The Great Eclipse of 2017 is Just Around the Corner!

One of the grandest spectacles in astronomy is a total solar eclipse. On 21 August 2017 there’s going to be a stunning event, as the shadow of the moon sweeps over the continental USA from west to east. I’ve recently seen suggestions that this might be the most photographed event in history (to date) when it happens. I’ll be in there too, dear readers, making plans for many months about the chance to photograph this spectacle. The next one that will be visible over the North American continent will take place on 8 April 2014.

eclipse book cover

Alan Dyer’s ebook on the 21 August 2017 eclipse is highly recommended. You can get your own copy here: http://www.amazingsky.com/eclipsebook.html 

A total solar eclipse is, of course, a transient event in which the moon passes directly in front of the sun from the perspective of some location on earth. Because of the coincidence of the similar relative sizes of the sun and moon as viewed from earth, the moon can just about block out the central disk of the sun. A total eclipse, as the name suggests, brings the sun, moon, and earth into alignment. A partial solar eclipse consists of part of the sun’s disk being blocked.

The 21 August event will be a partial solar eclipse in southern Ontario. For observers in a band a few kilometers across running from the west to the east coast of the USA it will be total.

Preparation for watching an eclipse is a must. Not only should anyone wanting to take this in be prepared from the perspective of observation itself, safety is a crucial concern. Although the disk of the sun is blocked by the moon during these events, the sun is still producing a great deal of UV radiation from the corona, the tenuous outer layers of the sun’s atmosphere. Always wear appropriate eye protection during these events, or observe indirectly, such as with a pinhole camera you make make from a simple cardboard box. For safe eclipse observing ideas, see: https://www.space.com/35555-total-solar-eclipse-safety-tips.html

In preparation I’ve been sorting out gear, trying things, and reading up. I highly recommend Alan Dyer’s comprehensive e-book on photography of this specific event. I’m planning on using several cameras to capture different aspects of the eclipse. At least one will be running interval photos that can later be stacked to produce this sort of effect:

Solar Practice 2017

A three hour sequence of solar photographs taken at the home base of the Pine River Observatory, at Lurgan Beach, Ontario on 29 August 2017. A Nikon D7000 digital camera was set up to take photos every 30 seconds, and was equipped with a Mylar solar filter and a wide-angle lens. Every sixth resulting photo was then stacked with StarStaX. The last photo, with the sun in the trees, was taken without the solar filter. It forms a background for the otherwise rather dull individual photos of the sun.

Another camera will be set up with a long telephoto lens and a Mylar solar filter. I am not quite sure yet whether or not I will set up any camera on a telescope mount to track the sun – as this trip requires some travel, lugging such things around is always complicated.

If you are able to take images of the eclipse, consider submitting them to SkyNews Magazine, Canada’s own astronomy magazine. They’re holding a contest for the best solar eclipse photo: http://www.skynews.ca/solareclipsecontest/ 

Safe observing!

Copyright 2017 David Galbraith

 

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Looking Forward – And Up – For 2017!

There are a lot of exciting things happening in 2017. Many are covered in detail on large astronomy web sites like Sea and Sky: http://www.seasky.org/astronomy/astronomy-calendar-2017.html

Here are just a few highlights to consider.

11 February 2017 – Lunar Eclipse

Following on from the full moon earlier on the same day, the moon will pass into the edge of the Earth’s shadow for a “penumbral lunar eclipse.” We should be in a great position to see the moon darkening in Ontario.  Here’s a link to a NASA PDF on the event: https://eclipse.gsfc.nasa.gov/LEplot/LEplot2001/LE2017Feb11N.pdf

1 April 2017 – Mercury at Greatest Eastern Elongation

The tiny planet Mercury will be visible in the evening sky in early spring; on 1 April it reaches its greatest eastern elongation, and will be visible in the evening sky at sunset.

7 April 2017 – Jupiter at Opposition

On 7 April the Earth will pass directly between Jupiter and the sun. The planet will be very bright in the night sky, rising at sunset. Even a small telescope should reveal the four Galilean moons of our solar system’s largest planet.

