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Observing session February 14th, 2020

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#1 Astrojensen

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Posted 14 February 2020 - 05:41 PM

Friday February 14th was wonderfully sunny here, but as the Sun set, high, thin clouds began to move in from the west. In bright twilight, I set up my Zeiss Telemator (63/840) to at least get a short glimpse of Venus, before the clouds rolled in. 

 

Venus was quite sharp in the 6.7mm ES82 eyepiece (125x), so I naturally started to hope, that I could catch sight of a few other things, before the clouds came. Looking up, I could begin to see the brightest stars. Rigel in the southeast caught my eye. Using the finderscope, I centered it directly in the 6.7mm eyepiece. Despite the bright twilight, I could see the companion immediately. The seeing was VERY good for the low altitude Rigel always has here at 55° northern latitude. It was quite a superb sight. I experimented with other magnifications, 76x (11mm ES82), 96x (8.8mm ES82) and 179x (4.7mm ES82). All showed the companion, but 125x was the best balance between brightness and magnification. 96x was also very good, but I preferred 125x. 

 

More stars were slowly coming out now. I aimed at Castor next. This time I started with just 35x (24mm ES68), but I could still split it rather easily. Again, 125x showed a most superb sight. Castor was at a much higher altitude and the seeing was nearly perfect, with the diffraction rings just moving ever so slightly. The sky was still so bright, that I couldn't see the fainter companions, even at 125x. 

 

Even higher in the sky, Auriga was coming out. I could just see Theta with the naked eye, so I aimed the Telemator at it, once again with 125x. I was rewarded with the finest view of this challenging (in this scope) double, I've had in the Telemator for many years. The  golden yellow airy disk of the main star was perfectly sharp, with broken arcs of its first diffraction ring coming in and out of visibility, and to the north, in the 11 o'clock position (as seen in a diagonal), the faint dot of the companion popped into view, when I held my view perfectly steady. A most superb view. 

 

Now I could see Orion, so I turned to Zeta Orionis. It was immediately split at 125x, although with a bit of the companion hiding behind the main star. There was no sight of the C star, the sky was still too bright. 

 

The Trapezium showed four stars at 35x, but the fourth was quite dim. 125x didn't show more. 

 

Delta Orionis was easily seen at 35x. 

 

Sigma Orionis was quite superb at 125x. I could not see the fourth, dimmest companion. The two others were clearly seen. 

 

The Pleiades were just lovely at 35x. 

 

It was starting to get a bit darker, so I returned to Zeta Orionis and now I could also see the C component. 

 

I had to take a break, because it was time for dinner, and when I had eaten, it had become much more hazy. Still, I could see the stars, so I decided to continue. It was immediately apparent, that not only was it now very hazy, the seeing was also worse than before. Not unusable, but decidedly not as fine as before.  

 

I started with a seeing check on Rigel at 125x. Shockingly, I could no longer see the companion, despite the seeing still being good enough that I could see the diffraction rings in the better moments. Was the haze really THAT thick? Apparently so. A quick naked eye check also revealed that it was quite unevenly distributed and moving around. 

 

Castor now showed the dimmer companions at 125x, but was itself trembling a bit in the seeing. 

 

Zeta Cancri was surprisingly dim at 125x. The AB - C pair was easy enough, while the A - B pair was more difficult, but in the best moments, I could clearly see, that it was slightly elongated. Had the night been better, I am sure this observation would have been much easier. 

 

Looking at Iota Cassiopeia, I was at first not able to see any of the companions. I was so perplexed by this, that I starhopped to it several times, each time being sure, I must have gotten the wrong star. The haze simply dimmed the companions to invisibility. I revisited it later, when I could see that Cassiopeia was in a clearer spot and then managed to see both companions at 125x. 

 

6 Cassiopeia was not split. Not a hint of it. Little wonder, StelleDoppie says it's around 1.5" now. 

 

Eta Persei was easily resolved at 125x. The main star has a beautiful, golden yellow color. It's been a while since I've looked at this star and I was a bit surprised to see that it's a nice, visual triple, with a second companion almost directly opposite the brightest one, a bit more than twice as far out from the main star. Intrigued, I looked it up in StelleDoppie and googled it, and was surprised to see, that this star isn't considered to be a companion, but several, much fainter stars are, despite some of them being only very marginally closer. 

