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Month: December 2022

A little bit of snow

A little bit of snow

The fog gives it that Close Encounters of the Third Kind look. On a related note, these shoes with the Michelin snow tire tread work really well on ice.

Ecoflow Battery + Generator Testing

Ecoflow Battery + Generator Testing

I had mentioned a few months back that I was testing out an EcoFlow Delta Pro portable battery pack. I used it when doing some remote astrophotography late in the summer. It is a pretty compact unit that has 3.6kwh of storage along with a 3.6kw inverter, 1.6kw solar input, and the usual DC outputs.

When I used it this summer I paired it with a small Honda 1800W generator, which worked well. The biggest downside was the lack of integration. Ecoflow has their own generator that is designed to be a companion to the battery unit, so I picked one up.

It is a similar generator to the Honda, being 1800W AC output plus some DC outputs. The biggest advantage is the combination of the autostart (it has an electronic starter) and the integration into the battery unit. It can also run on propane which is very convenient for stored fuel situations.

You can configure the battery back to control the generator. If the battery level reaches a certain level it will auto fire up the generator to recharge the batteries, turning the generator off once things are charged. That makes a super automated power system that doesn’t require much intervention, and is very efficient. Using just a generator alone is very inefficient if you have varying and low loads. With the battery/genset combo you get the advantage of only running the generator at nearly full load to recharge, which is where the engine is most efficient.

There is also the small advantage that the generator has a special DC output for that charging, which removes a second AC/DC conversion.

Happy Birthday to me!

Happy Birthday to me!

Today I am completing my 52 trip around the fusionball in the sky. A friend mentioned the yearly trip in an email recently, and it reminded me of something interesting I learned many years ago. When I was around 8 or 9 I bought a book called ‘Practical Astronomy with you Calculator’ which was a fantastic book explaining how to use a calculator to determine the position of objects in the sky, the locations of the planets, time of eclipses, and other similar things. Of all of the chapters the one on ‘time’ was the most interesting.

The time for the earth to go around the sun is on average 365.24219 days. The extra bit beyond the 365 ( the .24219) was the reason Julius Caesar created the leap year in 45 BC. If you add one day every 4 years you get a mean year of 365.25 days, which is pretty close to the actual. The small error wasn’t seen as that critical, and indeed this leap year scheme lasted until the late 1500s. In 1582 Pope Gregory XIII created the modern Gregorian calendar by adding an extra rule to the Julian leap year system. A leap day would be added every 4 years, but additionally every 400 years three leap days would be skipped (not added). He chose to make it such that if a year was divisible by 100, but not by 400, it would not be a leap year. This meant that the years 1700, 1800 and 1900 were not leap years even though they were divisible by 4. That small change removed 3 leap days every 400 years, which brings the average length of the year down to 365.2425, which is very close to the actual mean 365.24219.

Perhaps even more interesting was that in 1582 the errors of the previous years had accumulated enough to have a noticeable effect on the start of the seasons and the calculation of Easter. To get us back on track Pope Gregory ordered that Thursday October 4th,1582 would be followed by Friday October 15th,1582. The dates between those two don’t exist. Pope Gregory deleted 10 days from the calendar to get us back on track. It is an oddity of the calendar that most people don’t notice.

There was a cool party trick I learned for quickly calculating the ‘day of the week’ from any given date. You can ask someone their birthdate and quickly tell them what day of the week is was on (a Monday for instance). However that trick only works for days after October 15th, 1582. Equally no one can have a birthdate of October 5th, 1582, because it doesn’t exist in the Gregorian calendar.

Cheers my friends to another year of interesting and challenging problems to solve, people to meet, and the past to appreciate.

First look at the Vespera ( Automated Telescope)

First look at the Vespera ( Automated Telescope)

I normally use a regular telescope setup with an equatorial tracking mount and dedicated astro camera for astrophotography. It is complicated to setup, heavy, and a bit time consuming to get up and running. It has the advantage of being larger aperture and far more capable in terms of exposure time, with the tradeoff in complexity.

At the other end of the spectrum are the newest fully automated electronic telescopes. These are devices you turn on, connect to with an iPad and image away.. virtually no setup at all. A few years ago a company called Vaonis made a device in this category called Stellena, and in 2021 they releases a 2ng gen device called Vespera. I recently got a Vespera unit and fired it up for the first time last night.

I turned it on, hit an init button in the software, and it spun around and did a few captures, plate solves, and generated the internal calibration. I then selected the dumbbell nebula in the catalog, and 10 seconds later it appears on my screen. It could not have been easier. It continually shoots and integrates, so the picture gets better and better as time goes by. I picked a few more good targets including the Pleiades, the Veil, and Horsehead, and Orion.

Keep in mind this is from my house in the city of Portland, so Bortle 7 in terms of darkness[terrible light pollution], and it was a 1/3 moon. These are jpgs directly from the device, no processing at all. Just as it appeared on the screen.

Downright amazing results for such a small 70mm aperture with a fully automated stacking system. You can download the original subs and do your own stacking with much improved results, and I’ll give that a try tonight.

I have the Vespera specific HA/O3 filter on order, and once that comes in I should be able to really improve the nebula shots.

This really is an easy way to get into astrophotography with very fast return on your time investment.

ZWO Mount testing

ZWO Mount testing

I’m trying out a new mount for astrophotography – A ZWO AM5. It is somewhat unique in being a harmonic drive instead of a worm gear. It doesn’t need a counterweight, and there is no backlash. It is also really quiet. I’ll be using an ASIAir Plus to control it as well as the guide camera and primary camera. With autoguiding and good polar alignment I should be able to get some good photon collections.

Looking forward to some clear skies and experimenting with this setup.