Some old telescopes brought back to life

 A neighbor recently brought over a large box of telescope parts, hoping that I could help make sense of what he had.  After some sorting, puzzling, and discarding of useless parts, it turned out that there were three potentially useful telescopes.  It took only a modest investment in new parts to create a working alt-azimuth mount.  I was also able to contribute some other accessories that have been sitting unused in my closet for many years.

The three scopes, which are now all in operating condition with interchangeable accessories, are:

1.  Celestron C90 f/11 (1000 mm focal length)
   
2.  Tasco 60mm f/15 (900 mm focal length)
3.  Celestron Firstscope 60Az f/12 (700m focal length)

The focal ratios are rounded to the nearest integer.  The stated focal lengths are the numbers printed on the scopes.  The C90 is a Gregory-Maksutov design with the old classical helical-focusing barrel. Based on the date printed on the manual (10/98) it is probably from the late 90s or early 00s.  The the 60mm scopes are air-spaced achromats of unknown age.

Last night the sky cleared unexpectedly after a snowy and rainy day.  I took two of the scopes out to test them on the Moon and Saturn.

Here is the Celestron Firstscope:

The mount consists of a Neewer 36mm low-profile ball head, a PrimaLuceLab 140mm PLUS dovetail plate, and two JJC TR-1II tripod mount rings supplemented with felt.  The dovetail plate is dual-sided: one side has an Arca-Swiss dovetail groove and the other side is a Vixen dovetail.  That makes it compatible with photo mounts or telescope mounts, depending on which side is facing out.  The tripod mount rings are made for Canon telephoto lenses but work quite well with this tube diameter (63mm) when padded out with felt strips.  

This mount configuration works much better than whatever came with the telescope originally.  It is possible to rotate and slide the tube for optimal balance and accessory position, and the long dovetail gives additional balance adjustment as well as being compatible with most standard photo and telescope mounts.  In the above photo both the dovetail plate and optical tube are pushed well forward of normal to balance the weight of the camera.

Here is a picture of the 5.8-day-old moon taken with this setup:

C60 + E-M5iii, ISO 800, 1/50 s.  Untracked.

These "beginner" telescopes can perform quite well when used with proper mounts and accessories.  The moon diameter in this image corresponds to a focal length of 704mm, very close to the number printed on the scope.  The actual focal ratio is then 704/60 = 11.7.

The C90 started out on the same ball-head mount:

 After a few exposures I decided to switch to a computer-driven mount and astro camera in order to get higher resolution.

Here the C90 is riding on an iOptron SmartEQ Pro+ computerized mount with a ZWO ASI178MC camera.  The iPad tablet controls the mount via wifi and the laptop computer is running the camera over a USB cable connection.

I took short videos of the Moon and then switched over to Saturn.  The files were processed with AutoStakkert and Registax. 

Looks like a great scope!

The measured diameter of the moon in the above shot with the C90 yields a focal length of 791 mm.   The focal length of moving-mirror scopes (like this one) will change to match the exact position of the focal plane (image sensor location), so this difference between the measured and labeled focal lengths might be completely normal.

I didn't night test the Tasco scope, but I did use it to snap a few daytime pics of the local mountains.

Bristol Head

Any photo taken at this distance with this focal length (900 mm) will be affected by atmospheric blurring and this one is no exception.  However, it performed quite well in spite of the turbulence.

Tasco 60mm f/15 on a Stellarvue M002C alt-az mount.

The Tasco scope in this photo is using the same rings and dovetail bar as the Celestron 60mm, but the dovetail bar has been flipped over so that it will fit into the Vixen slot in the Stellarvue mount.

added 11/20:

It is 24° F with snow on the ground, but the sky is clear so I set up the Tasco on the porch and took a quick shot of the 8.1-d old moon:

Tasco 60mm f/15 + E-M5iii.  ISO 400, 1/160 s. Untracked.

The moon diameter in this image yields a calculated focal length of 909 mm, within 1% of the number printed on the scope.

As usual, click an image to get into gallery view, then download or open in a new tab to see the full-size images.

