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With clear skies and cool temperatures at dusk I set up the TMB 175mm f/8 refractor on my AP 800 equatorial mount to observe some deep-sky objects and the Moon. There was only about an hour between the end of astronomical twilight and Moon rise however so I did not have time to observe too many, and this was the first time I have had the opportunity to observe deep-sky objects without interference from Moon light since I received this telescope. The seeing was variable ranging from fair to good with the limiting magnitude around 5.3.
I spent most of the time observing NGC 6543, a planetary nebula known as the Cat's Eye Nebula located in Draco. It has a magnitude of 8.8. It was discovered by William Herschel on February 15, 1786 while using his 18.7" aperture reflecting telescope that had a focal length of 20 feet. Of the nebula he wrote:
"A planetary nebula. Very bright. Has a disk of about 35" diameter but very ill defined edge. With long attention a very bright well defined round center becomes visible."
Herschel discovered over 2500 new deep-sky objects, and classified them into the following categories:
I. Bright nebula.
II. Faint nebula.
III. Very faint nebula.
IV. Planetary nebula. Stars with burs, with milky chevelure, with short rays, remarkable shapes, etc.
V. Very large nebula.
VI. Very compressed and rich clusters of stars.
VII. Pretty much compressed clusters of small or large stars.
VIII. Coarsely scattered clusters of stars.
Since The Cat's Eye Nebula was the 37th planetary nebula he discovered it was given the designation of H IV-37. NGC 7009, the Saturn Nebula, was given the designation of H IV-1 as it was the 1st planetary nebula he discovered, while NGC 7662, the Blue Snowball Nebula, was given the designation of H IV-18 as it was the 18th planetary nebula he discovered. Herschel wasn't quite sure how to classify planetary nebula as he wrote: "that from their singular appearance leave me almost in doubt where to class them". He referred to them as planetary nebula as they seemed to share characteristics of both nebula and planets.
Through the TMB 175mm at 34x I could distinguish The Cat's Eye Nebula from a nearby star by its light blue or duck egg blue color and its larger apparent size. At 70x the nebula appeared somewhat elongated in shape and the interior appeared slightly darker, while at 88x the 11th magnitude central star was visible at times with the variable seeing. From 100x through 175x I could hold the central star clearly, and the interior of the nebula appeared to have an oval shape to it. The nebula vaguely reminded me of the episode entitled "The Doomsday Machine" from the original Star Trek series as seen from head on except for the oval shape and blue color of NGC 6543.
I swung the telescope over view some deep-sky objects in the southern sky including M 16, M 17, and M 22. As with NGC 6543, no filters were used.
M 16 (NGC 6611) - The Eagle Nebula, an open cluster and emission nebula located in Serpens with a magnitude of 6.0. At 41x it appeared very large with eagle shape of the nebula easily visible and cluster resolved.
M 17 (NGC 6618) - The Swan Nebula is composed emission nebula and open cluster located in Sagittarius. At 34x the familiar Swan shape of the nebula was prominent. At 70x dimmer and brighter portions of the nebula were visible, as was a serrated edge along the bottom and a detached portion of the nebula at the front. The pretty orange colored star TYC 6265-1256-1 was visible off to the top of the nebula.
M 22 (NGC 6656) - even at low powers of 25x this globular cluster (sometimes referred to as the Great Sagittarius Cluster) was resolved and appeared large, bright and very pretty. Off to one side of M22 a pretty orange colored star, 24 Sagittarii, formed a triangle with the stars 25 Sagittarii and TYC 6857-628-1.
One of the things that impressed me about the performance of the telescope on deep-sky objects was how many of the smaller stars were resolved into tiny pin-pricks against the night sky, something I have not noted before in other telescopes I have used in the past. Plus the colors of the stars were much more pronounced.
