Wednesday, November 8, 2017

Occulatation of Aldebaran


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

Points Of Interest On The Waxing Gibbous Moon

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

First images made with the TeleVue Barlow lens and the 2017 Deep South Stargaze

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.

Saturday, October 14, 2017

Close ups of the waxing gibbous moon

The horrid weather continues here, either rain, thunder and high wind, cloudy nights or nights murky like a bowl of milk were the norm for the past month. Then a hurricane came my way, then veered to the west knocking out the power as it went by. Fortunately, no damage resulted. It's finally starting to cool down and last night when I was observing with the Celestron I opted not to use the dew heater and chose to use the dew cap alone. Since skies were too poor to make driving to the airstrip worth the time and effort, I set up at home and concentrated on the Moon instead.
 
 
The 60 mile wide complex crater Copernicus was well positioned for imaging, so I made an effort to get plenty of video of it. The close up view was made with the use of my 2.8X University Optics Barlow lens between the camera and telescope. The wider area image was made with the camera alone at the telescope's prime focus. Because the sensor in the camera is very small, the camera sees the same field of view that a 5mm eyepiece would show through the same telescope. That is why I am using my film camera to take whole disk photos of the moon and Sun, it would take most of the night to take videos of the whole of the moon, then I would have to mosaic together the resulting still images. The video eyepiece is great for specific features on the moon through.
 

The odd color haloes visible in the video files are due to the Barlow lens I am using. Per advice from another amateur astronomer who is also a lunar and planetary imager, I just bought a 3X TeleVue Barlow lens. Then it'll be time to see what improvement in the sharpness of the views I am recording upgrading to a TeleVue Barlow lens offers. I plan to incrementally build up a set up that enables me to get high quality lunar and planetary imagery. A very good opposition of Mars is coming next year. Jupiter and Saturn will also be imaged as soon as they are back into a good position for imaging too. I'm also going to try for Mercury, Venus, Uranus and Neptune, even though they will be very tiny turquoise or ice blue orbs even with a 3X or stronger Barlow lens and superb seeing.
 
 
I noticed this field of craters as I was scanning the face of the moon with the Celestron, and thought it would make an interesting subject. Note the crater floors are still in darkness while the rims are sunlight, evidence of their great height above the surrounding plain.

 
The craters Messier and Messier-A were made by a pair of asteroids hitting the surface at the same time. Because they came in at a very shallow angle relative to the surface, they hurled jets of pulverized lunar rock ahead of them, forming the twin streaks extending from the craters. This feature is obvious even near full moon with a small telescope.

 
The ancient lunar highlands crater Ptolameus dominates the frame in this photo. Note the completely flat crater floor, other than the small impact crater in it, it's completely filled with hardened lava that welled up from below between three and four billion years ago. The crater to the left is Alphonsus, which is where the Ranger 9 lunar probe slammed into the moon at the end of its mission to take close up pictures of the moon. It's impact at 8,800 feet per second or nearly 6,000 mph excavated a crater over 40 feet across that was spotted by the Lunar Reconnaissance Orbiter. Right up to the moment it was destroyed on impact, it relayed ever sharper pictures of what was then a completely unknown lunar surface.

 
 
I re-imaged the Archimedes crater region and got better video than the last time. With that Registax yielded a much better image. I find that processing video and extracting a still image is tedious work, requiring a great deal of experimentation with the wavelet functions to get a good view. The effort however can and does pay off in amazing high resolution close ups of the Moon and planets. It is somewhere in this area the Luna 2 spacecraft crashed into the moon back in 1959.


 
This picture of the 2-day old moon was taken on Fujicolor 200 print film at prime focus with my Nikon F-3 and an exposure time of 1/15th of a second. Despite the low elevation, the moon displays great detail along the terminator.

 
A week later I imaged the moon again with the same camera and film after using the video eyepiece to take close ups. Here I used a shutter speed of 1/125th of a second.
 
 
Four days after that I imaged the 13-day old moon with the same camera and film, but I used a shutter speed of 1/250th of a second. I recently found a good cable release so use of the self timer was no longer needed. I did however use the mirror lock-up as before. After taking delivery of the 3X TeleVue Barlow, I plan to acquire a flip mirror to make finding and centering objects in the camera's tiny field of view easier, as well as a 2X TeleVue Barlow lens. It will be used for the times when less magnification is needed, but more than what I would get if I used the camera at prime focus. Then it will be time to get a better camera. The current camera has neither very good resolution or dynamic range. It is little more than a web camera repurposed into a video eyepiece.
 

 

Sunday, September 17, 2017

The 22-day old moon and first attempts at deep sky objects.

Two hurricanes have plowed into the Gulf Coast in the past three weeks, and even though they missed my area the weather has been abysmal for astronomy. My area was very fortunate to say the least, Irma could have easily came for us instead of Florida. When it wasn't raining, the skies were as milky as a bowl of milk. So when I came home from the night shift, and saw the clear skies overhead, I seized the chance to observe and take a few photos too.
 