The Flying Star

 The star 61 Cygni in the constellation Cygnus (The Swan) has the largest proper motion of any naked eye star at 5.3"/yr, about half that of Barnard's Star.  The motion was first noted by Giuseppe Piazzi  in 1804 (three years after he discovered Ceres) and the star acquired the nickname "Piazzi's Flying Star".  It's distance was measured via parallax by Friedrich Bessel in 1836.  Bessel's result was the first direct distance measurement for any star other than our sun. At 11.4 ly it is the 14th closest star system and the 5th closest naked-eye star, after Procyon. 

61 Cygni is actually a double-star system with the two stars having a combined magnitude of 4.8.  Separated by about 31" they are an easy target for small telescopes.  Under fairly dark sqml=21.4 skies I was just barely able to make out this star with averted vision after a few minutes of letting my eyes adjust, so the "naked eye" designation is definitely a personal attribute.  It was dead easy with a 2x54 binocular.

Cygnus setting over Bristol Head. 61 Cyni is marked by the white circle. EM1iii + Leica 15mm f/1.7 + softon. ISO 1600, 60 s.

 

E-P5 + Rokinon 135mm f/2.  ISO 1600, 60 s. 2° field.

61 Cygni. E-M5iii + AT60mmED f/6 refractor. ISO 1600, 10 s. 0.5° field.

Imaging the Gas Giants

 The Gas Giant planets are Jupiter, Saturn, Uranus, and Neptune.  I recently decided to take a try at capturing images of Jupiter and Saturn.  How hard could it be?  Pretty hard, it turns out.

The problem with high-resolution imaging is that air currents are constantly shifting the image of the object under study.  When we view an object through an eyepiece our brain tends to filter out the small movements and we learn to perceive detail in spite of the motion.  A camera is not so forgiving.  A single exposure captures the image at one moment in time when things might be in rapid motion and therefore blurred.  The solution is to record video and then select the sharpest frames and add them together to get an integrated picture using only the best data obtained.  So that is what I did, after watching many online videos to benefit from the experience of others.

For these images I used a Celestron C8 SCT (Schmidt-Cassegrain Telescope).  The video camera was a ZWO ASI178MC astro camera, which has 0.0024 mm pixels.  With this pixel size and the 2032 mm (approximate) focal length of the telescope, the image scale was 0.24 arcsec per pixel.  An 8" scope has a resolution of about 0.6 arcsec, so this is probably an adequate amount of oversampling.

The video clips (each less than one minute long) were processed with a program called AutoStakkert.  The sorted and stacked images were then further processed with a program called RegiStax.  The results are shown below.

Saturn, 04 Nov 2023.  Celestron C8 + ASI178MC.

Jupiter, 04 Nov 2023.  Celestron C8 + ASI178MC.

As a first try (ignoring earlier non-video attempts) I am pleased with the results.  However, these images are not so great on an absolute scale.  On a quality scale of 1-10, where "1" represents a blurry image from a cellphone hand-held up to the eyepiece, and "10" represents Hubble-esque images from 11-14" scopes produced by skilled practitioners, these rank at about a "3" (maybe 4, but definitely no higher).  There is much room for improvement.  Will I continue?  I don't know - these kind of images require a lot of computer processing and storage and are really a lot of work.  I think I would rather spend my time fishing, biking, or skiing rather than sitting in front of a computer monitor.

As a counterpoint, I also captured a wide-angle image of Uranus which was a single 60 sec exposure at an image scale too large to see the planet's disc.  This one-and-done type of imaging is more to my liking.

Uranus, 04 Nov 23.  E-P5 + Rokinon 135mm f/2.  ISO 1600, 60 s. 2° field.

Past and Future Supernovas

The red supergiant star Betelgeuse is a well-known and prominent feature of the constellation Orion (The Hunter), forming the right shoulder of the imaginary hunter.  Betelgeuse is about 18 times the mass of our sun and is only 10 million years old.  Stars this massive burn rapidly, however, so Betelgeuse is actually nearing the end of its lifetime.  When its nuclear fuel is exhausted the outer layers will collapse and then rebound in an immense explosion as a supernova.  Predicting when this collapse will occur is very tricky, but current estimates range from tens to thousands of years. 

