Early this week the weather predicted clear skies, so I was excited to get a little observing done. Astronomical twilight is not until after 9pm, and as these were work nights the sessions would be short. I used the 8-inch to keep pace with my AL Carbon Star and Stellar Evolution lists, which are well suited for this scope. However both nights were hampered by a thin marine layer blown in during the night. The waxing moon's light was amplified and washed out much of the naked eye stars, so my star hops were much longer than usual. On Monday night the moon resided in Virgo, for example, and the only star I could make out was Spica. I could still star hop to Porimma, and even split it, but I could not find SS Virginis in the glare. All the same, both nights were enjoyable. Here are the observations, all at 113x / 0.9°:
Y Canum Venaticorum, carbon star, "La Superba": Orange in finder, bright pure orange in the scope. By far the brightest in field, est. 5.0, C5 [AAVSO 5.3, C5]. One of the reddest stars in the sky, the brightest example of J-star, a carbon star with large amounts of carbon-13. 19th century astronomer Angelo Secchi gave it its common name. It is likely in the final stages of fusing its remaining helium into carbon and shedding more material; it is ready to eject its outer layers to become a planetary nebula, with the remaining star to become a white dwarf.
RY Draconis, carbon star: Nice orange with a little yellow. Brightest in field, est. 7.5, C4 [AAVSO 7.2, C4]. Uncertain period of around 200 days, 6.0-8.0 magnitude range
SAO 157721 (Virgo), carbon star: Very faint yellow orange star at the end of string of two other stars. In glare of moonlight in thin marine layer. Est. 9.0, C4. [AAVSO N/A. 8.5, C2]
V Coronae Borealis, carbon star: Faint, small, faintly red in a rich field. Est. 9.5-10.0, C5 [AAVSO 10.0, C6] Long period variable, from 6.9 - 12.6 over 357 days. To find this I used my 7x35 extra wide field binoculars and could fit all of this beautiful constellation in the field!
RR Herculis, carbon star: Small, faint, very red in arc of stars trailing NW to W. Est. 8.0, C5 [AAVSO 8.5, C5-C8]
SAO 46574 (Hercules), carbon star: yellow-red, brightest in field, in a string of four stars W-E. Est. 7.5-8.0, C2 [AAVSO N/A; 7.3 - 7.7, C3]
Beta Comae Berenices: Long hop from Eta Virginis due to poor transparency and moon halo. Very bright star, yellowish white color. Main sequence dwarf star. It is similar to our sun, slightly larger and brighter and only 3 billion years old.
Spica / Alpha Virginis: Very bright, blue-white star. It's a spectroscopic binary with orbital period of four DAYS! Each star is distorted by the other. Both rotate faster than their orbital period, and the highly ellipsoidal orbit may mean this is a very young star system. It is a polarimetric variable: protostellar material might be entrained between the two stars.
Arcturus / Alpha Bootis, Very bright, yellowish. Brightest star in north celestial hemisphere. An orange giant, has exhausted the hydrogen in its core and in active hydrogen shell burning phase. Jean-Baptise Morin observed it during the day with a telescope, first time for that, in 1635. A red giant star, 110x brighter than the sun, stronger in the infrared, while being only slightly larger than the sun. It has a high proper motion of two arcseconds a year, and a possible planetary system.
Theta Bootis: F-type star Pretty, orange yellow color, bright. 47 light years from earth, so the photons entering my eye are the same age I am!
HD 139341, Bootes: Double star, both type K Blue-white A, slightly yellow B double star. 4/3 the mass of the sun but 11x larger, but only 3 billion years old. A planet discovered in 2009.
14 Herculis: Yellow-white, ordinary looking. It is an orange dwarf, 90% the mass, 70% the radius, and 36% the luminosity of the sun, but with 2x the metal content. Two planets have been discovered to orbit it.
