394 ARI – Struve 394
394 ARI is a nice sight and contians a primary and secondary of almost equal size and magnitude with a primary with an obvious yellow tint and a secondary with an equally noticeable blue tint. This double stands fairly alone in the FOV at this magnification, but it is a very nice and easily observed double residing in Aries.
Krueger 60 A and B
I began observing and recording the position angle of Krueger 60 A and B also
called ADS15972 during the fall of 1978. In another 15.5 years I will have
observed these close orbiting red dwarf binary stars through one complete orbit.
This pair of stars also demonstrates an annual proper motion westward of nearly a
second of arc. Both of these stars are M class and are among the 40 nearest stars
to earth at just 13.1 light years. The current separation between the pair is 2.3”
of arc. In actual measurement the components are 9.2 AU apart which is about the
distance between the Sun and Saturn. The smaller component B is less than 10% the
mass of our sun and is famous for its irregular flare outbursts which can last for
10 minutes as the brightness doubles. The A component star is magnitude 9.8 and
the B component glows at magnitude 11.3. Both stars are in the constellation of
Cepheus about 45 minutes of arc from Delta Cephei which is famous as the prototype
for all Cepheid
variable stars.
Sketching:
Date and Time: 9-23-2007, 5:10-5:45 UT
Scope: 10” f/5.7 Dobsonian. 12mm eyepiece 121x
8”x12” white sketching paper, B, 2B graphite pencils, scanned and inverted, star
brightness adjustments using Paint
Averted vision was a very useful aid in this sketch.
Seeing: Pickering 8/10
Transparency: above average 4/5
Nelm: 4.8
Frank McCabe
I’ve never tried sketching doubles before. But the sunset was so pure that I wanted
to enjoy the night outdoors. Sketching Albireo seemed a nice plan under a moonlit
sky. While the full moon was rising from the East, I was covered by the shadow of
our house. I did not expect much to see in the field of view, only a little double
star. But much to my surprise the field was full of little sparks. I guess my
telescopic LM was about mag 11.5 at x63. The nelm was about mag 4.5 under a dark
blue sky. Even the telescopic sky appeared blue to me. I tried not to overdo the
colors. I have a hard time detecting colors in stars. So here is my little sketch of
Albireo. I hope you like it. (edit: the sketch has been reworked, once Sheliak was
finished. This to adapt the relation in brightness a bit.)
Date : August 29, 2007
Time : 21.00UT
Scope : Skywatcher 102/500
Vixen LV zoom at 8mm
Power : x62
FOV: 50′
Filter : none
Seeing : 3.5/5
Transp. : 2/5
Nelm : 4.5
Sketch Orientation : N up, W right.
Digital sketch made with PhotoPaint, based on a raw pencil sketch.
Rony De Laet
Last evening I was out observing with a telescope and thinking about how another
summer is ending and the fall season is upon us. With the exception of the month
of August which was mostly cloudy and rainy, the summer here was a good one for
observing. The first three weeks of September has been a welcome return to the
good observing nights like I experienced in June and July. At a public open
viewing night this past Friday I was showing the attendees the famous double
double ( Epsilon 1and 2 Lyrae). At the end of the evening I realized I had
forgotten to show them the other double double in eastern Lyra with the wider
separation and nearly parallel components rather than perpendicular as with
epsilon 1 and 2. I have never sketched this combination of double stars so I
decided to do just that and maybe next time I won’t forget to point out this view.
I am not a binocular observer but these stars would I am sure look great and split
nicely in a pair of astronomical binoculars. The northern pair of stars are designated
Struve 2470 they are both white stars at magnitudes 6.6 and 8.6 at a position angle
of 271°. The separation of this pair is 13.4” of arc. The other double pair 11 minutes
to the south is Struve 2474; this pair of pale yellow stars glow at magnitude 6.7 and 8.7.
they are separated by 16” of arc and are in position angle 262°. This is the way they
looked to me at the telescope eyepiece. These stars are about 19hrs. 9min.
Right Ascensionand +34° 40min Declination. Both pair fit nicely in one field of
view and are easy to split.
Sketching:
Date and Time: 9-20-2007, 2:25-2:50 UT
Scope: 10” f/5.7 Dobsonian. 21mm eyepiece 70x
8”x12” white sketching paper, B, 2B graphite pencils, scanned and inverted, star
brightness adjustment using Paint
Seeing: Pickering 7/10
Transparency: above average 3/5
Nelm: 4.5
Frank McCabe
Delta Lyrae, Stephenson 1
A drawing of a double star that was supposed to be a walk in the park turned out to
be a lot more challenging. This moonless night was filled with plenty of stars. So
was the field of view around Delta Lyrae. Countless milkyway stars were scattered
like pinpricks in the sky. Leaving them out of the sketch was no option. I also read
that Delta Lyrae is part of a sparse little cluster called Stephenson 1. I had a
hard time to recognise the grouping as a cluster. Here is the sketch.
