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Zodiacal light can be worse than light pollution

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#1 Araguaia

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Posted 19 August 2019 - 06:12 AM

I have observational evidence.  I went out last night with 10x42 binoculars, right after twilight and before moonrise.   I swept around for globs, nebulas, and galaxies, and after M83 decided to see if I could find M104, low to the west.

 

I looked at Corvus, and the northern half of the constellation, where the galaxy is, was awash in light pollution!  I looked at the western horizon and saw the small light dome from the town 37 km away, glowing up to about 10 degrees altitude, as usual.  But that was not the source of my LP.  Corvus was about 30 degrees to the south of it, and right on the edge of the zodiacal light, which formed a funnel of glowing sky pouring out of the zodiacal band, which itself crossed the sky all the way to the Sagittarius Milky Way.  It was bright enough to make the Sombrero galaxy disappear, even though I had just easily seen M83, of lower surface brightness and also low in the sky.  

 

I measured with my fist at arms length.  The town's light dome was visible up to about 10 degrees.  The zodiacal light was glowing with equal brightness to at least 30 degrees above the horizon, with the band carrying the glow in a narrow lane past the zenith.

 

I also noticed the LP effect of the zodiacal band last month, looking at M33 pre-dawn.  In order to hold it comfortably in direct vision, I had to block out both the Perseus Milky Way below and the zodiacal band to the east with my hands.

 

This is an effect that seasonally degrades the view of all sorts of famous DSOs near the ecliptic, like the galaxies in Leo and Virgo, the Eskimo planetary, etc.


Edited by Araguaia, 19 August 2019 - 06:15 AM.

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#2 BradFran

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Posted 19 August 2019 - 07:46 AM

Dark Sky problems... grin.gif Bloody Jupiter. Bloody Zodiacal glow. Darned Milky Way blinding me!


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#3 TOMDEY

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Posted 19 August 2019 - 07:51 AM

That's a good point! Often, "natural" light from out there contaminates what we are trying to see. I find that the abominable gegenschein can be terribly distracting, but only when I'm enjoying a really good night at a very dark site. Fortunately, that spot isn't very big, and moves out of that part of the heavens within a month, certainly two. I most noticed it when I was in Panama, low-humidity midnight (the dark Atlantic side) back in the early 1970s.    Tom



#4 Araguaia

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Posted 19 August 2019 - 08:30 AM

Dark Sky problems... grin.gif Bloody Jupiter. Bloody Zodiacal glow. Darned Milky Way blinding me!

lol.gif

 

No, really, I mean that the zodiacal glow is worse than the light pollution of a town of 50 thousand inhabitants.  I am sure it affects mildly light-polluted sites.

 

Jupiter, of course, is far worse.


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#5 LDW47

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Posted 19 August 2019 - 08:38 AM

Dark Sky problems... grin.gif Bloody Jupiter. Bloody Zodiacal glow. Darned Milky Way blinding me!

I hate all those problems too, lol ! Then again lots probably wish they had those great problems from their sites !


Edited by LDW47, 19 August 2019 - 08:41 AM.


#6 jaraxx

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Posted 19 August 2019 - 10:12 AM

Yeah, if I had to choose between peering thru the streetlights in a city of 50,000 or dealing with the dreaded zodiacal glare I know which line I would be in - the very long line to get somewhere dark!


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#7 Arcticpaddler

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Posted 19 August 2019 - 09:34 PM

In my area the aurora borealis has been known to wreck my DSO observing on occasion.  The  Zodiacal Light is distinct on spring evenings, but I don't point my scope in that direction...



