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Prenumbral eclipse on July 5th, what’s the best way to capture it?

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#1 Diomedes

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Posted 02 July 2020 - 12:00 AM

Should I take a picture before the eclipse begins and during. Or  maybe record a video - I read this type of eclipse is subtle but will I be able to tell the difference when looking through a telescope ? This would be my first eclipse.



#2 james7ca

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Posted 02 July 2020 - 12:24 AM

You might see a little darkening and a pearl-like shading to the eclipsed part of the moon, but it will be fairly subtle. But, probably the best way to view a lunar eclipse is with binoculars. For imaging you need a fairly wide field.


Edited by james7ca, 02 July 2020 - 12:25 AM.

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#3 Tom Glenn

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Posted 02 July 2020 - 12:31 AM

It’s doubtful that much will be detected by eye, even with binoculars. NASA says penumbral magnitudes less than 0.6 are undetectable. This one is 0.35. Will be an interesting test. I think any visual detection would be borderline and prone to ones imagination. Even imaging will be fairly lackluster. Not a great first eclipse to be honest. See my response in the post below.

 

https://www.cloudyni...y-4/?p=10302354


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#4 james7ca

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Posted 02 July 2020 - 02:44 AM

Tom has raised a valid issue, being that "any visual detection would be borderline and prone to ones imagination." Likely very true given that the changes on the moon will be very gradual and it's unlikely that you will be able to precisely recall what the moon's appearance was 30 minutes ago in comparison to how it appears now.

 

However, I wonder what would happen if you captured a timelapse where you could play back the entire eclipse in just a matter of seconds. To record something like this you'd want the eclipsed moon high in the sky and near to the local meridian (to increase transparency). Unfortunately (for us in the U.S.), this eclipse will be timed so that you'd need to be in central South America to get those kind of conditions. But, maybe central Bolivia will be a good location to try something like this (in La Paz the peak of the eclipse will happen when the moon is at 82 degrees altitude and very near to the local meridian). It certainly would be unlikely from a spot as far north and west as California, since this eclipse definitely favors the eastern areas of North America.


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#5 Tom Glenn

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Posted 02 July 2020 - 03:14 AM

James, I would hazard a guess that if someone was able to capture a series of images throughout the eclipse, as the Moon transited high in the sky as you outline, that you could probably detect a slight dimming on the limb of the Moon that passes into Earth's penumbra.  However, each image would have to be captured and processed with identical settings, and then carefully adjusted so that the exposure is close to identical as possible for the brightest portions of the Moon.  This would necessitate very little change in sky transparency throughout.  Most examples I can find online of penumbral eclipse images are all taken during much deeper eclipses, with penumbral magnitudes well above 0.6, and usually at ~0.9 and above (anything above 1.0 becomes a partial eclipse as the Moon enters Earth's umbra).  I'm just not sure what a 0.35 penumbral magnitude would look like.  However, as you know, from our location the Moon will only be about 14 degrees elevation at the time of maximum eclipse, so we are not in a good position to document this one.  


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#6 MarkGregory

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Posted 02 July 2020 - 03:40 AM

These types of eclipses are not what most people think of when they visualize eclipses. Kind of a bust. However, i never let that deter me from taking a peek. I actually captured a pretty cool image of one in the past using my Sony digital attached to a 32mm eyepiece. I’ll find it. Mark. P.s. I would definitely shoot before and during images. Why not? It will be fun to put them side by side for comparison. If we get clear skies here (doubt it though), I may try to do the same.

 

 

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Edited by MarkGregory, 02 July 2020 - 04:49 AM.

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#7 Diomedes

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Posted 02 July 2020 - 01:33 PM

thanks guys, I'll wait for a more visible one. I'll still try to see if I can notice any difference however imagined lol


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#8 jrkirkham

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Posted 02 July 2020 - 01:45 PM

I was wondering about imaging this eclipse. I lot of times I don't come away with good pictures. I just get a thrill out of exploring the night sky and identifying new objects.

