Comet at Dusk

Comet NEOWISE After Sunset

I saw comet NEOWISE at dawn for the last time on July 12th. One day later, on the morning of July 13th, the comet rose above the northeastern horizon in bright skies. As Earth turned during daylight hours the comet circled above Polaris, the North Star, and headed toward the northwestern horizon to appear low in the sky there at dusk. I thought I would need to drive somewhere to find an unobstructed northwestern horizon, but, before doing that, I decided to see if the comet would be visible from my front porch. Just by luck the front porch view included the comet! Here's the front porch scene on July 13th at 9:39 pm DST.

The comet appears under stars of Ursa Major very near the horizon treeline in the lower image center. (You may need to enlarge the image to see the comet.) Neighborhood lights degrade the scene. The next image a few minutes later at 9:44 zoomed in to eliminate foreground lights. It didn't improve the comet's appearance by much.

The convenience of observing from my front porch outweighed the unfavorable neighborhood lighting environment. I was surprised to find the northwestern horizon reasonably clear of clouds because clouds usually increase dramatically by evening at this time of year.

Murky haze occupied the horizon on July 16th. The comet, now higher above the trees, was barely visible through haze at 9:40 as you can see in the next image. I also viewed the comet through my big 25X100 binoculars on this night. The binocular view revealed the bright head and beginning of the tail, but the field of view was too small to see the tail's full extent.

On July 18th the comet was even higher. The next image shows the scene at 9:32.

The next animation shows the comet between 9:33 and 9:44 on July 18th as it sank toward the horizon.

A few nights later I discovered the comet was high enough to appear above the roof in my backyard. This offered limited escape from lights visible from the front porch. Unfortunately, the usual thick haze made images nearly worthless. Since July 18th I've had no luck seeing the comet in clear sky. 

After three or four evenings observing the comet I noticed an increasing accumulation of bug bites on my legs. On all nights I struggled to get images with my old DSLR, but discovered every single one of these images was out of focus. The old DSLR just isn't made for night images. It's extremely hard to tell if stars are in focus when looking through the tiny viewfinder, and setting the focus to infinity still leaves stars unfocused. I envy the many beautiful images from photographers throughout the world made with more modern cameras in dark skies with higher ISO numbers. The only way to surpass the images from my phone is to buy a new camera more suited to night sky photos.

The comet is now fading as it moves further from the Sun. It was fun while it lasted. 

Comet at Dawn

Comet NEOWISE Before Sunrise

Comet C/2020 F3 NEOWISE has been surprisingly bright and pleasing this July! (NEOWISE stands for Near Earth Object Wide Infrared Survey Explorer - the Earth-orbiting satellite that discovered the comet. C/2020 means a non-periodic comet discovered in 2020. F3 means the 3rd comet discovered in the second half of March.)

On three successive mornings my drowsy body stumbled outside well before dawn at 3:50 am to set up a tripod-mounted phone camera in my backyard. The first attempt on July 10th was unsuccessful. The sky was clear everywhere to the northeast except at the position of the comet! In the next picture the comet was hidden behind clouds stretching across rooftops and treeline.

Bright Venus is peeking out just above the clouds on the right edge. The stars in the center are part of the constellation, Auriga, whose brightest star, Capella, is centered in the image. 

The next day, July 11th, presented only one momentary glimpse of the comet during a temporary cloud gap. An arrow points to the comet in the next image. You may have to click on the image to enlarge it so you can see the comet.

Finally, on July 12th, success! At 4:20 am DST I first detected the comet's tail rising above a rooftop. The next animation shows the rising tail along with troubling clouds approaching from the west during 8 minutes between 4:20 am and 4:28 am.

My backyard is a convenient viewing location, but it's not ideal. Neighboring porch lights reflect from vinyl siding even when I'm shielded from direct view to lights. I hunkered down behind fencing to escape most lights. 

On this July 12th morning the sky was completely clear except for one large patch of clouds initially not blocking the comet. It wasn't long, however, before I discovered the clouds slowly moving toward the comet. I used the zoom feature on my phone camera to try keeping approaching clouds out of the frame. The next animation shows clouds creeping in from the left defeating my attempt.

The time between 4:32 am and 4:35 am is shown in the next animation made with even higher zoom as clouds invaded.

The comet was rising higher, but clouds were getting closer. I wish I had stayed in one position with one zoom factor. Then I could have produced longer, more continuous animations.

The next single zoomed image taken at 4:36 am is the best image I got of the comet's head and tail.

