David Trowbridge

Aug 232014

North America Nebula

The North America Nebula looks like a map of North America. The nebula on the right resembles a pelican. Together, the North America and Pelican Nebulae are known as NGC 7000. This image was taken August 21, 2014. It represents a total exposure of 2 hrs 20 min, the result of 28 5-minute exposures.


Aug 052014

Visitors to the Observatory often ask whether it’s possible to see the International Space Station (ISS) through the telescope. I finally decided to give it a try, aided by new features in TheSky X, software that controls my mount. It’s a bit tricky to follow, since you need to set up for high magnification and the satellite moves rapidly across the sky. But after a few failed attempts, I was able to capture this movie on August 4, 2014 around 10:10 pm. The sounds you hear are the of the mount tracking the satellite and the dome rotating (near the end of  the video) to keep the slit in the proper orientation.

Jul 312014

M51, Whirlpool Galaxy

This image of the Whirlpool Galaxy was captured thje night of July 29-30, 2014. It represents a total exposure of 3 hr 40 min (44 5-minute exposures). The Whirlpool Galaxy, M51 is 23 million light-years from earth. M51 interacts with its companion galaxy NGC 5195 (above). ImagesPlus 5.75 and Photoshop were used for image processing.


Jul 222014

Great Nebula in Hercules


The Great Nebula in Hercules, M13 contains about 300,000 stars. It is a globular cluster that resides within our own Milky Way Galaxy. M13 is roughly 25,000 light years from Earth. (The Milky Way is somewhat greater than 100,000 light years in diameter.)

This image represents a total exposure time of 4 hours 26 minutes. Each individual exposure was 5 minutes long, using a Canon 6D DSLR camera on my  Takahashi Mewlon-250 telescope at f/19.2. The telescope was autoguided. Images were calibrated, aligned and stacked using Deep Sky Stacker 3.3.2. The resulting stacked image was edited using Adobe Photoshop CC.

Nov 262013

M42 Orion NebulaNext time you see the constellation of Orion, find the three stars forming the sword just beneath Orion’s belt. If you look carefully at the middle star in the sword, you may notice that it looks a little fuzzy. It looks smeared out because it isa nebula containing many stars, that glow amidst vast regions of gas and dust. The bluish color comes from reflected light emitted from hot, young stars that have recently formed in this “stellar nursery.” The reddish color is due the red light that is emitted when ionized hydrogen nuclei (protons) recombine with electrons and form neutral hydrogen atoms.

The large red and blue smear curving down toward the right is M42; the small pink arc connected to its upper left is M43. The bluish nebulae surrounding the bluish stars above surround a dark void are sometimes called the “Running Man.” Can you see his head, arms and legs?

I captured this photo on the evening of November 21 by combining 22 3-minute exposures with a Canon 6D camera, a Takahashi FSQ-106 telescope at f/5, autoguided.

Nov 262013

M33 Triangulum GalaxyThe Triangulum Galaxy (M33) is a member of the Local Group of galaxies that includes the Milky Way, the Andromeda Galaxy (M31) over fifty other galaxies that are bound together gravitationally. M33 is somewhat smaller than the Milky Way and M31, and at nearly 3 million light years away is more distant than M31 (about 2.5 million light years). Under clear dark skies, M33 can sometimes be seen without a telescope as a dim patch of light about twice as wide as a full moon, making it the most distant object that can be seen with the naked eye.

To created this image, I combined 73 3-minute exposures on a Canon 6D camera connected to a Takahashi FSQ-106 telescope at f/5.

Nov 012013

M31After purchasing a new DSLR camera, a Canon 6D, one of the first targets I wanted to focus on was the Andromeda Galaxy, M31. This image was taken in morning of October 29. It represents a total of 135 2-minute exposures. Processing was done using ImagesPlus 5.5. Compare with an image taken in 2008.

Oct 202013

Comet ISON (C/2012 S1) is visible through a telescope in the early morning hours. I captured this image on the morning of October 6, 2013.


Total exposure time was 24 minutes (twelve 2-minute exposures), tracking the comet, which moved appreciably against the background of stars during that time. This image was processed in a special way to prevent smearing, and to preserve the stars as points of light.

Comet ISON will swing around very close to the sun on November 28. If it survives its fiery encounter, it may be visible on the other side during the evening.

Check the Sky and Telescope magazine website for updates.

Jun 062012

A Transit of Venus (Venus passing across the face of the sun) is a rare event. This alignment of Venus directly between the Earth and the Sun will not occur again until the year 2117, when I am 169 years old. So I really wanted to see this one. Cynthia and I had planned to drive to Eastern Washington if the sky conditions there looked more favorable. But on the contrary, on Tuesday morning the forecast for East of the mountains looked worse than for here (cloudy to mostly cloudy). So we decided to stay on Whidbey and take our chances.

It was raining here early Tuesday afternoon, June 5 and the sky was overcast. The Venus transit was to begin at 3:06 pm. But this ever-optimistic astronomer went out to turn on his equipment in the observatory and set up the “sun funnel” he built for this occasion.

Friend Sue and second cousin Emily showed up full of hope, believing that anything is possible: for all we knew, we could get lucky and the sky could clear just in time. We couldn’t open the observatory dome right away, but by 2:30, the rain had turned to a light mist so we opened the dome.

Telescope at the Tinyblue Observatory

Takahashi 4" refractor telescope mounted on Paramount ME mount with sun funnel

sun funnel

This "sun funnel" is attached to the telescope eyepiece.

It was too cloudy during First Contact (when Venus first appears to touch the disk of the sun) and Second Contact (when Venus is completely inside the disk). But about 45 minutes after the transit started, the clouds thinned out a bit. We never had a clear sky, but the clouds were thin enough that we could see an image of Venus, along with a few sunspots and clouds drifting by.

Image of Venus crossing the face of the sun

Venus crossing the face of the sun

Transit of Venus

Transit of Venus about an hour after first contact

Cynthia viewing the transit of Venus

Cynthia viewing the transit of Venus

Be sure to take a look at the movies taken by the Solar Dynamics Observatory, which is an earth satellite in a geosynchronous orbit at an altitude of 22,000 miles.

So thank you, Sue and Emily and Cynthia for your optimism. I’m glad I don’t need to wait until I’m 169 to see my first transit of Venus.

Sep 052011

Measurements of the brightness of supernova SN2011FE are plotted on the AAVSO website. My data points (Observer TDW) appear with boxes.

By extending the curve through next week (when I won’t be able to make any new observations), I predict that the brightness (V-filter) at 00:00 on 2011-09-14 will be 9.6.

I’ll measure it at that time and compare with my prediction.