Equatorial Seestar

 New Mounting Option

During the past year I saw so much information about using Seestar in equatorial mode that I decided to try it myself. Manufacturer ZWO offered a relatively inexpensive wedge compatible with Seestar's tripod, so I ordered the wedge and installed it as shown in the next picture.

The wedge allows one of Seestar's rotational axes to point at the north celestial pole. At my location the pole is 37.4 degrees above the horizon. This tilt is visible above. The long handle accomplishes the tilt aided by the angular scale shown below. The wedge also allows azimuth adjustment with the other graduated scale. I had to fully lengthen the tripod legs to keep Seestar from tipping over!

When one rotational axis is properly aligned with the north celestial pole, rotation about this axis can follow objects as they cross the sky from east to west due to Earth's rotation. Consequently, once an object is centered in equatorial mode only ONE Seestar motion is required to keep it centered. Without the wedge Seestar operates in altitude/azimuth mode where TWO motions are required to keep an object centered. So, tracking should improve by switching from altitude/azimuth mode to equatorial mode.

I have been using Seestar in altitude/azimuth mode for a couple years now. During every long exposure a significant number of 10-second subframe exposures are rejected due to tracking errors. Sometimes as many as 80 percent of the subframes are rejected! In this case only 20 percent of Seestar operation time is producing useable results! The best I've ever achieved was about 33 percent rejected frames. I hoped many fewer rejected frames would result from improved tracking in equatorial mode.  

I had to wait several weeks for clear skies to use equatorial mode for the first time on April 14th. The first target was galaxy M51 in Ursa Major. Inevitable first time fumbling and inefficiency caused more than an hour of wasted dark time. With everything finally aligned and M51 centered I initially tried taking 20-second subframes instead of my usual 10-second subframes. It was disappointing to see roughly half of these 20-second frames rejected for poor tracking. I stopped the 20-second exposures and restarted using 10-second exposures instead. What a difference! Now no frames were being rejected - not one single rejection!

I wanted to try an exposure of several hours, but, unfortunately, the sky became increasingly hazy from wildfire smoke after midnight. I had to stop the exposure after 85 minutes. Incredibly, the entire 85 minutes produced useable results! Seestar produced 510 useable subframes with no rejections! The next image shows the result. (Click on the image to enlarge.) Notice small fuzzy elliptical galaxy NGC5198 toward the left edge.

As years go by more satellite trails and airplanes interfere with astrophotography. Although an airplane passed through the scene as shown below, I was able to manually remove the trails to produce the previous image.

This initial result made me anxious to try much longer exposures. If no subframes get rejected, I might be able to get up to eight-hour exposures of some objects.

Six days later on April 20th another clear sky opportunity arose. Having overcome my beginner mistakes made while setting up on April 14th I was much more efficient initiating equatorial mode. My target this time was galaxy M101 in Ursa Major. I was able to let Seestar run from just before 11 pm (EDT) to about 5:20 am when the northeastern sky was just beginning to brighten before sunrise. The result was a 397-minute exposure (6 hours 37 minutes) my longest exposure yet. This time 2,382 ten-second subframes were useable and only one was rejected!

This long exposure produced the next image showing M101 much better than a previous 90-minute exposure made in 2024. In particular, the outer spiral arms are brighter, and the inner portions show more detail. Notice fuzzy galaxy NGC5474 near the upper right edge and dimmer small galaxy NGC5477 near the top edge.

Just as with the M51 image, satellite tracks ran through the picture as you can see in the next image if enlarged to full size. I manually removed the tracks for the image above.

Sky transparency varied throughout the M101 exposure. It's rare to get truly dark sky at my location.

Despite some modest moonlight on April 22nd the sky was cloudless. My target this night was edge-on galaxy NGC4565 in Coma Berenices. After a late start I was able to get a 297-minute exposure (4 hours 57 minutes) before the galaxy set behind a nearby roof at about 5 am. On this night 1,786 10-second subframes were useable. 83 subframes were rejected because the galaxy was blocked by the roof near the end. The long exposure revealed some detail in the outer arms as you can see below if you enlarge the image. Notice small galaxy NGC4562 to the upper right and brighter fuzzy galaxy NGC4555 near the left edge.

