I would like to invite any interested people (or other semi-sentient and higher level of consciousness beings) to participate in an end of season, Astronomical Show And Tell, at our general meeting tommorrow. As previously worded, astro-imagers, gear heads, software freaks, and adventure nuts are invited to contribute. Available time is dependent on participation. Early arrival will help coordination. Hook-ups and projector are available for your laptop. Show your best pictures, tell your tallest tales. With warmest regards, Dave Bernson. 2010 President, Salt Lake Astronomical Society. ____________________________________________________________ Mortgage Rates Hit 3.25% If you owe under $729k you probably qualify for Obama's Refi Program http://thirdpartyoffers.juno.com/TGL3141/4cbc8985e1f8637c7a7st01vuc
Hello -- I've always been curious to qualify for myself the effect of the moon on deep sky observing. I was in LA last week when we had the good weather and no moon, so it's been about a month since I've been out. I decided to go this morning and take advantage of 1 1/2 hours without moon, and I added a little time with moon to the beginning. I crossed the 300 line on the H400 list... So I started at about 4:30am in the driveway at Rockport State Park. The moon was up a little in the west, but I was looking mostly south in CMaj, Mon, and Pup. It was nice to be able to set up by moonlight. I did not fail to find any of the ten or so open clusters I was looking for in the area. None was particularly faint, but most were somewhat diffuse. By 5:00, the mountains to the west had blocked out the moon. I kept going in Puppis, and caught Zeta Pup over the horizon, so I reached down for the fantastic NGC 2477. The other big-and-bright cluster nearby (I forget its number) was not naked eye, due to being so close to the horizon, but nice in the scope. After the moon was mostly obscured, I found some small and faint galaxies in Lynx and Leo Minor. These were the most difficult targets, but not so bad. So I'm curious about other peoples' experience: how far away from an object does the moon have to be to affect its visibility? If the moon is out, and near full, but on the other side of the sky, does it have little effect? If it is still technically not set, but obscured from view by a mountain, is that even better? Even when set, you can still see the light from the moon. Is this basically benign, if you're looking the other way? First subfreezing observing session of the season for me! Much dew collected on my beard, but my equipment was not much affected. Even my books and notebooks stayed somewhat dry. ---- Rev. Michael A. van Opstall Department of Mathematics, University of Utah Office: JWB 313 opstall@math.utah.edu
Well, I think the effect of the moon is two-fold. It affects your dark adaption and decreases the darkness of the sky. If there are clouds the moon light will illuminate them and increase the moons effect. It sounds like you chose your objects fairly well, while star hopping may be harder star clusters seem less effected to the loss of contrast.
For me a moon limits me to double stars, clusters, planets, and planetary nebula, IE objects that a gray sky will effect less. It does help to look in the opposite direction but it seems once the moon is up the sky gets gray, IE less black and contrast decreases. Hello --
I've always been curious to qualify for myself the effect of the moon on deep sky observing. I was in LA last week when we had the good weather and no moon, so it's been about a month since I've been out. I decided to go this morning and take advantage of 1 1/2 hours without moon, and I added a little time with moon to the beginning. I crossed the 300 line on the H400 list...
So I started at about 4:30am in the driveway at Rockport State Park. The moon was up a little in the west, but I was looking mostly south in CMaj, Mon, and Pup. It was nice to be able to set up by moonlight. I did not fail to find any of the ten or so open clusters I was looking for in the area. None was particularly faint, but most were somewhat diffuse.
By 5:00, the mountains to the west had blocked out the moon. I kept going in Puppis, and caught Zeta Pup over the horizon, so I reached down for the fantastic NGC 2477. The other big-and-bright cluster nearby (I forget its number) was not naked eye, due to being so close to the horizon, but nice in the scope.
After the moon was mostly obscured, I found some small and faint galaxies in Lynx and Leo Minor. These were the most difficult targets, but not so bad.
So I'm curious about other peoples' experience: how far away from an object does the moon have to be to affect its visibility? If the moon is out, and near full, but on the other side of the sky, does it have little effect? If it is still technically not set, but obscured from view by a mountain, is that even better? Even when set, you can still see the light from the moon. Is this basically benign, if you're looking the other way?
First subfreezing observing session of the season for me! Much dew collected on my beard, but my equipment was not much affected. Even my books and notebooks stayed somewhat dry.