In the constellation Taurus, about midway between Orion and Auriga, lies the remnant of a previous supernova that occurred less than a thousand years ago, in 1054 AD.  This remnant is known as the Crab Nebula.  It was discovered by the English astronomer John Bevis in 1731. It was subsequently observed in 1758 by the French comet hunter Charles Messier, who was searching for the predicted return of Halley's comet.  When Messier realized that the object was not moving it inspired him to begin his catalog of comet-like objects now known as the Messier Catalog.  The Crab Nebula (the name it acquired in the 1840s) is the first object in the catalog: M1.

Betelgeuse is the orange star in the middle of the frame.  The position of the Crab Nebula is marked with a white circle.  Sony A7iii + Laowa 15mm f/2  + softon filter.

When viewed in a small telescope M1 is an indistinct fuzzy blob.

M1, The Crab Nebula.  The bright star lower left is magnitude-3 Zeta Tauri.  E-P5 + Rokinon 135mm f/2.  ISO 1600, 60 s. 2° field.

 The supernova that produced the Crab Nebula was recorded unambiguously by Chinese astronomers of that time, but there is also a pictograph on a cliff overhang in Chaco Canyon, NM that is theorized to be a depiction of the event.

Chaco Canyon, NM, 1987.

For the pedants:

Supernova (noun): plural supernovas or supernovae

The River and the Whale

 The neighboring constellations Eridanus (The River) and Cetus (The Whale) cross the southern meridian during late night in mid-October.  Between the two of them they contain four of the nearest star systems and two of the nearest naked-eye stars: magnitude-3.7 Epsilon Eridani (Ran) and magnitude-3.5 Tau Ceti.  These two stars are circled in the image below, Epsilon Eridani on the left, Tau Ceti on the right.

E-M1iii + Leica 15mm f/1.7 + softon filter.

Epsilon Eridani, aka "Ran",  is 10.5 ly distant, the third closest naked-eye star (after Alpha Centauri and Sirius), and the 9th closest star system overall.  Tau Ceti is 11.9 ly distant and is the 9th closest naked-eye star and the 19th closest star system.  

Epsilon Eridani has one known planet and two asteroid belts. Tau Ceti has two confirmed planets and possibly an additional six that are suspected.  Both of these stars are slightly smaller than our sun at about 80% of the sun's mass.

The finder chart below shows both naked-eye stars and two nearby red-dwarf stars: UV Ceti and YZ Ceti, which are the 6th and 21st closest star systems, respectively. These two stars are too faint to show up in the image above, but were discussed in a previous post here.

credit: SkySafariAstronomy.com

 

Open Clusters in Auriga

 The constellation Auriga contains three open clusters cataloged by Charles Messier: M36, M37, and M38.  

Auriga and star clusters

M36.  E-P5 + Rokinon 135mm f/2. ISO 1600, 60 s.

M37.  E-P5 + Rokinon 135mm f/2. ISO 1600, 60 s.

M38 + NGC 1907 (below).  E-P5 + Rokinon 135mm f/2.  ISO 1600, 60 s.

All of these clusters are 4000+ light years distant.  The region including M36 and M38 is shown here in a 4° view:

Orion Ascending, and more bumps in the night

 

E-M1iii + Sigma 30mm f/1.4 + softon filter, ISO 1600, 60 s.

The yellowish (in this image) star to the bottom left is Betelgeuse, a red supergiant star and future supernova that is the 9th brightest star.  At the right edge is Rigel, the brightest star in the constellation Orion, and the 7th brightest star.  At the top is Aldebaran, the 13th brightest star.

 

Constellation Auriga.  E-M1iii + Sigma 30mm f/1.4 + softon filter.

This shot of the constellation Auriga is much different than my previous attempt, when the sky was red with auroral glow.  In the upper left quadrant is Capella, the 6th brightest star.

When I stepped outside to set up for these shots I heard some noises off to my left.  The high-intensity setting on my headlamp revealed a constellation of glowing eyes.  There was a herd of deer hanging out behind the shed just 30 ft away.  They were just as confused and surprised as I was and couldn't decide which way to flee, or if that was even necessary.

I was outside an hour later for some follow-up shots, but the sky had clouded over and the deer had moved on.

