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.


Pioneer Days

Things are crazy busy here at Wa-chur-ed Observatory, but I wanted to take a minute to tell you about the event we did last weekend, the Linn County Pioneer Picnic in Brownsville, OR.  This was a 3 day event filled with all manner of family fun.  We were located at the end of the vendor area, next to a rock climbing wall provided by the OR National Guard.  That drew a lot of people to the area, but was also a distraction.  In any case, it was great fun to watch kids climb the wall – especially the little ones, […]


The Eagle and the Unnamed

M16, the Eagle Nebula, is a beautiful and often photographed object in the southern sky (when viewed from the northern hemisphere).  It is the northern-most of a series of well known objects in the area, including M17, M18, M20, and M8.  But in this photo M16 is in the lower right corner and the object in the upper left is farther north.  What’s interesting about this is that although the object in the upper left is quite bright (and although smaller than M16, not particularly small compared to typical astronomical targets), it has no common name.  In fact, so far […]


To Capture a Globular Cluster

I’ve tried many times to get a good photo of M13, the Hercules Cluster, and this is the best one yet, although it’s done with a telescope that is a bit low in magnification for this object.  M13 is a “globular cluster”, a group of stars that are gravitationally bound to each other.  In this case, there are about 300,000 stars in the cluster, so the goal in photographing it is to be able to distinguish one star from another as much as possible (obviously, we can’t come close to seeing all 300,000), which means getting excellent sharpness. Theoretically, a […]


Astronomy Season has (Finally) Arrived

Over the past week we’ve had some really great weather here in the Pacific Northwest, and I took advantage of the clear skies to start the astronomy season – with astro-photography, of course.  There are some dark-sky star parties going on as a write this, and I didn’t go because there is too much work to do at home, but that didn’t keep me from opening up the observatory and starting some semi-automated captures. The target this time was NGC6888, the Crescent Nebula.  This is a popular target in the Cygnus constellation, and is often photographed, both in natural color […]


You Don’t Always Get What You Want

We had some clear skies here for a few days, and although I’ve been too busy to stay up all night for deep-space object (DSO) photography, I had been waiting for the opportunity to try planetary imaging with the ASI174 camera I got a few months ago, and there was a transit of Io across Jupiter happening that night.  I didn’t get it. Here’s what happened:  The picture above was taken well before the transit started (I think the dim spot just to the left of Jupiter is Io) with the camera attached directly to my 8″ EdgeHD telescope.  This […]


PerfectStar Goes Bipolar

In this case “bipolar” does not refer to a disorder, but to a type of motor.  The current version of PerfectStar, like most focus controllers, uses “unipolar” stepper motors.  The indirect reason for this is that I (and probably most of my competitors) designed the controller to be compatible with existing motors (and for the motor to be compatible with other controllers) despite some significant advantages of bipolar motors over unipolar.  I’ll provide more details on that later, but first, I want to point out some other changes. In the above photo we see the “front” end of the controller. […]


NEAF was NEAT!

My first time at NEAF (North East Astronomy Forum) was great fun – like a kid in a candy store!  The above picture was taken just after the Saturday morning opening, so the place was not very crowded yet.  I heard people say that the attendance was down a little this year.  The presumed reason was that people are saving their travel budget to view the eclipse later this year.  It’s probably also true that there were fewer visitors from outside the U.S. because they are concerned about how they would be treated at the border. NEAF is run by […]


Going to NEAF

The Northeast Astronomy Forum (NEAF) is one of biggest astronomy events on planet Earth and I’ve never been to it – until now!  This years forum is next weekend, April 8&9 (see http://www.rocklandastronomy.com/neaf.html for details). NEAF should be a great experience for anyone interested in astronomy and/or space travel, but I’m particularly excited because I’ll finally get to meet a bunch of people I’ve known only online or by phone for many years.  This includes vendors from whom I have made purchases, customers who have bought my products, and fellow astro-photographers (with some overlap between all these categories).  There will be more […]


Can we get some sunshine here?

The solar telescope I ordered months ago just arrived, which likely means the Sun will not show itself any time soon.  This is a Lunt LS60THa with pressure tuner and straight-through 12mm blocking filter.  Except for the “straight through” part (as opposed to the diagonal that is normally used for visual observing) this is a pretty common solar telescope, allowing you to safely view the Sun and see details of regions in the hydrogen-alpha band.  This is the same spectral line that I often use in photographing nebulae, but for the Sun a much narrower filter is required.  I use […]


Exploring the Intersection of Art & Science

As noted in a previous post, next Wednesday (Feb. 22) evening Dr. Katherine Kornei and I will be speaking at the 510 Museum in Lake Oswego, OR (http://artscouncillo.org/events/).  I will show some of my astro-photos and talk about how I capture and process them, while Dr. Kornei will talk about science behind some of the objects in my photos.  We gave a similar presentation last year at a private club meeting, but this is the first time it will be available publicly.  One addition to the presentation is that Dr. Kornei will talk about some prominent women in astronomy, in […]