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Old 29-08-2019, 02:30 PM
Startrek (Martin)
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Startrek is offline
Join Date: Dec 2017
Location: Sydney
Posts: 1,903
East Heavy , Guiding and Meridian Flip

I just re arranged the guide scope on my 6” f6 newt from its offset location in the little shoe bracket to the central axis location on the OTA using a losmandy bar mounted on the tube rings
This so I can have my finder scope and guide scope mounted on the OTA together.Previously I would remove the finder and replace it with the guide scope once framed up ready for imaging ( a bit of a pain in the butt )
Obviously I had to rebalance the mount with the added payload, which I did but both counterweights were pushed to the end of the rod with no spare space.
I balanced RA and Dec as best as I could
Last night in Sydney there was a window of 3 hours to Image so to test the new guide scope position I decided to capture M16 .”, I’ve only captured this object from my dark site south coast NSW
Guiding was troublesome at first so I re calibrated due to the new location of the guide scope and it improved a little ( counterweight east , OTA west )
After a meridian flip guiding improved dramatically ( counterweight pointing west , OTA east )
My question is firstly explain balancing the mount “East Heavy”in relation to the position of the counterweights and OTA
I totally understand the “concept” of East Heavy where the imbalance of a small amount of weight against the drive system tightens up the gearing and reduces the slop and therefore inefficiency and error in tracking
I’ve watched so many clips and read so much and no one explains or details what happens after a meridian flip in regard to East Heavy
In my case last night, my mount was evenly balanced and guiding improved dramatically on the other side of the meridian later into the night
Conditions last night were stable and seeing was average most of the night from starting imaging at 8.00pm until the cloud rolled in around 11.00pm and obviously my guiding went totally off the rails after that so I shut down and captured my darks

Could some of you experienced folk explain East Heavy ( especially after a meridian flip) and possibly why my guiding improved so much after the meridian
NB : M16 moved from around 70 to 55 degrees Altitude throughout the capture so still nice and high

Thanks in advance
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