I ended the night by observing the Moon, which was one day before last quarter. The seeing was mostly fair at best so I was limited to using mainly 100x in the binocular viewer. Some of the features visible on the lunar surface included the ejecta ray systems extending out from Copernicus and Kepler into Mare Imbrium and Oceanus Procellarium respectively, as well as the wrinkle ridges and different shades of the lava flows across the other mares. This included dark mare to the east of Copernicus, and Sinus Roris which is located in the north west portion of the Moon, as well as the horseshoe shaped feature in the south east portion of Mare Vaporum. Portions of the Montes Alpes appeared as individual peaks. The isolated mountains in the northern portion of Mare Imbrium appeared 3-D including Montes Recti, Montes, Teneriffe, and Mons Pico. The Hyginus region was pronounced, with Rima Hyginus prominent, and Rima Ariadaeus appearing to gain elevation as it extended up towards the western edge of Mare Tranquillitatis.
I set the TMB 175mm f/8 refractor on my homemade Dobsonian-style mount on a couple of nights in mid-October to observe some deep-sky objects, Saturn and Venus. During this first observing session the sky was clear with the limiting magnitude of around 5.4 and the seeing was mostly fair. During the second observing session when observing open clusters in Cassiopeia there was some interference from moonlight and increasing clouds so I had to end the session early.
As with previous observing sessions with the 175mm I noted that the colors of the stars were more pronounced than other telescopes I have used, particularly orange and red colored stars. This made my observing session interesting as I found myself scanning around and seeing stars I had not noted before.
The first object I observed was NGC 7662, The Blue Snowball Nebula, a planetary nebula located Andromeda. It has a magnitude of 9.2 and is 12.0" in diameter. It was discovered by William Herschel on October 6th, 1784 while using his 6.2" aperture reflecting telescope that had a focal length of 7 feet and a focal ratio of f/13.6. This was the 18th planetary nebula he discovered so is given the designation of H IV-18. Of the nebula he wrote:
"A bright, round, pretty well defined planetary disk of about 15" diameter."
When viewed with his larger 18.7" reflector that had a focal length of 20 feet and a focal ratio of f/12.8 William Herschel felt it appeared a little elliptical and the diameter was closer to 12". It was his son John Herschel who was the first observer to notice a blue tint to the nebula.
Through the TMB 175mm at 45x the nebula looked non-stellar as it showed a disk and had a light blue color to it. At higher magnifications of 88x and 117x the nebula appeared slightly elongated, and brighter around the edge than the inner portion which looked somewhat mottled, with a darker portion near the top.
Next up was The Andromeda Galaxy M 31 (NGC 224). It is a spiral galaxy that has a magnitude of 3.4 and is over 3 degrees in diameter. At low power it appeared very large with a brighter central region and star-like nucleus at its center. Two dust lanes were visible along its northwestern rim, and at higher magnifications of 88x, 100x, and 117x the dust lanes appeared to have darker and lighter material within them. These dust lanes were visible around each side of the nucleus and provided kind of a "race-track" appearance around the nucleus. NGC 206, a starcloud in one of the arms of M31, was visible as well.
M 32 (NGC 221) and M110 (NGC 205) are starlight galaxies near M31. M32 is a dwarf elliptical galaxy with a magnitude of 8.2 and is 8.5'x6.5' in size. At 45x to 88x the central region appears bright and star-like, with the galaxy appearing compact and elliptical in shape. It has a bright central region that fades out to the edge, and a star-like nucleus at its center. There were times I thought I could see a second star-like feature offset to one side of the central region.
M 110 is an elliptical galaxy with a magnitude of 8.0 and a diameter of 19.5'x11.5'. Although M110 was observed by Charles Messier in 1773 he failed to include it in his catalog, but it is now called M110. Caroline Herschel, William Herschel's sister, independently discovered it ten years later in August 1783.
Through the 175mm at 45x to 88x M 110 appears large, very elongated, with a brighter central region, and shows a mottled appearance with some variation in tone. In photographs M110 often appears to stretch out towards M31 with a bridge of material between the two. While I did not see this bridge I did get the impression that the influence of M31 has stretched M110 towards it.