Auroral Glow and Nearby Galaxies

 I was out in the early evening to take a few quick constellation photos.  The sky brightness was once again rather poor (sqml=21.15) for this area.  The previous night I had measured sqml=21.25 and could see the familiar green tint of airglow in the out-of-camera images.  Here is one of the first images I shot last night, after processing:

Olympus E-M1iii + Sigma 30mm f/1.4 + softon filter.

There are two galaxies in this image marked by white circles: the famous Andromeda Galaxy (M31), at the top, and the Triangulum Galaxy (M33), near the middle.  Triangulum is the constellation name associated with the three stars that form a narrow triangle in the lower middle of the image

The red glow in the bottom left of the image bothered me.  I thought perhaps I had left my headlamp on during the exposure, or there was glow from the cabin lights behind me.  I went out to reshoot the image a half hour later with this region higher in the sky.  I also added a shot of the constellation Auriga rising over the northern ridgeline.  That shot was a big surprise:

E-M1iii + Sigma 30mm f/1.4 + softon filter.  ISO 1600, 60 s.

The earth was recently hit by a CME (Coronal Mass Ejection) from the sun causing auroral displays in the north.  Although it was not obvious to the naked eye, that pink auroral glow has extended down into southern Colorado and shows up intensely in photographs. 

 My original purpose for being out last night was to get a wide-angle shot showing the relative locations of the Andromeda Galaxy (M31) and the Triangulum Galaxy (M33). The Triangulum Galaxy is the third largest galaxy in our Local Group (after M31 and our galaxy).  It is 2.8 million ly distant and is just visible to the naked eye in a sufficiently dark sky (not the case last night) if you have good eyes (not me).  If you do manage to see it you will be gazing at the most distant object possible to see without optical aid.  The Andromeda Galaxy is a bit closer at 2.5 million ly distant and is much brighter and easier to locate in a dark sky.

Triangulum Galaxy.  E-P5 + Rokinon 135mm f/2.  ISO 1600, 60 s.

 

Some Early-Morning Showpieces

 While hunting nearby stars in the pre-dawn hours on Oct 25, it was hard to resist pointing the camera at some well-known showpiece objects.

Horse-head nebula

Messier 35 + NGC 2158

Messier 41

Messier 42+43 (and satellite tracks)

Messier 46 (left) + Messier 47 (right)

All images are with an Olympus E-P5 + Rokinon 135mm f/2 lens, ISO 1600, 60 s exposure.  Cropped to 2° field of view.  There was some strong green airglow on this morning (sqml=21.25), so the stars take on a more reddish hue than normal after compensating for the green background.

Messier-catalog objects are usually abbreviated as M41, M42, ..., etc.  The Horse-Head Nebula (Barnard 33) is a dark nebula silhouetted against the glow of the emission nebula IC434.  It sits just below the bright star Alnitak at the end of Orion's belt.  The Horse Head, along with the Orion Nebula (M41), the Andromeda Galaxy (M31) and the Pleiades (M45), is one of the most photographed objects in the sky.  And, why not?  These are all iconic celestial sights and everyone wants their own personal memento.

Messier 35 is an open cluster in the constellation Gemini, about 3000 ly distant.  The fuzzy blob to the right and below M35 is another open cluster, NGC 2158.  This cluster is much farther away, about 16,500 ly.

Messier 41 is an open cluster in the constellation Canis Major, about 4° below Sirius. In a dark sky it is visible to the naked eye and was possibly recorded by Aristotle in 325 BC.  It is about 2300 ly distant.

Messier 42, otherwise known as the Orion Nebula, is the bright naked-eye nebula in the Orion's Sword asterism.  It is one of the nearest star-forming regions to our solar system at a distance of about 1400 ly.  M43 is the smaller comma-shaped blob detached just above the main nebula.

Messier 46 and Messier 47 are open clusters in the constellation Puppis.  M46 is about 4900 ly distant and M47 is much closer at 1600 ly.  There is a planetary nebula (NGC 2438) in the same line of sight as M46, visible as a small bluish blob in the image above.  This nebula is a foreground object and not part of the cluster.

Two nearby stars and two star clusters

 In an hour before dawn on Oct 26 I was able to image two more nearby stars and two star clusters.  These are all winter objects, but viewing them now in the early morning has the advantage of fall temperatures (balmy 26° F on that morning) rather than the bitter cold of winter.  The two stars are Lalande 21185 and Ross 128, and the two star clusters are M44 and M67.

