November 21, 2023

A fine telescope in late autumn: yes, this is my happy place.

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If November isn't my favorite month to observe here in Washington, DC, it's right up there with March and April. Most nights are cool, crisp, and imbued with an ineffable fragrance - of decaying leaves in autumn, of budding blossoms in spring - that encourages deep breaths. The mosquitoes are resting after (or before) the horrors of summer, and seeing hasn't yet slumped to its winter lows.

I try to use my telescopes as much as I can in late autumn and late spring, but there's a problem: these are the busiest times in the academic calendar, and it's not always easy to juggle my hobby with my work. Worse, both seasons are times of unrelenting illness for any parent with young children. So it is that while the sky has been routinely clear for the last month, with seeing typically average, I haven't had much chance to exploit it.

Finally, on November 13th, I felt just healthy enough to venture outside with my TSA 120. At just before midnight, Jupiter was nearing zenith. Although atmospheric conditions were not exactly ideal, I couldn't pass up the chance to have a look. 

I had let my TSA 120 sit outside for about 45 minutes before using it, and it paid off: while temperatures were no higher than 10 degrees Celsius, the telescope had completely cooled down. Yet when I turned to Jupiter, the planet initially resembled a circle of bubbling milk, surrounded by a smattering of drops (the Galilean moons). Why had I sacrificed sleep for this?

Then, as I considered packing up, the atmosphere abruptly stabilized - and now a staggering wealth of detail shimmered into view. It was fleeting - "revelation peeps," to use a Lowellian term, often are - but it was more than enough to keep me glued to the eyepiece. Over the next hour, belts, zones, and the Great Red Spot all flickered across the pale Jovian disc, and I nearly lost track of time. Finally, it dawned on me that even a bad night's sleep was slipping away, and I hastily carried my equipment inside. 

Perhaps it's a character flaw that I like to obsessively compare my instruments; if so, it is a flaw I share with most amateur astronomers. In this case, I couldn't help but reflect on the TEC 140 I once owned. In a vacuum, I might prefer that telescope over the TSA 120. But the difference in the optical performance of both telescopes is slight enough that I prefer the far greater portability of my TSA 120 setup. It weighs half as much, and that makes it so much easier to use when I'm tired. 

Of course, when it comes to portability and ease of use it's hard to beat my EVScope 2. With Orion starting to rise high above the horizon in the wee hours of the night, I decided to use that telescope to view the constellation's famous nebula. On the 18th I parked the telescope in my backyard, found a gap in the increasingly bare trees, and had a look. 

This is an unedited image, though there's some distortion from a nearby balcony.

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As usual, within seconds the EVScope delivered a view that no traditional telescope could match under an urban sky. Yet using the telescope so soon after observing with my TSA 120 gave me a clear sense of what bothers me about it. The EVScope is easy. There are no "revelation peeps" - no flashes of transcendence - because everything is smoothed out in a (relatively) pretty picture. There's no craft to observing, no sense of taking in the universe with your own eyes. You see more - but you feel less. 

Sometimes, that's okay. There are whole classes of object - white dwarfs for example - that I can only glimpse with my EVScope (at least in our light-polluted skies). Yet if I were forced to give up one telescope, I would choose the EVScope without a second's hesitation. 

This setup is absolutely rock steady, but I can lift it with one arm.

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My health improved this week, and my workload (temporarily) eased. Now I steeled myself for a challenge I've dreaded for weeks: collimating my new Mewlon 210. I've been so unwilling to try it that I even - very briefly - placed the telescope for sale. Yet I read up, prepared my Allen key - and left the Mewlon out for an hour to cool down. 

When I returned outside, I found that the telescope still had not completely acclimated to temperatures that were not far above freezing. I waited another half hour, then tried again. Now the telescope seemed cool enough, but to my surprise my first view of a star was so underwhelming that I again considered whether to sell the telescope. A blob is the best I could get - a far cry from the pinpoints I see through my refractors. 

I'd hoped that I'd been wrong about the Mewlon's collimation, but now there was no doubting it: the telescope's secondary mirror simply did not perfectly align with the primary. I set to work tightening bolts, and to my surprise I didn't mind it. Years of tinkering with mechanical watches and bicycles had prepared me well, I suppose, because after 15 largely painless minutes I was just about done. 

I could scarcely believe my eyes when I returned to that star. Instead of a blob, there was a perfect little diamond. To my amazement, the telescope's diffraction spikes - a product of the four vanes that hold its secondary mirror - actually added to the star's beauty. It wasn't perfect - seeing was actually below average - but it was about as beautiful a stellar image as I can remember seeing. 

Jupiter offered some of the same revelation peeps I'd enjoyed with my TSA 120, except with a bit more color (and this time, the diffraction spikes were a bit distracting at lower magnifications). Turning to the Trapezium in Orion clearly revealed five, perhaps six stars - a challenge for fine optics even in good seeing - but it was Betelgeuse that truly stole the show. The star was simply a spectacularly beautiful orange gemstone when viewed through the Mewlon. The telescope's large aperture (compared to my refractors), total lack of false color, and yes, diffraction spikes made me appreciate simple stars as I never have before.

With any luck, I'll use the Mewlon to spend happy hours admiring the double stars that are easily visible in our city. But on this night, it was time to pack up - and to banish all thought of selling the Mewlon.