SS Virginis, carbon star: SS Vir was blocked by moon two nights ago, now out of the way; but still a long hop from Spica due to moon halo in marine layer. SS Vir is a faint orange in the finder and intense orange in the scope. Est. 7.0, C6. [AAVSO 6.8, C6]. It is a carbon Mira variable, hydrogen alpha emission increases as it grows brighter in its 361 day period. radius is 500 sol.
T Draconis, carbon star: Moved scope to other end of yard to clear roof. Orange red and rather faint, rich field, Est. 8.0-8.5, C7. [AAVSO 10.0, C6-8].
Wednesday night I had a look at Jupiter. At the start of my session the Great Red Spot was dead center on the band. Before going inside two hours later, the Spot had moved so its further edge was just touching the limb, and it was greatly foreshortened. Very cool to see the change.
Both nights I spent some time looking at the moon's terminator at high magnification. Really good contrast despite the conditions. One of these days, I'll learn the names of all these features.
Saturday, May 21, 2016
Wednesday, May 11, 2016
first time using the 30-inch challenger telescope
Monday night I used the Challenger telescope on my own for the first time. I knew it wouldn’t be a great night transparency wise, but I really wasn’t expecting to accomplish much serious observing. I just needed time to learn the ropes. The maritime metaphor is apt: a thick marine layer spread over all the surrounding valleys and looked like a ghostly ocean, its slow swells tinted by the setting sun. As I stood high atop the wooden rolling steps holding the massive yet smoothly moving telescope in my hand, the wind blowing and the wood observatory creaking, I felt like a sailor atop the rigging of a ship setting off on a voyage.
I made the usual rookie mistakes. I’d forget to change the secondary’s position after shifting the telescope to different parts of the sky, so I’d have to lower it back down and reset. Or I’d forget to remove the 3” to 2” reducer from one focuser to the next. Or I’d remember to change the secondary’s position but left my eyepiece in the wrong focuser. I struggled to find a good position for the wooden rolling steps, and I rammed the concrete pier more than a few times. I slowly learned which focuser position would be best for different angles of the scope. It was weird looking at an object with my back to it and me on the steps looking up. What is worse, I couldn’t get the key to open the cabinet to retrieve the finder scope eyepiece, so I was left to use just the Telrads to find targets. The number of objects I can find with the Telrad is limited, but it was enough to get me through the night. To use the Challenger effectively in the future I will need to learn how to use its digital setting circles.
I started out with the Leo Triplet, just to get orientated; both of M65 & M66 were bright and large, and NGC 3628 showed up well despite the sky not being fully dark.
Once darkness came I wandered about the sky, practicing how to move the telescope. Omega Centauri was pale, but it was submerged in low haze. M68 was bright and broken apart, well resolved to the core. There was a very faint round haze with a brighter core, just to the side of a nearby star: it was galaxy ESO-506-29. M4 looked like a dot-to-dot picture of a barred spiral galaxy, with many curving loops and bands twirling away from the core, which has a bright red star just off center.
Around midnight coyotes started singing to each other from two distant hilltops, and I noticed that the telescope had become pretty well drenched with dew. I rolled the roof back over it and went into the observatory's classroom for a rest. I fell asleep in a chair, and surprised myself awake at 2:30am.
By then the scope was dry, and the sky was still and much improved, registering a respectable 21.36 on the SQML. Summer targets were higher. There was Daneb, last seen sinking to the west on New Year’s night. And what is Cassiopeia doing, rising already in the east?
NGC 6528 & 6522, twin globular clusters off Gamma Sagittari, the tip of the teapot’s spout, seen at 118x in the same FOV. I experimented with different eyepiece combinations and filters while scanning around the summer Milky Way. What does the core of M22 look like at 1463x? Like shining from shook foil.
The core of M13 at 915x is a spangle of stars surrounding a small, grayish round cocoon of yet unresolved stars, with many dark paths twisting away from it. All those dark lanes really surprised me.