Date : September 4, 2007
Time : 21.00UT
Scope : Skywatcher 102/500
Meade 4000 SP 26mm
Power : x20
FOV: 150′
Filter : none
Seeing : 3.5/5
Transp. : 3/5
Nelm : 5.3
Sketch Orientation : N up, W right.
Digital sketch made with PhotoPaint, based on a raw pencil sketch.
Rony De Laet
Alcor and Mizar. Pencil on white paper inverted in Photoshop. This is the first
sketch I’d been able to make, in my first observing session for months (due mainly
to bad weather and constant cloud cover). It was made on August 24th, 2007, using
my 4″ refractor, ideal for double star observations. The conditions were pretty
horrible – milky skies and a waxing, almost full Moon.
Date: 24th August 2007
Instrument: 4″ refractor
Magnification: 42x
Location: My backyard, Isle of Wight, England
Conditions: Horrible! Waxing, almost full Moon, hazy skies. Not much use for
‘proper’ deep sky observing.
NELM: 5.0
Notes; A well-known double. A beautiful sight in the refractor
Faith Jordan
The goal of splitting the double star, Antares, had been tempting me for a while. I never seem to have the sort of seeing conditions that would make for a nice clean observation of this double. So I gave it a try on this less-than-perfect evening, and was successful in spotting the secondary star with my SkyView Pro 6LT (6″ f/8 Newtonian) at 240X. Antares’ primary star flickered like a coppery flame in the jumping air currents, so I had to be patient and wait for the ripples of diffracted light to show me the way. The secondary began to coalesce as a consistent lump in the fluttering kidney beans of orange light near the position of the primary star’s second diffraction ring. It’s color was hard to pick up, but gradually, I perceived what looked like a yellow-green tint. To help keep myself honest, I had not checked data on the secondary’s current position angle ahead of time, and it looked to be at a PA of about 280 degrees. Checking Brian Workman’s
double star calculator a couple days later gave a PA of 277° for 2007.5. The separation comes out to 2.18 arcseconds, which is fairly close for my ‘second diffraction ring’ sighting–that works out to 2.5 arcseconds in my scope.
When preparing my double star sketches for presentation online, I scan my original sketch to use as a template. Using that template, I then recreate the double star components using painting tools in Adobe Photoshop. See my Double Star Digitizing Tutorial for a detailed discussion of the process I use. After preparing that tutorial, I came up with a system for representing double star magnitudes consistently across all my sketches. A discussion of that system can be found at this link. Although these methods give me a consistent way to present my double star observations, they don’t handle very close doubles well. The proportions compared to the eyepiece field of view are just too tight (a discussion about this issue can be found at this link. Based on suggestions from experienced observers such as Eric Graff and Ed Zarenski, I decided to supplement my sketches of close double stars with an inset graphic showing how the diffraction patterns of the double stars interacted.
This sketch of Antares shows the most extreme example to date of how I’ve tried to convey the highly magnified optical interaction between two closely paired stars. Presenting something this complex was quite a learning experience for me, but I think it does a fairly decent job of rendering what I saw. This can be seen in the detail portion of the sketch. You just have to imagine all of that jumping around and moving from moment to moment. You’ll notice that I was fortunate enough to have the spider vanes in a position that didn’t interfere with the secondary star.
I made three different pencil sketches at the eyepiece, trying to describe how the secondary appeared within the jumping glare of its orange primary. These raw sketches can be seen below (note that they are shown prior to rotating the sketch to my usual position of North up):
When creating this part of the digital sketch, I used a semi-soft paintbrush to plot the position of the primary star’s diffraction disc. I then used the circle selection tool to stroke progressively fainter rings around the primary. I have been using the excellent information from Ed Zarenski’s article “Understanding Resolution” to help me better proportion the position of these rings to the size of the primary star’s diffraction disc. After plotting these rings, I used a soft eraser tool to erase gaps in them to mimic what I had drawn in my sketches. I then came back with a small, soft paintbrush to slightly brighten up the second diffraction ring where I had noted the position of the secondary star. I then used coloring techniques described in the tutorial above to colorize the image.
It really was a beautiful and challenging sight. Watching the colorful light from a distant star give up it’s wave properties as it passes through the telescope and then tempt you to dissect its secrets is an enjoyable task. Give it a try sometime and see if you can identify the secondary in that bubbling mass of starlight. Someday I hope to observe and sketch this duo under much smoother seeing. Full details about the observation can be found here.
Jeremy Perez
