Beta Scorpii (Graffias)
Sketch by Michael Vlasov
This pair of hot B-class stars lies about 530 light years away. Their separation of 14 arc seconds places them at least 2200 astronomical units from each other. Beta-1 has another companion hugging it much closer at .5 arc seconds. Both Beta-1 and Beta-2 are also thought to be spectroscopic binaries, bringing the total number of stars in the system to 5.
Source: Wikipedia.
Gamma Virginis
Sketch and Details by Jeremy Perez
Move mouse over sketch to compare change in position from January 2007 to April 2008.
Click the image for a larger version.
About 38 light years away in the constellation Virgo, this pair of twin stars orbit one another once every 169 years. When I last observed them in January 2007, they appeared as a single, elongated, pill-shaped star. On April 10, 2008, the diffraction discs were now clearly separated into two distinct stars with no overlap. Position angle had also proceeded about twenty degrees clockwise since my last look.
During my January 2007 observation, I estimated a position angle of 60 degrees. However, the data in Brian Workman’s Double Star calculator indicated they should have been 49 degrees. I thought this was strange at the time, since I would probably have guessed 45 degrees if that were the case. Recently, I had a look at some more refined data provided by Brian Skiff. Plugging that into the calculator led to January 2007 value of 58 degrees–much closer to my estimate at the time.
For the April 10, 2008 observation, I was able to put the astrometric eyepiece to use on the pair, and arrived at a position angle of 36 degrees. Skiff’s data points to a value of 37.9 degrees. Based on diffraction discs that are not quite touching, I estimated a separation of .92 arc seconds. Skiff’s data comes out to .993 arc seconds.
I was excited to see such a pronounced difference since last year. What a privilege to watch the slow dance of this stellar couple.
| Subject | Gamma Virginis (Porrima / STF 1670) |
| Classification | Double Star |
| Position (J2000) | Virgo [RA: 12:41:39.9 / Dec: -01:26:58]* |
| Position Angle* | 36° [My measurement 2008.27] 37.9° [Skiff Data interpolated 2008.27] |
| Separation* | 0.92″ [My measurement 2008.27] 0.993″ [Skiff Data interpolated 2008.27] |
| Magnitudes* | 3.6; 3.7 |
| Spectral Types* | – |
| Date/Time | APR 10, 2008 – 10:30 PM MST (APR 11, 2008 – 05:30 UT) |
| Observing Loc. | Flagstaff, AZ – Home |
| Instrument | Orion SVP 6LT Reflector (150 mm dia./1200 mm F/L) |
| Eyepieces/Mag. | 12 mm Meade Astrometric Eyepiece+ 2X Barlow (200X) |
| Conditions | Clear, calm, first quarter moon |
| Seeing | 6/10 Pickering |
| Transparency | NELM Mag ~5.0 |
| *References | The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996); Brian Workman’s Double Star Calculator (Using orbital elements supplied by Brian Skiff) |
Epsilon Trianguli
Sketch and Details by Barry Chase
Took a shot at this.. The 5.4 mag primary was about to dance a jig through the seeing conditions. So I thought it would be fun to try and capture that.
95 Herculis
Sketch and Commentary by Wade V. Corbei
With a exceptional contrasting blue & orange, this is a nice, fairly easy 5th Magnitude double (4.96 for 95 Herculis A, 5.18 for 95 Her B) for those who enjoy vivid doubles.
Castor (Alpha Geminorum / Struve 1110)
Sketch and Commentary by Jeremy Perez
The fussy seeing provided a beautiful view of this brilliant double. The diffraction patterns shimmered and danced, adding a bit of challenge to viewing the pair, but also providing a mesmerizing, speckled light show. The primary of Castor appeared bright white while its companion hinted at a subtle blue.
Measuring this duo using the Dobsonian scope was very challenging. I was attempting the PA measurement without my external dial, and although it was very tough to get the primary to drift through the exact center of the eyepiece, the measurement worked out fairly well–differing from Workman’s calculated 2008.2 value by only .8 degrees. The separation estimate was worse though, since I couldn’t track and allow the stars to hover over the scale. (My estimate of 6.9 arc seconds was a bit over compared to the calculated value of 4.5 arc seconds).
