Perseids

[DougPaul]

The Perseid meteor shower peaks tonight (Fri-Sat, Aug 12-13). Viewing will not be at its best--the moon is nearly full.

http://earthsky.org/astronomy-essentials/earthskys-meteor-shower-guide

Doug

 

[Tom Rankin]

The Perseid meteor shower peaks tonight (Fri-Sat, Aug 11-12). Viewing will not be at its best--the moon is nearly full.

http://earthsky.org/astronomy-essentials/earthskys-meteor-shower-guide

Doug

I plan to get up around 3:30. BTW, the moon will be pretty low by 5:00 AM, but dawn will be approaching. You can't win!

 

[DougPaul]

Went out ~midnight. Saw a bright one within a minute. Stayed out for another ~5 min but didn't see any more. But two mosquitoes found me... (Or maybe it was one mosquito twice--the bites were 1/2 inch from each other.)

Doug

 

[Tom Rankin]

Went out ~midnight. Saw a bright one within a minute. Stayed out for another ~5 min but didn't see any more. But two mosquitoes found me... (Or maybe it was one mosquito twice--the bites were 1/2 inch from each other.)

Doug

Was it coming from the NE? I usually wait till Perseus is higher in the sky to observe them.

 

[DougPaul]

Was it coming from the NE? I usually wait till Perseus is higher in the sky to observe them.

Yes, from the NNE. The track was ~70 degrees above the horizon to the north and about 10-20 degrees long.

Didn't want to stay up that late...

Last year I tried to photograph a meteor without success. If I had brought a camera outside with me, I would have missed this one while setting the camera up.

Doug

 

[Kevin Judy and Emma]

Last night...

Last night I saw about 25-30 good ones before midnight despite the full moon. I was on the summit of Middle Sugarloaf near Twin Mountain. I got a couple of faint photos. Any tips on shooting them, Doug? ISO etc? Thanks!

KDT

 

[Tom Rankin]

Last night I saw about 25-30 good ones before midnight despite the full moon. I was on the summit of Middle Sugarloaf near Twin Mountain. I got a couple of faint photos. Any tips on shooting them, Doug? ISO etc? Thanks!

KDT

I assume you have a tripod...

Rule of thumb for night exposures: You can go about 30 seconds if shooting w/a 50 mm lens, before you start to notice the stars streaking. Proportionally longer if the lens is wider.

When you open the shutter, keep something dark in front of the mens for a second or so, to minimize the camera shaking after being touched.

 

[Kevin Judy and Emma]

Thanks!

I shot about 75 30 second exposures @ f 2.8 ISO 100. I got a few, but faint...

Full ghost probably didn't help...

KDT

 

[DougPaul]

Any tips on shooting them, Doug? ISO etc? Thanks!

I assume you have a tripod...

Rule of thumb for night exposures: You can go about 30 seconds if shooting w/a 50 mm lens, before you start to notice the stars streaking. Proportionally longer if the lens is wider.

When you open the shutter, keep something dark in front of the mens for a second or so, to minimize the camera shaking after being touched.

Don't bother--camera shake from the mirror (when you are using a tripod) is not an issue for 15-30 second exposures. (The vibration will die out quickly and have minimal effect.) A cable or remote release is a good idea. However, I used manual release without problems.

General howto:
* use a tripod.
* use a fully charged battery
* use your widest lens (I used 16mm eFL.)
* focus at infinity. (You can do this with autofocus by focusing on a distant terrestrial light and setting the lens to manual focus without changing the focus.)
* use an exposure that leaves the sky dark grey, but not fully black. The stars will show fairly brightly at this exposure. My exposures were 15 sec, ISO 1600, F4.0 in a suburban area (not the darkest skies...). Anything equivalent or similar should be ok.

A web link:
http://luminous-landscape.com/tutorials/meteor.shtml

Doug

 

[forestgnome]

Kevin....nice!

a few comments...

