Not possessing a lot of patience, when I saw that it would be clear on Wednesday night, just one day after purchasing my 'scope, I decided to tote it outside and set it up just north of the buildings that I lease for the studio. Back in 1968, when I built my very first "real" telescope (an 8" f8 reflector) the very first thing I looked at was Saturn. I didn't even have a mount for the scope yet, and basically had a neighbor friend and fellow amateur stand very still while I leaned the telescope on his back and tried to find Saturn. I'll never forget that first glimpse as it shot across the field - just couldn't get my friend to be steady enough! So its kind of a tradition that whenever I complete a new telescope the first thing I look at is Saturn, if its up. If it isn't, even if its going to be up later in the evening - well the hell with tradition! Thankfully, for the sake of tradition, on this evening (Wed., Jan 18th, 2006) Saturn was well up in the SE sky. As the hand control on the telescope was defective (returned it the next day) I pointed the 'scope by hand, got Saturn centered in the finder, then took a look. It was gawd awful! Easilly the worst view of Saturn I'd ever had. Oh my god! Was my 'scope a lemon? Okay, time to collimate!
I had gotten one of those laser collimators when I purchased the telescope so I decided to try it first. BAD DECISION! The collimator wiggled inside the eyepiece holder making it impossible to get consistent readings. Not only that, I didn't have a straight-through visual back so I was using the 2" diagonal. So I quickly went to "plan B", which was to collimate using a star. As I mentioned, the hand controller was fried so the drive wasn't working. The only thing I could do was use Polaris, so I swung the scope in that direction (and also turned the base a bit to make it easier to point near the pole) and centered up on the North Star. Rack it out of focus a bit and, yup! The collimation was out by a fair bit. Not surprising, of course. So I fetched a phillips-head screwdriver to fit the collimation screws and started pondering which of the three screws I needed to loosen or tighten to move the secondary shadow in the direction I wanted. Aw heck, it would be easier just to adjust one at random and observe its effect and proceed accordingly. So up to the front of the scope I go to loosen one of the screws, only to find that it was actually already loose. So I decided to tighten it instead. One half turn and still very little resistance. About 3/4 turn and a bit of resistance - then loose again! The screw was stripped! ARGH! Thankfully it turns out they are fairly standard screws. So off to the nearby Home Depot to pick up some #6x32 machine screws. I decided to replace all three screws with ones which were 1/8-inch longer and add some washers if necessary. I first replaced the stripped one (praying that the secondary mirror support itself wasn't stripped out - it wasn't), then each of the others, making sure that two screws were securely attached before removing the third.
Okay, so following that diversion I was again ready to collimate. I kept notes on which way the secondary shadow was moving depending on which screw I was tightening or loosening - always loosening two to tighten the third - and fairly quickly got the shadow centered, producing a nice looking donut! Back to Saturn and guess what? It still looked like crap! The seeing was horrendous! Okay, so that wasn't really surprising either. The skies had cleared earlier that day following a strong cold front that had dropped temperatures by about 20F. The scope was sitting on an asphalt parking lot looking over a tarred flat warehouse roof. Not exactly ideal! So I decided to snap a quick picture of Saturn using a hand-held Nikon Coolpix 5000 digital camera - camera and eyepiece both focused to infinity (afocal method) resulting in the picture, below. The very first astrophoto! Time to shut things down for the night, so I started putting things away. I noticed that there was a rotating nosepiece on the secondary mirror assembly that would "hide" the collimation screws so I decided to rotate it to hide the screws. To my surprise the entire secondary mirror/baffle tube structure rotated!
It turns out that the rotational orientation of the secondary is important and is set at the factory to optimize the overall optical performance of the telescope. With the secondary mirror housing loose as it was, whatever alignment had been set at the factory was lost. The following day I called Celestron customer service where, after some begging on my part, I was able to get a technician to describe how I could re-set the alignment that had been performed at the factory. They had originally wanted me to send it back to California (at my cost - about $200) and could promise no better than a six week turnaround. I couldn't believe it and so begged them to tell me how to do it myself, which they did. It was a piece of cake, taking less than five minutes. WHEW!
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| Here's the current StarFarm. A parking lot in a southwest Baltimore warehouse district. Ugh! The van was positioned to block an even brighter light. No need for a flashlight. The picture at right is the very first astrophoto taken with the 14", shot afocal using my Nikon Coolpix 5000. Some fine seeing, eh? | |