If I were to use a long telephoto lens on a DSLR, then put the camera on totally manual mode, then adjust a full moon picture until is was just slightly underexposed, then took a shot every half hour through the eclipse, I wonder if I would be able to go back and identify the penumbral shadow as it skimmed along the corner of the moon? If it isn't too cloudy it might be worth the experiment.


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#9 Tom Glenn

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Posted 02 July 2020 - 02:15 PM

I was wondering about imaging this eclipse. I lot of times I don't come away with good pictures. I just get a thrill out of exploring the night sky and identifying new objects.

If I were to use a long telephoto lens on a DSLR, then put the camera on totally manual mode, then adjust a full moon picture until is was just slightly underexposed, then took a shot every half hour through the eclipse, I wonder if I would be able to go back and identify the penumbral shadow as it skimmed along the corner of the moon? If it isn't too cloudy it might be worth the experiment.

You would not want to underexpose the Moon for any reason.  A proper exposure for any lunar image of the entire Moon (IMO) has the brightest portions run right up to maximum brightness, without having significant regions clipped to white (just a few pixels is OK).  Exposing much below this level will look unnecessarily underexposed and unnatural.  That aside, recording this event with a telephoto lens and DSLR will be a challenge, because of the issues mentioned previously relating to how weak this penumbral eclipse is.  It is far weaker than any eclipse images you will readily find online.  The images Mark posted above are from a partial eclipse.  This is a penumbral eclipse, and a very weak one at that.  But it doesn't hurt to see what you get.  


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#10 jrkirkham

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Posted 03 July 2020 - 10:10 AM

You would not want to underexpose the Moon for any reason.  A proper exposure for any lunar image of the entire Moon (IMO) has the brightest portions run right up to maximum brightness, without having significant regions clipped to white (just a few pixels is OK).  Exposing much below this level will look unnecessarily underexposed and unnatural.  That aside, recording this event with a telephoto lens and DSLR will be a challenge, because of the issues mentioned previously relating to how weak this penumbral eclipse is.  It is far weaker than any eclipse images you will readily find online.  The images Mark posted above are from a partial eclipse.  This is a penumbral eclipse, and a very weak one at that.  But it doesn't hurt to see what you get.  

Yes, that is what I meant by underexposed. I just wanted to drop the exposure enough to make sure no highlights are blown out. It is so easy to blow out highlights on a full moon. It certainly runs the risk of looking unnatural when the exposure of a full moon is reduced enough for the details to show. I don't think I could capture the subtle differences without bringing the exposure down just a little. The goal wouldn't be to look natural, but to capture the eclipse.

You are probably correct about not being able to detect the eclipse. I don't have a lot of hopes. I seem to always be trying things that don't work out. I am working an an Astronomical League Solar System Club right now. For part of that club I need to observe a lunar eclipse. They don't come around every day. I figure the worst that can happen is not get the picture. The best that could happen is that I could turn in a viable report and learn something new about penumbral eclipses.

I plan to use my DSLR on a tripod and use my wildlife lens. I should be shoot between 800 & 900 mm focal length. I hope this allows me to capture the entire moon, but still be sharp enough to tease out details. If nothing else a night out under the night sky is worth the adventure.



#11 Nicole Sharp

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Posted 04 July 2020 - 11:56 AM

It’s doubtful that much will be detected by eye, even with binoculars. NASA says penumbral magnitudes less than 0.6 are undetectable. This one is 0.35. Will be an interesting test. I think any visual detection would be borderline and prone to ones imagination. Even imaging will be fairly lackluster. Not a great first eclipse to be honest. See my response in the post below.

 

https://www.cloudyni...y-4/?p=10302354

 

How important would light pollution be for photographing a partial penumbral Lunar eclipse?  Since most of the full Moon is illuminated, would that make artificial light pollution less of a nuisance, or since the change in visual magnitude is so small, would artificial light pollution be more of a nuisance?


Edited by Nicole Sharp, 04 July 2020 - 11:57 AM.


#12 Nicole Sharp

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Posted 04 July 2020 - 11:59 AM

Tom has raised a valid issue, being that "any visual detection would be borderline and prone to ones imagination." Likely very true given that the changes on the moon will be very gradual and it's unlikely that you will be able to precisely recall what the moon's appearance was 30 minutes ago in comparison to how it appears now.