As clouds moved closer I zoomed out to show a pretty scene at 4:40 am. Bright Venus is very close to the star Aldebaran in the v-shaped Hyades cluster on the lower right. Also, on the right above Venus is the Pleiades star cluster. Soon after this, clouds covered the comet as the sky brightened.

This experience is motivating me to purchase a better camera - a new, modern DSLR with good night sky capability. My phone camera is surprisingly effective, but limited. All the images above were made with 10-second exposures.

The comet is now moving into the early evening sky in the northwest. During summer months clouds usually build during the day, so a clear northwestern horizon is unlikely. But, maybe, with luck, I'll have an opportunity to get more images during the evening apparition.

  

Solar Energy Production

Solar Panels in Action!

After passing all inspections and approvals my ten solar panels are finally producing usable energy. 😎

I can monitor solar energy production throughout the day on my laptop and phone. For example, the next image shows energy produced on June 26th, the best day I've had so far.

June 26th began with completely clear skies which lasted until about 2:00 pm. After 2:00 pm hazy clouds slowly thickened until sunset. Although thin clouds covered most of the sky, energy production continued as significant sunlight continued to reach the panels.

Notice how the production curve above is almost perfectly symmetric. I believe this results from the smoothly changing angle of sunlight on the panels throughout the day.

Imagine two arrows. One arrow points down perpendicularly into the solar panels. Call this the panel arrow. The panel arrow direction is fixed because the panels are rigidly attached to my immovable house. The second arrow points from the Sun to the panels. Call this the solar radiation arrow. The solar radiation arrow changes direction from sunrise to sunset as the Sun changes elevation and moves across the sky. When the solar radiation arrow is parallel to the panel arrow (that is, when there is zero angle between the two arrows) sunlight falls perpendicularly on the panels for maximum absorption. When the solar radiation arrow is perpendicular to the panel arrow, no solar radiation falls into the panel because radiation then skims along parallel to the panel surface without entering. During the day the angle between the two arrows varies smoothly, from some large value as the Sun rises, up to some minimum amount near midday, and then back to some large value as the Sun sinks. Radiation absorption varies with the changing angle between the two arrows. Energy production varies with the cosine of the angle between the arrows, or vectors. It varies with the "dot product" of the two vectors.

Also notice the flat peak energy production around noon when the Sun was highest in the sky. It looks like the panels produce the same maximum amount of energy for a few hours while the angle between the two vectors is near minimum. I investigated radiation absorption issues in detail for my particular system. For the day of June 20th I explicitly calculated the angle between the panel vector and the solar radiation vector between the hours of 9:00 am and 2:00 pm (DST). The minimum angle value of 0.61 degrees occurred near 11:30 am when radiation absorption was 99.99 percent of the maximum possible. The absorption rate was greater than 98 percent for one hour and 40 minutes from about 10:40 am to 12:20 pm. During this time the angle between the two vectors was 11 degrees or less. This calculation is only valid for one day, June 20th. Obviously, the Sun will take different paths across the sky at different times of the year. 

Another interesting phenomenon is illustrated in the June 26th graph above. Notice the asymmetrical tail after about 6:00 pm. After about 6:00 pm on June 26th my roughly southeastward-facing panels were in the shade! The Sun was still above the horizon, but below my roof peak line. Yet some energy was still being produced! I think reflected sunlight from the sky, clouds, and surrounding buildings was still falling on the panels, so they were still producing some energy.

My system was activated on June 18th, two days before the summer solstice! This is the best time of year for solar energy production when the Sun is highest in the sky and above the horizon for the longest time. I hoped to see what would happen on a cloud free day day with transparent blue skies from sunrise to sunset. Unfortunately, in my area of Virginia at this time of year, clouds show up in some form almost every day. For example, on June 22nd the morning was clear, but afternoon thunderstorms developed and cut off energy production after about 2:30 pm as you can see in the next graph.

On June 23rd the morning was cloudy, but the afternoon was mostly clear. So not much energy was produced during the morning in the next graph.

June 25th was cloudy and rainy almost all day. Nevertheless, enough infrared light fell on the panels to produce some energy, as you can see in the next graph below. It's amazing how the panels still produce energy even on cloudy days in the absence of bright yellow sunlight. Obviously, some visible and infrared light is getting through the clouds. Otherwise we would be stumbling around in complete darkness on a cloudy day.

A new electric meter was installed to accommodate solar energy production. The new meter continuously cycles between four different digital displays. Two displays are irrelevant. The other two displays alternate between the amount of energy I have received from Dominion Power and the amount of energy the panels have put back into the Dominion power grid.

