A Winter Adventure with a 130mm f/5 Newtonian.

Plotina; the author’s 130mm f/5 Newtonian doing its stuff under a Christmas sky.

Sunday, December 23 2018

With the Christmas holidays now upon us, we were lucky enough to enjoy a beautifulĀ  winter day, with clear blue skies illumined by a feeble Sun. This time of year, darkness falls very early, well before supper time, and as luck would have it, the sky remained clear after dark. I decided to field my trusty 130mm f/5 reflector, mounting the telescope on an old Vixen Porta II mount at about 4.00pm local time, and let it cool down to ambient temperatures, which had already reached 0 C by sunset. Accompanying the telescope was a 8 x 42 roof prism binocular, used for finding fainter objects more quickly than with the telescope and its finder alone.

The cold weather was never a concern though; afterall, the telescope has strutted its stuff many times in sub-zero temperatures, as I’ve described in many previous blogs. At 4.45pm I began my observations with a look at the Red Planet, Mars, which by now had greatly receded from the Earth, but at least had now reached a very decent altitude in the south. Inserting a Parks Gold 7.5mm eyepiece coupled to a Meade 3x achromatic Barlow lens yielding a power of 260 diameters, I was greeted by a tiny little salmon-pink orb, quite obviously gibbous in cast, with a few dark markings visible across its surface. The view was good and steady and very satisfying given the great distance to which it had receded to since its glory days during the summer, when the planet swelled to an enormous size as seen through the same telescope.

But what I was really after this evening was a suite of double stars, my staple observational targets for many years now. Having abandoned small refractors and Maksutovs for the greater efficacy of the 5.1 inch Newtonian reflector, I turned the instrument on Epsilon 1 & 2 Lyrae, a summer favourite, but still suitably placed for observation in the early evenings of December. Keeping the same eyepiece and Barlow in the focuser, I obtained a wonderful, text-book perfect split of all four components. And though I had seen such an apparition more times than I care to remember, it still brought a broad smile to my face to see these old friends in a Christmas sky.

From there, I moved over to Delta Cygni, a much better test of atmospheric turbulence than the four stars of Epsilon Lyrae. Carfeully centring and focusing the bright white luminary, I obtained an excellent and stable image of the faint, close-in companion at 260x. It was at that point I knew that conditions were good enough to attempt the trickier targets that were lining up in the sky.

Moving the telescope further west, I could see bright Altair, so I tried my hands at the difficult and faint Pi Aquliae nearby, which I first reconnoitred with the 8 x42, before centring it in the 6 x 30 finder ‘scope of the main telescope. Keeping the power at 260x, I achieved a reasonable split of these fairly closely matched components but I could see that it was noticeably inferior to how it looked in the late summer and early autumn, when it was higher up in southern skies. Still, I was well chuffed to have bagged this system so late in the season.

Moving several degrees east into the diminutive but lovely constellation of Delphinus, I immediately aimed for the jewel of the celestial Dolphin; Gamma Delphini. The 5.1″ reflector made light work of this easy but fetching double star which was best seen at 118x using my Meade 5.5mm Ultra-wide angle eyepiece. From there, I sped over to Cygnus again and quickly located the multiple star, o^1 Cygni using the 8 x 42. Training the telescope on the system brought another huge smile to my face, as the beautiful and wide colour constrast triple system came to a perfect focus, their tiny Airy disks and faint first diffraction rings calmly presenting themselves in the frigid air.

After that, I panned the telescope eastward until I centred Almach (Gamma Andromedae) in the 118x eyepiece and was greeted with a beautiful split of this comely, colour-contrast double star. Even after all these years of observing it, it never ceases to inspire me! “That was easy,” I said to myself, ” but let’s have a go at a much more tricky system.” With that thought I trained my binocular at a patch of sky in eastern Cygnus, specificially looking for a faint pair of stars, the brighter of which was Mu Cygni. Quickly aligning the telescope on the same patch of sky, I inserted the 260x eyepiece-Barlow combination described earlier and carefully focused. Voila! There it was; a wonderful text-book perfect split of this very close binary system, with the wider, fainter star visible in the same field comprising the triple.

Finally, I visited the endlessly lovely Albireo, now fairly low in the western sky. Needless to say, it was a sight for sore eyes. It’s true; some of the most beautiful objects in the night sky are the easiest to access!

So far, so good. I took a break for a few hours, enjoying a good, traditional Christmas roast with my family, keeping the telescope in an unheated outhouse all the while, so as to allow me to quickly engage with the night sky. Beginning again around 10:15pm, with the bright Moon having risen in the sky and the temperatures having dropped to -2C, IĀ  started in Orion, which at the time of observation, had still not culiminated in the south. Hoping for a continuation of the steady skies experienced earlier in the evening, I trained the 130mm Newtonian on mighty Rigel. Slightly anxious, I carefully focused the bright white luminary in the 118x eyepiece and was relieved to see that the primary Airy disc was small, round and virtually free of turbulence. And there beside it was the tiny spark from its feeble, close-in companion. It was a beguiling sight!

