Free Solar Observing Today at Royal Botanical Gardens

We’re going to hold Royal Botanical Gardens’ third “Solar Thursday” today (29 August 2013) from 12 noon to 1 PM, on the lawn area in front of the main visitor entrance to RBG Centre. Everyone’s welcome to join us for a view of the sun through special, safe telescopes.

If you have a solar telescope you are very welcome to join us in presenting the amazing spectacle of the sun to the public. We like to be “open for business” at 12 noon, so coming a little earlier to set up would be helpful. We have electrical power available if your telescope needs it. We start packing things up around 1 PM. RBG is located at 680 Plains Road West, Burlington, Ontario.

We will be looking through specially-equipped telescopes that filter the bright light from the sun. These filters make it safe to observe the sun’s surface. Remember:

No one should ever look directly at the sun without special, appropriate equipment. Permanent eye damage or blindness may result from inappropriate attempts to see the Sun, or the use of incorrect equipment. We will be using telescopes designed specifically for solar observation, or those equipped with filters specifically made for this purpose.

Once you’re familiar with the equipment and have things in focus, you will be able to take in the sights in just a few minutes! Some nice sunspots are visible today.

Visitors to Royal Botanical Gardens, 680 Plains Road West, Burlington, Ontario enjoying views of the sun live during RBG’s second “Solar Thursday” event, 15 August 2013.

Copyright © 2013 David Allan Galbraith

View Nova Delphinus 2013 – A Limited Time Opportunity

Nova Delphinus 2013 (left) and planetary nebula NGC 6905 (right), cropped at full scale from the same photograph taken on the evening of 24 August 2013. While I’m generally pleased with the images I took that evening, there is evidence of some problems on this 30 second exposure – the pulled out stars should all be points. More details follow below.

Although a lot has been made of two comets passing through our skies in 2013, August has given us an unpredictable and much rarer astronomical event: a nova, visible to the naked eye. Nova Delphinus 2013 has proven to be the brightest nova in five yeas – definitely worth a look. Novas are fleeting, however. There isn’t much time.

According to Space.com, Nova Delphinus 2013 was discovered on 14 August 2013 by Koichi Itagaki in Japan. Prior to brightening more than 100,000 times in its explosion, the star was a dim little 17^th magnitude. It became as bright as 4^th magnitude in the days since it was first spotted, and is now fading a bit. Over the coming days and weeks it will fade completely.

I set out on the evening of 24 August from our cottage in Bruce County to see if I could see it. Novas are exploding stars, and the initial flash doesn’t last too long. First, I had to find out the coordinates of this transient object.

The nova is located in the constellation Delphinus, the Dolphin, not too far from the “tip” of another constellation, the arrow, Sagita. The astronomical coordinates are RA. 20 h 23′ 31″, Dec. +20° 46′.

Some near-by land marks help, too:

• Altair (α Aquilae), at 0.9 Magnitude, in Aquila, is the nearest very bright star.
• Sualicin (α Delphini), 3.6 Magnitude, in the held of the dolphin, Delphinus, is the nearest named star.
• A little blue planetary nebula, “The Blue Flash Nebula,” NGC 6905 is so close that it will appear in the same field of view through a wide-angle eyepiece. The 12^th magnitude nebula is located at RA 20h 23m 02.52, Dec+20° 08’57.2″

A wide-angle chart of the area of Nova Delphinus 2013, rendered with the freeware planetarium program Cartes du Ciel. This chart covers about 30° of the sky. The nova and the planetary nebula NGC 6905 are so close together that I’ve just indicated the nebula here.

A narrow-angle drawing of the areas of Nova Delphinus 2013, prepared with Cartes du Ciel. This chart covers about 5°. The nova sits just within the boundaries of the constellation Delphinus (indicated by the faint purple lines).

As it will appear in most telescope mount “go to ” databases, finding NGC 6905 is a great way to get to the area of the nova quickly.

I set out to a gravel parking area near the Bruce Botanical Food Garden on the east side of Ripley, Ontario, at 8:30 PM on the evening of Saturday 24 August 2013 to see if I could spot the nova. I had found this site the night before, and it proved reasonably quiet, and fairly dark, although there are some near-by houses a few hundred yards away.

Some high clouds made the night of the 24^th a little disappointing, and with moonrise set for 9:55 PM I knew I had to work fairly fast. I admit that I had trouble finding the nova with binoculars. I could see a fairly rich star field between Delphinus and Sagita, but really couldn’t decide if I was seeing my target or not.

I reverted to the aid of SynScan on my EQ6Pro mount to save the day, and wasn’t disappointed – eventually. I did found the nova, but only on photographs after the fact. Looking through a 28mm eyepiece on an 8” Newtonian, I couldn’t be sure at all what I was seeing. So, I re-reverted to imaging.

