2020 Nebraska Star Party: What Might Have Been

Fans of NSP know it was cancelled for 2020 due to the pandemic. The cancellation may have seemed a bit premature when it was announced on June 12, but to me it was clearly the right thing to do. During the last month the virus has been spreading almost unchecked in some parts of the country. Nebraska itself has seen a mild rebound in the number of positive tests, but not nearly as bad as what is happening elsewhere. Possibly the good people of Nebraska have more sense than those in a few other states and they're not afraid of masks?

The 2019 NSP was a real dud with only one decent night of the five I was there. Mostly it was clouds and rain. There was hope that 2020 would be better. Then came the virus.

What follows is a night by night summary of what the 2020 NSP sky would have been, based on satellite cloud images, North Platte radar, and observations at Valentine. I don't use cloud observations from Valentine because I don't trust their accuracy. (Valentine will sometimes report clear skies when there is high overcast; go to the bottom of this entry to see an example.) I don't doubt some people are staging a private NSP and can provide better estimates, but until they report I'll depend on my estimates.

Please note that all times are approximate. The time of total darkness each night is now five hours six minutes, extending from about 11:17 P.M. to 4:23 A.M. I'll take this as five hours and rate each evening on a five-star basis; one star awarded per hour of possible imaging. A perfect night would look like (⭐⭐⭐⭐⭐). Because I usually arrive on Sunday and depart Friday morning I'm only going to report on five evenings. How many stars will NSP 2020 earn of the possible 25?

Sunday, July 19 (No Stars)

Daytime: High 87° with dew point around 61° most of the day.

Overnight was cloudy from dusk to about 4:15 A.M. with thunderstorms and rain around 11 P.M. and again at about 12:15.

Monday, July 20 (⭐⭐⭐)

Daytime: High 88° with dew point again around 61° most of the day. Thunderstorms with rain from about 8 until 9 P.M.

Overnight: Overcast until about 12:30 A.M., then clearing with occasional clouds until about 4 AM. About three hours of imaging were possible.

Tuesday, July 21 (No Stars)

Daytime: High 84° with dew point around 59° or 60° most of the day.

Overnight: Blowoff from thunderstorms in southeastern Wyoming spread overhead between 9 and 10 PM. Clearing began around 4:30 A.M. No precipitation was indicated by radar.

Wednesday, July 22 (⭐⭐)

Daytime: High 92° with a 69° dew point (heat index a very sticky 97°). At 9 P.M. (20m before sunset), it's 83° with dew point temperature 69°, winds are 14mph, and cloud cover is about 50%.

Overnight: A poor quality night, with broken high clouds most of the hours of darkness. Occasional wind gusts around 21mph, and heavy dew from dew point temperatures between 71° and 69°. "Clearer" periods from 11:30 P.M. to 1 A.M. and 2:00 to 3:00. Probably some light frames could be gathered during these short holes? If not, then it's a zero stars night.

Thursday, July 23 (No Stars)

Daytime: An even more unpleasant day (96° with a 67° dew point at 4 P.M., heat index 100°), but without the relief of the Wednesday air-conditioned high school.

Overnight: Persistent scattered clouds until a little past midnight, then cirrus from a thunderstorm passing to the south. Winds gusting up to 32mph until 3 A.M. Dew point temperatures around 69 all night. I think the clouds and wind would have essentially caused this evening to be useless for imaging. Visual observers would do better, but the scopes would have been bouncy and the transparency poor for much of the evening.

Friday, July 24 (No Stars)

If you would have hung around for Friday, ugh. The day was miserably hot and humid with a high of 99° and dew point of 70° most of the day. And then there were the thunderstorms and clouds to ruin the evening. A complete loss.

Saturday, July 25 (No Stars)

Well, wow. Hot, miserable day, then storms and clouds again. This completes one week of what might have been NSP 2020.

Summary

There were only 5 hours of imaging out of 25 possible:

Sun 😡😡😡😡😡
Mon 😡😡⭐⭐⭐
Tue 😡😡😡😡😡
Wed ⭐😡😡⭐😡
Thu 😡😡😡😡😡
Fri 😡😡😡😡😡
Sat 😡😡😡😡😡

It's even worse if you include the two additional washouts of Friday and Saturday: 5 good hours out of 35 possible, the equivalent of one good night in a week. It was a very good year to stay home; the virus didn't deprive you of much.

I hope to make it to NSP 2021! It has to be better than NSP 2019 and NSP 2020!

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Here's an example of problems with cloud reporting. This is not unique to Valentine, but is a consequence of how cloud observations are made in this era of automation by devices called ceilometers. A quote from an abstract for a 2016 study of ceilometer errors indicates the problem:

The limited areal coverage of ceilometers results in error when skies are heterogeneous, but these errors are small compared to those caused by the limited vertical range: observations of clear sky or few clouds are often in error as the instrument cannot detect the presence of upper-level clouds. [My emphasis.]

The hourly report for Valentine, NE on July 24 at 5:52 P.M. CDT. indicates CLR (i.e., clear) sky at 5:52 P.M. CDT.

A satellite image of Cherry county and Valentine taken four minutes later at 5:56 P.M. shows the sky is at least half covered with high clouds.

The position of the Valentine weather station is just south of the letters KVTN, at Valentine Municipal Airport.

Unfortunately it is often the case that clouds causing considerable extinction are completely missed by weather reports. This is partly by intent, as high clouds are not of importance to aviators.

The lesson here is: Don't assume the sky is clear because a station report says it is. It may in fact be unsuitable for imaging.