Here is a finder chart:

credit: SkySafariAstronomy.com

Lalande 21185

Lalande 21185 is a magnitude-7.5 red dwarf star in the constellation Ursa Major.  It is the brightest red dwarf in the northern hemisphere but still requires a small telescope or binoculars to be seen.  It is 8.3 ly distant, making it the fourth closest star system, after Wolf 359. It was first cataloged by French astronomer J. Lalande in 1801, but its high proper motion and close distance were not discovered until 1857-58.  At that time it was thought to be the second closest star system, after Alpha Centauri.  It is a fairly large red dwarf at 0.39 solar masses.  It has two and possibly three planets.

Lalande 21185. E-P5 + Rokinon 135mm f/2. ISO 1600, 60s.

Ross 128

Ross 128 is a magnitude-11.1 red dwarf star in the constellation Virgo.   It is 11.0 ly distant and the 11th closest star system.  It has a mass of 0.18 solar masses and has one known planet with an orbital period of 9.9 d. 

 

Getting an image of this star at this time of year was a race between the brightening pre-dawn sky and waiting for the star to rise over the eastern mountain ridgeline. 

 

Ross 128.  E-P5 + Rokinon 135mm f/2.  ISO 1600, 60s.

 

While waiting for Ross 128 to rise I turned the camera to a couple star clusters in the constellation Cancer.  M44, the "Beehive Cluster", is visible to the naked eye and is mentioned in ancient literature.  It is 610 ly distant.  It is an excellent target for binocular viewing.

M44.  E-P5 + Rokinon 135mm f/2.  ISO 1600, 60 s.

Nearby is the open cluster M67.  This cluster is about 2600 ly distant and is also a good target for binocular viewing.

M67.  E-P5 + Rokinon 135mm f/2.  ISO 1600, 60 s.

 All four images have a field of view of 2°.  Click to get the gallery view and access to the full-size versions.

A Harvest of Nearby Stars

 Early-morning observing sessions on Oct 23 and 25 yielded images of nine of the nearest stars. They are:

• (3) Wolf 359
• (5) Sirius
  
• (9) Epsilon Eridani (Ran)
• (13) Procyon
• (17) DX Cancri
• (20) Luyten 372-58 (GJ 1061)
• (22) Luyten's Star
• (24) Kapteyn's Star
  
• (29) Ross 614

 The number in parentheses is each star's rank in closeness to our solar system.  Three stars in the list are visible with the naked-eye (Sirius, Ran, Procyon), the rest are red dwarf stars that require a telescope.  Sirius is the brightest star in the sky and Procyon is number 8.

Below is a finder chart showing the relative positions in the sky.  Two stars that I discussed in previous posts (Teegarden's Star and van Maanen's Star) also show up on this chart.

credit: SkySafariAstronomy.com

Here is a real-life image of Orion rising over the not-so-distant hills:

Sony A7iii + Laowa 15mm f/2 + softon filter.  ISO 1600, 30s.

I have already discussed Wolf 359 in a previous post, so I will take the remaining eight stars in order.

Sirius

Sirius (Alpha Canis Majoris) is the brightest star in the sky at magnitude -1.4 and is 8.7 ly distant, the fifth closest star system to ours. It is about twice the mass and 25 times the luminosity of our sun.  It is a double star with a white dwarf companion that is an observational challenge for amateur astronomers.  The companion is actually quite bright at magnitude 8.4, but in a telescopic view it is overwhelmed by the brightness of the main star.  This companion star was once more massive and more luminous than Sirius itself and was a red giant star in the Cretaceous Period 120 million years ago.

 

Sirius.  E-P5 + Rokinon 135mm f/2. ISO 1600, 30 s.

 Ran (Epsilon Eridani)

Ran is very similar to our sun, with about 80% of the mass and one third the luminosity.  It is 10.5 ly away.  At magnitude 3.7, it is the third closest star visible to the naked eye (after Alpha Centauri and Sirius).  It is the 9th closest star system. 