 

By now, I could see that the haze was getting very thick in the west. I turned eastward and took a peek at Algieba (Gamma Leonis), before packing up. At 125x, the companion gave the impression, at least in glimpses, of being ever so slightly pale bluish, in contrast with the deep, golden yellow of the main star. Both stars showed a fine, thin first diffraction ring, just like in the textbooks. 

 

All in all, a fairly productive evening, despite very mediocre conditions. 

 

 

Clear skies!
Thomas, Denmark


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#2 flt158

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Posted 15 February 2020 - 10:52 AM

Utterly sensational report, Thomas!

I've a good mind to reread again later on. 

What a very fine small scope you have in Denmark. 

Thank you for your dedication in reporting all what you observed with the rest of us. 

It has all been worth it!

May others do the same.

 

Clear skies after Storm Dennis, 

 

Aubrey. 


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#3 fred1871

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Posted 16 February 2020 - 09:08 PM

Thomas, a very impressive list of observations for such a small aperture telescope. The Telemator has a fine reputation, and your descriptions of what you saw support that reputation. Surprising, really, that so much can be seen with 63mm, including seeing elongation on Zeta Cancri AB.

 

Your description of Theta Aurigae shows that you found it easier than Sissy Haas did with a 125mm achromat, as recorded in her book. This is another example of a double that's highly sensitive to seeing conditions, and it shows the possibilities of small apertures when the atmosphere co-operates. Haas used twice your aperture, and her description suggests it was not as well seen.

 

Makes me think that perhaps I should get a smallish scope of high quality to use for the nights when setting up a bigger scope feels like too much work. In recent years I've not used anything smaller than a 140mm refractor. A smaller high quality scope provides opportunity for enjoyable observing with less physical work required before and after. Not everything in the sky needs larger apertures all the time.


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#4 Astrojensen

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Posted 17 February 2020 - 01:40 PM

Thomas, a very impressive list of observations for such a small aperture telescope. The Telemator has a fine reputation, and your descriptions of what you saw support that reputation. Surprising, really, that so much can be seen with 63mm, including seeing elongation on Zeta Cancri AB.

 

Your description of Theta Aurigae shows that you found it easier than Sissy Haas did with a 125mm achromat, as recorded in her book. This is another example of a double that's highly sensitive to seeing conditions, and it shows the possibilities of small apertures when the atmosphere co-operates. Haas used twice your aperture, and her description suggests it was not as well seen.

 

Makes me think that perhaps I should get a smallish scope of high quality to use for the nights when setting up a bigger scope feels like too much work. In recent years I've not used anything smaller than a 140mm refractor. A smaller high quality scope provides opportunity for enjoyable observing with less physical work required before and after. Not everything in the sky needs larger apertures all the time.

Hi Fred

 

It surprises me, that Haas has trouble with Theta Aurigae in a 5". I find it rather obvious in that aperture at 100x or higher, as long as the seeing is fair. 

 

I do encourage people to get a small, high quality refractor for those evenings, where the weather is less than perfect or a long workday takes its toll. It is better to be with a small 60mm under the stars, than not being under the stars at all. And it is indeed surprising what it can show, if one goes to the eyepiece with an open mind and not exclude targets based on numbers alone. Double stars is one area in which a small scope can shine, as the airy disks will look the same, regardless of aperture, as long as the optics are perfect. You just need brigther stars to show them in the small scope. Luckily, there are many bright doubles to entertain oneself with in a small telescope. 

 

 

Clear skies!
Thomas, Denmark


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#5 Bonco2

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Posted 17 February 2020 - 04:56 PM

Thomas,

Nice report. Lot's of attractive doubles this time a year for doubles and small telescopes. My little 60mm Unitron does a great job on some toughies like Pi AquiIa,  Rigel,   Delta Cyg,  Izar and many others. For bright colorful doubles a small refractor can provide stunning views as you described. The easy doubles like Castor, Alberio and dozens of others seem most attractive in small apertures.

Bill   


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