Photo – Sun April 21st 2018

After a weeks of clouds, rain and even snow, I finally get a sunny weekend without a cloud in the sky.  With the warmer temperatures, time to take the telescope out. Unfortunately no significant sunspot happening on April 21. Just a small region (AR2706) on the western part of the sun.

Canon 80D (ISO 100, 1/400s)
Skywatcher 80ED (80mm F/7.5)

Sun with sunspot AR2706 (21-apr-2018). Benoit Guertin

Sun with sunspot AR2706 (21-apr-2018). Benoit Guertin

Does Earth Influence the Sun?

I recently came across an article in the french Science & vie magazine, where a reader asked if Earth influences the Sun. I found it rather interesting, and while I had my doubts I still wanted to know more about it.

sun-earth

The reader wasn’t the first to wonder if there was any interaction, various models and observations have been put forward since the late 1800s. We often read about two bodies interacting in space. The first exoplanet was discovered due to its gravitational influence on its star causing it to wobble. This type of gravitational influence works when two bodies have a mass within one or two orders of magnitude of each other.  But in the case of our Sun, it is 99.86% of the solar system’s mass, and most of the remaining is taken up by Jupiter and Saturn.  Therefore from a gravitational perspective Earth has no effect on the Sun.

But could the 11 year period in solar activity, characterized by the rise and fall of number of observed sun spots be caused by the planets? The exact source of that periodicity has yet to be clarified.  Well a team of researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) put out a paper in 2016 after demonstrating that every 11.07 years the planets Venus, Earth and Jupiter are aligned.  Coincidence?

They explained that while the effects are rather small, the repeated nudging could be enough to tip the Sun’s magnetic field instabilities one way or the other causing this 11 year solar cycle that we observe, much like an object entering into resonance.  In this case it’s the Sun’s magnetic field acting like a dynamo that would resonate due to the planet’s alignment every 11 years.

However many are skeptical about any real effect pointing that the source of the Sun’s magnetism comes from deep within, while the planet’s effect, if ever, would be limited to the Sun’s surface. But the crushing blow is when you look at fact that the solar cycle varies between 7 and 14 years, the number 11 just happens to be the average over the last 24 observed cycles.  Unfortunately the three planet’s alignment don’t vary by that amount.

In the end, the Sun is still king and does what it wants in this solar system, regardless what the planets say or do.

December 25th – No Sunspots

The sun has been without sunspots for two days, but that is expected as we are heading to a minimum in the 11-year cycle.

Cycle 24 Sunspot Number

Cycle 24 Sunspot Number (NASA)

Nevertheless as it was a nice afternoon grabbed the scope and did some observation of the sun.  A little of a challenge to focus when there is no contrasting details to base yourself on.

December 25th 2016 - No Sunspots

December 25th 2016 – No Sunspots

Skywatcher 80ED
Canon XTi (450D) ISO 100 – 1/800sec
Thousand Oaks R-G Solar Film

Sunspot 2529

Sunspots on the sun come and go.  Count them for many years and you’ll soon find out that there is an 11 year periodic cycle when the solar magnetic activity peaks.  We are presently in Solar Cycle 24 and on the tail end of the double peak of 2011 and 2014.  So why would I want a solar filter when the Sun is heading into a quiet period?

Number of sunspots observed and predicted for 1995 to 2020

Number of sunspots observed and predicted for 1995 to 2020

Well, just because the number of sunspots goes down doesn’t mean that there’s not good some great observing opportunities.  Sunspot 2529 provided that perfect occasion to finally try out my new solar filter.

Sunspot 2529 (April 10, 2016) - Benoit Guertin

Sunspot 2529 (April 10, 2016) – Benoit Guertin

The above image was captured on April 10th, 2016 with on my Skywatcher 80ED with Canon 400D at ISO 200 and 1/500s.  19 frames were processed with Registax6.  Sunspot 2529 is still visible today and may be there for another week as readings indicate that it’s quite stable.

There are various types of solar filter out there.  They all essentially do the same thing which is to permit only a small percentage (roughly 0.001%) of the white light to pass through.  Solar filters are not designed to allow observation of prominence and flares, special hydrogen-alpha narrow-band pass filters are required for that,  but they do allow a view of sunspots and granulation if you happen to have sufficient focal length.  By blocking out most of the sunlight, you can then safely observer or photograph the sun.  Remember not to install your finderscope, and move the telescope away from the sun before removing the solar filter.  Your telescope is a MIGHTY strong magnifying glass.

Shopping around there are generally two types of solar filter: glass and film.  While the glass are more durable, the films offer just as good optical performance at a lower price, especially for larger aperture.

Thousand Oaks Optical R-G Solar Filter

Thousand Oaks Optical R-G Solar Filter

Normally for anything in the optical path, especially filters, backyard astronomers are always looking for the smoothest and most parallel surfaces, but for solar film, it appears that the ripples from the loose film have no effect on the image quality.

The filter that I selected is the R-G Solar Filter from Thousand Oaks Optical.  It provides a light yellow pleasant view of the sun, and works very well both visually and with the DSLR.  I enhanced the yellow in the photo of the sun above, but it’s quite close to what can be seen and photographed.

Mark your calendars for May 9th 14:57UT, Mercury will transit in front of the Sun.  The last time that happened was 2006.

The Sun in Like You’ve Never Seen Before

Video

A few weeks ago NASA released a video in stunning 4K quality showcasing some of the sharpest and most detailed views of the Sun at different wavelengths. These images were captured by NASA’S Solar Dynamic Observatory launched in space in 2010.

As stated in the introduction,  each minute of video takes 10hrs in the hands of specialists to process. Not too bad considering that I’ve sometimes spent hours to produce a single image.

Reference :NASA