There may be a problem with the goto star model and we may only allow FAAC members inside while we are setting up the model. The public is welcome to stop by, but we may be busy and not have a lot to show you, and you might only get a glimpse through some other small telescope or have to wait.
If your not a FAAC core member or FAAC member, feel free to stop by and check it out, but don't go out of your way to block off a large amount of time for tonight, because as you can tell there's a chance we will be pretty busy.
It can take an hour or two to get the mount setup. I'm not sure what happened to the star model but I have some ideas what might have messed it up. We need another star model in there anyway.
Sorry about the long and kind of conflicting post. My operating norm seems to be to show others the scope and the skies if things are worker fairly well. We haven't had a perfect model in the mount for some time and have had some issues with the star model in the goto controller in the past.
There is also a way to disengage the model and create a Tpoint model in the computer to have some separate star model.
One potential problem is in diagnosing another problem I moved the mount slightly manually, which is a mistake that can throw off the model.
What is a star model? It's basically a map of stars in relation to the telescope mount setup. It maps the stars and tells the computer chips inside the goto controller where the mount is pointing in relation to the stars in the sky. The goto controller has things like a clock and gps position set inside it. Using some clever math and programming, the mounts goto controller should know where it is pointing and be able to point the telescope to a star and object map to one of many thousands of objects in the sky.
Some computerized mounts with small telescopes you can buy like a Celestron Nexstar series of telescope or some Meade models of telescopes have a goto mount. A goto mount can tell the mount where to move automatically and often will control motors in the mount to cause the mount to move and point at an object the user selects. There are dozens of configurations of goto type mounts and also other various types of computerized setups. Some mounts have a something called digital setting circles, which read the position of the mounts shafts as they rotate. Giving a feedback as to where the scope is pointing. Most goto mounts just memorize where you pointed the scope because you told it what the telescope is pointing to. And these will control the motors and know how far a motor should turn to move from one position to another. So the goto controller will tell the motor where to point. But it will not receive feedback from the mount unless it has digital setting circles. This means most goto mounts are using guesswork as to where the mount starts pointing. And as long as the mount isn't moved manually, it stays pointing where the computer last thought it would be pointing. But if you move the telescope, the mount doesn't report where the telescope moved to, because it didn't use the motors to move it, but instead you used your hands to move the scope. So the scope moves, but the computer goto controller doesn't know it's moved. It has no sensor to realize the mount has moved. So the start model is OFF.
There can be other problems as well. There may be some kind of error or power glitch that may throw off the model. In theory a power glitch should not throw off a model but this may be one of the things that has been happening at the observatory as well.
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By the way everything was basically back in order in the observatory. I manually moved the scope to get Saturn into the field of view after telling the scope to goto Saturn. The telescope went to a location about 10 degrees away from Saturn, but still had a basic star model in the goto mount. It was just off by maybe 10 degrees for eastern objects.
ReplyDeleteOnce I had Saturn in the field of view, a goto command to the controller toward Mars brought the red planet into view. Mars of course is moving away from us so there's much less detail now compared to some months back in the spring when it was out in opposition to the sun on our side of the sun.
Mohammed a member of the FAAC club showed up and actually brought his father so I could give them both a tour. It was late when they showed up and we didn't have a lot fo time. There were able to look at three or four objects. It was hazy and the transparency conditions were much worse than predicted by the clear sky chart. According to a second hand weather report from Greg Ozimek, via phone call, the reason for the foggy and hazy conditions was all the rain and humidity on the ground. This proved to be true, so the clear sky chart was overly optimistic for Sunday night predictions.
I was able to give Mohammed and his father a quick run down of the observatory. I kind of went over some facts quickly and we focused on finding and looking at objects. It ended with them looking at the moon. as they left I noticed Jupiter was up high enough to view so I looked at it with the C14 telescope. Conditions were not very good however and the view wasn't as clear as I hoped it might be. I packed up and made it home and didn't even bother to try looking at Jupiter with the binocular telescope. Conditons were not going to be that good and I figured I'd be disappointed. I ended up doing a few other tasks at home before turning in very late Sunday night.