The past few weeks saw two artic cold snaps that left sleet and ice behind, along with cloudy skies and bad seeing. One Friday night however turned out to be decent and so I set up the Celestron in the driveway and proceeded to observe deep sky objects until the moon was high enough to get a good look at. After observing lunar craters and other features on the Moon, I replaced the eyepiece with the Nikon and exposed a roll of Fujicolor 200 color print film using shutter speeds from 1/250th to 1/15th of a second. After each series of exposures, I refocused the telescope to ensure at least one frame will be sharply focused. The DW-3 finder I use on my Nikon F-3 has a magnifier that greatly aids in getting accurate focus, and so does the entirely fine matte focusing screen used in place of the standard focusing screen equipped with central split image rangefinder and micro-prism array. After processing, I scanned the film as usual with my Canon flatbed scanner and filmstrip adapter. The image was stretched, converted to grayscale and cropped in Adobe Photoshop.
Wednesday, December 27, 2017
Winters has finally arrived, and so has the clouds and rain, even snow on one occasion in my area. Until last Thursday, I saw no reason to set up the Celestron up with either of the cameras I using. That night turned out to be clear and steady enough for photography, so I drove off to a nearby site where a hospital once stood to set up and photograph the three day-old moon then do some visual observing.
As usual, I set up the 8-inch EdgeHD on the AVX mounting, using an extra counterweight on the declination axle to balance it in right ascension and another counterweight on the dovetail to balance the telescope in declination. Then I used my Nikon to take a series of photos with exposure times ranging from 1/30th to 1/4 second, then additional photos with exposure times of 4, 8 and 16 seconds to record the night side of the moon. The picture above was a 16 second exposure. The film as before was Fujicolor 200 print film.
This picture was exposed for 1/15th of second on the same film. In both cases, I used the mirror lock up and cable release to eliminate vibrations that would blur the picture. I also used vibration suppression pads under the tripod's feet. Once I had exposed an entire roll of film, I removed the camera and replaced it with my 2-inch mirror star diagonal and eyepieces and observed some objects before taking the telescope down and returning home.
After picking the developed film from the lab, I used my flatbed Canon scanner and film strip adapter to scan the film and import it into Photo Shop. Then I adjusted the brightness levels, removed dust and corrected the color balance. Light sharpening was used after I created a lower resolution, smaller image from the original high resolution scans.
Sunday, December 3, 2017
Last Sunday night I had the Celestron set up in the driveway for gathering more video imagery of the moon. The areas of interests this time were the craters Arazchel, Ptolamaeus and Alphonsus, Rupes Recta or the Straight Wall, and a curious chevron like feature I cannot recall noticing before. Instead of using the 3X TeleVue Barlow, I opted to use the 2X Barlow because the wider field of view was needed and the seeing was okay but not great. It also made finding the area I wanted to image easier. The moon was higher up in the sky, which also lessened the prism like color fringing that appears when it's close to the horizon.
The craters Ptolemaeus and Alphonsus nicely fit in the field of view. While both were flooded by mare lavas that erupted through faults onto the crater floors, Alphonsus still has a visible central peak while Ptolemaeus' central peak is buried under lava flows, if it exists at all. In 1965 the Ranger 9 probe crashed in the Alphonsus crater near it's central peak at 6,000 mph at the conclusion of it's successful mission. The probe was sent to take and images of the lunar surface back to mission control until impact. The goal of the Ranger lunar probes were finding out what the nature of the lunar surface was and to see if manned spacecraft could land there. Small craters are scattered across the floor of Ptolemaeus.
The trio of craters Cyrillus, Theophilus and Catharina are one of the most recognizable features on the moon even through binoculars.
The crater Arazchel was rapidly flooding with sunlight while sunrise is taking place at Rupes Recta or the Straight Wall at the right side of the image. The low sun angle at the site accentuates the rugged topography in the area around Rupes Recta, which led to the ground dropping 1,300 feet or 400 meters on one side of the fault relative to the other. The Straight Wall is not actually a wall at all, it's a 70 mile or 110-kilometer long thrust fault. Along it's length the slope is only about ten degrees or so, an astronaut can hike from the bottom to the top with ease. Hidden in the shadow is a shallow rille through which very fluid basaltic lava flowed. As the sun angle rises higher at the site, it becomes visible through small telescopes.