Meter readings on the morning of June 19th showed 10 kwhrs received from Dominion and 5 kwhrs sent back to Dominion. We were gone for the next week. When we returned on June 26th meter readings showed we had received 35 kwhrs from Dominion and sent back 95 kwhrs to Dominion! We were a net energy producer during that week! Of course, we were away, so only the refrigerator and occasional air conditioning needed power.

How much energy is used by various electrical devices in my house and how much energy can the panels deliver? The kilowatt-hour (kwhr) is the relevant energy unit here. Over the past 19 days the panels have produced a daily average of 16.3 kwhrs. Here are some examples of energy use.

The energy needed to fully recharge a completely discharged car battery in my Chevy Volt hybrid is about 17.5 kwhrs. This would require a full day of solar energy collection on most days. But I almost never completely discharge the battery in typical trips around town. Instead, it usually takes only 2 to 8 kwhrs to bring the battery to full charge after local drives. This amount could be completely supplied by the panels. It's interesting to think I can be driving my car around town completely powered by solar energy!

Air conditioning is our major household electrical energy requirement. We usually only run air conditioning overnight. Our small house is so well insulated that overnight cooling is sufficient to keep the house comfortable during most of the daylight hours. A typical hot, humid, overnight air conditioning run might use about 16 kwhrs. So the panels could supply this energy amount during a day of operation. Of course, the panels don't produce energy overnight, but any extra they produce during the day is sent back to Dominion Power and deducted from our bill.

Laundry also requires substantial energy, especially the electric dryer. Laundry day consumes about 11 kwhrs.

Let's consider a day when the temperature is in the 60's all day and night. Then air conditioning isn't needed. If the washer and dryer aren't used, and the electric car doesn't require recharging, only the refrigerator, a few lights, laptops, stove, and the TV need power. In this case our house typically only consumes about 4 kwhrs during the day! The panels easily deliver this amount and send extra energy back to Dominion under these circumstances. Energy consumed by lights in our house is negligible.

Of course, the financial bottom line comes with an actual electric bill. So far I haven't received a bill with kwhrs displayed. Dominion Power said it would take "two billing cycles" before my new situation was entered in their system. In the meantime, naturally, they are still deducting payment. Somehow they can manage to calculate and obtain their payment, but they can't manage to produce a bill. Such is the wonder of modern technology. Last year my bill for June was $65.12. This year, with the panels operating from June 18th onward, the June bill was $41.44. Last year during July we used 945 kwhrs. This July, with the panels, we are on track to use less than about 400 kwhrs from Dominion. So my July bill should be cut approximately in half. It will be very interesting to see how much money we actually save during the course of a year.

Fun at the Beach

Outer Banks 2020

A June trip to the beach in Southern Shores, NC is becoming a family tradition. This year my daughter, Ellen, joined us earlier than usual. Ellen and her Mom really enjoy the beach and set off directly for some time by the sea.

We had a bit more rain this year compared to other years, but not enough to ruin the trip. One evening a passing thunderstorm produced a beautiful rainbow over the ocean.

A porch overhang blocked the view in the previous picture. There was a better panoramic view from the rooftop crow's nest. (Click on the images to get a bigger view.)

Ellen and her Mom went down to the beach to see the rainbow.

One morning I finished my run at the beach overlook where I was surprised to find three guys dressed in Samurai outfits slowly practicing ritual movements with swords. Daggers were also stuck nearby in the sand.

One of our silly traditions is completing a big jigsaw puzzle during our stay. This year we assembled the 1,000-piece Tree of Life puzzle.

The puzzle was finished surprisingly quickly this year.

Keegan was kind enough to bring my mountain bike along on his bike carrier so we could take a family bike expedition. Ellen now rides a massive electric bike to pull Annabelle's big trailer. Our rental beach house is in the background.

The main road, Route 12, has no shoulders and is usually filled with non-stop traffic. It's not suitable for a relaxed bike ride. Although Route 12 has a narrow bike trail along much of its length, this trail is crowded with walkers and runners. It was also flooded in many places by recent rain. We rode, instead, on lovely, wide, quiet, traffic-free side streets through beautiful neighborhoods.

When not romping in the water, Sophie looked quite grown up reading on the beach.

We went to see the sunset one beautiful evening on the Duck boardwalk. Unfortunately, Annabelle was not very happy doing this. Her continual complaints made us cut the evening short.

Grandma tried to comfort Annabelle.

It was a lovely evening.

Next year we might try a new rental house to keep Annabelle a bit happier.