gspith
Newbie
Posts: 1
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« on: May 16, 2008, 10:19:23 AM » |
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Hi,
I am not that new in astronomy but also not that experienced. I have a Lightbridge 12'' for over a year now and I am still not fully happy.
The collimation problems I faced at the beginning were solved by replacing all knobs (both primary and secondary mirrors) and primary springs with those sold by Bob'sKnobs.
Regading focus, I had to buy an extender and still sometimes I have to place the eyepiece halfway into the focuser in order to achieve focus.
Has someone had the same problem?
Does someone know a way to calculate the minimum focus distance of a telescope? I am asking this because I have also tried to focus on terrestrial targets with no result.
Thanks
George
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ckkrish
Newbie
Posts: 10
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« Reply #1 on: June 28, 2008, 08:34:35 AM » |
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Hi George,
I have the same problem, but to a lesser degree. Just last night I found that I need to use the extender tube to get focus on the 26mm eyepiece that came with the telescope. This was the first use after I changed the collimation bobs and springs and did a complete re-collimation.
Sorry, I don't have answers to your focus distance question. If you have gained more insights into the situation, kindly post to the forum.
Regards,
Krishnadas
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provencial
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« Reply #2 on: July 04, 2008, 03:46:50 PM » |
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You may want to try using a star diagonal to help achive focus, they are fairly inexpensive and help put the eyepeice in a more comfortable viewing postion.
good luck!
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steelken
Newbie
Posts: 3
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« Reply #3 on: April 24, 2009, 10:22:46 AM » |
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Hi I had the same collminating problems and also changed to Rob's equipment. I also had to centre the main mirror ! 1 to do this cut a circle out of ridgid cardboard the same inside diameter of the upper tube, 2 mark the center and at 6 inch radius make 3 1/4 inch holes at 120 degree intervals . place this in the top tube above the spider. look through the eypiece holder and have someone adjust the main mirror until you can see half of all 3 holes. Now your main mirror is centered and you can perform your cllmination.
regards Ken
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hamdul
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« Reply #4 on: April 25, 2009, 11:16:39 AM » |
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Provencial.
Have you ever used a star diagonal on a reflecting scope? I didn't think it was possible unless you were triple jointed in the facial area
Fred
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