Double and Multiple Stars

Warm Astronomy – first attempt.

So, the clocks have gone back, the dark evenings are here and (when the clouds and rain leave us alone) there’s some great stargazing to be done. Within reason I’m quite happy to get my thermals on and put up with a bit of cold to enjoy the show, but I also like to share (inflict?) my hobby with my nearest and dearest and my chances of getting them outside in this weather for any length of time are pretty slim. Over the summer I’ve been good friends with eBay and have picked up some bits and pieces to enable me to bring the hobby indoors.

The kit I’m using is: HEQ5 Mount, Skywatcher 130P-DS, ZWO ASI224 Camera (with an LP filter) and a laptop running Cartes du Ciel (I know lots of club members like Stellarium, but my geriatric laptop doesn’t!) to control the mount, SharpCap to run the camera and TeamViewer to control the laptop remotely (I tried using Remote Desktop, but Windows wasn’t having any of it).

First chance to use it came up on Sunday night- full moon or not! Altogether it took about half an hour to set up (hopefully this will drop with practice). Pictures below show the setup (complete with frost) and then images of what we could see in the session. Whilst we were running I saved the captures and later stacked them along with a dark stack (not sure I’ve got this bit right) and did a histogram stretch- these are shown alongside.
Altogether, it worked well- both being able to easily show images and the novelty of pointing at something on screen and then images of it appearing a minute or two later. Some friends popped over and they were quite taken with being able to all see it at the same time and discuss rather than taking turns at the eyepiece and being unsure of what they were seeing.

The brighter objects were certainly better- the targets we looked at were:
Albireo – right image is 15 x 10s exposure.
M57 Ring Nebula – right image is 15 x 30s exposure.
M27 Dumbbell – right image is 30 x 30s exposure.
M15 – Globular – right image is 35 x 30s exposure.

Gain was set to 300 throughout. I also tried the Double-double, which became the Single-single and M81 which just came out as a blob- I think this and the Dumbbell might work out better with a bit less moonlight. Overall it was a really successful evening- the setup time is a bit of a pain compared with the 5 mins it takes to set the Dob up (and that includes making a cup of tea!), and it lacks the magic of finding it yourself and seeing with your own eyes. But for sharing with others it’s brilliant, and later on I even managed to get my month-end books done with the scope still on which made that task less of a drag than usual!

Oh- and thanks for the earlier post in the blog about using old storage boxes to protect your laptop/shield the light from its screen- worked a treat!

 

Pushing a 4″ refractor to it’s limits.

 

Swadlincote 29/10/17 Vixen 102 SP.

After months of barging through faint clusters , deep sky and sub 1.5″ separations , I thought of going with the 102 f10. Finding out what it can do gave a session full of surprise and little wonders. At max I got up to x218 , but usually kicked around x44-x100.

4″ long ota gives colour , contrast , easy focussing and sharp views . It’s the most of efficient optical systemS. If you like your diffraction discs like marbles , it’s all going here ! Against the 150 frac,it’s more interesting to open sub 2″separations and get those dim contrasting companions. A bright moon and a fair amount of light glow , but a wonderfully chill still night and it’s all go !

Kicking off with an old favourite , Miriam,η Persei (SAO 23655) and a lovely orange and blue.
Σ162 ( also in Andromeda) SAO 37536 and this lovely triangular triple showed up at x150.
θ ,theta Persei split at x100 (SAO 38288), a delicate +10companion here.
Σ425 gave a clean 2″ separation at x180 (SAO 56613), a lovely pair of twins.
ΟΣ59, a slightly uneven , but wider 2.7″ split here. (SAO 39031). Really chuffed to see what 4″ can do.

Now a few old favourites,
ζ ,Zeta Persei (SAO 56799), yellow and blue , a mini Rigel. Challenging as the intrusive primary glare focussed in an out and I wasn’t certain. Returning with my sketch board ,I looked again. A clean marble of the primary with a clear speck (+2.9
and +9.2). Same thing with primary glare happened with the nearby
ε Persei, (SAO 56840) narrower , with a +2.9 and +8.9, lovely lemon and blue colours here. Wait for them to appear , revisit , these things come with a big of care !
Σ483 gave a wonderfully open split at 1.6″,the separation here is increasing from the often quoted 1.3″. Clean separation shows good seeing and super 30 + year old Vixen optics.