15 June 2017 – Saturn at Opposition

In mid-June Saturn and its magnificent rings will be as bright as possible this year. Like Jupiter in April, at opposition the Earth lies directly between Saturn and the sun. Rising at sunset, the planet will appear as a fully-illuminated disk through a modest telescope, nestled within its amazing rings.

cassini_saturn_orbit_insertion

Saturn will be worth watching in 2017 on another front. The Cassini mission is drawing to a close. Throughout the year, NASA mission controllers are swinging the wonderful car-sized spacecraft through Saturn’s rings for the first time, willing to take risks at the tail end of the voyage. Launched 20 years ago (1997), Cassini reached Saturn in 2004 and has been performing nearly flawlessly ever since. Later in 2017 the mission will be brought to an end and the spacecraft will be plunged into Saturn itself, a fiery demise to ensure that the environments of Titan and the other moons of Saturn are not contaminated. The feature image on this post is an artist’s rendering of Cassini and its attached Huygens probe undergoing the orbital insertion maneuver over Saturn in 2004 (Public Domain image; source NASA: http://photojournal.jpl.nasa.gov/catalog/PIA03883).

21 August 2017 – The Great Eclipse

Perhaps one of the big events in 2017 will be the “Great Eclipse” – a total solar eclipse that will cross the continental United States from west to east coasts. On Monday 21 August 2017 the moon will pass directly between the Earth and the Sun, casting a vast circular shadow and giving millions of people a chance to see a true natural spectacle. Totality will pass through states like Kentucky and Tennessee, but from Ontario we will still see a great partial eclipse in the afternoon. Here’s NASA’s posting for eclipse information: http://eclipse.gsfc.nasa.gov/SEplot/SEplot2001/SE2017Aug21T.GIF

13 November 2017 – Close Conjunction of Venus and Jupiter

Just before sunrise Venus and Jupiter will be very close to each other in the sky – just 0.3 degrees apart, or less than the diameter of the full moon.

I hope you can get out and enjoy these and other exciting sky events in 2017! As we get closer to each I will post additional information on viewing – and when possible taking pictures of – these events.

 

A New Year, a New Night-Time Photography Class!

I’m happy to report that Royal Botanical Gardens has asked me to lead another Night-Time Photography class! If we get sufficient response, we’ll start at 7 PM on the evening of Thursday 26 January 2017, at RBG’s Nature Interpretive Centre. The class will run for a total of four sessions, weekly.

The class will be a hands-on opportunity to take photos at night, with an emphasis on capturing beautiful images of the sky. We’ll cover equipment, celestial objects, post-photography processing, and more. This isn’t an astronomy class per se, but we will talk a bit about astronomy. By the end of the course I am hoping everyone will feel confident going out at night with their cameras and experimenting with capturing beautiful images.

We’ll try to end each two hour classroom experience with a quick dash outside to see be seen. Guidance will also be given on photo opportunities taking place between classes.

RBG’s public program calendar is available on-line at: http://www.rbg.ca/files/pdf/education/publicPrograms/RBGexperiences1116.pdf

You can register on-line for any of the RBG programs at: https://tickets.rbg.ca/PEO/

To find the Night-Time Photography course, just click 26 January 2017 on the calendar on the web site. Registration is limited to 20.

If you are planning to take the course, please contact me ahead of time for more information. It’s recommended that participants bring their digital cameras and tripods to the first class. Digital cameras should be able to be operated completely manually. A wide-angle lens is best for this sort of photography. Tripods should be very sturdy. I can make recommendations if anyone has any questions.

 

 

Happy Birthday Tycho Brahe

Tycho Brahe (14 December 1546 – 24 October 1601) is commemorated in one of my favourite craters on the moon (crater Tycho) and he’s well worth remembering. Tycho made many observations of the positions of the planets and stars in the days just before the invention of telescopes. By observing new stars – we call now them novas – and showing by their position observed over time that they must lay outside of the atmosphere, Tycho proved that they were not atmospheric phenomena. Thus, he proved that the realm of the stars was not immutable.

