily at the red end of the spectrum. Some of this light will end up reaching the moon’s surface and the result is a moon illuminated by light that is strongly in the red wavelengths. I’m not sure why we just don’t call it a red moon.

So, although we did not see much of the eclipse here, I hope those who did enjoyed seeing the large, red moon caused by the lunar eclipse during the second full moon of January 2018 when the moon was close to perigee. Ok, maybe saying the super blue blood moon sounds better!

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