Over to Andromeda. Just a touch of peanuts with 36 Andromedae. Ho 197 showed a right angled triple here at x50.
Es 2725 showed up in a lovely field with the obviously orange 8 Andromedae and the white 11 Andromedae.
Σ3004 gave a wide pair. The +6.3 primary and the delicate +10.1 make a lovely view.
I tried kappa , but the Moon had bleached out the lovely multiple view. Colour and the delights of Almach and Alpheratz before moving on.

Up to Cassiopeia and the best view of iota yet , open up just three lovely marbly points. Not as bright as β Monocerotis, but lovelier.
Inside and to the top (frac view) of the cluster IC1848, a few doubles here, but it was a surprise to open up Σ306 at 2″(SAO 12470) there is a third fainter component here.
γ Cassiopiaea and a no show, such a violent star !
ψ (Psi) was full of colour and a delightful show (SAO 11751).

Very pleased to have pushed the scope, the 23mm Panoptic gave tremendous wide views. In most cases ,it was easy to pick out binaries. The 5.5mm Meade uwa swept up the finest of splits.

Well aided by a huge brass focussing wheel crafted by a good friend. This greatly eased fine r&p focussing , I am loathe to change anything much on older gear !
Time to get out there and pick up some wonderful colour and detail of multiples,under clear skies ! Nick.

Observing Log Friday 27/10/2017 7-9:30 pm

The forecast was correct, clear skies, a chance to used the skywatcher ST102 bought earlier in year and only used for solar work so far. ( see pic.1)

I started under the carport ,as moon was not visible from back garden, not quite first quarter, used it to complete lining up red dot finder, took some getting use to smaller image after the 8″ Newtonian or the 9.25″ SCT. When at IAS I bought a smartphone adapter to take afocal images using the wifes’ new smartphone, now was on opportunity to try it out, pic.2 shows adapter and phone, pic.3  image of moon, notice the chromatic aberration, however visually it was not noticeable. The image was taken with a 30mm plossl eyepiece with this 500mm focal length refractor this gives a mag of x17. The crater marked with a red dot in the centre is Ptolemaeus, at slightly higher magnifications the centre of crater appeared to have horizontal bands across it, is this an artefact, blemish on objective/ diagonal?? at a mag of x83 (6mm plossl) all was revealed there were shadow bands from the peaks on the Eastern crater wall, the wall reaches heights of 3000m (9000+ ft) and with the sun relatively low on the moons horizon the peaks cast some long shadows, it was fascinating watching the shadows shorten even over a relatively short period of time , Liz had taken her phone back, so I have attempted a sketch of the shadows cast over the crater floor ( see pic.4),  the floor is relatively smooth, having been flooded with lava, some very minor impact craters formed since, the darker shading on the west is due to floor slumping towards crater wall. This was the first time I have seen such marked shadows on a crater floor formed by the crater walls, shadows from central  peaks are usually observed and just blanket shadow from the wall, the continual changing of relative positions of sun and moon makes the terminator a dynamic visual environment, there is always something new to see, even in one evening.

I then relocated to the back garden, starting in the SW with Albireo in Cygnus, the 10mm plossl  ( x50) clearly showed B1 cyg ( Alberio) as a orange red K class star and B2 cyg B class blue star. Taking a line down to zeta Aq from Albireo, bisecting the line from Vega to Altair, just slightly left the Coat hanger asterism fell neatly into the field of view using a 40mm plossl ( x12.5) , normally I would use binoculars for this target, but the wider field of view afforded by this small refractor enables it to be seen in its entirety. Up into Lyra,aiming between Sulafat and Shellak to locate the Ring Nebula ( M57), fuzzy ring but no hint of central white dwarf in this planetary nebula. Continuing west into Hercules M13 and then up to M92, even with 6mm plossl ( x 83) not a lot of detail. Better with the double cluster in Perseus and as I headed to M31, Andromeda galaxy the cloud had rolled in bring the session to a close at around 9:30.

