Solar Eclipse Blog

Yes, DarkerView has been a solar eclipse blog over the last couple weeks. No worries, it will soon be over and regular programming will resume… After the obligatory photos from the eclipse expedition!

Sun on Aug 10, 2017
The Sun as it appeared August 10, 2017 with sunspot AR2670
A few articles? Yes, just a few…

Total Solar Eclipse 2017
Eclipse Observing Checklist
The Eclipse Plan
Safe Eclipse Viewing
Two Solar Film Filters
Countdown to the Eclipse
The Sun on Eclipse Day
The Solar Corona on Eclipse Day
Correcting a Baader Solar Film Solar Image
The Eclipse Petroglyph

Miss any?


In the end it is a Celestron C8 telescope drive and forks containing custom electronics, a Meade heavy duty wedge from an LX-90, a hand-made tripod, holding a Televue 76mm APO telescope, using a Vixen style dovetail base, with a Baader film solar filter.

It is tempting to call it Frankenscope after the similarities with the classic monster.

Hodgepodge setup on the side of Mauna Kea with the TV-76mm and Telrad on the plate

To further add the the Mary Shelley plot similarities, much of this was revived from the junk pile. I very nearly decided to toss the drive and fork, they were that bad, peeling paint and rusty bolts. A great deal of work was necessary to re-animate these components.

The wedge came from a telescope that was killed in an unfortunate incident with an aquarium heater. The heater was used to de-humidify the OTA and prevent fungus on the optics. Note: Aquarium heaters are not made to operate out of water.

The Hodgepodge mount assembled for the first time

Several new aluminum parts were machined from scraps, some of which were scavenged when the observatory shop was being cleaned out and a lot of metal stock was tossed.

Many of the electronic components used to build the drive corrector were also scavenged parts from dead electronics, this includes the 1.8432MHz crystal that forms it’s beating heart. This heartbeat keeps the mount turning at exactly sidereal rate.

Yeah, you could call it Frankenscope.

But I will call it Hodgepodge.

Correcting a Baader Solar Film Solar Image

Take a photo with a thin film solar filter and you get a blue-white image of the Sun. Correcting this to a yellow gold image is fairly simple in most any photo processing package.

Baader Film Solar Image
The Sun as photographed through a Baader film solar filter
Correcting is probably the wrong word here. The Sun is actually closer to white as we define color. After all, the Sun is our normal source of light, what our eyes evolved to use.

Color is a fluid subject, simply our interpretation of frequency across a very small slice of the electromagnetic spectrum. As such there is no absolute right and wrong, just a set of conventions we normally use.

The issue is that people expect the Sun to be yellow-gold. Present an image of the Sun in any other hue and it is rejected as fake, or false color. We are accustomed to certain visual cues to identify and interpret our world, color is a major part of that. Unless you want to argue with a million people or two, you are better off making your Sun photos yellow-gold.

Continue reading “Correcting a Baader Solar Film Solar Image”

The Solar Corona on Eclipse Day

With a quiet Sun, no active sunspot regions on the face or limb of the visible disk, one wonders what the solar corona will look like. What will we see when the Moon blots out the Sun and the corona is revealed.

MSLO K-Corona NRGF Image
The K-Coronagraph image from the Mauna Loa Solar Observatory from Aug 13, 2017
Unlike solar observers of old, we can look at the corona without waiting for an eclipse. We have both spacecraft and ground based telescopes equipped with coronagraphs. With these we can view the corona in real-time everyday!

Just up the hill from me is the Mauna Loa Solar Observatory. I know a couple folks that work there and have toured the facility. MLSO is a fairly modest telescope equipped with some very specialized instruments. This telescope stares at the Sun all day, every day, monitoring our star as part of a worldwide network of solar observatories.

Continue reading “The Solar Corona on Eclipse Day”

Two Solar Film Filters

When travelling to an eclipse, one solar filter is not enough. I need a backup!

Two Solar filters
A Baader film solar filter beside an Orion Safety Film filter, both for the 76mm refractor
This is particularly true as my primary filter is a Baader film filter. While a very nice and effective filter, it is also very thin film, and easily damaged. Thus I have borrowed a second filter (Thanks Chris!), the borrowed filter being an Orion E-Series Safety Film filter.

Having the two filters available for use mean I must choose between them when the moment is critical. Which is better? Some testing is in order to find out.

The two filters appear very different, the thin silver film of the Baader quite different than the thicker black polymer film of the Orion filter. Both filters are safe to use and provide decent solar viewing. Both provided pleasing solar images using my Televue 76mm APO telescope at low and medium power.

Stepping beyond basic use I do find that they perform quite differently. So differently I felt some notes are in order.

Continue reading “Two Solar Film Filters”

Safe Eclipse Viewing

While the total phase of this month’s total solar eclipse can be viewed directly without protection, as soon as the Sun peeks out from behind the Moon you will need a safe way to view the Sun. That means a proper, and safe viewing method.

Partial Solar Eclipse
A partial solar eclipse from Kawaihae, 9 May 2013
I have previously posted on safe viewing of the Sun, discussing both filters and projection methods. It is time to re-post that information!

Safe Solar Viewing

Personally? I will have a small telescope with a filter available for viewing and photography, along with proper solar sunglasses available to monitor the partial phases as the eclipse begins.

Total Solar Eclipse 2017

On August 21 this year a total solar eclipse will sweep cross the mainland United States, something that has not happened since 1979.

1999 Total Solar Eclipse
The 1999 Total Solar Eclipse, image credit Luc Viator
I have witnessed only one total solar eclipse in my lifetime, the February 1979 eclipse that crossed Oregon and Washington. Our family viewed the eclipse from near Maryhill, Washington, atop one of the high bluffs overlooking the Columbia river. We had a perfect view, a vivid memory that remains with me nearly four decades later. The 2017 event will be similar in some respects, sweeping into North America near the Washington-Oregon border.

Our plan for this eclipse? A little preliminary yet, but starting to shape up. Eastern Oregon should provide a good chance for a clear view in August. Stay in the LaGrande area with family, heading south on eclipse day to a good vantage point near the center-line. Most likely somewhere south of Baker, Oregon. There are a lot of high elevation meadows and mountain roads that should provide a memorable place from which to view this eclipse.