| Subject | Alpha Geminorum (Castor / STF 1110) |
| Classification | Multiple Star |
| Position (J2000) | Gemini [RA: 07:34:35.7 / Dec: +31:53:16]* |
| Position Angle* | 59° [2008.2 my measurement] 58.2° [2008.2 Brian Workman’s DS Calculator] |
| Separation* | 6.9″ [2008.2 my measurement] 4.5″ [2008.2 Brian Workman’s DS Calculator] |
| Magnitudes* | 2.0 / 2.9 |
| Spectral Types* | A1V / A2Vm |
| Date/Time | MAR 19, 2008 – 10:45 PM MST (MAR 20, 2008 – 05:45 UT) |
| Observing Loc. | Phoenix, AZ |
| Instrument | Orion XT8 (203 mm dia./1200 mm F/L) |
| Eyepieces/Mag. | 10 mm Sirius Plössl + 2X Barlow (240X) 12 mm Meade Astrometric EP + 2X Barlow (200X) |
| Conditions | Mostly Clear, Gibbous Moon |
| Seeing | 3-4/10 Pickering |
| Transparency | NELM Mag ~4.0 |
| *References | The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996); Starry Night Pro Plus 5.8 |
Alpha Geminorum or Castor
By Wade V. Corbei
Geeze…I so enjoy the oncoming winter and the splendid objects and constellations that it offers. Below is a sketch of Castor, the double star that makes up one of the “heads” of Gemini, The Twins. In Arabic Castor is called Al-Ras al-Taum al-Muqadim, meaning “The Head of the Foremost Twin”.
Both stars seemed close to the same size and magnitude, being 2.8 and 2.0 respectively, with just a hint of a blue fringe around both. A close double that is easily split with higher magnifications.
Wade V. Corbei
NGC 2024, The Ghost of Alnitak
By Rony De Laet
Hello,
We’ve had a full week of clear nights! So every night, after work and family, I tried to capture some DSO targets. This one is a little bit of a special object because I drove to a darker site some 130km from home to sketch it. I’ve glimpsed NGC 2024 at home before, but it always remained a uncertain view. The most annoying thing is the bright presence of Alnitak. I tried to keep Alnitak out of the way, but it didn’t work. Otherwise, NGC2024 would not be such a tough target. More to the south is also the weak glow of NGC2023. So here is my sketch, from the highest point of Belgium : a whopping 690m asl. There was still sufficient oxygen in the air to breath
Date : February 12, 2008
Time : around 22.00UT
Scope : Skywatcher 102/500
Eyepiece : 15mm Plösll
Power : x33
FOV: 90′
Filter : UHC
Seeing : 3/5
Transp. : 4/5
Nelm : 5,8
Sketch Orientation : N up, W right.
Digital sketch made with PhotoPaint, based on a raw pencil sketch.
Epsilon Perseus
By Wade V. Corbei
Epsilon Perseus
Here is a simple Double Star (and another I never knew about until dilly-dallying with the COL). I don’t know if this is normal for the primary star, but on the night I observed this double, there was a large halo surrounding the star in addition to the diffraction spikes.
I have noticed that there are times when some stars have a halo or diffraction spikes (although I think this is the only time I have seen both at the same time, I’ll have to check my notes); and other times they have none.
Is this a result of weather/atmospheric conditions by chance. It seems as if I notice these oddities when it is getting damp or dewey.
The Gamma Cygni Starfield
By Rony De Laet
The Gamma Cygni Starfield, in search of IC 1318
Here is a sketch of a crowded milky way starfield. I waited for Gamma Cyngi to reach zenith, in an attempt to glimpse IC1318. I did not know what to expect and centered on Gamma Cygni. I was worried about the amount of stars that would be visible within the field of view. The UHC filter helped in reducing the number of faint stars to be drawn. I spent almost two hours behind the eyepiece. So here is my impression. I don’t know if I succeeded in observing IC 1318, I just represented the luminosity observed with the UHC filter.
Date : October 14, 2007
Time : 21.00UT
Scope : Skywatcher 102/500
TV Plössl 32mm
Power : x16
FOV: 192′
Filter : Lumicon UHC
Seeing : 3.5/5
Transp. : 3/5
Nelm : 5.2
Sketch Orientation : N up, W right.
Digital sketch made with PhotoPaint, based on a raw pencil sketch.
Hind’s Crimson Star
By Wade V. Corbei
R Leporis – Hinds Crimson Star
This is the first time I have observed Hind’s Crimson Star, and I have to say that it is indeed adequately named. A variable star found in the constellation Lepus, Hind’s Crimson Star (R Leporis) is a very deep red/crimson variable star that stands out among the white stars nearby. I have long been a fan of the Garnet Star (Mu Cephi); but I have to say that Hind’s Crimson Star displays its namesake coloration to its fullest extent.
If you have never taken a moment to observe R Leporis, you will want to do so…or just revisit it and take a looksie if this is not a new object for you.