 

However, I wonder what would happen if you captured a timelapse where you could play back the entire eclipse in just a matter of seconds. To record something like this you'd want the eclipsed moon high in the sky and near to the local meridian (to increase transparency). Unfortunately (for us in the U.S.), this eclipse will be timed so that you'd need to be in central South America to get those kind of conditions. But, maybe central Bolivia will be a good location to try something like this (in La Paz the peak of the eclipse will happen when the moon is at 82 degrees altitude and very near to the local meridian). It certainly would be unlikely from a spot as far north and west as California, since this eclipse definitely favors the eastern areas of North America.

 

I was planning to do a timelapse using an intervalometer and a DSLR zoom telephoto lens on a fixed tripod.  Depending on the focal length, would need to realign the camera every 15 minutes or so.  Was planning to use 10-second intervals for the intervalometer (40 GB for 6000*4000 RAW), but not sure about what exposure time to use.


Edited by Nicole Sharp, 04 July 2020 - 12:01 PM.


#13 Nicole Sharp

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Posted 04 July 2020 - 12:04 PM

James, I would hazard a guess that if someone was able to capture a series of images throughout the eclipse, as the Moon transited high in the sky as you outline, that you could probably detect a slight dimming on the limb of the Moon that passes into Earth's penumbra.  However, each image would have to be captured and processed with identical settings, and then carefully adjusted so that the exposure is close to identical as possible for the brightest portions of the Moon.  This would necessitate very little change in sky transparency throughout.  Most examples I can find online of penumbral eclipse images are all taken during much deeper eclipses, with penumbral magnitudes well above 0.6, and usually at ~0.9 and above (anything above 1.0 becomes a partial eclipse as the Moon enters Earth's umbra).  I'm just not sure what a 0.35 penumbral magnitude would look like.  However, as you know, from our location the Moon will only be about 14 degrees elevation at the time of maximum eclipse, so we are not in a good position to document this one.  

 

It is forecasting as partly cloudy skies here, so even using an intervalometer in 10-second intervals for 3 hours, some clouds will likely be passing by here and there during the eclipse.  The alternative would be to use 1920*1080 video, but I think 6000*4000 RAW+JPG would produce much better results, especially since I have to use a shorter focal length on a nontracking altazimuth mount to keep Luna in the field of view without having to realign every couple of minutes.


Edited by Nicole Sharp, 04 July 2020 - 12:04 PM.


#14 skysurfer

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Posted 04 July 2020 - 02:03 PM

No way to see it visually, even when the Moon is in the zenith as in Bolivia. It is only one third in the penumbra and as others say, it should be at least 60% when our eyes discern it.

But a time lapse might indeed reveal something, provided all exposures have the same aperture, exposure time and ISO value.

 

I remember a similar event, it was my very first lunar eclipse. As a boy of 10 I did not know the difference between a penumbral eclipse and a real umbral eclipse. It was on 8 Dec 1965, 88% penumbral magnitude, similar to the last one on 10 Jan 2020 (three saroses later). I expected that the Moon would become red, but nothing happened, I did not notice the dimming on one side. So I considered the prediction as fake.


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#15 Tom Glenn

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Posted 04 July 2020 - 02:57 PM

No way to see it visually, even when the Moon is in the zenith as in Bolivia. It is only one third in the penumbra and as others say, it should be at least 60% when our eyes discern it.

But a time lapse might indeed reveal something, provided all exposures have the same aperture, exposure time and ISO value.

 

I remember a similar event, it was my very first lunar eclipse. As a boy of 10 I did not know the difference between a penumbral eclipse and a real umbral eclipse. It was on 8 Dec 1965, 88% penumbral magnitude, similar to the last one on 10 Jan 2020 (three saroses later). I expected that the Moon would become red, but nothing happened, I did not notice the dimming on one side. So I considered the prediction as fake.

Your points are valid.  I constantly see media headlines (referring to the Moon putting on a "show" tonight, etc.) which are only setting people up for disappointment.  These stories hype up the event and only casually mention that the penumbral eclipse will be "difficult" to see, yet they still imply that observers will see something.  This will be especially disappointing to kids and parents who are led to believe they will see something.  