M 33 (NGC 598), is a spiral galaxy located in the constellation of Triangulum that has a magnitude of 5.7 and is 68.7'x41.6' in size. It was discovered by Charles Messier on August 25 1764. Of the nebula he wrote:
"The nebula's light is whitish, and almost even in density, but is slightly brighter over the central two-thirds of its diameter, and does not contain any stars."
M 33's spiral structure was detected by Lord Rosse in the mid-1800's using his 72" reflector.
At 25x and 34x magnification in the 175mm M33 appears large and light green in color with an elongated brighter central region. There appear to be faint spiral arms visible. At 54x and 70x the central portion appears mottled with many variations in tone, and the spiral arms are better defined. The two prominent spiral arms that give this galaxy its s-shape are well defined, as are two or three fainter arms. Within the arms there appear to be several HII regions, including NGC 604, as well as some stars.
M 42 (NGC 1976), The Orion Nebula, is an emission nebula and cluster with a magnitude of 3.7 and is 90.0'x60.0' in size. Messier observed it on March 4, 1769, and wrote:
"The position of the beautiful nebula in Orion's sword, around the star Theta, which lies within it together with three other, fainter stars".
William Herschel was known to observe the Orion Nebula on many occasions as it became his lifelong interest. Later his son John compared the nebula to a:
"surface strewn with flocks of wool - or like the breaking up of a mackerel sky when the clouds of which it consists begin to assume a cirrus appearance".
In the 175mm the central and outer portions of the nebula had this mackerel and cirrus appearance to it. The colors were also pronounced, particularly at low powers, where the "bat wings" along the bottom of the nebula, as well as the central region where the "fish mouth" was located appeared light blue-green, while the outer regions appeared striated and tinged with red. When the seeing settled down I was able to resolve the six stars in the Trapezium.
In addition, the comma-shaped nebula M43 (NGC 1982) was visible below M42, as was NGC 1977. The 175mm provided me with one of the most remarkable views I have ever had of the Orion Nebula. I have seen more detail in larger telescopes like my old 20" reflector, but the contrast, sharpness, and image brightness of this telescope provided a more aesthetically pleasing view, and helped to enhance the fainter differences between the various portions of the nebula.
After I finished observing the deep-sky objects I turned the telescope over to observe Saturn which was very pretty as always. One of the things that struck me was how little light scatter there was around the planet, as well as how high the contrast was when compared to other telescopes I have observed it with over the years. This helped to bring out detail even though the seeing was only fair at best. This included a faint Equatorial Band (EB) that divided the Equatorial Zone (EZ) into the EZ south (EZs) and EZ north (EZn). The EZ appeared light yellow, while the South Equatorial Belt (SEB) light brown. In the South Polar Region (SPR), the South Polar Cap (SPC), the South South Temperate Zone (SSTeZ), and the South South Temperate Belt (SSTeB) appeared green in color.
The Crepe Ring was visible in front of the globe, with the Cassini Division prominent, and the A-Ring appearing darker then the B-Ring.
Four satellites were visible near Saturn including Rhea, Dione, Tethys, and Titan. When the seeing settled down Titan appeared as a disk and had a slight orange-reddish color to it.
When observing Saturn I noted also that the North Polar Region (NPR) was visible just below the rings. The last time the NPR was visible was in spring 2000. The rings will continue to open in the coming years and the Northern Hampshire will become more prominent. As seen from Earth the rings vary from 0 degrees to -27 degrees when the southern portion of the globe is visible, then from 0 degrees to +27 when the northern portion of the globe is visible. There is evidence to suggest that this change in ring angle cause seasonal color changes of Saturn's atmosphere. For example, when one hemisphere has been in eclipse by the rings for a number of years, as the Northern Hampshire is now, the color of that hemisphere has more of a gray, gray-green, or blue-gray color to it. When one hemisphere had been exposed to the sun for a longer period of time, such as the Southern Hemisphere is now, the colors appear more yellow and yellow-brown in appearance.
