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Issues with objects being "ripley" or almost as if they are viewed through heat

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#1 arian487

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Posted 10 April 2021 - 05:58 PM

So I recently bought an ethos 6mm and a delos 17mm and I was in death valley over the week. I woke up really early to catch jupiter and saturn rising and the viewing was less good then expected. When viewed with the ethos the images were quite blurry almost as if they were being viewed through a heat source. Even viewing the moon I noticed the same ripley effect and the moon was rising quite late as well. I noticed this affect with both the delos and ethos though it was more pronounced with the ethos.

As time went on they did improve a bit though so perhaps it was just because they were very low on the horizon and also in the same general direction as las Vegas where I could see a hue of light pollution in the air. I don't have enough experience to know if there was something I did poorly or if the conditions were not ideal. I couldn't wait around for too long for the planets to rise higher since they were only up for a couple hours before it started getting light out.

#2 Sheol

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Posted 10 April 2021 - 06:04 PM

               This is what is known as "Bad Seeing" and is caused by heat rising & causing the air to be unstable. It is often severe in deserts in the evening & no amount of fancy, expensive EP will fix it. The higher your magnification the worse it will be..

               Also, always make sure your scope has an hour or two of sitting outside before you start viewing.

               Blacktop, concrete, & fine coral type sand may make it worse, also..

 

                       Clear Skies,

                           Matt.


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#3 Tangerman

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Posted 10 April 2021 - 06:08 PM

Welcome to viewing at high magnifications! The rippling is an effect of seeing, which is basically how stable all the air is that you're looking through. If the air is moving (and not all the movement is together; for instance, a small, uniform breeze doesn't really affect things), then it'll look like you're viewing above a heat source. Another source of this could be your telescope optics still cooling down, although as this was early in the morning, I suspect this wasn't the case. The higher the magnification, the worse this gets, and it's difficult to predict when it will be bad. Many places out west have generally poor seeing. When I moved from Utah to Atlanta, I was astounded at how many more details I could see in planets and how steady they appeared. Atlanta seems to be one of the few places with good seeing, though, but as you gain more experience, you will have nights of good seeing. Nights where seeing is bad can still be well used looking at galaxies and nebulae and the like.


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#4 barbarosa

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Posted 10 April 2021 - 06:51 PM

You don't say where you were, in the valley at Furnace Creek of a camp site way up in the mountains. If you were in the valley, quite near sea level one way or the other, your view is complicated by particulates raised by the surface winds, two mountain waves, and quite often 100mph winds aloft this time of year. The Las Vegas and LA light domes are trivial factors.

 

Low magnification views of DSOs at higher angles are often quite good and once you get away from direct lighting it is impressively dark. My little story. We drove up to a parking area north of the HQ to set up an 8" SCT. When we arrived the lot was filling with cars and there were many LED lamps along the paved trail from the paved lot.  A naturalist was giving a talk about the night sky so we dropped in to ask about the lights. "Why the lights?" said the naturalist, "Because people complained that the area was too dark for comfort."

 

Those who want the best dark sky experience do not go to the valley. There are campgrounds at 4000, 7000 and 8000 feet in the park. Some are easy to reach, some might be better with a 4wd vehicle.


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#5 arian487

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Posted 11 April 2021 - 01:51 AM

Very informative replies! Thanks. I also tried to find some DSOs but I was totally inept at that, going to require some more practice. I'll probably take my scope the next time I go to Yosemite and try again! I'll be at higher elevation then when I was in death valley.

#6 Tony Flanders

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Posted 11 April 2021 - 05:55 AM

I can imagine that Death Valley at predawn might have truly awful seeing. On a clear windless night in a valley cold air sinks down from the sides and pools on the floor, where under certain circumstances pools of cooler and warmer air can roll around more or less at random, leading to wildly wavering images. And of course viewing objects that are low in the sky hugely exacerbates any possible problems due to thermal instability.

 

You would probably get far better views of Jupiter and Saturn in the predawn from the California coast, where the ocean acts as a giant thermal moderator. In fact the California coast is famous for good seeing.



#7 BromoGNU

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Posted 12 April 2021 - 10:44 AM

. I woke up really early to catch jupiter and saturn rising and the viewing was less good then expected. When viewed with the ethos the images were quite blurry almost as if they were being viewed through a heat source. Even viewing the moon I noticed the same ripley effect and the moon was rising quite late as well. I noticed this affect with both the delos and ethos though it was more pronounced with the ethos.

I get this even in New England, it's atmospheric turbulence.  And it changes depending upon the layers of air from ground to space and weather day to day.  When everything lines up right, you will see much less of that ripple effect and people will change plans when it's coming.