M57 was pretty high so I gave it a try. It was a fat greenish tube, with annular wisps pinched out from the NE and SW rims. Its companion star was a bright steady button. I increased magnification to 915x and, while bringing my eye to the center of the eyepiece, glimpsed the shy central star, which quickly withdrew into the dim central nebulosity. I coaxed it back out with my averted eye. It appeared for a while as a nebulous condensation, then the small round button of star flashed out, held with averted vision for about five seconds. Tendrils of nebulosity reached from the inner ring into the dimmer center. The Challenger’s spot-on tracking really helped because I could concentrate on looking rather than bumping the scope along to keep pace with the sky. What is more, I was able to see IC 1296 as an extremely faint, small elongated glow off to the west of the Ring while viewing at 281x.
In the morning I gazed over the marine layer as the sun tinted it, now from the brown brink eastward. I hiked to the summit to take in the full panorama, and to add my small shadow to the shadow the Peak cast on the ocean of clouds below.
I made the usual rookie mistakes. I’d forget to change the secondary’s position after shifting the telescope to different parts of the sky, so I’d have to lower it back down and reset. Or I’d forget to remove the 3” to 2” reducer from one focuser to the next. Or I’d remember to change the secondary’s position but left my eyepiece in the wrong focuser. I struggled to find a good position for the wooden rolling steps, and I rammed the concrete pier more than a few times. I slowly learned which focuser position would be best for different angles of the scope. It was weird looking at an object with my back to it and me on the steps looking up. What is worse, I couldn’t get the key to open the cabinet to retrieve the finder scope eyepiece, so I was left to use just the Telrads to find targets. The number of objects I can find with the Telrad is limited, but it was enough to get me through the night. To use the Challenger effectively in the future I will need to learn how to use its digital setting circles.
I started out with the Leo Triplet, just to get orientated; both of M65 & M66 were bright and large, and NGC 3628 showed up well despite the sky not being fully dark.
Once darkness came I wandered about the sky, practicing how to move the telescope. Omega Centauri was pale, but it was submerged in low haze. M68 was bright and broken apart, well resolved to the core. There was a very faint round haze with a brighter core, just to the side of a nearby star: it was galaxy ESO-506-29. M4 looked like a dot-to-dot picture of a barred spiral galaxy, with many curving loops and bands twirling away from the core, which has a bright red star just off center.
Around midnight coyotes started singing to each other from two distant hilltops, and I noticed that the telescope had become pretty well drenched with dew. I rolled the roof back over it and went into the observatory's classroom for a rest. I fell asleep in a chair, and surprised myself awake at 2:30am.
By then the scope was dry, and the sky was still and much improved, registering a respectable 21.36 on the SQML. Summer targets were higher. There was Daneb, last seen sinking to the west on New Year’s night. And what is Cassiopeia doing, rising already in the east?
NGC 6528 & 6522, twin globular clusters off Gamma Sagittari, the tip of the teapot’s spout, seen at 118x in the same FOV. I experimented with different eyepiece combinations and filters while scanning around the summer Milky Way. What does the core of M22 look like at 1463x? Like shining from shook foil.
The core of M13 at 915x is a spangle of stars surrounding a small, grayish round cocoon of yet unresolved stars, with many dark paths twisting away from it. All those dark lanes really surprised me.
M57 was pretty high so I gave it a try. It was a fat greenish tube, with annular wisps pinched out from the NE and SW rims. Its companion star was a bright steady button. I increased magnification to 915x and, while bringing my eye to the center of the eyepiece, glimpsed the shy central star, which quickly withdrew into the dim central nebulosity. I coaxed it back out with my averted eye. It appeared for a while as a nebulous condensation, then the small round button of star flashed out, held with averted vision for about five seconds. Tendrils of nebulosity reached from the inner ring into the dimmer center. The Challenger’s spot-on tracking really helped because I could concentrate on looking rather than bumping the scope along to keep pace with the sky. What is more, I was able to see IC 1296 as an extremely faint, small elongated glow off to the west of the Ring while viewing at 281x.
