Fellow jazz musician Tony "Sax-Smith" DeVincentes surprised me last Saturday by turning up at the house bearing a "garage sale special" in his hatchback.
Although Tony has loved astronomy since he was a kid, he really didn't know what he had purchased. All I got out of him was that it was "big"! And he was excited to have his first scope as an adult.
Tony and I walked over to the car. Based on his description ("BIG") I had visions of a 10 inch dob. Well I was right - the scope was a newt - but it was equatorial mounted and had a "bore" of 114mm. Spending out of pocket money, Tony had purchased a 4.5 inch F8 Infinity Newtonian manufactured in Taiwan and distributed by Meade.
Exteriorally, the scope and mount were in good shape. However, the finderscope was, well how shall I say this "unfindable". There was a single, 25mm, .965 inch 2 element eyepiece in the "bag of goodies" that came with the scope.
Fortunately, I had a couple of Orion Explorer eps around. Unfortunately there was no 1.25 inch adapter. So we made due by removing the .965 inch adapter and wrapping cardboard around the barrel of the 1 and 1/4" Kellners...
Being daylight, we set up the scope and peered at the cell phone tower on the hillside some 2 miles from my home. Using the 25mm Kellner, I could just detect the signal cable spanning the side of the tower.
But my eye had trouble accommodating. The scope was in a "bad way". Dust had accumulated on the main and secondary mirrors. There were also obvious collimation issues.
Tony and I spent several hours cleaning stuff and collimating to the best of our ability. Progress was slow and erratic. Too many surfaces were out of alignment. AND the cotton cloth I used to wipe the mirror surface (after washing away all the crud in soapy warm water) ended up scratching the oxidized aluminum on the primary.
I was unhappy about doing harm to his scope - but had at least warned Tony in advance that both mirrors would probably need new surfaces...
With an initial pass of cleaning, collimation and eyepiece accommodation complete, we made a few more checks of the cell phone tower, along with a sweep of the snow fence dividing a nearby high meadow. To my eye, either the seeing was very poor or the scope was still in a very bad way.
Thankfully I did not communicate these doubts to Tony. He of course, was quite pleased with his acquisition. I pointed out that the EQ2 mount alone was worth what he spent and consoled myself with that thought...
Tony packed up the scope and headed out. We had a practice session planned for latter that afternoon. As the session ended, the near full moon cleared the rooftops. We assembled Tony's newt and checked out the Moon.
The Moon wasn't that bad - if you didn't mind seeing "two" of everything. So let's say you are looking at Crater Copernicus. You would see the real Copernicus quite bright and present AND ypou would see Copernicus "doppelganger". Copernicus and Copernicus's reflection. Cool huh? "Two, yes two, that's two craters in one!"
Poor Tony I thought - he thinks the Moon looks great through this scope. Why sometime's its terrible being "optically correct".
I swung the scope around on Vega - terrible! Huge elongated football shaped outfocus images that swung a 90 degree turn as you passed through focus. I started tweaking the knobs on the primary - things got worse! Tony looked through the scope and said so! I was a hack! Sure I was, there was nothing about this scope that was in good shape! Not a single surface was collimated, adjusted, or in the right place at the right time, and I had gone and scratched his mirror!
I dissassembled the scope and put it back in the Tony's hatchback. Tony and I parted - still friends.
On Thursday-past I swung by Tony's bakery to do some music business and get the d**n scope. Thankfully Tony was more than willing to turn it over to the "Optics Hack".
Spent three or four hours traying to figure out what made the newt tick. UNlike the Pup, there were adjustments all over the place. Big ones and little ones and fasteners and screws everywhere.
Took the lens out of the .965 Huygins eyepiece and turned it into a cheshire for collimating the diagonal. Got things "just right" but realized there was one main problem with this scope. The diagonal mirror never appeared round - it was always elongated. In addition, the primary could never be seen in its entirety within the diagonal - so it was vignetted!
Sometimes vignetting is not such a bad thing. Say you have a primary with a "turned edge". You really don't want light from that edge entering the eyepiece - it's useless stray, disorganized photons will only distract from what you are looking at! Good optics organizes light in a virtual semblence of the image source. Bad obtics, takes light and just tosses it everywhere - complete chaos!
So vignetting isn't necessarily bad. But an "oval" of light is a starkiller. That d**n able secondary would be hell to pay while attempting to star test and finalize the collimation.
And that Thursday night out was h**l to pay! I could see some fairly decent diffraction patters both inside and outside of focus coming off the primary. But that elongation would simply turn the best alignment of the optical cone into a football that reversed positions as focus was traversed!
There was really nothing to be done until the secondary could show a perfectly round presentation to the eye through the cheshire...
By 9:00 pm that evening I had put the newt away in disgust and had Argo out giving unparralled views of Selene and Saturn. What a difference a scope makes!
Today, I spent three hours completely reworking every aspect of the newts optical path. One concept was to back the primary away from the secondary so it would fill the elongated secondary display with a perfect circle.
Well, that was a mistake! Cranking the primary adjustment screws all the way in ended up breaking off a piece of the primary mirror! Crunch, tinkle, tinkle went the mirror. d**n , you mean to tell me the designer of this scope didn't use adjustment screws short enough to prevent this? Of course they didn't they designed a secondary mirror that vignetted the primary and gave a football shaped extrafocal image!
OK, so dissassemble the primary cell and inspect. Thank the Diety it was only a small piece on the edge that broke off. As suspected, the tips of all four screws partially butted right up against the back of the mirror. So I backed them away and reassembled everything. Then stood in front of the scope peering down the barrel making small adjustments until my eye, the secondary housing and the reflection of the secondary housing all queued up properly.
Then I went at that secondary with a vengence. Used every possible adjutment to get that thing to show a circle rather than an oval through the cheshire eyepiece. Got close, but still not perfect.
Around 6:30 the sky got dark enough to star test the scope on Vega. The adjustment process was slow, so I switched over to a more stationary Polaris. Using only the locking bolts on the primary I managed to clean up the extrafocals enough so that Polaris companion could be seen. Polaris A however still displayed visual artifacts due to the improperly designed secondary mirror...
Turned the finderless scope toward the Double Double. Lots of sweeping around at 36X eventually turned up the pair. REplaced the 25mm with the 10mm Kellner. At 91X, by avoiding the "doppelgangers" could see a nice clean split of both pairs.
With the Milky Way in Cygnus just visible, managed to also track down M57. Even at 36x, could make out the fact that the "King of Rings" was an annularity. At both 36 and 91x was able to hold the 11.6 mag star in the "Challice of the Ring" direct. At 91X could see the 12.3 magnitude star with slight aversion.
So not bad, the litte newt could see down to magnitude 12 at less than 100x. And most stars (dimmer than say magnitude 6) looked reasonably pin pointy.
If you weren't distracted by the "doppleganger effect", the scope even resolved the Double Double.
So what about this doppleganger effect?
Well I suspect that should Tony manage to get the primary and secondary polished and re-aluminized this too shall pass.
So, OK Tony goes out, buys a cheap finderscope from Orion for 20 bucks, and a carrying case for 50, orders the 15 dollar 1.25 inch eyepiece adapter from Meade, and spends another 50 re-aluminizing both mirrors. For about 175 dollars, Tony has a passable starter scope that could be purchased new with all the above for about $350.
Is it worth it? Well despite my frustrations going over the scope to the best of my hack-ability, I had fun and learned alot! Is it worth it for Tony?
That's for him to decide...