In the eastern sky Venus shown brightly in the constellation of Leo so I swung the telescope over to observe it. The seeing was worse for Venus than for Saturn, but Venus did show its gibbous shape and there were some dusky markings along its terminator.
Cassiopeia has a number of open clusters in it including M103, NGC 654, NGC 659, and NGC 7789. On the night I was observing these clusters with the 175mm there was interference from moonlight and the clouds were on the increase so I was only able to observe two of them, M103 and NGC 659.
M103 (NGC 581) has a magnitude of 7.4 and is 6.0' in size. It was discovered by Pierre Mechain in 1781 and later added to Messier's catalog. It is located about a degree northeast of Delta Cassiopeia. At low power (25x) M103 appeared as a small smattering of stars that forms a Christmas-tree shape with four or five brighter stars and many smaller and fainter stars. As I was star hopping from Delta Cassiopeia to M103 I noticed a small collection of stars in a shape that reminded me of a mini-Little Dipper. One of these stars, TYC 3682-905-1, was red in color.
Nearby to M103 is NGC 659, and open cluster with a magnitude of 7.9. NGC 659 was discovered by Caroline Herschel in 1783. It was given the Herschel designation of H VIII 65, as it was the 65th object classified into category VIII, which is "Coarsely scattered clusters of stars". William Herschel observed the open cluster on November 3rd 1786 and noted:
"A small cometic or resembling a telescopic comet a little of small stars not very rich".
NGC 659 is smaller than M103 with a size of 5.0'. It lies about 10' to the northeast of a conspicuous triangle of stars formed by 44 Cassiopeia at magnitude 5.9 and two other stars with magnitudes of 6.5 and 8.5. Through the 175mm it appears as a small group of stars in a C-shape, with one of the stars TYC 4032-1662-1 orange in color.
One of the things I enjoy about being under the night sky with a telescope is the serenity and sense of connection with the universe. For example I can observe light that left the Andromeda Galaxy over 200 million years ago when the dinosaurs still roamed the Earth, and yet at the same time listen to nature that exists on our world today. This includes an owl in a nearby tree calling out to its mate, or geese in a nearby field as they suddenly honk a few times and rustle around a little bit before settling down again in the cold night air. Or a coyote as it howls in the distance. Astronomy has a way of helping us to see where we fit in the grand scheme of things, whether it is here on a small planet we call home or in the larger universe.
On Tuesday morning November 9th, 2004, Jupiter was occulted the Moon a little after 16:00 UT. I woke up early before sunrise and noticed how striking the crescent Moon, Jupiter, and Venus appeared in the eastern sky. Shortly after sunrise I estimated the distance between the sun and Moon so that it would be easier to find the Moon and Jupiter just before the occultation was due to begin. I had noted in the past that sometimes it could be hard to locate the crescent Moon in the sky during the day. To estimate the distance I held my fist at arm's length and sighted past it with one eye closed, which covers about 10° of sky. By using this technique I was to determine that the Sun and Moon were approximately 35° degrees apart.
About 10 minutes before the occultation was to take place I brought out my Oberwerk 11x70mm and Oberwerk 22x100mm binoculars . The 11x70mm binoculars have a 4.5° field of view, so after scanning about 35° from the sun I was able to find the Moon and Jupiter in the southwestern sky. I then located the Moon and Jupiter in the 22x100mm binoculars, which were mounted on a study tripod.
While the seeing was only fair at best and the bright sky background washed out some of the detail I was able to see the Moon and Jupiter clearly through the 22x100mm binoculars. On the Moon some craters and mare were visible, while on Jupiter there were times that the South Equatorial Belt (SEB), North Equatorial Belt (NEB), and Equatorial Zone (EZ) were visible. None of the Galilean satellites were visible however. Jupiter slowly approached the limb of the Moon until it appeared to sit on the edge of it, and then slowly began to slide behind it. At one point Jupiter appeared as a large dome along the limb of the Moon.