It was nice to get out with some clear skies and I found the AZ3 mount that came with the ST102 easy to use and manoeuvre and although the refractor shows some chromatic abberation as shown by the photograph of moon , visually it was not noticeable enough to be a problem.

here’s to more clear skies!!!

Pete H


Challenging binaries in Bootes.

A beautiful constellation , headed by Arcturus. Look at the line to Vega, first you’ll find is the arc of the “northern crown ”   Corona Borealis. Continue to Vega and there’s the “keystone ” of Hercules.

Bootes contains some easy binaries , for those with a bit more aperture and sharp eyes there are some challenges below 2.8″ separation, Nick.

April kick off !

Swadlincote 1/4/17 C6r.
By ten it was tolerably dark, but a light haze didn’t help with galaxy views. Dropping off Chara there were a few there , down to NGC 4449. Leo was hardly better and only M64 showed in in Coma Berenices.

Jupiter wobbled like a huge jelly, M3 was very faint,time to hunt out a few favourite binaries. For the first time I caught a sub 1″ separation. Worth carrying on for decent seeing at high altitude.

Leo . Σ1426 (SAO 118241) and a lovely view of this group. Σ1447 (SAO 81415) and a white star with a bluish “smokeball, some 676AU separation.

Coma Berenices. Σ1639 (SAO 82293) a widening 1.8″ at 166AU.

25 Canum Veneticorum. (SAO 63648) , some super contrast here, white and blue at 1.7” and 103AU separation.

With difficult atmosphere and light pollution, it’s worth giving these super sights a shot. The great constellation Bootes is climbing with a feast of binaries. Clear skies ! Nick.

“La Superba”, Y Canum Venaticorum.

The happy hunting grounds of the “Hunting Dogs”, Canes Venatici are well placed. This glorious area beneath the handle of Ursa Major. A favourite area and kicking off point for the Coma Virgo galaxy clusters.

It holds many galaxies including the magnificent M51( 27 million light years away) M94 (16 million lys away)and M63. A few years ago these were good targets from the edge of town. Light pollution has worsened . On rare nights  “The Whale”, “Cocoon” and “Hockey Stick” still come out. The most stunning being NGC 4449 which resolves to stars. However for small scopes and bad skies there are some stars worth locating.

Canes V is marked out as a line between Cor Caroli (“Heart of Charles”)at 115 lys away and fainter Chara at 27 lys away. These are useful pointers for galaxies. Cor Caroli is a wonderful binary for small scopes. It’s easy to find by eye and half way between it and Arcturus is the globular bright M3. A most useful pointer.

In addition there is a lovely star in CNv which I use as a tester for observing conditions, the fabulous “La Superba”. Once again, small aperture will serve you well, scooping up maximum colour. See what you think. If you can still get “Hind’s Crimson” star, you’ll see the much finer colour of this “Vampire Star”. Be aware that both these carbon giants are variable , catch them at their brightest !

Back to the superb one.Here’s its location and a few notes from Jim Kaler.

Y Canum Venaticorum – La Superba
Y Canum Venaticorum, called “La Superba” by the 19th-century Italian astronomer Father Angelo Secchi, is one of the deeply red-toned “carbon stars.” Y CVn is a semi-regular (SRb) variable star; its magnitude range is from 4.8 to 6.4, over a period that averages roughly 157 days. Other periods, including one of 2000 days, are suspected. “Y” is one of the reddest stars in the sky, and is classified variously as a C7 supergiant, or as a CN5 supergiant. Its beautiful poppy-red tone is easy to see in 50 mm binoculars.

Properties

Carbon stars are highly evolved cool red giants with atmospheres rich in carbon molecules. Most red giants and supergiants are richer in oxygen than carbon; carbon stars reverse the ratio. The unusually deep red color of these stars is the consequence of the efficiency of these carbon molecules in absorbing the star’s blue light.

