Post by rgm on Aug 22, 2013 7:10:46 GMT -5
This past full moon was very bright and there was little to observe other than doubles. I live north of the Great Lakes, and seeing conditions are often average at best. Last night saw steady skies and just for fun wanted to see how much magnification my Istar could handle.
Used the Double/Double as my test. Started with my longer focal length EPs and quickly moved to the Nag 3-6 zoom. At 6mm/246x, image was perfect. Going up to 3mm/492x saw no differnece. I have never gone this far with my C8 or 10" dob. Those scopes usually start to have image breakdown at 300x.
Next up was my 2.5 barlow and the Nag zoom. At 6mm/615x and 5mm/738x still showed a great image. Only at 4mm/922x did i notice an image change. Part of this was no doubt due to seeing conditions. The stars were still focused. I finally tried 3mm/1230x. The image again was reduced slightly in quality, but was still focused. Stars were nice and round.
As the final test, I defocused as 1230x and tried to refocus. No problem. I could not believe it.
It is a good thing that Istar does not have a trade-in program. I am already tempted to try a larger scope.
Bob
Used the Double/Double as my test. Started with my longer focal length EPs and quickly moved to the Nag 3-6 zoom. At 6mm/246x, image was perfect. Going up to 3mm/492x saw no differnece. I have never gone this far with my C8 or 10" dob. Those scopes usually start to have image breakdown at 300x.
Next up was my 2.5 barlow and the Nag zoom. At 6mm/615x and 5mm/738x still showed a great image. Only at 4mm/922x did i notice an image change. Part of this was no doubt due to seeing conditions. The stars were still focused. I finally tried 3mm/1230x. The image again was reduced slightly in quality, but was still focused. Stars were nice and round.
As the final test, I defocused as 1230x and tried to refocus. No problem. I could not believe it.
It is a good thing that Istar does not have a trade-in program. I am already tempted to try a larger scope.
Bob