I set up a Nikon D800 body on the telescope, focused on a faint star using live view, and took a series of 30 second exposures at ISO 800. The nova turned out to be the brightest star in the frame, as expected. Actually, I spotted NGC 6905 first! The little blue ball was a charming sight on the photographs, and really stood out. I also have another admission, about NGC 6905. I didn’t know it was in the area of the nova until I saw my photos. At first I thought it was likely an artifact, but a quick check of the area on charts confirmed that in fact it was a planetary nebula, known as the Blue Flash Nebula. NGC 6905 is well worth a look on its own. It’s considered as a very lice planetary, and was discovered by William Herschel in 1782. This was another first for me – my first image of a planetary nebula. An added bonus for a night of nova hunting! The nova itself registered as a bright white star, bright enough to show faint diffraction spikes from the telescope’s secondary mirror spider.

Nova Delphinus 2013 (left) and the Blue Flash Nebula, NGC 6905 (right), photographed on the evening of 24 August 2013 at 9:51 PM EDT, from the east side of Ripley, Ontario. North is approximately toward the left. The single 30 second photograph was taken through a SkyWatcher 8” imaging Newtonian telescope with a coma corrector, and a Nikon D800 body, set to ISO 800, on an EQ6Pro mount. This copy has been reduced down in resolution and cropped from the original frame. The two smaller images at the head of the post are from the same frame, without reduction in resolution.

If weather and conditions permit, I recommend having a look for Nova Delphinus 2013. In the coming nights the moon will be rising later each night, and dropping in brightness, so this is a great time to try, while the nova is still bright. For southern Ontario Delphinus is nice and high in the sky after sunset. No reason not to go have a hunt for a truly rare sight!

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:

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.

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.

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.

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:

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.

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

Enchanted by the Sun

This summer I’ve been delving into solar studies. Perhaps it’s like the proverbial goldfish not noticing the water that surrounds him, but I really hadn’t paid much attention to our nearest star. Last year I did start to take my own look at the sun, using solar filters on an old 80mm f15 refractor, and that was pretty interesting. Somehow the solar bug has really bit me this year.

I’ve added some equipment to Pine River Observatory this year, and that’s helped. In addition to my Meade ETX 125 Terabeam telescope, which I now have equipped with both a Kendrick Astro Mylar solar filter and a Baader Planetarium continuum filter, I picked up a Coronado 60 mm Solar Max II BF15 Hydrogen alpha telescope a couple of months ago. The upshot of all of that is that I can take a look – and am starting to photograph – the sun at two quite different wavelengths, corresponding to different structures on its surface.

There’s an interesting feedback loop here. As I’ve been able to see the sun for myself, and consider how to take photos, and even explain what can be seen through a telescope to others taking a look, I’ve found that my curiosity has risen. I’ve been reading more, seeking out a deeper understanding of what I’m seeing. That in turn has made my observations a little better, I think, and certainly has meant I’m doing a better job of interpreting for others.

It’s also been exciting to see that there’s a lot happening in terms of science and solar observation right now. Consider these three news items from the past month alone:

• A new ground-based solar telescope (the New Solar Telescope or NST) at the Big Bear Observatory in California has just started to produce incredible images of the photosphere and sunspots – with a resolving power that approaches 30 miles on the sun’s surface (http://www.bbso.njit.edu/)
• A new solar observatory satellite, Interface Region Imaging Spectrograph (IRIS) achieved “first light” in July, and is already transmitting wonderful images back to earth (http://iris.lmsal.com/)
• NASA has updated information available on the progress of the present solar maximum. This event, every 11 years or so, is marked by a peak in sunspot numbers, and represents a reversal in the orientation of the sun’s magnetic field. The present solar maximum was anticipated for 20111 but it’s a little late. The magnetic flip is anticipated between now and November.

These are just examples of the activity around solar observations in the past little while. The more I’ve read, too, the more I want to find out. The sun is quite addictive! More postings to come.

The sun’s “surface,” or photosphere, photographed from Burlington, Ontario’s LaSalle Park Marina on the morning of Monday 5 August 2013. This image was captured using a Meade ETX 125 TB telescope equipped with a Kendrick Astro Mylar solar filter and a Baader Planetarium continuum filter. These filters produce a green image that highlights contrast around sunspots and solar granulations. The image is a mosaic of two shots taken with a Nikon D5100 at prime focus, as the image produced by the telescope is larger than the D5100’s APS-C-sized sensor. The image was processed with Paint.net, a free image processing program. Although we might think of the sun as a big ball of hot gas it’s structure is much more remarkable than that. At its core the density is enormous – a liter of the gasses would weight 150 kg. At the surface we can see, as in this photo, the density is less than 1% of that of our own atmosphere at ground level.

 

Copyright © 2013 David Allan Galbraith