Celestial Navigator for September 2015

Supermoon Rising
Supermoon Risin September 3 – Neptune at Opposition. The blue giant planet will be at its closest approach to Earth and its face will be fully illuminated by the Sun. It will be brighter than any other time of the year and will be visible all night long. This is the best time to view and photograph Neptune. Due to its extreme distance from Earth, it will only appear as a tiny blue dot in all but the most powerful telescopes.

September promises lots of exciting night sky activity – ideal for camping and stargazing.  The first half of this month will bring us great views of Mercury and Neptune, a new moon, and a partial eclipse!  During the latter half of the month, the September (autumnal) Equinox occurs, and the fall Supermoon – also known as the Harvest Moon. Perhaps most exciting of all – a total lunar eclipse for North America at the end of the month.

  • September 4Mercury at Greatest Eastern Elongation. The planet Mercury reaches greatest eastern elongation of 27 degrees from the Sun. This is the best time to view Mercury since it will be at its highest point above the horizon in the evening sky. Look for the planet low in the western sky just after sunset.
  • September 13New Moon. The Moon will located on the same side of the Earth as the Sun and will not be visible in the night sky. This phase occurs at 06:41 UTC. This is the best time of the month to observe faint objects such as galaxies and star clusters because there is no moonlight to interfere.
  • September 13Partial Solar Eclipse. A partial solar eclipse occurs when the Moon covers only a part of the Sun, sometimes resembling a bite taken out of a cookie. A partial solar eclipse can only be safely observed with a special solar filter or by looking at the Sun’s reflection. The partial eclipse will only be visible in southern Africa, Madagascar, and Antarctica. (NASA Map and Eclipse Information)
  • September 23September Equinox. The September equinox occurs at 08:21 UTC. The Sun will shine directly on the equator and there will be nearly equal amounts of day and night throughout the world. This is also the first day of fall (autumnal equinox) in the Northern Hemisphere and the first day of spring (vernal equinox) in the Southern Hemisphere.
  • September 28Full Moon, Supermoon. CNlBALCWEAAoIbUThe Moon will be located on the opposite side of the Earth as the Sun and its face will be will be fully illuminated. This phase occurs at 02:50 UTC. This full moon was known by early Native American tribes as the Full Corn Moon because the corn is harvested around this time of year. This moon is also known as the Harvest Moon. The Harvest Moon is the full moon that occurs closest to the September equinox each year. This is also the second of three supermoons for 2015. The Moon will be at its closest approach to the Earth and may look slightly larger and brighter than usual. This will be the closest full moon of the year.
  • September 28Total Lunar Eclipse. A total lunar eclipse occurs when the Moon passes completely through the Earth’s dark shadow, or umbra. During this type of eclipse, the Moon will gradually get darker and then take on a rusty or blood red color. The eclipse will be visible throughout most of North and South America, Europe, Africa, and western Asia.
excerpts from seasky.org

Celestial Navigator – June 2015

How to Photograph the Moonjune-2015-full-moon

If you own a DSLR or a point and shootwith an optical zoom, I’m sure that every once in a while you see a beautiful moon and you think about taking a picture of it, especially when the moon is full and beautiful. There are other times when you spot a news announcement about a Lunar Eclipse and you think about capturing the moment, but do not know how to do it right. Or you want to capture the moon together with a foreground object such as a house or a lone tree, but the picture is not coming out right because the moon is much smaller and looks like a white blob. If you had any of these situations or simply want to find out how to take a picture of the moon with a digital camera, then this guide is for you.

1) Why does the moon look smaller in pictures?

Before we start talking about how to take a picture of the moon, let’s first answer some basic questions. I’m sure if you have already attempted to take a picture of the moon, you probably ran into a problem where the moon looks tiny in comparison to what you saw while taking the picture. Why does the moon get photographed so much smaller? The simple answer is – you are probably taking a picture of the moon with a wide-angle lens. Keep in mind that your eyes are like a 50mm fixed lens and if you are taking a picture with a wide-angle lens that is shorter than 50mm, the moon will be captured in smaller size! So, if you want to capture an object like a big tree or a house with the moon, you would need to stand further away and photograph the scene at least at 50mm to try to match what you saw with your eyes. And even at 50mm the moon might look smaller, especially if it was near the horizon when you took a picture of it. This also happens because of a phenomenon called “Moon Illusion“, where the moon appears bigger to your eyes, when in fact it is not.

