Saturday, August 17, 2013

Astrophotography Report (Nova Del 2013)

Photo obtained from AAVSO
On August 14, 2013 Koichi Itagaki of Yamagata, Japan found a nova in an image he had taken of Delphinus. This nova or "new star", was not present in a previous image he had taken the night before. news spread quickly of the nova. It did not take long for it to be confirmed. The nova's initial brightness was just under the naked eye limit. It steadily brightened to just under mag 4.5. Anyone at a dark site would be able to see it without the aid of binoculars or a telescope. It was a bit tougher under light polluted skies as I found out. Use this star chart to help you find the nova.

A nova in the making.
Image obtained from Universe Today

So what is a nova?

You might be thinking, 'oh you mean its a Supernova?', No. A supernova is basically when a star destroys itself in a massive explosion. A nova occurs when a when a White Dwarf pulls hydrogen from its companion star. The hydrogen reaches the surface of the white dwarf where it is compacted and heated. The hydrogen piles up until it is dense enough and explodes like a bazillion thermonuclear bombs. This process typically repeats itself several times.

So, now to my story.

After hearing of the news of the nova I was excited to get back outside and try to photograph it. Thunderstorms developed on the afternoon of the 15th threatening my chances of observing. This was going to be my first time seeing a stellar explosion only hours after it appeared. Thankfully the skies began to clear shortly after 10pm, but, thunderstorms had formed to the West of Houston. Even though they were not going to move our way, the cloud tops were being blown East. This meant there was a small window of clear skies.

I went outside, set up the camera and started snapping a few test shots to make sure I had my settings dialed in. I had no idea where Delphinus was. Thankfully with help from an app and star charts I was able to find the stars I had determined would help me point to the nova. I zoomed in to the star Altair and snapped a photo. Altair was in the center pf my photo, Delphinus and Sagitta, my other two guide constellations were to the left. I moved my camera to where both constellations were in the center and Altair was over to the right. I snapped several photos adjusting my focus here and there. After several minutes I could see those clouds moving in from the west. So I called it a night and went inside.

Pulling the images off my camera I quickly zeroed in on one. I could see all the constellations and stars I had determined would help me find the nova. Right in the middle of all of them was a star. According to everything I had used that was Nova Del 2013. But when I would compare my image to star charts, there were a few very slight differences. Plus let's be honest. I have never done anything like this before. I can find constellations using charts but anything in between dont count on it. I spent about an hour trying to confirm on my own if I had found the nova. Eventually I posted the photo to the Houston Astronomical Society (HAS), forum and I sent the same photo via Twitter to AAVSO

The morning of the 16th I awoke to a reply from AAVSO, "Mike, Thats It, NICE Job!". All day reports were coming in that the nova was still getting brighter. Those reports continued till late on the afternoon of the 16th, when the brightness was reported to have stabilized. I had found, seen, and photographed my first explosion in space!

Nova Delphinus 2013
Seen through a 55mm lens.
Thunderstorms again formed on the evening of August 16th. Again it would be a close call as to when the clouds would clear. For me I would only be able to observe this area of the sky till about midnight. After that my view would be obstructed by trees. This time I got brave. I pulled out my 70-300mm camera lens. I was going to capture that nova as close as I could. The skies cleared on my side of town about 10pm. As I did on the 14th, I started by taking a few test shots. I could barely make out the nova with my naked eye. Using my 55mm lens I could tell the nova was brighter. I attached my big lens and slowly zoomed in, taking a photo every so often to make sure I was centered on the nova. I snapped several photos at 300mm & 200mm. I finally called it a night after about an hour. It was very humid and I was sweating buckets.

Nova Delphinus 2013
Seen at 200mm.
Going over the photos I could see that all the photos taken at 300mm were not really going to work. Even though I was doing 5sec exposures, zoomed in that close the stars still move just enough to produce star trails in the image. Thankfully the images I shot at 200mm all came out.

It was exciting sharing this experience with others around the world. To see the reports flood in for two days. To see the nova for myself with my eyes and through my camera and binoculars was awesome! That i could see this happening to a star possibly thousands of light years away.

With the help of HAS this will hopefully be the second of many other observations of the night sky.

I would like to thank the folks at AAVSO for their helping me confirm I had found the nova. Thank you to Universe Today and Sky & Telescope for the very helpful star charts. Also thank you to HAS for providing the forums where I have been sharing most of my images with other local star gazers. For those wondering the app I used was Distant Suns

UPDATE 8-19-2013:

Just wanted to post a small update. Went back out last night, 8-18-13, and snapped a photo of Nova Del 2013 at 300mm. Its still visible through binoculars. The magnitude or brightness has dimmed some, but has remained steady for the last two and a half days. This will most likely be my last photograph of the nova. Unless it completely disappears or something dramatic happens.

Nova Del 2013
Seen at 300mm

Wednesday, August 14, 2013

Astrophotography 8-13-2013 (Satellite)

Before may of this year, I had not expeirence with astrophotography using a DSLR camera. Even now my experiences so far have mostly been reading a few tips in my books, running outside with the camera snapping away and looking over the results later. Hopefully learning something each time. Tonight I finally found the zone I believe is correct. Also, I might not know a lot about astrophotography, but I know even less about image processing. So the images I present here have very very little processing. All I have done is and "Auto Contrast" and a Color Inversion.

 I basically started out the same. Going outside picking a target take a shot, view the result, make any adjustments if needed, and repeat. Towards the end of my secession I pointed the camera straight up and took a photo. When I looked at it I noticed a small faint white streak at the top. So quickly I took another. There it was again! But in a different position. I took 3 more shots finally realizing what it might be. A satellite passing overhead. I have seen satellites passing overhead at the George observatory. But i never thought I would capture one on camera in the middle of light polluted skies.

My camera is a Nikon D3100. The lens I was using is a Nikkor 18-55mm. I was zoomed all the way in. 800 ISO at a 5 sec exposure.

Click to enlarge!

Monday, August 12, 2013

Orbits of Potentially Hazardous Asteroids

Are asteroids dangerous? Some are, but the likelihood of a dangerous asteroid striking the Earth during any given year is low. Because some past mass extinction events have been linked to asteroid impacts, however, humanity has made it a priority to find and catalog those asteroids that may one day affect life on EarthPictured aboveare the orbits of the over 1,000 knownPotentially Hazardous Asteroids (PHAs). These documented tumbling boulders of rock and ice are over 140 meters across and will pass within 7.5 million kilometers of Earth -- about 20 times the distance to the Moon. Although none of them will strike the Earth in the next 100 years -- not all PHAs have been discovered, and past 100 years, many orbits become hard to predict. Were an asteroid of this size to impact the Earth, it could raise dangerous tsunamis, for example. Of course rocks and ice bits of much smaller size strike the Earth every day, usually pose no danger, and sometimes creating memorable fireball and meteor displays.