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#16 Diomedes

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Posted 04 July 2020 - 03:39 PM

Your points are valid.  I constantly see media headlines (referring to the Moon putting on a "show" tonight, etc.) which are only setting people up for disappointment.  These stories hype up the event and only casually mention that the penumbral eclipse will be "difficult" to see, yet they still imply that observers will see something.  This will be especially disappointing to kids and parents who are led to believe they will see something.  

I read a few articles just like this, and got very excited. 



#17 Cali

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Posted 04 July 2020 - 08:54 PM

thanks guys, I'll wait for a more visible one. I'll still try to see if I can notice any difference however imagined lol

Diomedes

 

Regardless, be sure to take a look.

 

I have a 127mm Orion Mak too and am looking forward to the view.

 

- Cal



#18 Dave Mitsky

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Posted 04 July 2020 - 09:31 PM

At least, Spaceweather got it right.

 

LUNAR ECLIPSE MAY BE INVISIBLE: There's a lunar eclipse tonight! Bad news: It may be invisible. Eclipse expert Fred Espenak, formerly of NASA, believes that the Moon will not dip deeply enough into Earth's shadow to make the eclipse visible to the naked eye. "I fear the general media is hyping this event when there's really nothing more to see than a Full Moon--although that’s beautiful in its own right," he says. 

 

https://spaceweather...-lunar-eclipse/


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#19 SMark

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Posted 05 July 2020 - 12:05 AM

Saw absolutely no eclipse from Atlanta tonight. Just the same old full moon I see every month.
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#20 Frisky

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Posted 05 July 2020 - 12:35 AM

Nothing here. Tried with binoculars and unaided. No noticeable dip in brightness at all.

 

Joe


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#21 emh52

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Posted 05 July 2020 - 01:03 AM

I shot both visible and IR images as bracket series there "might" be a tiny bit of shading but I am not convinced. The image in thumbnail here and full resolution on flickr. I did not see anything with my eye without the telescope and I had the impression there might be the slightest shading with the telescope but since I also knew where to look that might well be my own expectation. The list is heavy in Tucson which doesn't help. The IR was in the theory the shadow might just show more, which it didn't.

 

The flickr image: https://flic.kr/p/2jiehdn
These are at max eclipse.

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#22 james7ca

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Posted 05 July 2020 - 01:26 AM

I think if you wanted to increase the potential contrast to detect the shadow a blue filter would have been better than IR. The shadow probably tended to be more red than blue, so IR would have made the shadowed area brighter. If you use a red filter on a red object it will appear more white, whereas if you use a blue filter red areas will appear black.

 

That said, to make use of a filter you'd probably want to have the moon as high in the sky as possible since at low elevations you are going to pick up more of a color tint from the atmosphere.

 

I went out at around the time of maximum eclipse but the moon was so low in the sky that the smoke from the local fireworks made the moon appear very yellow/orange colored.


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#23 emh52

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Posted 05 July 2020 - 07:43 AM

I think if you wanted to increase the potential contrast to detect the shadow a blue filter would have been better than IR. The shadow probably tended to be more red than blue, so IR would have made the shadowed area brighter. If you use a red filter on a red object it will appear more white, whereas if you use a blue filter red areas will appear black.

 

That said, to make use of a filter you'd probably want to have the moon as high in the sky as possible since at low elevations you are going to pick up more of a color tint from the atmosphere.

 

I went out at around the time of maximum eclipse but the moon was so low in the sky that the smoke from the local fireworks made the moon appear very yellow/orange colored.

The dust and smoke in the air in Tucson remains terrible from the fire, so while the Moon was higher seeing is really degraded and I too had an orange moon. Perhaps blue might have helped but even so it was not much of an eclipse.


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#24 Steve Cox

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Posted 05 July 2020 - 09:19 AM

I couldn't tell any difference at all here, not even when the Moon's brightness was occasionally masked by some thin cirrus clouds.


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#25 skysurfer

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Posted 05 July 2020 - 12:52 PM

Conclusion: it was a fake eclipse......


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