Wednesday, November 29, 2017
Poor weather when skies are dark, bright moonlit skies when they are clear have been a maddeningly consistent pattern for the past couple of months, so when a couple of opportunities came alone to observe deep sky objects from the airstrip I would have otherwise passed up, I took them.
One idle evening in the driveway included a side trip to the usually neglected and very scattered open cluster Collinder 463 in northern Cassiopeia. This is really more suited to bigger binoculars than a telescope due to it's very large apparent size. A 30mm Explore Scientific 82 degree eyepiece was the perfect way to view this scattered but quite obvious and isolated open cluster. It occupied much of the nearly two degree true field of view my 10-inch Dob delivers with that eyepiece. The light pollution at home doubtlessly diminished the cluster's appearance compared to how it looks from a dark site.
The first night was getting cloudy so no sooner than I arrived I had the 10-inch Dob set up and ready for observing. I opted for the galaxies in eastern Cetus because there's some fairly bright galaxies I wanted to sketch. NGC-955 is fairly small, bright, very elongated with a tiny bright core. Despite the milky skies, it was easily located and observed at 149X through the 10-inch Dob.
Pointing the telescope a few degrees away took me to the larger and fainter galaxy NGC-958. Larger and with a weak central brightening, this galaxy has a lower surface brightness but is still an easy mark for a 10-inch. Not quite as elongated as NGC-955, NGC-958 has a more lens like shape surrounded by abundant field stars.
During the holiday weekend, a very clear night came along, and despite the presence of a 5-day-old moon, I drove back to the airstrip with the 15-inch to observe some faint fall objects I wanted to sketch. One of them was the old, and very faint open cluster NGC-136 I have observed before, but did not sketch until now. Through the 15-inch at 142X, it appeared as a faint patch of light that brightens towards the center, sprinkled with very faint stars at the limit of visibility.
Also observed was the larger and brighter open cluster NGC-189 also in Cassiopeia. Fairly large and scattered, this star cluster lies in the thick Milky Way star fields yet stands out well from them. Its member stars are fairly bright and vary in color.
One of many galaxies available to amateur astronomers in Pisces is NGC-670, a spiral galaxy that shows a tiny bright core and a very elongated shape. The galaxy also rapidly brightens towards the center and has a fairly high surface brightness.
NGC-7076 is one of a number of faint planetary nebulae within the constellation Cepheus that revealed itself through the 15-inch despite interference from the moon. It was barely visible without a filter, but adding an O-III filter made the nebula much more apparent at 181X. Also known as Abell-75, this planetary nebula was a nearly featureless round disk a little smaller than Jupiter in apparent size. No central star was visible with or without the O-III filter.
The open clusters NGC-7788 and 7790 proved to be a treat through the 15-inch at 111X. Both open clusters are small, rich and fairly concentrated, making them obvious against dense Milky Way star fields. It resembled a fainter and poorer version of the Double Cluster.
Wednesday, November 8, 2017
Last Sunday night the 17-day-old moon occulted, or passed in front of the bright star Alpha Tauri or Aldebaran. This star is an orange giant star 65 light years away and un-related to the Hyades star cluster that's twice as far away from Earth. It marks the bull's angry eye as it charged Orion, who stands ready with his club and skin. The disappearance occurred behind the moon's bright limb and because I was a little too far west it happened when the moon was too low to see above the tree line. An hour later Aldebaran re-appeared from behind the dark limb, which I missed but soon after that I began watching the moon move away from it for a few minutes.
Then it was time to replace the star diagonal and eyepiece with the camera. Once all was ready, I shuttered exposures for the moon alone from 1/250th to 1/60th of a second, then I took some exposures one full second long to record the star. Both images were taken at the 8-inch EdgeHD SCT's prime focus.
After getting the developed film back from the lab, I scanned one negative that shows the moon alone, another that shows the star, then combined the two in Adobe Photoshop.