I have been fortunate to observe other interesting planetary occultations in the past. One was Mars Occultation of Epsilon Geminorum on April 8, 1976. Another was the Moon occulting Venus in the late 1970's. Venus showed some faint light scattering around it as it approached the Moon. The scattering suddenly disappeared as the planet seemed to sit on the edge of the Moon before sliding behind it. In 1989 I observed a rare occultation of a bright star 28 Sagittarii, 5.4 magnitude by Saturn and its ring system and watched as the light intensity of the star varied as it passed behind the rings and globe. More recently I watched as the Moon occulted Saturn, and as the globe of the planet slid behind the Moon its rings looked like the Saint Louis Gateway Arch above the lunar limb. While this occultation of Jupiter may not have been as visually impressive as these other occultation's I have observed, it was never the less very enjoyable and interesting to watch.
I set the TMB 175mm up on its home made Dobsonian-style mount to observe the comet. It wasn't the best night for observing. There was haze and some high clouds, which reduced the limiting magnitude to around 4.3. The comet was faintly visible to the unaided eye so I estimate its magnitude was around 4.0. On better nights it is easily visible to the unaided eye.
When I first began observing the comet it was located near a dim star. The star was embedded in the coma of the comet giving the appearance as if the pseudonucleus had divided into to pieces. However the comets motion away from the star was noticeable after a couple of minutes.
Despite the observing conditions the pseudonucleus, inner coma and outer coma were relatively large and bright through the telescope, and had a light green color. At lower power using the TV Panoptic 41mm, Nagler 31mm, 26mm, and 20mm I could make out a couple of tails, but was not able to see the detail clearly. So I switched over to the TMB 16mm Supermono. The higher image brightness and contrast in the Supermono made it easier to see the detail in the two tails as well as a fainter third tail.
The dust tail extended off of the outer coma to the southwest and was slightly curved up to the west. It was the shortest and brightest of the three tails. It appeared feathered with some darker portions in it.
The ionized gas tail extended off of the outer coma to the northeast, and was slightly brighter along its northern edge. It was the longest of the three tails.
The third tail extended off of the outer coma to the southeast. It was thinner than the gas tail and was not as well developed or as long. It was the dimmest of the three tails.
Considering the observing conditions I was very impressed by how well the TMB 175mm performed in bringing out the fine detail. Also the TMB Supermono eyepieces helped to bring out detail that was not easy to discern in the Panoptics and Naglers.
I set the TMB 175mm up on the AP 800 German equatorial mount to observe deep-sky objects, the Moon, Saturn, and Jupiter. It wasn't the best night to observe deep-sky objects (DSO's) as the Moon was one day past first quarter, and a lot of moonlight was reflected off of the snow on the ground. Also the seeing wasn't the best. Still I have not had much a chance to observe lately, and Saturn was near a pretty double star TYC 1359-797-1 and TYC 1359-2674-1, as well as NGC 2392, the Eskimo Nebula, so I decided observe anyway.
At low power, 25x (56mm Meade, FOV ~2.0°) and 34x (41mm TV Panoptic, FOV ~1.9°), Saturn, the double star, and the Eskimo Nebula all fit into the same field of view. Saturn looked nice with several nearby moons. The double star TYC 1359-797-1 and TYC 1359-2674-1 were pretty, one a blue color and the other yellow in color, reminding me of a winter version of Alberio, albeit further apart. At 41x the Eskimo Nebula appeared somewhat resolved and had a light blue color to it, with a star-like center to it and an outer shell.
William Herschel discovered the Eskimo Nebula on January 17th, 1785 using his 18.7" reflector that had a focal length of 20 feet and a focal ratio of f/12.8. Of the nebula he wrote:
"A star 9 magnitude with a pretty bright milky nebulosity equally dispersed all round. A very remarkable phenomenon."
