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.


  • 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

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.

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.

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.



 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.
*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

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

Lunar “X” during 2018

Posted by as Observing Highlights

Lunar X feature - photo by Michel Michaud
Lunar X feature – photo by Michel Michaud

by Michel Michaud, RASC Victoria Centre Observing Co-chair & Librarian

The Lunar X is a claire-obscure effect in which light and shadow creates the appearance of a letter “X” on the rim of the Blanchinus, La Caille and Purbach craters. The X is visible only for a few hours before the first quarter slightly below the lunar terminator. Near the X, the lunar V is also visible, formed by Ukert crater and several other small craters.

If you never had the chance to view the Lunar X, also known as the Werner X, there are several time this year that feature could be visible from Victoria. The time predict the beginning of the event and all in LOCAL TIME.

  • 23 January 2018, 2042 (8:42 pm) – Tuesday evening event
  • 23 March 2018, 2357 (11:57 pm) – Friday evening event
  • 21 May 2018, 0002 (12:02 am) – Monday evening event
  • 19 July 2018, 2314 (11:14 pm) – Thursday evening event
  • 16 September 2018, 2332 (11:32 pm) – Sunday evening event
  • 14 November 2018, 0059 (12:59 am) – Wednesday evening event

Werner “X” observation – 2014