In the morning I gazed over the marine layer as the sun tinted it, now from the brown brink eastward. I hiked to the summit to take in the full panorama, and to add my small shadow to the shadow the Peak cast on the ocean of clouds below.
Monday, May 2, 2016
public viewing at fremont peak
I took Valerie out with me Saturday night to Fremont Peak, where there was a large public star party. Around 60 local community college students were there to complete a lab assignment by viewing and taking notes on at least four objects. Plus the usual visitors from the campgrounds around the Peak. There were a lot of astronomers there to help out; all the pads were in use when we arrived, so we set up next to the observatory -- a bad spot, but ok for a public night.
As it grew dark Valerie showed Jupiter to the visitors and could find it by herself in her "baby blue" 6-inch f/4. Prior in the week I attached screw-on stool legs to the bottom of the base, so the telescope was brought up to her eye level. I started showing Mizar, the middle star of the handle of the Big Dipper, which is a double star. Seeing a recognizable star in a new way pleased all the viewers. Later I switched to M44, and moved Val's scope to it too. Most people liked it.
I was using the 10-inch f/4.7 Dobstuff I acquired, and I think it will be a good scope. I could see more of airy disks in the stars as it grew darker and the temperature settled. I had a really nicely framed view of the Leo Triplet at 39x, 2.1 degrees TFOV. I asked the viewers to tell me what they saw instead of telling them beforehand. Everyone picked out the bright smudges of M65 & M66. I asked them to pretend those were eyes and to look down in the field for a mouth. They could all see NGC 3628. They were all impressed to think these were each a separate galaxy. To me the view was very nice, and would probably be even nicer if without the stray light and with better dark adaptation.
Valerie had been doing fine until an hour into it when she came to me complaining of her stomach and feeling cold. We took a break in the observatory building to try to warm up. She had plenty of jackets on and I realized she had a little fever. She couldn't continue and wanted to go home. I tore down the scopes and then apologized to everyone to warn them I had to back my car up and have them shield their eyes since I couldn't control the back-up lights. I started the car, honked, then backed out; and then I started driving away from the observatory very slowly with all my lights out until I reached the ranger's house, enough away from the people to turn them on. Val slept all the way home and fortunately felt fine the next day.
As it grew dark Valerie showed Jupiter to the visitors and could find it by herself in her "baby blue" 6-inch f/4. Prior in the week I attached screw-on stool legs to the bottom of the base, so the telescope was brought up to her eye level. I started showing Mizar, the middle star of the handle of the Big Dipper, which is a double star. Seeing a recognizable star in a new way pleased all the viewers. Later I switched to M44, and moved Val's scope to it too. Most people liked it.
I was using the 10-inch f/4.7 Dobstuff I acquired, and I think it will be a good scope. I could see more of airy disks in the stars as it grew darker and the temperature settled. I had a really nicely framed view of the Leo Triplet at 39x, 2.1 degrees TFOV. I asked the viewers to tell me what they saw instead of telling them beforehand. Everyone picked out the bright smudges of M65 & M66. I asked them to pretend those were eyes and to look down in the field for a mouth. They could all see NGC 3628. They were all impressed to think these were each a separate galaxy. To me the view was very nice, and would probably be even nicer if without the stray light and with better dark adaptation.
Valerie had been doing fine until an hour into it when she came to me complaining of her stomach and feeling cold. We took a break in the observatory building to try to warm up. She had plenty of jackets on and I realized she had a little fever. She couldn't continue and wanted to go home. I tore down the scopes and then apologized to everyone to warn them I had to back my car up and have them shield their eyes since I couldn't control the back-up lights. I started the car, honked, then backed out; and then I started driving away from the observatory very slowly with all my lights out until I reached the ranger's house, enough away from the people to turn them on. Val slept all the way home and fortunately felt fine the next day.
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