2) Why do I see the moon as a white blob?

If you have taken a picture of the moon after sunset and it looked in the picture like a white circular object rather than the moon, it is because the moon was overexposed. When you take a picture of the moon with other objects around it (as in the example with a tree above), your camera by default will meter, or calculate the exposure, based on everything but the moon. This happens because the moon is too small in comparison with the objects around it and a single spot of light should not affect the overall exposure of the picture. Think of it as a light bulb – if you take a picture of a dimly lit room with a visible light bulb, the room will be exposed normally, while the light bulb will be overexposed. If the camera measured exposure on the light bulb, the room would be completely dark, while the light bulb is properly exposed. The same thing happens with the moon – it works just like the light bulb at night and it will always be overexposed. During the day, however, this is not a problem, because the amount of light coming from the moon would differ only slightly in comparison with the objects around it, including the sky. So, why do our eyes see everything normally, while a digital camera cannot? That’s because our eyes and our brain can see a much broader range of light. In photography terms, this is known as “dynamic range“.

3) Where and when to photograph the moon

Obviously, you should be taking a picture of the moon on a clear night with no clouds in the sky. Even a thin layer of clouds will make it impossible to get a clear picture of the moon, so absolutely make sure that the sky is clear. Pollution in large cities, especially in hot summer days will also play a big role, so I recommend getting out of town and traveling to a remote location with no light or air pollution, preferably at a higher elevation. The less the distance between you and the moon, the better the pictures. In terms of when to photograph the moon, take a look at this US Navy Moon Phases page, where you can find out what phase the moon is currently in and you can also calculate what it will be by picking the date from the bottom of the page. As for the time of the day – any time works, as long as the moon is visible.

4) Required equipment – Camera and Lens

  1. A DSLR camera with a 200mm+ telephoto lens or a point and shoot camera that has an optical zoom capability.
  2. A stable tripod.
  3. Remote camera trigger (optional). If you do not have one, a timer in your camera will also work

If you want to enlarge the moon and show the details of the moon surface, a good telephoto lens longer than 200mm is almost required. The longer the lens, the better. If you have a telephoto lens that can take teleconverters, I highly recommend adding a teleconverter to increase the overall focal length. For example, a 1.4x teleconverter will increase the focal length of a 300mm lens by 40% or to 420mm total, while a 2.0x teleconverter will increase the focal length of the same lens to 600mm. The only thing to keep in mind, is that teleconverters negatively impact image quality and decrease the maximum aperture of the lens, so if you had a 300mm f/4 lens, it would essentially become a 420mm f/5.6 lens (which is not that big of a deal, because you will be using higher apertures for moon photography anyway). As the focal length is increased, camera shake can also become a big problem. At long focal lengths of 300mm and above, even a slight move can screw up the picture. That’s why if you are using a telephoto lens, a stable tripod is required to be able to produce a sharp image of the moon. Having a remote camera trigger also helps reduce the camera shake and if you have a Mirror Lock Up (MLU) feature in your camera, you can almost completely eliminate all vibrations.

The best setup for moon photography is an astro-telescope with a camera mount. Basically, you mount a digital camera to a telescope, which works as a long telephoto lens. But those setups can get very expensive and are suited best for dedicated astrophotography.

5) How to photograph just the moon

To photograph just the moon by itself, without any objects in the foreground, you will need a long telephoto lens like explained above to magnify the moon and try to fill as much of the frame as possible. Even with a good telephoto lens setup though, you will most likely be cropping the final image, simply because only a telescope would be able to provide enough magnification to fill the entire frame. With your telephoto lens mounted in your camera, secure it on a tripod and point at the moon. Make sure that your tripod is good and stable enough to accommodate and hold your lens and your camera. When it comes to shutter speedaperture and ISO, here is what I recommend for general use:

  1. Camera Mode: Set your camera mode to full Manual Mode.
  2. ISO: Set your ISO to 100 if you have a Canon DSLRand to 200 if you have a Nikon DSLR (basically, whatever base ISO you have in your camera). For most other brands, the base ISO is also 100. If you have a point and shoot camera, see if you can find a menu setting to set your ISO to 100. Make sure “Auto ISO” is turned Off.
  3. Aperture: Set your aperture to f/11.
  4. Shutter Speed: Set your shutter speed to 1/125 on cameras with base ISO 100, and to 1/250 on Nikon DSLRswith base ISO 200.
  5. Lens Focus: Set your lens to manual focus(either through a switch on the lens or on the camera) and set your focus to infinity. Be careful while setting the focus to infinity, as some lenses allow focusing beyond infinity. On more advanced DSLRs such as Nikon D300, there is a handy feature called “live-view with contrast detect”, which can accurately acquire focus on distant objects. I have used it many times for my moon photography and it works great! If you do not have such a feature in your camera, then try setting your lens to the center of the infinity sign, then take a picture and see if it came out sharp by zooming in the rear LCD of the camera.

