Greg Marshall

About Greg Marshall

I am a retired electronics engineer and after a few months of enjoying my leisure I began to miss doing product development. My astronomy hobby always needed new solutions to unique problems, so I decided that whenever I came up with a good solution I would try to make it available to others.

The Mercury Transit Tomorrow, Nov. 11th, the planet Mercury will pass between Earth and the Sun, appearing to take a leisurely stroll across the Sun over a period of about 5.5 hours.  Unfortunately, it is likely to be cloudy here, and even it it isn’t, this “transit” as it is called will be more than half over by the time the Sun comes up.  But on the East coast people will get to see most of it, weather permitting. Because Mercury and Venus are closer to the Sun than Earth is, we get to see them somewhat differently than we do the […]

Back to the Cave

This past weekend we had a New Moon and, surprisingly for this late in the year, good weather.  So I went to my favorite dark sky site, SkyView Acres, in Goldendale, WA.  I don’t think I’ve ever gone to a star party this late in the year.  My primary goal was to get some good RGB data of the Cave Nebula to go with the narrowband data I captured recently from home. The first night was great, although a bit cold.  I was getting some of the sharpest images I’ve had in this area, with an average FWHM of 2 […]


I won’t admit to having any particular phobias, but do believe that it’s quite insane to be crawling around through narrow passages deep underground (I’ve also never had even the slightest desire to jump out of an airplane).  So I recently explored a different kind of exotic structure, the Cave Nebula.  This is one of the targets I attempted to capture during the last dark site star party a few weeks ago, but something went wrong with that capture, so I’ve been working on it from home on the handful of clear nights we’ve had since then.  The Cave is […]

Fast Motors

My standard focus motors are designed for typical astrophotography needs, meaning that accuracy and high capacity (for heavy duty focusers and large cameras) are more important than speed.  But recently, a friend asked me to make a motor for visual use.  Using a focus motor for visual observing can actually be very helpful because it allows you to adjust focus without touching the telescope, thus avoiding the vibrations that generally happen when you touch a telescope.  The rotary knob on the PerfectStar family focus controllers makes for a very easy transition from direct focusing to motorized focusing.  Backlash compensation also […]

Bursting Bubbles

For the most recent New Moon I went to my favorite dark sky site, SkyView Acres, in Goldendale, WA.  Prior to that I had been capturing narrowband data of the Bubble Nebula (NGC7635) from home, so I thought I would add some RGB data from the dark sky site.  I had dreams of making a glorious multi-hued portrait of this popular object, but after playing around with it for hours, I have to say that my bubble has been burst:  I just couldn’t come up with a way to combine the data that looked any better than straight narrowband or […]

Feeling Blue?

The last of my images from OSP is NGC6914, a small reflection nebula in Cygnus.  To be honest, this includes a lot of data captured from home in addition to what I captured at OSP.  Specifically, the majority of the image (the red areas) are hydrogen, and knowing that I could get that with a narrowband H-alpha filter from home, I didn’t shoot with that filter at OSP. But combining the RGB and H-alpha data did not work out the way that I had hoped.  If there were no stars in the image it would be a simple matter of […]

A Pinwheel in the Northern Sky

Here’s another image from the 2019 Oregon Star Party, M101, the Pinwheel Galaxy.  Also cataloged as NGC5457, the Pinwheel is a large galaxy in Ursa Major, and about 21 million light-years from Earth.  Although not as large in diameter as our Milky Way (170,000 light-years versus 258,000 light-years), M101 has about 1 trillion stars, twice as many as the Milky Way.  It also has a lot of hydrogen regions that are typically star-forming regions. As with most of my broadband (natural color) images, this was captured and processed using LRGB, with only a handful of color frames (8 each of […]

Another Wild Flower from OSP

It seems that every year when I go to OSP (Oregon Star Party) I end up shooting this beauty, the Iris Nebula, and each year it gets a little better.  I had not planned to shoot it again this year, but when I saw how good the seeing was on the second night, I just had to drop what I was doing and move on to the Iris. The Iris (NGC7023) is a reflection nebula in the constellation Cepheus, which has many great targets for astrophotography.  As with the Pleiades cluster, the blue appearance is really just the color of […]

Off to OSP

I’m packing up my gear to go to the 2019 Oregon Star Party.  OSP has always been held near the New Moon period in August, but this year we have 2 New Moons in August.  Since there has been some pressure to move the star party to earlier in the Summer, I guess it was pretty easy to choose for this year.  The reason for the pressure to move is that in recent years the event has been marred by smoke from wildfires, and there is a lower risk of fires earlier in the Summer.  But earlier also means a […]

The Cocoon Nebula

The other target I captured at the Golden State Star Party is the Cocoon Nebula (IC5146), which is, coincidentally, somewhat similar to the Trifid Nebula in appearance and structure.  The red portion is emission nebula, but the faint blue and brown regions are reflection nebula.  The Cocoon is in the constellation Cygnus, so much higher in the sky than Trifid.  Although it was nice to be able to photograph objects farther south, I wanted to get at least 1 target that was not so close to the horizon and the blurring that happens down there.  There was still a fair […]