Perhaps his greatest contribution to astronomy was in fact sharing his observations with his protégé Johannes Kepler, who then used the detailed location information for the planets in the developing of his laws of planetary motion.

He was a complex and colourful character. For more details, take a look at the profile of his life and contributions on Wikipedia: http://en.wikipedia.org/wiki/Tycho_Brahe

Try Cell Phone Afocal Photography – Especially for Sidewalk Astronomy

There are a great many different ways to take a photograph of astronomical objects. If you are looking through a telescope at a bright object like the moon, it’s possible to take satisfying photos “on the fly” without even having to attach a camera to anything. It’s called afocal photography. It’s very well suited to public or “sidewalk” astronomy events where nearly everyone visiting will have their own camera of some sort.

Afocal photography is the process of shooting a photo with a camera simply by lining the camera up to the telescope (or microscope, or spotting scope, where this technique is sometimes called digiscoping) eyepiece. It does not require attaching the camera to the eyepiece (although there are ways of attaching the camera that makes things much easier. This post is about just trying it hand-held). There’s a nice introduction to afocal photography on Wikipedia (https://en.wikipedia.org/wiki/Afocal_photography).

I thought a demonstration might be fun, using a very ubiquitous and simple digital camera, that built into an iPhone 3GS. If you want to try this with any camera more advanced than that on an iPhone 3Gs, please make sure that you turn the flash off!

On the evening of Saturday 14 September 2013 the Hamilton Amateur Astronomers (http://www.amateurastronomy.org)  presented a public astronomy evening in the parking area of a visitor centre in Grimsby, Ontario. I went along with my little Meade 125mm Maksutov-Cassegrain telescope, an iPhone 3Gs, and also a Nikon D5100 body. I thought it might be nice to compare two photo methods: afocal (putting the iPhone over the telescope eyepiece) and prime focus (replacing the eyepiece with the camera all together) photography of the moon.

DAG_2722 800px

A public observing night put on by the Hamilton Amateur Astronomers on the evening of 14 September 2013 in Grimsby, Ontario. These events are terrific fun and a chance to see many different types of home telescopes in operation.

After setting up my telescope I was happy to have lots of members of the public come by and take a look at the moon through a wide-angle eyepiece. The Meade telescope has a focal length of 1,900 mm. With a wide-angle eyepiece of 28 mm focal length, the combination had a magnification of 67x (magnification, or “power,” in telescopes is calculated by the ration of the focal length of the tube divided by the focal length of the eyepiece).

Meade

My Meade Terabeam (TB) 125mm telescope set up for photography of the moon at the Grimsby public astronomy event. This compact little telescope is very versatile.

In between looks through the telescope, I held the iPhone’s camera over the eyepiece as “flat” as possible – in line with the long axis of the eyepiece, pretty much up against the rubber eye cup. Once I could see the bright light of the moon showing up on the iPhone screen, I moved the phone carefully around a few mm at a time until more and more of the moon showed up.

iPhone 1

A first afocal exposure of the moon taken with the camera built into an iPhone 3Gs. At least one crater is visible – a good, if humble, start!

It takes a little time and patience to line up the camera over the eyepiece, but in a few minutes I got the hang of it and started taking photos.

2

Getting closer! Nearly the whole moon is visible in this afocal shot, one of many taken to ensure a good one is captured.

After about a dozen images recorded, I captured one that I thought was pretty good.

3

A pretty satisfying image of the moon, one of about a dozen tried. Hand-held afocal photography is very much a trial-and-error process.

Some shops actually carry devices to hold cameras of various kinds (including cellphones) up against telescope or spotting scope eyepieces. These would be really helpful, especially if you wanted to take video or longer exposures. As it was, in this case I used the default camera app on the iPhone, allowing the camera and phone software to control exposure and focus.

afocal3rot1800px

The afocal image above, rotated, and flipped left-for-right. I’ve also adjusted the brightness, contrast, and sharpness very slightly. This compares very well to the image of the moon taken with a Nikon D5100 dSLR body at prime focus, below.

