Quote:
Originally Posted by AstralTraveller
Chris,
If you move straight from Sirius to Acrux the reading should be pretty close to right; the stars don't move far in 5 minutes. {As an aside to 'rider', on the scope I used to use the pointer moved with the rotation of the RA shaft. That way it was always right once you set it up at the beginning of the night. Don't modern mounts have some equivalent system?}
I note that when you move from Sirius to Acrux you travel 12 26 - 6 45 = 5h 41'. Now 00 15 - 6 45 = -6 30. So it may be that you have some scale a**e about. However I still can't explain the 00 49 discrepancy. Perhaps something grips or slips when it isn't supposed to.
You do have it aligned pretty right don't you? You can follow starts for 5-10 minutes just by moving the RA shaft?
If all else fails you can join us trogolites and just learn to star-hop  .
|
Hi Astral Traveller,
Yes, I do have a pointer that travels around with the RA circle, I have attached a photo of the mount showing the two markers that I am using. The R/A mark in white is what I am setting the circle to and it stays fixed while the setting circle rotates past it to the next location and that is what I am reading it off.
While taking the pictures, I have noticed that the difference in hh mm ss between the silver pointer in photo 3 and the R/A marker in photo 2 is 22 - 15 10 = 6 hours 50 mins?? could this be the phantom 49 mins you mentioned???
Am I doing this all wrong? should I be setting the R/A circle from the white marker dial or spinning the R/A marker to line up with the metal pointer? Or is the metal pointer deliberately supposed to be 90 degrees (or 6 hours) away from where the R/A mark should be?
I have locked down the allen keys holding down the outer ring that has the R/A mark on it and this can move by about +/- 1 hour so perhaps this is supposed to be lined up at 6 hours west of the silver pointer?
Sorry, this has now got me all confused all over again, can someone please put me out of my misery?
NB I am reading the scales at the bottom of the RA ring as per the instructions which said the Southern Hemisphere is the bottom.
Chris