#8 Redbetter

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Posted 24 August 2019 - 01:50 AM

That's a good point! Often, "natural" light from out there contaminates what we are trying to see. I find that the abominable gegenschein can be terribly distracting, but only when I'm enjoying a really good night at a very dark site. Fortunately, that spot isn't very big, and moves out of that part of the heavens within a month, certainly two. I most noticed it when I was in Panama, low-humidity midnight (the dark Atlantic side) back in the early 1970s.    Tom

The gegenschein becomes rather large when the sky is dark enough and transparent enough.  In those sort of conditions it becomes more apparent that it is increasing the difficulty for lower surface brightness targets.  I have found it problematic for detailed study of IC 1613 on more than one occasion, and the latter is about 4.5 degrees from the ecliptic.  On one of those nights, one in which the sky was running somewhat worse than normal at  21.5 MPSAS, I "measured" the gegenschein at ~20 degrees wide by 18 degrees tall.  Part of the difficulty in determining the width is where to decide it stops and the zodiacal band starts--on the good nights with ecliptic high, the band stretches across the sky to join the zodiacal light.

 

I do find the zodiacal light pretty bright, enough that I don't generally point a scope that way and start packing up as it takes over more of the sky.



#9 Special Ed

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Posted 24 August 2019 - 11:14 AM

I've had the zodiacal light interfere with comet observations more than once. Unfortunately,  if you want to see the comet you can't look elsewhere.  smile.gif 


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#10 Astrojedi

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Posted 24 August 2019 - 11:55 AM

I want this problem... seriously !


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#11 Starman1

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Posted 25 August 2019 - 05:00 PM

I have observational evidence.  I went out last night with 10x42 binoculars, right after twilight and before moonrise.   I swept around for globs, nebulas, and galaxies, and after M83 decided to see if I could find M104, low to the west.

 

I looked at Corvus, and the northern half of the constellation, where the galaxy is, was awash in light pollution!  I looked at the western horizon and saw the small light dome from the town 37 km away, glowing up to about 10 degrees altitude, as usual.  But that was not the source of my LP.  Corvus was about 30 degrees to the south of it, and right on the edge of the zodiacal light, which formed a funnel of glowing sky pouring out of the zodiacal band, which itself crossed the sky all the way to the Sagittarius Milky Way.  It was bright enough to make the Sombrero galaxy disappear, even though I had just easily seen M83, of lower surface brightness and also low in the sky.  

 

I measured with my fist at arms length.  The town's light dome was visible up to about 10 degrees.  The zodiacal light was glowing with equal brightness to at least 30 degrees above the horizon, with the band carrying the glow in a narrow lane past the zenith.

 

I also noticed the LP effect of the zodiacal band last month, looking at M33 pre-dawn.  In order to hold it comfortably in direct vision, I had to block out both the Perseus Milky Way below and the zodiacal band to the east with my hands.

 

This is an effect that seasonally degrades the view of all sorts of famous DSOs near the ecliptic, like the galaxies in Leo and Virgo, the Eskimo planetary, etc.

I have observed at sites where the serious galaxy observers avoided the constellation containing the Gegenschein because it added too much light pollution in that area.lol.gif foreheadslap.gif



#12 dark sky newbie

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Posted 25 August 2019 - 07:45 PM

Too much light pollution to notice the Zodiacal light, and you think the Zodiacal light is worse than the light that obliviates it?

Wish I had your problem.



#13 Special Ed

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Posted 26 August 2019 - 08:20 AM

I would not characterize the zodiacal light, gegenschein, or moonlight as light pollution as several in this thread have--they are natural sources of light (as is airglow).   They may be an annoyance thwarting your observing goals--but not pollution.


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#14 LDW47

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Posted 26 August 2019 - 09:35 AM

I would not characterize the zodiacal light, gegenschein, or moonlight as light pollution as several in this thread have--they are natural sources of light (as is airglow).   They may be an annoyance thwarting your observing goals--but not pollution.

It all falls in with peoples way of thinking, the brainwashing of the modern era ! What was once a natural shrine is now pollution like garbage at a dump or floating in the oceans ! Sad but not surprising ! Its gotten to the point where no one really knows what should or shouldn’t be !   PS: As a bit of an aside, a deviation from this post, You should see / hear what some so called self made experts are saying about animal droppings that have been scattered throughout the bush, the fields, the natural areas for millennia ! It to is quite unbelievable !




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