Astro Thread

We just came in from seeing that fuzzy spot in the sky called comet Lovejoy. I now have a kink in my neck, but it was interesting to see it. Here in Oregon, using Orion's Belt as a pointer, follow that path quite high in the sky. I needed my birdoculars to find it, then we put the spotting scope on the comet.
 
It's a clear January evening here in NorCal. I went out back and took a few shots after dinner.


Shot with 85mm 1.8. Not very long, but fast. ISO 6400




Shot with 70-200 f4 (I just sold off a 2.8 / 200mm :oops: ) ISO 6400


 
There are Lovejoy viewing star parties at Stub Stewart State Park near Vernonia Oregon west of Portland. Just heard about it on the local KGW TV news.

That might be out of town enough for limited light polution.

Paul
 
Tried finding Lovejoy from the backyard last night but was not successful. Could be from too much light and will try again when we are out camping this weekend. But just to be sure, I want to make sure I'm looking in the right place. I looked at the attached links for location but don't know my star charts very well. I gathered that I should be looking in a generally south direction and up at an angle slightly more than 45 degrees. Is this correct?
 
Beautiful shots, Lighthawk! You really caught the green color of the comet. What were your exposure times? Pretty short, I guess, since I don't see star trails in the first image. I see short star trails in the second image, so that one had a longer exposure time?

Ted, Lighthawk's second shot shows the Pleiades, so that may help you locate the comet. Scan your binoculars W of Orion and S of the Pleiades. This weekend, scan SW of the Pleiades. Wandering Sagebrush uses the belt of Orion as a pointer to the general location, and that will still work for the next several days. Good hunting!
 
I think we've talked about the 'Rule of 500'. Divide the lens focal length into 500 to get your longest exposure without star trails. For a 100mm lens, that would be a maximum of a 5 second exposure. Some photographers use 400 instead of 500.
 
Good points about exposure times, WS. :)

To answer Highz's question about exposure times. The first shot is shot at 85mm focal length with a 4 sec, f1.8, iso 6400 exposure. The second shot, which shows the Pleiades in the top right of image is @ 70mm, 15 sec, f4, iso 5000.

So, to apply Rule of 500 we can take my 85mm Canon lens and divide the focal length into 500
500/85 = 5.9 sec exposure. I shot less than than duration at 4 sec so the image captured the stars without trails.

The other shot at 70mm looks like: 500/70 = 7.1 sec.
So my exposure of 15 sec definitely shows a fair amount of star trails, but my 'slow' f4 aperture needed more time to record the faint light.

If we use the more conservative ration of 400, then my exposures should be 4.7 sec @ 85mm and 5.7 sec @ 70mm

Think about it this way. The more magnification you have, the greater the angular movement of the stars, even in a short time period. There are tracking devices, similar to what are used with telescopes, to keep you camera following the astral movement, but that's beyond me.

Here's a 10 sec shot at 400mm, f5.6, iso 6400 where you can see how much movement there can be with a longer focal length.


What I really want is a 300mm f2.8, which a few of our more serious photogs probably have in their kit. ;)
 
Lighthawk said:
What I really want is a 300mm f2.8, which a few of our more serious photogs probably have in their kit. ;)
Click to expand...
I'm dreaming of a long fast lens also....................................... :)
 
highz said:
On another astro topic, Mercury is at greatest eastern elongation now, so enjoy watching the sunset and stay out for an hour or so longer and catch Venus and Mercury setting in the west.

http://earthsky.org/tonight/mercurys-greatest-elongation-from-setting-sun-on-january-14?utm_source=EarthSky+News&utm_campaign=0435d5b0ab-EarthSky_News&utm_medium=email&utm_term=0_c643945d79-0435d5b0ab-393870289
Click to expand...
Cool. I thought so! :)
A few days ago, when camping in southeast Oregon, I noticed what I knew was Venus and another less-bright but still noticeable object closer to the horizon after sunset I thought it might be Mercury. I think I've only seen it once or twice in all the years I've been looking at the sky. There have been many opportunities...but now I can say for sure: seen it at least twice.
 
Asteroid 2004 BL86 will pass close to Earth tomorrow. At the closest, it will be about 3 times the Earth-Moon distance, but since it is relatively large it will be easily visible in large aperture binoculars or small telescopes. Basically, you will need to see down at least to magnitude 9.5, and will want a stable mount. This might make it a tough target for wanderers who aren't packing a small telescope. If you are home, you can watch a live feed at http://live.slooh.com

Here's a little more info.
 
Not as clear a photo I had hoped for,but it was nice seeing it.
Last night (20 Feb) the moon after sunset had Venus and Mars with it.
Don't get to see a lot of night events as we get fog a lot of the evenings.

Tonight it's said Uranus will also be visible in the area between the moon and Venus/Mars.
No luck for tonight as it's already overcast.
Frank
 

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Casa Escarlata Robles Too said:
Not as clear a photo I had hoped for,but it was nice seeing it.
Last night (20 Feb) the moon after sunset had Venus and Mars with it.
Don't get to see a lot of night events as we get fog a lot of the evenings.

Tonight it's said Uranus will also be visible in the area between the moon and Venus/Mars.
No luck for tonight as it's already overcast.
Frank
Click to expand...
Cool! I only read about this conjunction this morning, so missed it last night. I think it was overcast anyway...
 
Gosh, we saw the moon with Venus out the kitchen window last night while doing up supper. Never thought to look for Mars. :(

Nice photo Frank!
 
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