As the Eskimo Nebula was the 45th planetary nebula Herschel discovered it was given the designation of H IV-45. To some observers this nebula reminds them of a clown face so it is sometimes referred to as the Clown Face Nebula. To the late Robert Burnham Jr., author of "Burnham's Celestial Handbook", this nebula reminded him of W.C. Fields. It sometimes reminds me of a Vorlon named Koch from the science fiction TV show Babylon 5. The nebula has a diameter of 47.0"x43.0", with an magnitude of 9.9, while the magnitude of the central star is 10.5.
Through the TMB 175mm at 88x (16mm TMB Supermono) and 100x (14mm TMB Supermono) the nebula appeared to have a fainter outer shell elongated towards a bright star off to the top of the FOV. I was able also to see portions of the brighter inner shell, which was separated from the outer shell by a dark zone. The ability to rotate the Feather Touch Focuser on the 175mm made it easy to position the eyepiece for comfortable viewing and the fine focusing knob made it easy to keep a sharp focus.
As I mentioned above it was not the best night for observing DSO's due to the Moon being one day past first quarter, and a lot of moonlight was reflected off of the snow on the ground. To help cut out stray light from entering my eye I positioned my gloved right hand inside of my hood and under my hat and cupped it around my observing eye. I also tucked my eye in as close as I could to the eyepiece as close as possible to the eyepiece.
When observing I often take detailed notes at the eyepiece or make a sketch, and I always try to keep my observing eye closed when writing or sketching using my red filtered flashlight. However on this night there was a persistent westerly breeze that dropped the wind chills into the teens. This not only made it feel colder but was causing my non-observing eye to tear up as I made my notes. So I went back inside and got heavier winter cloths on, and when I came back out I rotated the observing table so I could keep my back to the wind while taking notes. I was reminded of William Herschel and his sister Caroline. When William Herschel began his survey of DSO's he at first tried to write down the notes himself, but found that he lost his dark adaption with the lights he tried using. So he asked his sister Caroline to take notes as he called his observations out to her. It was so cold on some nights that the ink froze in the ink bottle.
The nebula takes magnification well. At higher magnifications using the 7mm TMB Supermono through 5mm TMB Supermono (200x - 280x) the blue color of the nebula was still prominent and I was able to resolve more of the inner shell so the nebula had more of a look of a face to it. Also the outer shell took on the appearance of a fuzzy parka hood.
After observing the Eskimo Nebula I swung the scope back over to Saturn and inserted the Baader binocular viewer but the seeing wasn't very good. The seeing was somewhat better for the moon that showed a remarkable amount of detail, in particular in the Montes Apenninus and Montes Caucasus where it appeared that material from higher elevations in these mountain ranges had flowed down slope. It was one of the most impressive and detailed views I have ever had of these areas.
Next up was Jupiter, and even though the seeing wasn't very good the detail that was visible shows promise when I am able to observe it under better seeing conditions. For example limb darkening was easily visible on both the preceding and following limbs as well as in the north and south Polar Regions. Also there was a blue or gray colored festoon along the North Equatorial Belt, a rift in the South Equatorial Belt, and the moons were resolved as different-sized disks.
Looking to the eastern sky I noted there were some spring and summer constellations rising so I decided to observe a couple more objects before calling it a night. One was M13, which was pretty as always. I found that it was somewhat easier to resolve when using the binocular viewer then when using a single eyepiece in a star diagonal. Studies have indicated that since our brain is wired for input from both eyes, it tends to "believe" more what it sees than when we use one eye. So in the case on M13 the central portion of the cluster and star chains were easier for me to see when using the binocular viewer than a single eyepiece. The cluster appeared somewhat brighter in the single eyepiece however.
The last object I observed was Izar, a very pretty double star in the constellation Bootes. The primary star is a yellow-orange color with a magnitude of 2.47, while the secondary is bluish in color and has a magnitude of 5.04. It looked very nice in the TMB 175mm with the 9mm TMB Supermono (156x).
So despite the fact it wasn't the best night for observing it was enjoyable to be out under the stars again. Saturn, the Eskimo Nebula, and the double star will still be within ~1.5° in the coming weeks for those who wish to observe them in the same FOV.