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First light


Last night the weather forecast predicted some clear patches in the sky, so this was a good chance to test my new Orion XT10 telescope. Around midnight, I hauled the telescope outside : not an easy job, as the scope weighs around 25 kg... I would not say the observing conditions were ideal : far from, the moon was almost full, and rising in the south-east, there was lots of high altitude cirrus clouding and only a big patch open sky, so I needed to hurry.

I had quite some problems with the Object Locator : this uses an initial calibrating procedure called the 2 star alignment procedure (2SAP). After performing this, the Object Locator indicates the manual alignment error which they amusingly call 'Warp factor'. The warp factor should normaliter be below 0.5. An initial 2SAP attempt gave me a warp factor of 26. A second one gave a warp factor of 34. Then I knew there was something wrong. The next day, I tested out the alignment calibration function in the daylight, which indicated that the telescope wouldn't transmit any vertical movement to the Object Locator. In the Problem section guide of the manual, this should occur if
- there would be a problem with the cabling
- or the tension knobs of the telescope wouldn't be turned fit enough.

Unfortunately, both of these were Ok. I decided to disassemble the scope, and study where the Intelliscope system went wrong. It quickly seemed that the altitude encoder disc, which was responsible for the vertical movement measurement, didn't moved with the telescope. Only after studying this page with assembly instructions, it seemed that an extra nylon spacer on the tension knob prevented movement of the altitude encoder disc. After removal of the spacer, the disc nicely moved along with the scope. So, I was pretty glad I sorted this out. Next weekend, better weather is forecast, so I'm keeping my hopes high...

As the Object Locator was out of order, I quickly glanced to M13 in Hercules. There was lots of hindering light from the full moon, but the 20cm Dobson nicely resolved the center of this globular cluster into all of its stars. A second object was M57, the Ring cluster in Lyra, rather awkwardly located in the zenith. The ring was nicely visible, but the central star couldn't be resolved. I guess the moon was too much of an impediment. I then tried the UHC-E filter, which gave a slightly better result, but I was disappointed, cause I expected more of this filter. Again maybe the moon... At that moment, Lyra disappeared after the clouds, which took back control over the skies.

So, a rather disappointing first tryout. There's better weather announced, and the moon will slowly move out of the way, so I hope to have a better try in the next weekend...