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Balancing Act
I've just started autoguiding using Phd2 and have been trying to overcome some teething problems. Auto guiding using the 550mm Esprit 100 is not a concern but last night I did a test using the 1000mm 8 inch Newtonian. Balancing the Newtonian with a heavy DSLR hanging off the side has always given me grief, concluding that it will never balance correctly in every position.
My solution has been to just balance it as best I can in the position it will be guiding my target object. I've realised from last night's test this is the way to go with autoguiding as well. I had the scope balanced to shoot objects high above and a little to the north last night. This is the position where most of my clear sky sits in the front yard. Here I did two 4 min subs of NGC 253 and both were close to perfect but for 47 Tuc I had to throw four out of six 4 min subs away. Obviously the mount was struggling to maintain accurate guiding due to it being out of balance, as the object was in the south.
An important lesson on making sure your rig is balanced as best as possible for Phd2 to have a chance to guide accurately, especially at 1000mm focal length. This is one area where refractors have the advantage over reflectors, the camera sits at the end of the OTA.
These two shots at 8mins and 15mins integration are definitely not ones to hang on the wall but I'm glad I've proven that I can autoguide using this set up. It should come in handy for the warmer months when longer exposures will allow me to use lower ISO values to reduce noise.
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