1) are you sure your ISO was 100? Even at f/2.8 I'm surprised at that.

2) trailing stars... there are two factors: lens size and angular distance from the celestial pole(very close to Polaris)....
-a smaller lens can take a longer exposure before trailing stars
-the closer (angular) a star is to the pole, the less it will trail at any given lens size or exposure time

3) white balance...I have found that as the sky darkens I like to set the WB to Tungsten. It usually produces a more natural sky color....no idea why

 

[DougPaul]

2) trailing stars... there are two factors: lens size and angular distance from the celestial pole(very close to Polaris)....
-a smaller lens can take a longer exposure before trailing stars
-the closer (angular) a star is to the pole, the less it will trail at any given lens size or exposure time

Just a clarification, he is referring to the focal length of the lens, not the aperture.

If the exposure is short, the stars will appear as points--otherwise they will blur into trails. A rule of thumb is to keep the exposure time under 600/eFL to prevent blurring.

Doug

 

[rup]

Particularly rainy in NJ.

 

[dentonfabrics]

When you see a meteor flaming out across the sky, what altitude are they at? We saw a half-dozen or so this past weekend and what struck me was how low they seemed to be. Most of the ones we saw flew almost directly overhead (north to south, generally) and seemed to fly under a very low ceiling. Less than 5000'? That can't be right, can it?

 

[Nessmuk]

When you see a meteor flaming out across the sky, what altitude are they at? We saw a half-dozen or so this past weekend and what struck me was how low they seemed to be. Most of the ones we saw flew almost directly overhead (north to south, generally) and seemed to fly under a very low ceiling. Less than 5000'? That can't be right, can it?

You are correct, in that can't be right for cometary debris meteors which are made up of tiny bits of fragile dust. Rocky/metallic meteors of course do regularly reach the ground, but those are not in any way associated with showers such as the Perseids. People lucky enough to see a low altitude rock surviving as low as 5000' have reported hearing a sonic boom from it.

Here is a web page with the answer to your question.

 

[dentonfabrics]

Thanks Nessmuk, good info. Maybe it was the speed at which they crossed the sky (61 km/sec or 136,453 mph!) that gave me the illusion that they were lower than they were.

 

[Bombadil]

You are correct, in that can't be right for cometary debris meteors which are made up of tiny bits of fragile dust. Rocky/metallic meteors of course do regularly reach the ground, but those are not in any way associated with showers such as the Perseids. People lucky enough to see a low altitude rock surviving as low as 5000' have reported hearing a sonic boom from it.

Here is a web page with the answer to your question.

I saw quite a few on Saturday night as well, despite the full moon. I was surprised to see a fair number while the moon was in the eastern sky as well, bright suckers...

 

[Kevin Judy and Emma]

Thanks all!

Thanks all for answers to several questions. @ Patrick- Yes, I shot at ISO 100, but adjusted a little in LR3. I guess I should shoot at a higher ISO next time. 8 )

KDT

 

[Raven]

I saw a rainbow sun halo hiking during the day last Saturday. Would this have had anything to do with the meteor shower? Ice crystals from the Perseids in between the sun and earth at that time maybe?

Anyone else see that? I wish I had my camera.

 

[DougPaul]

I saw a rainbow sun halo hiking during the day last Saturday. Would this have had anything to do with the meteor shower? Ice crystals from the Perseids in between the sun and earth at that time maybe?

No. The high entry speed of the Perseids causes them to burn up and any water will be vaporized. (And the amount of water vapor is insignificant compared to the amount of water already in the atmosphere.)

The ice crystals came from atmospheric water.

Doug

 

[Raven]

No. The high entry speed of the Perseids causes them to burn up and any water will be vaporized. (And the amount of water vapor is insignificant compared to the amount of water already in the atmosphere.)

The ice crystals came from atmospheric water.

Doug

That makes a lot of sense. It did seem like quite a coincidence though since I don't often see them (sun halos).