Examples:
Nikon D90 DSLR: ISO 200, Aperture f/11, Shutter Speed 1/250.
Canon EOS Rebel XSi: ISO 100, Aperture f/11, Shutter Speed 1/125.

The above aperture and shutter speeds are derived from a Sunny f/11 rule, which is not necessarily very accurate for moon photography. I recommend starting with the above settings and adjusting the shutter speed based on the brightness of the moon. If it is too bright, set your shutter speed to a higher value. If it is too dim, set your shutter speed to a lower value. You can also play with aperture, but be careful, as changing the aperture to a small number can actually soften the image, while increasing the aperture to a very high number would mean slower shutter speeds. Remember, the moon moves pretty fast, so you definitely do not want to be photographing it with a slow shutter speed (certainly not below 1/100 of a second), especially when using a long telephoto lens.

Another thing I recommend doing is bracketing your shots. When I was taking a picture of the full moon, I noticed that some parts of the moon came out overexposed, while other parts were underexposed. I couldn’t get a perfect shot to properly expose all areas of the moon, so I decided to try taking multiple shots of the moon, then merging them into HDR in Photoshop. To my surprise, the result turned out to be better than expected – the first image in this article was done that way. If you do not want to do an HDR of the moon, I still recommend to bracket the exposures – in worst case scenario, you will keep the best photo and delete the rest.

Lastly, for those who have long telephoto lenses longer than 400mm, you might be able to use “Aperture Priority” mode instead of “Manual“, as long as you set your metering to spot metering. At 400mm and above, the moon fills enough of the frame to be able to use modes other than manual.

6) Why photograph the moon?

So, why would one want to photograph the moon? I was asked this question several times before and my answer is simple – because we only have one moon and it is beautiful, so why not? The moon also makes the otherwise boring night sky look more interesting and can add a sense of enigma to a picture. While photographing the moon by itself might be somewhat boring, including the moon as an element of composition can yield great results. In addition, there are moon phases (crescent to full) that give even more opportunities for various compositions. And lastly, why not experiment with something new and learn how to photograph bright objects at night? It is definitely a lot of fun, so get out and shoot some moon pics! 🙂

June Calendar of Night Sky Events

  • June 2Full Moon. The Moon will be located on the opposite side of the Earth as the Sun and its face will be will be fully illuminated. This phase occurs at 16:19 UTC. This full moon was known by early Native American tribes as the Full Strawberry Moon because it signaled the time of year to gather ripening fruit. It also coincides with the peak of the strawberry harvesting season. This moon has also been known as the Full Rose Moon and the Full Honey Moon.
  • June 6Venus at Greatest Eastern Elongation. The planet Venus reaches greatest eastern elongation of 45.4 degrees from the Sun. This is the best time to view Venus since it will be at its highest point above the horizon in the evening sky. Look for the bright planet in the western sky after sunset.
  • June 16New Moon. The Moon will located on the same side of the Earth as the Sun and will not be visible in the night sky. This phase occurs at 14:05 UTC. This is the best time of the month to observe faint objects such as galaxies and star clusters because there is no moonlight to interfere.
  • June 21June Solstice. The June solstice occurs at 16:38 UTC. The North Pole of the earth will be tilted toward the Sun, which will have reached its northernmost position in the sky and will be directly over the Tropic of Cancer at 23.44 degrees north latitude. This is the first day of summer (summer solstice) in the Northern Hemisphere and the first day of winter (winter solstice) in the Southern Hemisphere.
  • June 24Mercury at Greatest Western Elongation. The planet Mercury reaches greatest western elongation of 22.5 degrees from the Sun. This is the best time to view Mercury since it will be at its highest point above the horizon in the morning sky. Look for the planet low in the eastern sky just before sunrise.
*excerpts from photographylife.com and seasky.org

Celestial Navigator – May 2015

The night sky tonight and on any clear night offers an ever-changing display of fascinating objects you can see, from stars and constellations to bright planets, often the moon, and sometimes special events like meteor showers. Observing the night sky can be done with no special equipment, although a sky map can be very useful, and a good beginner telescope or binoculars will enhance some experiences and bring some otherwise invisible objects into view. You can also use astronomy accessories to make your observing easier. Below, find out what’s up in the night sky for the month of May.