From there I moved a wee bit to the northeast and centred Eta Orionis.This is a more difficult pair to resolve and so requires higher powers to tease apart. But at 260x it was easy; the two stars, plain white to my eye, appeared roughly east to west in orientation.

By now, mighty Auriga, the Charioteer, had risen to a great altitude, high in the east, and so I turned the telescope on its most prestigious double star; Theta Aurigae. The telescope made light work of this tricky system, the faint, steely grey companion being stably held in the frosty air.

A night of winter double star observing could never be complete without a quick look at Castor A & B in Gemini. Just east of the bright, near-full Moon, I had to battle with the glare a bit before centring the system in my 6 x 30 finder ‘scope. But at 260x, the twin white stars, pure as the driven snow, was a msemerizing sight in the telescope; the Airy disks small and round as buttons, each surrounded by a single, faint diffraction ring.

Finally, I thought I would try my hand at 36 Andromedae, which was first found with a bit of ferreting around using the 8 x 42 binocular. And sure enough, I was able to split this 1 arc second, near equally bright pair in the telescope without much effort at 260x. However, it was better seen using the higher power of a 4.8mm T1 Nagler eyepiece coupled to the same 3x Barlow yielding 408x. I was mightily impressed with just how good and stable the image remained as it shot across the field of view at this ultra-high power.

Vigil ended shortly before 11pm local time.

What a great night!

Simple pleasures with a simple telescope!

The stuff dreams are made of.


De Fideli.

5 thoughts on “A Winter Adventure with a 130mm f/5 Newtonian.

  1. Hello Niel,

    Still a pleasure to read your blog.

    Cheap astronomy is really fun.

    Merry Christmas,


  2. Hello Sas,

    Good to hear from you again!

    Yeah, that’s where I’m at!

    Merry Christmas to you and yours!


  3. Hello Neil
    I enjoyed reading your new adventures with the 130mm Newtonian reflector.
    Nine years ago it hapened to read about a kind test proposed by Norman Lockyer at page 164 of his book ”Stargazing ,Past and Present”.
    It is a sequence of six stars ,all crammed into the main asterism of Orion constellation :Delta ,Beta ,Zeta ,Sigma,Lambda and 52 Ori.
    The first five are visible with naked eyes and 52 Ori is visible through the smallest finder,so all are easy to find.
    Soon I found this gem of challenge , I had a go to it with my 125mm F/6.9 home-made Dobsonian.
    Needless to say , I failed a couple of time to run through all the sequence.
    At first ,I start having troubles already at Zeta where I failed to see the thight companion.
    If Zeta was split ,even more difficult was to see the third dim companion of Sigma , so to see this star as made of four components.
    But the real challenge was to split 52 Ori.
    I call this test ”The Lockyer Sequence”.
    I was so happy when I was able to split all those six stars.
    52 Ori is very close to the limit of my 125mm telescope.
    I’m very eager to know your opinion about the ”Lockyer Sequence”.

    I described this subject here on my blog , partially in Romanian language.


    I should revise my post ,this is a working link to the relevant page in the Lockyer book :

    Merry Christmas to you and your loved ones !

    Best regards,Mircea

  4. Hello Mircea,

    Many thanks for your very interesting post. I was not aware of this project by Lockyer but it sounds like a great activity to sink my teeth into over the next couple of months, what with Orion being well placed for observation before midnight.

    My little 130mm is still going from strength to strength!

    I will have a good look at Lockyer’s book; another fascinating historical source.

    Wishing you and yours a blessed Christmas.


  5. Good Evening Mircea,

    A Very happy New Year to you and yours!

    We had a beautiful crisp day here and after dark, the skies stayed clear. I had a go at attempting Lockyer’s list you kindly alerted me to on page 164 of his book with the 130mm f/5 Newtonian.

    I can report resolving all six with the instrument! I made some sketches of what I saw (their orientation) in the telescope and I will post a proper length blog very soon. I can confirm that Zeta is fairly challenging as the secondary is so close in that it can get lost in the glare of the brilliant white primary but it was doable.The first five were bagged earlier in the session, but I waited until 52 Ori near Betelgeuse had gained its maximum altitude at about 11pm local time. I was able to split it at 566x but I have an interesting story to tell about the eyepieces and Barlows used.

    Thanks once again for presenting the New year’s Day Double Star Marathon ’round mighty Orion!

    With best wishes,


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