After taking a photo I was satisfied with, I put the iPhone away and set up the Nikon dSLR on the telescope, at prime focus. This is the place where the telescope makes its basic image without an eyepiece. With this 1,900 mm telescope image of the waning gibbous moon, about two or three days past first quarter, just barely fit onto the APS-C sized sensor on the Nikon D5100. I had to rotate the camera to get it onto the sensor.

DSC_0120 cr1 1200px

A photo of the moon taken a few minutes after the afocal iPhone images, by placing a Nikon D5100 dSLR body onto the same telescope at prime focus (replacing the eyepiece with the camera).

The iPhone afocal image compares pretty well with that from the dSLR once both are reduced down to the same size of image. The dSLR image is more detailed than the iPhone photo taken on the 14th, in part because of the much bigger (16 megapixel) sensor on the Nikon, and in part because of the wide-angle eyepiece used. Put side by side, sections of the images at their original resolution give a good idea of difference in resolution.

side by side

The southern part of the moon imaged with iPhone afocal photography (left) and with a Nikon D5100 at prime focus (right). Both images were converted to black and white, and then a strip 400 pixels wide by 800 pixels high was cropped out of each. The two images here are presented in their original resolutions for comparison. the large round crater with two smaller ones along its edge, toward the bottom of both images, is Clavius. The smaller, circular crater to the north, with a prominent central peak, is Tycho.

Afocal photography is a “quick and dirty” method, but it’s also a lot of fun. One effect you might notice with this method is chromatic aberration, even if you are using a telescope that is an apo-chromat or a reflector that is not itself subject to this problem. It may show up, even on focused images, as colour ghost images or fringes.

As I noted at the beginning, this process is particularly well-suited for public astronomy nights. Nearly everyone (well, lots of people, anyway) has a cell phone or pocket camera with them these days.  If you are inviting the public to try looking through a telescope at something bright like the moon, ask them if they’d like to try to make their own souvenir of the event, too – their own photo of the moon, on their own camera. A few of our guests in Grimsby took away their own photos through my telescope, and they were pretty excited. I’m sure these were sent to a bunch of their fiends by SMS before too many more minutes had passed.

Copyright © 2013 David Allan Galbraith

Stitching A Lunar Panorama

Astrophotography today is becoming more and more about taking a series of individual images and assembling them into something else. This can be done in two sorts of ways. Very often, astophotographers will take repeated shots of the same area of the sky, and then use software to “stack” them, which has the effect of greatly reducing noise in the final image. As many of the objects in space are extremely faint, long, noise-free images are necessary to find them at all.

It’s also possible to make images of large areas of the sky by taking individual photos and joining them together, or stitching them. This can be a very effective way of using small cameras to produce large, high-resolution images. Despite the trend in some circles of seeking ever-bigger sensors dSLR cameras, stitching means that small cameras – like a web cam – can be used to great effect.

On the night of 16 August 2013 I was doing some observing and photograph form my west-facing balcony in Hamilton, and decided to try to make a large portrait of the moon using a small camera. I tried imaging the moon with several different cameras that night. My telescope was my Meade 125 Terabeam Maksutov Cassegrain catadioptric telescope mounted on an EQ6Pro mount with Synscan. Because of my balcony’s situation, it’s impossible to do an actual polar alignment; I can’t see Polaris. I can get to within a degree or so, which is good enough for taking a few images of bright objects like the moon.

The moon was lovely that night. After a few minutes of general moongazing, I mounted a Nikon D800 body on the telescope at prime focus, and was able to capture images of the whole moon’s face in one shot.

d800

A photo of the moon taken on the evening of 16 August 2013 from an apartment balcony in Hamilton, Ontario, using a Nikon D800 camera on a 125mm Maksutov Cassegrain catadipotric telescope.

I then changed the camera, replacing the big dSLR with a little imager sold specifically for lunar and planetary imaging, a Celestron NexImage 5. This little camera looks like a miniature hockey puck about 2″ across. Inside is a 5 megapixel colour image sensor, which attaches to a computer via a USB cable. In contrast to the very expensive Nikon camera, the NexImage 5 retails for under $200. Because the pixels are quite small compared to the dSLR, it is able to record images of much higher resolution on subjects like the moon, for a given magnification. It is able to do a variety of things, including recording AVI video files that can be used in the stacking process.

