Quote:
|
Originally Posted by g__day
Well I took my first steps towards more serious astronomy, and it was alot fun but I'm rapidly getting to the a few questions and is this gear working / initialised correctly (particularly star alignment and goto tests).
Achievements:
1. All set up, downloaded NexStar demo from hero, bought a ohine cable, hacked it, crimpped it, converted it to a serial port and tried controlling it -  huge yah!!!! Sees the scope, reads its co-ordinates, issues go to commnads fine.
Here the Problem:
1. When I think I've aligned it it does strange things on Go To. For example did a one solar body align on Jupiter around 8pm last night, used the controller to shift focus 10 degrees left then Issued a go to Jupiter command. Instead of slewing back (to around the 8pm position high in the sky, it pointed between my feet! ???
2. Did an two star align using Vega and Altair, then used controlledr to slew to Arcturus and issued a Identify command. STraight away it got it right.
3. Then I did a find Spica call. Including slewing along left to Spica it ended up doing a 180 ending up almost horizontal but pointing East not South.
So the GoTo is temperamental for me so far,
What I've tried
1. Reading the instruction book back to back
2. Checking time and date and location to the nearest metre using Google Earth amd using my rpecision location
3. Using an electronic compass to assist point the mount towards Celestial South
The Go To for a few other planets seem strange, can onyone please offer suggestion, tests to do a better. The set up manual usages book then three of operations where, a definite eay of testing the mount
* * *
All suggestions and advice gracefylly accepted! |
G'Day G__day!
Hmm. I have the same mount, and I have to say I have had 1 or 2 instances where it's done screwy things like you describe... but more than 99% of the time it's fine. I couldn't explain what went wrong on those 1 or 2 occasions. Both times I switched it off and started again.
Most times when it goes stupid, in my experience it's operator error, usually entering data incorrectly to the goto (I haven't tried controlling from the PC yet). Things to watch are:
- Date - make sure you get the day and month right way round. I haven't found a way to make it dd/mm/yy, it defaults to mm/dd/yy. Depending on the date, that can make a big difference!
- Position (your lat long). Do you have a GPS, or can you get a GPS reading of where you observe? It shouldn't make much difference but I would prefer to use a GPS reading than Google Earth.
- Polar alignment. Check you've got your magnetic declination right for your observing location so you have the scope pointing to celestial south. For the alignment procedures you mention that you've used I don't think the goto can calculate the cone error. I think you need to do a three star or auto alignment for that.
- The altitude (latitude) scale on the mount is pretty rough. If you can get the goto to behave itself, do a drift align (or partial drift align) to set your latitude.
I would suggest going back to basics for a start. Just use your goto till you get a handle on it - just to eliminate any bugs from the computer control.
Set it up as accurately as you can with your compass etc, double check all your data entries, and do an auto alignment. This will calculate the cone error for your scope.
I must say, even when things were all working well for me somethimes I felt the alignment and accuracy of the goto was not as good as I expected. I have since bought the GPS module for it, and now it is great! I think the biggest issue with accuracy before was time. The GPS module keeps accurate time, without it I think the goto fails to account for the time during the alignment procedure.
Hope something out of this helps, and I apologise if some of it sounds like sucking eggs - it's not intended to! Keep us posted with how you get on!
Al.