I look forward to trying long exposure equatorial mode along with mosaic mode on nebulas I've previously imaged.

Long Exposures

All Night - One Object

January 20th was the last opportunity for clear dark sky before future weeks of clouds and brightening moonlight. All neighboring glaring floodlights were miraculously turned off this night! This was a good time to attempt a long exposure on just one object. I pointed Seestar at IC443, the Jellyfish Nebula, in Gemini which was above the northeastern horizon. I hoped to follow the Jellyfish for as long as possible as it crossed the sky from east to west.

Seestar was plugged into external power so the internal battery wouldn't run out during the exposure. Eventually, I shut Seestar down after roughly seven hours when the Jellyfish was beginning to set behind a neighbor's house. About 64 percent of the 7-hour operating time produced 4.5 hours of frames suitable for stacking. The resulting 4.5-hour effective exposure of IC443 is the longest exposure I've ever achieved up to this point. Mosaic mode and light pollution filter were engaged to produce the following image.

The Jellyfish Nebula is a supernova remnant about 5,000 light years away within our own galaxy. The explosion happened approximately 33,000 years ago. The bright circular arc on the left is a blast wave interacting with relatively dense material. The bright star above the nebula is the foreground star Propus about 380 light years away in Gemini. Its yellowish color is washed out by overexposure.

After 19 subsequent days of clouds, moonlight, freezing temperature, and strong winds, a suitable imaging night finally arrived on February 8th. I attempted a long exposure on NGC2174, The Monkey Head Nebula, in Orion. Although Seestar worked for about 4.5 hours with light pollution filter engaged, it only produced a disappointing 80 minutes of usable subframes for stacking. So, only about 30 percent of Seestar's operating time actually produced the next image.

The monkey's "chin" is the lower left nebula portion. The monkey's "eye" is the V-shaped indentation above the "chin". (At least that's how I see a monkey head.) The red color is from glowing hydrogen gas excited by stars in the center. An interesting detail is the tiny red nebula centered on a star left of the "chin".

New Moon was approaching on February 13th. This would perhaps be the last cloudless dark night for another month, so Seestar was put to work again. I wanted to see LBN863, Lower's Nebula, in Orion - a nebula off the beaten path I'd never heard of before. With light pollution filter engaged Seestar took images for 5.5 hours. Only about 40 percent of these images were useful for stacking, however. The resulting 130-minute effective exposure is shown next.

While Seestar's aperture was open to the sky for 5.5 hours several neighbor lights were turned on and off. This caused a few blue streaks across the background sky. I removed these streaks, but in doing so, the red nebula color might have been slightly changed.

Another 24 days with clouds and bright moonlight elapsed before clear sky returned on March 9th. My target this night was the Leo Triple - galaxies M65, M66, and NGC3628 in the constellation Leo. I hoped to follow this group across the sky from east to west as long as possible, perhaps for as long as 8 hours. Seestar was plugged into external power, so battery capacity was no problem. Sky conditions were a problem, however. At my observing location it's hard to get 8 consecutive hours of clear dark sky. After about one hour scattered clouds moved in from the east. Fortunately, they soon dissipated. Then haziness gradually increased throughout the night. By 3:30am haze thickened so much that I ended the imaging run after Seestar had taken images for seven hours. Only about 61 percent of these images were suitable for stacking. The final result was an unfiltered 4.25-hour exposure using mosaic mode shown next. This exposure is the second longest I've been able to achieve.

In the image above, edge-on galaxy NGC3628 with dark bisecting dust lane is on the left.  Detail can be seen in the inner portions of galaxy M66 on bottom right. Galaxy M65 on the upper right has a subtle dark dust lane. (Click on the image to view best detail.) All these details show much more clearly than in a previous 20-minute exposure taken two years ago. Details would be even better if the blasted clouds and haziness hadn't been present!

It's probable that mounting Seestar equatorially would decrease the number of rejected subframes. Then a higher percentage of operating time would yield suitable frames for stacking. Unfortunately, equatorial mounting introduces another complication level that reduces Seestar's quick convenient use.

 

Science Monuments

Lifetime Experiences

Browsing through an old photo album recently triggered a desire to review a lifetime of science experiences. I certainly haven't "seen everything", but I've witnessed a satisfying number of interesting things. Here are some things I've done and seen.