 
I first photographed the 22-day old moon. After setting up the telescope, and getting the camera ready, I first set the clock drive to track at the lunar, not the sidereal rate. That ensured the moon stayed put in the camera's field of view as I took several exposures at shutter speeds from 1/125th to 1/15th of a second, using the mirror lock-up and self-timer to allow vibrations from touching the camera to die out. Then I refocused the telescope and repeated the sequence four more times. The result you see here is one of several successful shots I got on the same roll of film. As before Fujicolor 200 color print film was used, and the processed negatives were scanned with my Canon scanner and filmstrip adapter then processed with Photoshop.
 
 
After taking 20 photos of the moon, I decided to use the remaining frames to take test shots to answer two questions. One was how big would objects such as M-42 actually be on film, or a full frame sensor for a DSLR. The other was to see how well the EdgeHD 8-inch SCT would evenly illuminate a film frame or electronic sensor that large. I also wanted to see how film would work at F/10 on faint objects. I got those answers through these photos, which are trailed because the polar alignment was off and I do not yet have an auto-guider. If the control paddle's read out on the alignment is anywhere close to accurate, I was 15 arc-minutes off in altitude and 6 minute off in azimuth. Enough at 2,000mm of focal length to trail the image. The first shot is of the Double Cluster, and is a 5-minute unguided exposure. A surprising number of stars were recorded in this picture, even the colors came through well.

 
This photo is a 10-minute unguided exposure of the Orion nebula. The inner region is well exposed, and had I got the polar alignment were it needed to be, and used a focal reducer and auto-guider, I am sure I would have got at least a decent picture even through I took all three of the picture shown here from my light polluted driveway. Fujicolor 200 print film seems to work better on faint objects than I expected it would.
 
While neither of these long exposure photos are prize winners, they are a beginning since I never took any photos like them before. With better polar alignment and an auto-guider, I am sure I can get far better images than these in no time.

Saturday, September 9, 2017

Solar Eclipse Revisited And The Nearly Full Moon

Recently, I got the last of my photos of the 2017 eclipse developed, and I had a chance to try out the waist level finder for the Nikon out on the Sun and moon. The results seem very positive, focusing was easier with the magnifier built into it. It was also much easier on my neck since it allowed the camera itself to work like a star diagonal. I'm going to use it instead of the normal pentaprism from now on when I'm taking photos though the telescope.
 
 
This picture was taken at the height of the eclipse, using the same exposure of 1/500th of a second as the last photo on Fujicolor 200 print film. All the sunspot groups that were on the Sun's face were covered by the moon, leaving a featureless crescent before the moon began to move away from the Sun. Twenty minutes after that, clouds forced an end to observation of the eclipse and I began packing up the telescope for the trip home. Two eclipses are coming to the U.S. in 2023 and 2024. The first will be annular, which means the moon is not large enough to completely cover the Sun. Instead of the corona, a ring of exposed photosphere will surround the moon. The 2024 eclipse will be total. Both eclipses' paths of totality will cross into the U.S. in Texas then continue to the north and east until they reach the Atlantic Ocean. I am marking my calendars for both, since they pass over or near San Antonio TX, I can drive there in ten or twelve hours with my telescope and other gear.
 

The picture of the moon was taken on the same film with a shutter speed of 1/250th of a second through the same telescope. As before, I used the mirror lock-up and self-timer to suppress vibration and the vibration suppression pads as well. The waist level finder and it's built in magnifier enabled me to look for features along the terminator that allowed for critically sharp focus to be achieved. At the time the photo was taken, the moon was mere hours away from being full. This is valuable practice for the total lunar eclipse that is coming in January 2019, for which I will be perfectly placed, weather permitting. No doubt there will be occultations of bright stars or planets in the near future that can be photographed in the exact same way.
 

Friday, August 25, 2017

The 2017 Solar Eclipse

The day millions waited for years to come has arrived last Monday, and I was ready to observe and photograph the 2017 Solar Eclipse. While it was not total from my area, it was an 85 percent partial eclipse well worth the wait.
 
 
To take this photo, I used the same telescope, camera and film used for the whole disk pictures of the moon published here. Because I was photographing the Sun, an over the aperture solar filter was required. I considered opting for a glass filter, but instead bought a Baader safety film Mylar filter instead. It left the Sun with a bluish or violet cast but the image quality was excellent. The views are razor sharp and irregularities in the moon's limb were obvious at 64X through a 32mm Orion Optiluxe eyepiece and a 2-inch Highpoint mirror star diagonal. Even the photos show the rice like texture of the granulated photosphere of the Sun.
 
I shot a series of pictures with the mirror locked up, and the self timer used to eliminate vibration. Exposure times ranged from 1/2000th of a second to 1/125th of a second, with the best exposures being at 1/500th of a second. The sky darkened dramatically and the temperature fell noticeably. Shadows took on a peculiar sharp edge quality and though eclipse glasses the Sun was easy to see as a thin crescent.
 
I set up at a local school system's science education center, where the staff was video broadcasting the event and some staffers and students were enjoying the view between the photos I took. I mainly wanted to observe the eclipse visually, but I wanted to get a few photos too. Everyone enjoyed the experience and many came away with photos of their own.
 
I was able to watch the eclipse until about 20 minutes after the eclipse reached it's maximum for my area, before clouds moved in and threatened to douse the telescope in rain. I then dismantled the telescope and took the film to a local lab for immediate processing. I still have to look through the rest of the film and some Solar photos I took as a test the day before the eclipse. Once I scan and process them, they will be posted here.