I was wondering on the weather astronomy site I use also indicates the arc-second resolution caused by the air.  Here in my coastal micro climate ghe seeing is typically 1.5 arc seconds, which makes an aperture of 127mm overkill for resolution.  (Might not be for light gathering, and some seeing nights it can get as low as 0.6 or so, which would mean a 10 inch aperture (254mm)  would be just fine.

The arc second resolution by aperture is R= 134/D (R= arc second resolution, D= Aperture in millimeters)

The site I use, Meteoblue can predict the seeing with far more information than I know how to process yet, and there are other sites, too.

I had one night I was observing, and the biggest magnificaiton I could support was 60x, it was awful seeing, but it still was glorious and beautiful!  Just like fisherman say:  A bad day of fishing beats a good day of work.


Edited by BromoGNU, 12 April 2021 - 10:55 AM.


#8 Dave Mitsky

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Posted 12 April 2021 - 12:06 PM

The following articles discuss seeing:
 

http://www.damianpeach.com/seeing1.htm
 

http://www.damianpea...m/pickering.htm
 

https://skyandtelesc...ing-the-seeing/
 

https://www.skyatnig...nomical-seeing/



#9 Starman1

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Posted 12 April 2021 - 12:56 PM

So I recently bought an ethos 6mm and a delos 17mm and I was in death valley over the week. I woke up really early to catch jupiter and saturn rising and the viewing was less good then expected. When viewed with the ethos the images were quite blurry almost as if they were being viewed through a heat source. Even viewing the moon I noticed the same ripley effect and the moon was rising quite late as well. I noticed this affect with both the delos and ethos though it was more pronounced with the ethos.

As time went on they did improve a bit though so perhaps it was just because they were very low on the horizon and also in the same general direction as las Vegas where I could see a hue of light pollution in the air. I don't have enough experience to know if there was something I did poorly or if the conditions were not ideal. I couldn't wait around for too long for the planets to rise higher since they were only up for a couple hours before it started getting light out.

1) Don't observe any object below 30° unless you have to (in the deep south).  Wait for it to rise above 30°.  The air is twice as thick at 30° as it is at the zenith, and 10x as thick on the horizon.

Think about all that extra dust, smog, water vapor, etc.

2) make sure the source of heat isn't in the scope.  Make sure to use a fan or fans to cool the scope, and/or leave it out for at least 3 hours after dark before trying high magnifications.

3) in the desert, the air is turbulent with heat release until around midnight.  The best seeing is typically midnight until dawn.

4) every night will have a peak magnification due to seeing.  In my 12.5", it has been as low as 130x and as high as 777x.  Stable seeing at really high powers is rare.  Observe often, and you'll encounter nights of good seeing.

You'll also encounter nights of horribly bad seeing as well.

5) the planets will improve over the next few months.  When they reach the point of being on the N-S meridian at dawn until the date they reach the meridian at sunset is the period of time for best viewing.


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#10 Barlowbill

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Posted 13 April 2021 - 07:03 PM

What is your scope, please?



#11 Jon Isaacs

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Posted 13 April 2021 - 08:24 PM

1) Don't observe any object below 30° unless you have to (in the deep south).  Wait for it to rise above 30°.  The air is twice as thick at 30° as it is at the zenith, and 10x as thick on the horizon.

Think about all that extra dust, smog, water vapor, etc.

2) make sure the source of heat isn't in the scope.  Make sure to use a fan or fans to cool the scope, and/or leave it out for at least 3 hours after dark before trying high magnifications.

3) in the desert, the air is turbulent with heat release until around midnight.  The best seeing is typically midnight until dawn.

4) every night will have a peak magnification due to seeing.  In my 12.5", it has been as low as 130x and as high as 777x.  Stable seeing at really high powers is rare.  Observe often, and you'll encounter nights of good seeing.

You'll also encounter nights of horribly bad seeing as well.

5) the planets will improve over the next few months.  When they reach the point of being on the N-S meridian at dawn until the date they reach the meridian at sunset is the period of time for best viewing.

 

:waytogo:

 

An hour before sunrise in Death Valley, Jupiter was at 15° elevation, Saturn was at 21°.  Getting a crisp view of the planet's so low on the horizon is quite rare, particularly when looking out of a hole in the desert.

 

One might go the Death Valley for darker skies but it's a poor location for viewing the planet's.

 

Jon


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#12 michael8554

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Posted 14 April 2021 - 05:27 AM

"Ripley" ?

 

She's good to have around for them pesky Aliens.......:->




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