Observatory Visits

First, places with no pictures.

Sometime near 1980 I took a group of students to visit the Naval Observatory in Washington, DC. We viewed Saturn through the 12-inch Clark refractor there. Unfortunately, pictures are irretrievably stuck behind plastic in an old photo album.

It's a pity I also have no pictures from a 1985 visit to Lowell Observatory in Flagstaff, Arizona. The beautiful wood construction inside the dome housing the 24-inch Clark refractor was a wonderful sight. 

Yet again, I have no pictures from my brief time in 1993 within Harvard Observatory in Cambridge, Massachusetts where I saw a 10-inch refractor.

During a 2001 visit to Yerkes Observatory in Williams Bay, Wisconsin I stood under a massive dome next to the giant 40-inch refractor. The Yerkes telescope is the largest refractor ever made! It was an amazing experience to ride the movable observatory floor and see this beastly telescope move. I searched for pictures I might have taken but found none.

In 2006 I took some students to the National Radio Astronomy Observatory in Greenbank, WV where we saw the huge 100-meter radio telescope. Students even climbed part way up into the structure. Why can't I find any pictures?

Finally, Some Pictures!

A long switchback 1998 bus ride up Mount Evans in Colorado delivered me to the University of Denver's Meyer-Womble Observatory at an altitude of 14,148 feet. The building was closed, so I couldn't view the binocular telescope then housed within. I recall experiencing no adverse effects from the high altitude. Apparently, the dome seen here was lost in a windstorm in 2012, and the observatory was decommissioned in 2018.

It was quite an adventure getting to the top of Hawaii's Mauna Kea in 2002. This extinct volcano is a world class observing site home to a number of premier large telescopes. In the next picture C and I stand before (from left to right) the 3.58-meter Canada-France-Hawaii Telescope, the 8.1-meter Gemini North Telescope, the University of Hawaii 2.2-Meter Telescope, and the 3.8-meter United Kingdom Infrared Telescope.

Our group was allowed inside the huge Gemini North dome and into the control room. The telescope was too big to capture in a single photo. The best I could do without a wide-angle lens was an image of the upper structure seen below.

Upon exiting the Gemini dome I felt a bit lightheaded from the 13,800-foot altitude. In contrast, only four years before in 1998 I felt no altitude effect on Mount Evans in Colorado at 14,148 feet. I was determined not to be sent back down the mountain, so I concentrated on slowing down and breathing deeply. The dizziness passed. 

It was a thrill to see the twin 10-meter Keck Telescopes, the largest in the world at the time.

Twin Keck Domes.

Our group was allowed inside one Keck dome to view the rear of one of the 10-meter segmented mirrors.

Next is a more distant view of Keck Domes along with Japan's 8.2-meter Subaru Telescope on the left.

Standing before Japan's Subaru Telescope.

One year later in 2003 I attended a meeting in Tucson, Arizona. Participants were able to visit Kitt Peak Observatories and I gladly went along. Different telescopes are spread across the mountaintop at an altitude of roughly 7,000 feet as you can see in the next picture.

Here I'm standing before the 4-meter Mayall Telescope's dome. This telescope is the largest on Kitt Peak.

Standing before the concrete 4-meter Mayall mirror blank. These mirrors are huge! This is only half the size of 8-meter mirrors on Mauna Kea!

The next two pictures show Kitt Peak's McMath Solar Telescope.

The odd shape and telescope operation are shown in the next schematic.

The 1.6-meter mirror ultimately projects sunlight into a control room. On the day we visited our group was viewing a large solar image projected onto a white table.

A highlight of our time on Kitt Peak was an evening visit to a 20-inch telescope set up for public viewing. There I had the best eyepiece view of Jupiter I've ever seen. Although Jupiter's disc was large at 500X, what struck me most was the color! In all previous Jupiter viewings with modest telescopes at sea level I had only seen shades of gray. With this telescope on Kitt Peak Jupiter's cloud bands showed detailed colored swirls! A colleague of mine told me that once I had visually observed at a dark mountaintop site I would be forever spoiled for suburban sea level viewing. How right he was!