---- Rev. Michael A. van Opstall Department of Mathematics, University of Utah Office: JWB 313 opstall@math.utah.edu
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Michael, This is my experience based on my observing and my secondary hobby of sketching what I observe with the goal of capturing details in the objects. First, we know that the Milky Way itself impacts visual observing by the glow that it casts and thus the moon will also have a much greater impact. With the full moon up DSO's near it or in that half of the sky tend to lose contrast and detail that I normally can make out when there is no moon. Same holds true for DSO's across the sky opposite of the bright moon (say 70% gibbous, waxing or waning to the full) but to a slightly less extent. Details are still not as good as no moon because the sky's color changes causing a loss of contrast. I have found and I have also read online (can't find it right now) that with that large of the moon rising, sky glow in the east is impacted anywhere from 30 minutes to about 60 minutes from the rising/setting of the moon. I can see an impact about 20 to 30 minutes at max. before the rising of the moon while at setting in the western sky I see an impact for about the same personally. Once the moon goes past first quarter and until last quarter is up I usually avoid observing galaxies, PN's because of the loss of detail (unless they are some of the brighter ones), nebula and similar objects. At that time I focus on open clusters, double stars (it's what got me going on the AL Double Star Observing Club) and until its too bright, the moon itself with a good filter to block out some of its light, I use a SkyGlow Filter for that. You may find this older site interesting (though I believe his standard is way too high in the world we live in). http://www.astropix.com/HTML/L_STORY/SKYBRITE.HTM On Wed, Oct 20, 2010 at 8:20 AM, Michael Vanopstall <opstall@math.utah.edu>wrote:
Hello --
I've always been curious to qualify for myself the effect of the moon on deep sky observing. I was in LA last week when we had the good weather and no moon, so it's been about a month since I've been out. I decided to go this morning and take advantage of 1 1/2 hours without moon, and I added a little time with moon to the beginning. I crossed the 300 line on the H400 list...
So I started at about 4:30am in the driveway at Rockport State Park. The moon was up a little in the west, but I was looking mostly south in CMaj, Mon, and Pup. It was nice to be able to set up by moonlight. I did not fail to find any of the ten or so open clusters I was looking for in the area. None was particularly faint, but most were somewhat diffuse.
By 5:00, the mountains to the west had blocked out the moon. I kept going in Puppis, and caught Zeta Pup over the horizon, so I reached down for the fantastic NGC 2477. The other big-and-bright cluster nearby (I forget its number) was not naked eye, due to being so close to the horizon, but nice in the scope.
After the moon was mostly obscured, I found some small and faint galaxies in Lynx and Leo Minor. These were the most difficult targets, but not so bad.
So I'm curious about other peoples' experience: how far away from an object does the moon have to be to affect its visibility? If the moon is out, and near full, but on the other side of the sky, does it have little effect? If it is still technically not set, but obscured from view by a mountain, is that even better? Even when set, you can still see the light from the moon. Is this basically benign, if you're looking the other way?
First subfreezing observing session of the season for me! Much dew collected on my beard, but my equipment was not much affected. Even my books and notebooks stayed somewhat dry.
---- Rev. Michael A. van Opstall Department of Mathematics, University of Utah Office: JWB 313 opstall@math.utah.edu
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-- Jay Eads
--- On Wed, 10/20/10, Michael Vanopstall <opstall@math.utah.edu> wrote:
From: Michael Vanopstall <opstall@math.utah.edu>
So I'm curious about other peoples' experience: how far away from an object does the moon have to be to affect its visibility? If the moon is out, and near full, but on the other side of the sky, does it have little effect? If it is still technically not set, but obscured from view by a mountain, is that even better? Even when set, you can still see the light from the moon. Is this basically benign, if you're looking the other way?
Rev. Michael A. van Opstall Department of Mathematics, University of Utah
With long drive times and equipment setup I prefer to have at least a 4 hours of no moon between the astro twilight times for dark sky viewing.
From a very dark site I can detect the lunar twilight up to 2 hours from the rise or set of the half moon. Even a 20% crescent will make a glow that mimics the zodiacal light. So I pick a location where the moon will rise or set over the distant city glow where it will leave me the most dark horizions.
For social events for the public I will go out and look at the moon itself but I prefere a second option like Jupiter or Saturn to make the night more complete. Last Saturday I set up at SPOC with a bright moon and bright cloud cover but was still able to show people the Hercules cluster, the Ring nebula, the Double Cluster, and the Andromeda Galaxy, as well as Moon, Jupiter, Urans, and Neptune. DT
participants (5)
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daniel turner -
dustynebula＠juno.com -
erikhansen＠thebluezone.net -
Jay Eads -
Michael Vanopstall