G1-G2 Aurora activity for Late September 2020

Northern Lights Now – Geomagnetic activity reached G2 storm levels on September 27 bringing stunning views of aurora to high latitude regions. The activity is the result of a coronal hole high speed stream and is expected to continue for the next three days.

NLN forecast shows periods of G1 and G2 activity each of the next three days
NLN forecast shows periods of G1 and G2 activity each of the next three days

Update 07:30 UTC 9/29/2020 03:00 EDT

Geomagnetic activity reached G1 levels occasionally this evening as predicted. Conditions have moderated and the aurora is much less active now. At the beginning of the period, solar wind speed were around 625 km/s. They have since decreased to around 575 km/s. The biggest factor in the decrease in activity is the Bz. Look at how variable it has been over the last 12 hours:

Bz has been variable over the last 6 hours.
Bz has been variable over the last 6 hours.

During the period of G2 storming, there was over 4 hours where Bz was sustained south. Any deviation into north (positive on the chart) puts an immediate damper on northern lights activity. The CH HSS is expected to remain geoeffective for the next 24-48 hours, it is very possible we could get another sustained period of south-oriented Bz. Keep an eye on the solar wind data!

Original Post

Solar wind speeds reached 640 km/s, the highest readings Since the beginning of August. The higher activity is associated with a Northern Hemisphere coronal hole. The coronal hole has a wide longitudinal opening – meaning that it will influence Earth’s magnetosphere for several consecutive days. In addition, the remains of AR 2773, shown below as a brighter area to the left, are just to the East of the CH and have the potential to inject higher wind speeds and density into the stream.

Late September 2020 coronal hole with the refinements of AR 2773 just to its east
Late September 2020 coronal hole with the refinements of AR 2773 just to its east

To know exact timing of the expected activity, keep and eye on the solar wind. Generally, the more bars there are on the chart, and the taller they are, the more likely there will be higher KP readings.

Comet Neowise: Sightings Map

Northern Lights Now – Comet NEOWISE is now a rare surprise celestial event capturing the imaginations of millions of people. It was discovered in March 27 by the NEOWISE satellite. As late as the beginning of July, most astronomers expected the comet to be just barely visible by telescope or binoculars. The comet has surprised and is now visible to the unaided eye. Over the next several weeks, even more people will be able to see the comet as it starts to appear in the evening sky.

As a citizen science project, NLN has created a map to allow people to submit their sighting details. The should help everyone have a better chance of seeing the comet. You can visit the map here and see the photos that astronomers, amateur astrophotographers, and dark sky fans have shared.

Do you have a NEOWISE comet sighting to submit? Follow the link, add a pin, upload your photo with some date and time information and help the community.

Happy Hunting!

Comet NEOWISE: How to See it

Northern Lights Now – Comet NEOWISE will be visible in the Northern Hemisphere In July and August 2020. The best viewing times will be just before dawn between July 1st and July 15th, then in the evenings starting around July 12 and continuing in to August. In the mornings, the comet and it’s tail can be seen in the Northeast sky about 80 minutes before sunrise. In the evenings look in the Northwest sky, about 80 minutes after sunset. The comet won’t be visible in the Southern Hemisphere.

The comet is visible low on the horizon. This means viewers need an unobstructed view with no trees, buildings, mountains. A higher altitude will also give a better viewing. At the best viewing times there will also still be light in the sky from sunrise or sunset so the darker a place the better. Getting out of the city, climbing a mountain and getting a clear horizon will be increase chances of seeing the comet.

How Bright Will the comet be?

Predicting how bright this comet will be is tough and has defied and surpassed expectations thus far. The best short advice is to get out and see the comet soon because it may not be easy to see for long. Comet brightness is determined several factors:

How close is it to the Sun The closer the comet is to the Sun, the hotter it will be and the more gases and dust will be released from the surface of the comet making the tail bigger and more reflective. The comet was closest to the Sun on July 3, and so should be starting to be dimmer and have a smaller tail each day that goes by.

How close it is to Earth The closer the comet is to Earth, the easier it is to see. The closer it is the larger it will appear in our sky and the longer the tail will appear. More light reflecting off the tail arrives in our telescopes, binoculars, cameras and eyes when it is closer. The comet makes its closest approach to Earth (103 million miles!) on July 22. So until that date, expect the comet to appear bigger and brighter each night.

How reflective the comet and tail are We don’t know the exact structure of the comet. The tail is made up of dust and ice from the surface of the comet. It is entirely possible that an outer layer could burn off and exhaust a large amount of dust and ice into the tail. It is equally possible that the surface could cool and become hard and the tail could dissipate quickly. This is the big unknown in predicting a comet. It might get brighter or dimmer all of the sudden. So appreciate it now before it goes away.

The solar wind This is a more minor factor, but the solar wind interacts with the tail of the comet. If there were a solar storm or a bout of turbulence in the solar wind it could speed the dispersal of the gasses in the tail. This is unlikely as we are currently in solar minimum.

After accounting for each of those factors, astronomers predicted NEOWISE to potentially be just visible to an unaided eye (magnitude 5-7). Reports are already coming in that is has a magnitude of around 1-2 (the smaller magnitude the brighter it is in the sky). It is possible that as it approaches Earth it could become one of the brightest and most obvious objects in the evening sky. Or… It could also wink out tomorrow. So hurry out to see it.

Happy Hunting!