Carbon stars were originally classed as warmer “R” and cooler “N,” and are now combined into class “C.” As giants, they are dying, and are in a mass range where the carbon byproducts of helium nuclear fusion are lofted to the surface before escaping into space. Huge absorptions by carbon monoxide, cyanogen or CN, carbon-2, and carbon-3 are present, giving the star its remarkable spectrum. The beauty of the spectrum is what caused Father Secchi to gave the star its name. It was described by Agnes Clerke in 1905 as having “extraordinary vivacity of its prismatic rays, separated into dazzling zones of red, yellow, and green, by broad spaces of profound obscurity.”

With a surface temperature of 2200 K, La Superba is one of the coolest of naked eye stars, though one authority puts it at 2800. At 710 light years away, the star’s luminosity is 4400 times the Sun’s, after a large correction for infrared radiation. This gives it a radius of about 2 AU – notably larger than the orbit of Mars. La Superba is most likely in the process of becoming a luminous giant for the second time, brightening with a dead carbon-oxygen core. Its mass is not well defined, but was probably initially at least three times the Sun’s.

Typical of its breed, Y CVn is losing mass, at a rate of about one ten millionth of a solar mass per year – a million times that of our Sun’s own solar wind – with a flow velocity of about 10 km/sec. Y CVn is surrounded by a huge detached shell of matter with a diameter of around 2.5 light years. The shell subtends an astounding 11′, or 0.2 degrees, as seen from Earth. It implies that the mass loss rate was 50 times higher in the past. La Superba seems poised to eject its outer envelope, becoming a planetary nebula with its dead white dwarf core at the center.

La Superba is also the sky’s brightest “J star.” These are a very rare set of carbon stars which have a huge elevation of the heavy isotope carbon-13. Though carbon-13 (with 7 neutrons in its nucleus rather than 6) is readily made in the nuclear reactions that help generate stellar energy. But no one quite understands what causes it to be so abundant in the J stars.

[Adapted from STARS by Jim Kaler, Professor Emeritus of Astronomy, University of Illinois]

clear skies ! Nick.

Binaries under the Moon.

Cold , clear and a bright moon. It was struggle to get contrast with NGC 2903 just showing and M67 bleached out. The main stars of M44 held. Once again binaries gave some cracking views in particular with tight separations and some faint companions spotted.

Talitha in UMa proved once more very elusive , I spent some time with filters , eventually just managing to squeeze out the small puff of the secondary in the glare. There was lots of colour on show. The best being. Low power visit to ” La Superba ” in CNv. There are some fantastic binaries here.

Back to Cancer and “Tegmine”. What a superb split at x216. It held perfectly stable at a widening 1.1″.
57 Cancri showed a slightly easier 1.5″, delightfully bright and even in a lovely star field.
Up to the rising UMa .
57 giving a lovely delicate companion at x150.
65 showing the lovely triple of differing magnitudes. It’s superb to increase the magnification to split these open.
Then a real favourite and showcase at,
Σ1831,this obvious line of stars splits open to show a most delicate pair at x 150.

A bit of a struggle with the moon behind. Kept get bright flashes off my glasses ! High misty stuff with a deep ground frost completed a very satisfying session,
Old Nick.

Best binaries and triples in Taurus.

img_4363img_4362img_4361
Recently , observing has been through milky skies with weather systems shifting quickly at height. There hasn’t been enough contrast for filling in clusters or observing galaxies.
Time for some binaries. Early evening views of Taurus have meant sitting comfortably at the eyepiece. Taurus is stacked with binaries, one of the few visible by eye is in the Pleiades.

Σ479 shows a wide but delicate L shaped triple. RA 04h00.9m. +23 12′
Σ523 SAO 076552, dim pair at 10.2″.
52 Tauri (φ) SAO 076558, ghostly speck gives light red and blue.
Σ559 shows a wonderful bright exactly even pair, really lovely.SAO 094002, just spectacular.
Σ7 and Σ401 are both caught in the field of view at x50, this is better than the double double. A really beautiful sight.SAO 075970.
Σ430 shows a delicate and difficult amazing looking triple with two faint companions , I often wonder what a sky with three suns would look like.
SAO 11340.
Aldebaran is a binary with a wide +11.3 companion, worth spotting.

Finally across the Moon this morning , a glimpse of someone practicing delivery, Happy Christmas and all the best for 2017 !
Old Nick.img_4364