Lunar tile

One image captured by the NexImage 5 camera, including the famous craters Tycho and Clavius.

I decided to try making an image of the moon using single exposures with the NexImage 5. I set up the telescope to point at an area along the terminator of the moon, took a single image with the camera, and then manually moved the telescope so that it was pointing to an area that overlapped the first image by about 30 percent. In this fashion I worked my way across the entire surface of the moon, taking 41 individual images.

Having the pictures recorded was just the first step. The camera software had recorded the pictures as bitmap files (*.bmp), and so I used a free image processing software to convert them from bitmap to JPG files. I then used another free software package called Autostitch (downloaded free for personal use at: http://www.cs.bath.ac.uk/brown/autostitch/autostitch.html) to automatically bring all of the JPGs together, align them, and blend them together. I ran the program first on about a dozen overlapping tiles to see if it would work at all: Autostitch is designed for landscape photos – not moonscapes!

pano1 800px

A section of the lunar panorama made by using Autostitch to put together a dozen individual tiles.

Autostitch performed better than I could have hoped on my lunar frames! I re-ran the program using the whole set of 41 tiles, and in moments had my portrait of the moon in high resolution.

stitched

The moon, stitched together from 41 individual frames using Autostitch.

The final stage in assembling the image was to fill in the grey areas that were not actually captured by the imager.  I used another free software package, Paint.NET (not as capable as Photoshop but a whole lot less expensive!) to adjust contrast and brightness a bit, and paint in the grey areas with black. The results would be even better if each of the tiles had been prepared by the stacking process, which can result in dramatic improvements in such images. For now, I’m happy with yet another photo of the moon!

final

The final composite image of the moon, captured on 16 August 2013.

Copyright © 2013 David Allan Galbraith

Making a Lunar Imager out of a $20 Web Cam

One of the joys of astronomy for me is the interplay between technology, science, creativity, and a fascination with the universe itself. From the beginning astronomers (amateur and professional) have been masters at make-do. You have an idea, well, then try it out? No equipment? Make something!

There’s been a revolution in amateur astronomy in the past decade because of a new use for something never intended for that use. I have come back into astronomy as a passionate hobby via my other big interest, photography, and especially landscape photography. One of the drivers in photography is image size, and so cameras like the Nikon D800 with a 36 megapixel sensor, or its sister the D600 with a 24 megapixel sensor, or the similarly amazing Canons, seem to the wave of the future. RIght?

Not so fast. There are limitations to “big sensor” imagers, and they really show up in astrophotography. For one thing they are expensive. For another, they miss the fact that for many kinds of astrophotography – especially photos of bright objects like the moon and planets – very large sensor arrays are at a disadvantage because much of the detail being photographed only covers a few hundred pixels. A response? Bust up a cheap web cam.

Some very inventive people have found that not only can you make a working astronomy imager out of a web cam, but if you use it the right way and record a lot of individual frames with it – as an AVI movie, for example – you can then use software on your computer later to select the best individual fames and “stack” them – aligning and combining them to reveal details that were essentially spread out across the images, mostly by the movement of the air.

Web cams are small digital cameras designed to run off most computers, especially laptops. They are light, flexible, and inexpensive. Over the past three or four years I kept hearing that people were using web cams to take great photos of the planets and the moon. I wondered how, and decided to give it a try. This blog entry records my first attempt at such a “hack.”

One of my favourite stores is “Tiger Direct,” a big computer retailer in Ontario. I bought a 640×480 pixel web cam at the Burlington store for $19.99 plus HST, and proceeded immediately to break it, on purpose! The reading I had done about web cams for astronomy indicated that all that was needed was to get the sensor of the web cam to the prime focus of the telescope – exactly the same process as using a dSLR on a telescope, but via some creative improv. Some web cam gurus actually have created telescope adaptors that screw into a web cam and replace it’s original lens, which certainly would be a great way to do it. I figured that I’d try first with electrician’s tape.