Sunday, November 5, 2017
The results achieved the week before encouraged me to set up the Celestron when I normally would be doing little observing due to the waxing gibbous moon flooding the sky with moonlight. The color fringing I have been seeing must be due to the relatively low elevation above the horizon. The atmosphere does act like a weak prism, and that creates the color fringing still present. The tripling of the effective focal length, and hence the magnification achieved through the telescope does create another problem, and that is seeing. I find that when the seeing is poor, even with aggressive use of the wavelet function in Registax, I cannot get a very sharp image compared to others taken when the air overhead is relatively calm. It's clear that is the stars are twinkling, its probably not a good night for close up imaging of the moon and planets. However, the TeleVue Barlow lens definitely does have better color correction that the University Optics Barlow lens I had been using before. I also acquired an additional 12 lb. counter weight and another weight that is attached to the dovetail to fine tune the balance along the declination axis. This works wonder when I am using my Nikon SLR or the 2-inch star diagonal and heavy ultra-wide angle eyepieces. However, if I am using the video eyepiece, I only need one counter weight on the declination axle and no counterweight for the tube.
One of my favorite features is the plateau in Oceanus Procellarum that is dominated by the crater Aristarchus. This crater was blasted out some 450 millions ago and because of it's fairly recent origin it's interior is very bright. At high power, the central peaks and the terracing along the crater walls created when the initial cavity's wall collapsed in huge landslides during it's formation. Next to Aristarchus is a lava flooded crater nicknames the Cobra Head, and from that crater extends a large rille known as Schroeter's Valley. Massive volumes of lava surged through this rill into the mare that surrounds the plateau. Inside this volcanic valley along the center is a very narrow rille that orbiting spacecraft and even large telescopes on Earth have spotted.
Along the shores of Mare Humorum is the large, complex and lava flooded crater Gassendi. This crater shows a long, complex history of modification by volcanism, tectonic forces and impact cratering. This image was taken during local sunrise, and the low angle of illumination shows the rugged topography within the crater. One of the large rills that crisscross Gassendi's floor is also evident here.
The same crater was imaged a day later under better seeing. The higher sun angle at the crater now illuminates most of the crater except a narrow zone along the eastern wall. Near the crater is another large rill that extends all the way to the shore of Mare Humorum.
One feature along the shores of Oceanus Procellurum, or Ocean of Storms, is the region known as Sinus Iridum. This is a large impact crater that was overrun by the lavas that filled the impact basin or basins that underlie Oceanus Procellarum. Also known as the Bay of Rainbows, this is the landing site of the Chinese Yutu rover. Unlike the previous images, I removed the Barlow lens and imaged Sinus Iridum with the camera alone at prime focus.
While trying out the tube counterweight I had purchased, I took full disk photos of the eleven day old moon with my Nikon at prime focus with the usual Fujicolor 200 print film. The negative was scanned with my Canon scanner and then processed with Adobe Photoshop. I dispensed with the color information and converted the photo into a grayscale image. The photo is otherwise untouched, it's didn't even require sharpening. The detail visible in the full resolution scan is very good thanks to careful focusing and the inherit sharpness of the EdgeHD SCT used to take this picture. For those who ask the question is the additional money worth it even for visual observers. I would say the answer is most definitely, yes.
I am slowly putting together a workable set up for imaging the moon and planets with the 8-inch Celestron EdgeHD and AVX mount I purchased six months ago. Among other things, I will be purchasing a 2X TeleVue Barlow for the times when the 3X Barlow yields too much magnification. I am also looking into acquiring a flip mirror, because even with the camera alone at prime focus, the field of view is very tiny. Focusing is also challenging especially when the seeing is less than stellar. A better camera is also needed, but I will continue using the video eyepiece until I find a suitable replacement. It does have it's uses though, I have shown folks close ups of the moon through the Celestron in this way. This is a way to conduct outreach events for the public, so more than one person can "view" an object at the same time.
Saturday, October 28, 2017
The 2017 Deep South Stargaze came and went last week, and while poor weather limited everyone's opportunities to observe, those who arrived early were rewarded with fabulous views of summer and fall deep sky objects. Among the bright planets only Saturn was above the horizon when night fell, and shortly after that it disappeared behind the tree line. Only Neptune and Uranus were above the horizon until Venus and Mars rose before dawn. While Scorpius and Sagittarius were out of sight shortly after dark, I was sweeping Hercules, Aquila, Lyra, Cygnus and Sagitta before they too set. After that I shifted to Cetus and other fall constellations for the rest of the night.