Monday, May 18, 12:13 a.m. EDT New Moon

The moon is not visible on the date of New Moon because it is too close to the sun, but can be seen low in the east as a narrow crescent a morning or two before, just before sunrise. It is visible low in the west an evening or two after New Moon.

Monday, May 25, 1:19 p.m. EDT First Quarter Moon

The First Quarter Moon rises around 1 p.m. and sets around 2:15 a.m. It dominates the evening sky.

Thursday, May 17, evening twilight

This is the best evening apparition of Mercury this year for observers in the northern hemisphere. Use Venus to help you locate it. Mercury is most easily located by sweeping with binoculars, but once you’ve located it, you should be able to see it with your unaided eyes.

Wednesday, May 20, 8:06–8:35 p.m. EDT.  Double shadow transit on Jupiter

The shadows of Io and Ganymede will be on opposite limbs of Jupiter, while the moons Io and Callisto will be central on the disk.

jupiters moons

Friday, May 22, 10 p.m. EDT Saturn at opposition

Saturn will be in opposition to the sun. Note how most of Saturn’s moons are in the same plane as the rings, except for Iapetus, whose orbit is tilted 8.3 degrees. At opposition, Iapetus is close to maximum elongation towards the west, while Titan is close to maximum elongation towards the east.

Wednesday, May 27, 10:01 p.m.–12:18 a.m. EDT Double shadow transit on Jupiter

The shadow of Io chases the shadow of Ganymede across the face of Jupiter, catching up with it and passing it at 11:48 p.m. EDT. The Great Red Spot will also cross Jupiter’s disk during this period.

Planets

Mercury is well placed for northern hemisphere observers in the evening twilight sky for the first three weeks of May.

Venus shines high in the western sky after sunset.

Mars moves from Aries to Taurus on May 3, too close to the sun to be visible.

Jupiter is well placed in the evening sky all month.

Saturn is just north of Scorpius’ “claws.” At opposition on May 22, it is visible all night.

Uranus rises just before the sun in Pisces.

Neptune is in the eastern morning sky in the constellation Aquarius.

Skywatching Terms

  • Asterism: A noteworthy or striking pattern of stars within a larger constellation.
  • Degrees (measuring the sky): The sky is 360 degrees all the way around, which means roughly 180 degrees from horizon to horizon. It’s easy to measure distances between objects: Your fist on an outstretched arm covers about 10 degrees of sky.
  • Visual Magnitude: This is the astronomer’s scale for measuring the brightness of objects in the sky. The dimmest object visible in the night sky under perfectly dark conditions is about magnitude 6.5. Brighter stars are magnitude 2 or 1. The brightest objects get negative numbers. Venus can be as bright as magnitude minus 4.9. The full moon is minus 12.7 and the sun is minus 26.8.
  • Terminator: The boundary on the moon between sunlight and shadow.
  • Zenith: The point in the sky directly overhead.

Night Sky Observing Tips

  • Adjust to the dark: If you wish to observe faint objects, such as meteors or dim stars, give your eyes at least 15 minutes to adjust to the darkness.
  • Light Pollution: Even from a big city, one can see the moon, a handful of bright stars and sometimes the brightest planets. But to fully enjoy the heavens — especially a meteor shower, the constellations, or to see the amazing swath across the sky that represents our view toward the center of the Milky Way Galaxy — rural areas are best for night sky viewing. If you’re stuck in a city or suburban area, a building can be used to block ambient light (or moonlight) to help reveal fainter objects. If you’re in the suburbs, simply turning off outdoor lights can help.
  • Prepare for skywatching: If you plan to be out for more than a few minutes, and it’s not a warm summer evening, dress warmer than you think necessary. An hour of observing a winter meteor shower can chill you to the bone. A blanket or lounge chair will prove much more comfortable than standing or sitting in a chair and craning your neck to see overhead.
  • Daytime skywatching: When Venus is visible (that is, not in front of or behind the sun) it can often be spotted during the day. But you’ll need to know where to look. A sky map is helpful. When the sun has large sunspots, they can be seen without a telescope. However, it’s unsafe to look at the sun without protective eyewear. See our video