After opening the package I saw that this particular web cam had a plastic plate around the lens, which could be rotated to focus the camera. So, using a little dumb bruit force, I turned the plate until it came off! A few more turns and the lens came off too. Here’s what the web cam looked like without its proper front end:

Front of web cam opened up

A 640×480 pixel webcam with the front plate and lens assembly removed. I also cut off a small bracket that would allow this model to sit on a desk or other horizontal surface. The lens was attached by being screwed into the small black barrel visible inside, mounted on the circuit board.

2 sensor board

The “business end” of the web cam. The sensor is the rectangle roughly in the middle of the image, mounted on a dark blue support and attached to the circuit board. The larger black circular structure is the support for the now-removed lens.

Once the front plate was off, I could see the sensor and was very careful not to damage it in any way. Camera sensors are prone to picking up dust, so I gave it a squirt of air from a camera cleaning bulb, but otherwise let it be. I then lined up a 1.25 inch T-adaptor I had in my astronomy parts box. This is just a hollow tube that can fit in a telescope where the eyepiece would normally go. At the “back end” is a broad flange with threads so that it can be attached in turn to a camera adaptor. I wasn’t to interested in the threads – I just wanted a stable base to tape my web cam to. So , I did.

3 assembly

All that was required to make an astrophotography-capable web cam was attaching a 1.25 inch adaptor to the web cam, once the original lens was removed. Here’s a spare T-adaptor about to be attached to the web cam with tape.

4 final taped 600px

The assembled imager wasn’t exactly elegant. I held the web cam against the T-adaptor with tape, making sure to get the two surface to match up as flat as possible, and that no light could come in from the sides. The silvery 1.25 inch barrel at the left was put into a telescope in place of an eyepiece.

Once taped up, of course, the big question was “would it work?” There was only one way to find out. On the night of Friday, 16 August 2013 the moon was a nice sight over Dundas, Ontario, from my west-facing apartment balcony. I set up my Meade 125TB Maksutov-Cassegrain telescope on an EQ6Pro Synscan mount. These are two fairly sophisticated pieces of kit, admittedly. The Meade telescope has a focal length of 1,900 mm and has been a favourite of mine for lunar as well as solar observing and photography. The mount is very heavy-duty, rugged, and accurate – overkill, really, for this telescope, but in a lot of important ways, the mount makes the system. As I set this all up on my apartment balcony I also had another strike against me. I don’t have a view of Polaris from the only place I can set up the mount. So, all I can do is set up an approximate polar alignment, sight a few stars for Synscan to attempt to refine the alignment, and go for it!

So, once I had a telescope set up and trained on the moon, I slipped my Frankencam into the eyepiece holder and held my breath as I focused in, using my laptop screen to see the image coming off of the camera. And there it was. The surface of the moon, in amazing detail:

plato

A portion of the northeast area of the moon, photographed 16 August 2013 at about midnight, from an apartment balcony in Dundas, Ontario, with a $20 web cam (mounted on a somewhat more expensive telescope). Visible in the middle of the image is the crater Plato. To its left is Mare Imbrium (the Sea of Showers) and to its right (north) is Mare Frigoris (Sea of Cold). This is a single fame captured by the web cam, without subsequent processing other than a slight adjustment for contrast and brightness.

I was pretty excited to see the detail coming from this little camera. At just 640×480 pixels it’s a small imager, but it can produce very interesting results.

I have not yet started any serious attempts to use this to produce “stacked” images, but I’ll try that next. There is a free program called RegiStax that has been written specifically to process AVI video files and BMP individual frames of astronomical subjects recorded with web cams. I recorded some AVI video that night, and will to have a go at processing it with RegiStax some time soon. I’m a little skeptical at the moment, however, because of what appears to be a lot of “seeing” – air movement causing ripples in the images. We’ll just have to see how that turns out! For now, I’m quite pleased with this little web cam and what it can do.

southern highlands

A region of the moon’s southern highlands, imaged with the web cam. This is one frame from an AVI video I shot on the night of 16 August 2013. The bottom third of the prominent crater Clavius is visible at the top centre of the frame.

Copyright © 2013 David Allan Galbraith