The customary number of people attended this year, but the weather nosedived by Friday night. I and many others went home a day early to avoid the severe thunderstorms that swept through the area. Several members of the local club beside myself also attended, and a former member I have not seen for many years was also there. During the day there were presentations and door prizes were awarded. To my surprise I won a Pelican case, a very nice Sky & Telescope star atlas and a planisphere. While the weather was a disappointment, I nevertheless enjoyed taking a few days off to attend this years DSSG. To maximize the chances I would get at least one good night of observing under good skies, I always plan to stay for several days. Usually, that pays off. In years past, I has three or four great nights in a row.
While cruising through the constellation Cetus, I stopped to observe the galaxies NGC-833, 835, 838 and 839, also collectively known as Arp 318. All four galaxies were visible as oval or round objects with a bright core. They are all quite bright and do not require the light gathering power of a 15-inch to see. Because of it's compactness, higher magnifications work best on this Arp quartet of galaxies, which is among the easier systems for amateur astronomers with modest telescopes.
Much more challenging than Arp 318 is the faint emission nebula Sharpless2-84 in the constellation Sagitta, the arrow. This one took a slow, determined search with a 18mm Explore Scientific 82 degree eyepiece and a Orion O-III filter. What finally emerged from the very rich star field was this roughly arc-shaped nebula.
When I get to darker skies than I can get at home, I always stop to look at the Veil Nebula's two main sections. However, there are other smaller and fainter portions scattered between them, and NGC-6995 is the largest and most prominent of them. Also known as "Pickering's Wedge," this nebula shows much structure through a 30mm Explore Scientific 82 degree eyepiece and an Orion O-III filter. The combination of telescope and eyepiece yields a magnification of 66X and a true field of view of 1.2 degrees, enough to fit large deep sky objects into the field of view. It looked rather like an unraveled rope through the telescope.
While I looked at deep sky objects both well known and obscure, I remembered the comet C/2017O ASSN which is near both Earth and the Sun. I have tried to find it with binoculars when I saw that its magnitude was around 8.5, without success. When I finally found it, it became apparent why I was unable to see it before. It was a large, diffuse glow with a weak central brightening and no sign of a tail. After the first night, skies worsened dramatically the next night. While I was able to look at a number of brighter objects, the milky skies made observing the objects I wanted to search for impossible. Friday night was too cloudy to see anything, so to beat the heavy thunderstorms that were coming I took the telescope down and packed up in preparation for returning home the next day.
Once I returned home, it was cloudy and rainy for a couple of days before clear skies returned and I took delivery of a new TeleVue 3X Barlow lens. I first tried it on stars and Saturn to see how the color correction was, given the color fringing I was seeing with the University Optics Barlow I had been using before. At last the time came to try it out while imagine the Moon, and I wasn't disappointed. I think the color fringing is not just due to the Barlow lens, but the fact the moon as of late is low in the sky at that introduced the effects of the atmosphere acting like a weak prism. This close up of the craters Theophilus and Cyrillus was made with the 8-inch EdgeHD SCT and the 3X TeleVue Barlow lens. The seeing for once was halfway decent and this capture shows it.
This image of the same craters was made the night before, note the lower resolution compared to the first. Both required the aggressive use of the wavelet functions in Registax to sharpen the image harvested from the 30 and 60 second AVI files I recorded with my laptop at the telescope.
This image of the complex crater Posidinous was made on the same night as the first picture of Theophilus and Cyrillus.
This photo of the same crater was made the night before.
This picture is of the rille Rima Cauchy and the crater Cauchy below and to the left. Rima Cauchy is a graben, a trough formed from parallel faults between which the ground drops downwards relative to the ground on both sides of it. The low angle of illumination accentuates the rugged topography of the region.
The Rheita valley is near the southeastern limb of the moon and is a very long, broad and relatively shallow valley that evidently formed after the large craters that flank it on both sides. It extends 250 miles and is over half a mile deep with a maximum width of 20 miles. It's comparable to the Grand Canyon and other features like it on Earth. It's been eroded by the formation of impact craters that formed after its formation. Interestingly, it points at Mare Nectaris, which suggests it's formation is connected to the titanic impact that created the impact basin. The Rheita valley is the second longest valley on the near side of the Moon.