While in Tucson we visited the Steward Observatory Mirror Lab located under the University of Arizona's football stadium stands. Famous mirror maker Roger Angel directed the innovative construction of large 8-meter class mirrors here. We saw separate chunks of glass sitting in a relatively shallow 8-meter diameter bowl. This contraption would eventually be inserted into a rotating oven in which the glass would melt and form the desired concave mirror shape caused by rotation. In the next picture our group is looking at one of the nearly finished mirrors.

While in Italy in 2004 to observe the transit of Venus our group visited the Pope's summer residence at Castel Gandolfo shown in the next picture.

A modest observatory is located on the roof of the building above. We were taken inside the dome and saw the telescopes seen in the next image. The main telescope is a 15-inch Zeiss refractor with smaller telescopes mounted alongside. Notice the brass-colored 90mm Coronado solar telescope near the top.

During our trip to England in 2006 I was thrilled to visit historic Greenwich Observatory seen from a distance below.

A 24-hour clock and "public standards of length" were part of the attractions.

Looking out over the Greenwich Observatory roof.

You can't go to Greenwich without standing on the Prime Meridian and pointing to the north celestial pole!

One stop during our 2019 Australia tour was at Sydney Observatory.

I was unimpressed with the blurry image produced by the antique 1874 11-inch refractor inside.

Most impressive in Australia was Siding Spring Observatory. The main 4-meter telescope and dome along with a visiting kangaroo are shown in the next three pictures.

The historic Australian Parks Radio Telescope is still in operation. We went inside the base building.

We also saw multiple radio telescopes of the Canberra Deep Space Communication Complex which tracks and communicates with spacecraft including the very distant Voyager probes. 

Our last Australian observatory visit was at bleak and rainswept Mount Stromlo near Canberra. A wildfire in 2003 destroyed five telescopes here.

I regret not seeing famous California Observatories like Mount Palomar and Lick Observatory. Sadly, I never got to view the southern night sky and observatories in the Atacama Desert in Chile. I'll never get to these places now.

Physics Monuments

In Ithaca, New York I toured the Cornell Synchrotron in 1988 but have no pictures.

Closer to home in Newport News, Virginia I attended two open houses at the Jefferson Lab. Seeing complex mind-blowing equipment there was quite an experience. Here are two pictures looking along the electron accelerator beam line in 2014.

Next are two more Jefferson Lab pictures from 2016.

Human Monuments

Here are some monuments of a different kind.

I stood before Marie Curie's family home in Warsaw, Poland in 2001.

I also shivered in 2001 before the Copernicus statue in Warsaw.

The Santa Croce Church in Florence, Italy contains tombs of Michelangelo, Machiavelli, Galileo, and the composer Rossini among others. I stood before Galileo's tomb in 2004.

I've been fortunate to see some monumental human scientists in person during my life.

As a graduate student I attended a lecture by Nobel Prize winner Werner Heisenberg at Princeton!

I humbly sat at a seminar table with John Wheeler also at Princeton. Wheeler worked with Niels Bohr, was Richard Feinman's thesis advisor, and could be considered the founder of modern general relativity research into black holes.

I stood next to Edward Teller, Oppenheimer nemesis and "father of the hydrogen bomb", while he talked with students at Randolph Macon Woman's College after he gave a lecture in support of Reagan's proposed "Star Wars" missile defense system.

I accompanied Nobel Prize winner Leon Lederman during his visit to Randolph Macon Woman's College. Lederman was responsible for several fundamental discoveries in particle physics and was the director of Fermilab.

I attended the 1978 Jansky Lecture at the University of Virginia given by Nobel Prize winner Subrahmanyan Chandrasekar creator of the Chandrasekar limit for the mass of a white dwarf star.

Also, at the Jansky Lectures in 1983 and 1984 I saw Nobel Prize winners Robert Wilson and Arno Penzias who discovered the Cosmic Background Radiation left over from the Big Bang.

I heard Jocelyn Bell who discovered the first radio pulsar give a wonderful description of rotating neutron stars in the 1995 Jansky Lecture.

Finally, I briefly shook hands with groundbreaking evolutionary biologist and public intellectual Richard Dawkins before his smashing, show stopping lecture on his book, The God Delusion, at Randolph Macon Woman's College.

I've seen some things!