 

Many of the brighter stars have names with roots in antiquity, but Epsilon Eridani did not have an official name until 2015 when Ran (Norse god of the sea) was chosen in a contest sponsored by the International Astronomical Union.

Epsilon Eridani (Ran).  E-P5 + Rokinon 135mm f/2. ISO1600, 60s.

Procyon

Procyon (Alpha Canis Minoris) is one corner of the "Winter Triangle", along with Sirius and Betelgeuse.  It is 11.4 ly away, the 13th closest star system, and is the 8th brightest star at magnitude 0.3.  Like Sirius, Procyon has a white dwarf companion. 

Procyon.  E-P5 + Rokinon 135mm f/2, ISO1600, 60s.

DX Cancri

DX Cancri is a magnitude-14.8 red dwarf star in the constellation Cancer.  At 11.7 ly it is the 17th closest star system.  With a mass of about 9% of our sun, it has an estimated hydrogen-burning lifetime of around 8 trillion years.

 

The image below is a 1-deg field, upscaled by x2 from the original.  DX Cancri is a faint dot at the center of the circle with a brighter star just up and to the left.

DX Cancri.  E-P5 + Rokinon 135mm f/2.  ISO1600, 60s.

 GJ 1061 (Luyten 372-58)

German astronomer Wilhelm Gliese published the Gliese Catalogue of Nearby Stars in 1957.  An extension to the second edition of this catalog was published in 1979 in collaboration with his successor Hartmut Jahreiß.  Stars referenced in this later edition are prefixed with the letters "GJ".  Willem Jacob Luyten was a Dutch-American astronomer who cataloged thousands of high-proper-motion stars.  Since nearby stars also exhibit high proper motion they will appear in several catalogs with overlapping characteristics.

 

GJ 1061 is a magnitude-13.1 red dwarf star 12 ly distant, the 20th closest star system.  It has 1/8 the mass of the sun and does not exhibit flares, unlike most red dwarf stars.  It has two known planets.

 

 

GJ 1061. E-P5 + Rokinon 135mm f/2.  ISO1600, 60s. 2° field of view.

Luyten's Star

Luyten's Star is a magnitude-9.9 magnitude red dwarf 12.3 ly distant and the 22nd closest system to ours.  Its position in the sky is just under 3° from Procyon.  In space, it is only 1.2 ly from Procyon.  If we were that close to Procyon it would shine at magnitude -4.5, sixteen times brighter than Sirius.  Luyten's Star is a fairly large red dwarf with a mass of about 29% of our sun.  It has two known planets and two more suspected.

Luyten's Star.  E-P5 + Rokinon 135mm f/2. ISO1600, 60s.

Kapteyn's Star

Kapteyn's Star has a proper motion of 8.7"/y,  which was the highest known at the time of its discovery by Dutch astronomer Jacobus Kapteyn in 1898.  In 1916 Barnard's Star was discovered to have a proper motion of 10.35"/yr, moving Kapteyn's Star to second place.  Kapteyn's Star is a magnitude-8.8 red dwarf at a distance of 12.8 ly, 24th closest to the solar system.  It has a mass of about 28% of our sun.

Capturing an image of Kapteyn's Star was a challenge because at this latitude its maximum distance above the horizon is only 7.3°.  Wildfire smoke and local hills interfered with the first two attempts.  Significant green airglow at this elevation also forced a shorter exposure time.

Kapteyn's Star.  E-P5 + Rokinon 135mm f/2. ISO1600, 40s.

Ross 614

Astronomer Frank Ross was the successor of E.E. Barnard at Yerkes Observatory, home of the 40" Alvan Clark refractor, the world's largest.  Ross repeated many of the photographic surveys inherited from Barnard and discovered more than 1000 high-proper motion stars by comparing the newer to the older images.  Four of the nearest 32 star systems are known by their Ross catalog numbers (Ross 154, Ross 248, Ross 128, Ross 614).

Ross 614 lies near the center of the "Winter Triangle".  It is a red-dwarf double star with two components of magnitude 11.1 and 14.2.  At 13.4 ly it is the 29th closest star system. The two stars have masses of about 22% and 11% of our sun.

Ross 614. E-P5 + Rokinon 135mm f/2. ISO 1600, 60 s.