Source for LongerT-2 Extension?
- marktownley
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Re: Source for LongerT-2 Extension?
What is it you need? a 4" long T2 extension tube?
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- rsfoto
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Re: Source for LongerT-2 Extension?
See below ...
https://www.amazon.com/s?k=T2+extension ... _sb_noss_2
https://www.amazon.com/Astromania-Astro ... 041&sr=8-2
regards Rainer
Observatorio Real de 14
San Luis Potosi Mexico
North 22° West 101°
Observatorio Real de 14
San Luis Potosi Mexico
North 22° West 101°
Re: Source for LongerT-2 Extension?
Edmunds sells a 100mm Part number #65-969
What scope are you using where you need 100mm extension? Is this for the back side or the front of the telecentric?
The front, then the TZ4 sits about 48mm in front of prime focus. The best way to see what you need for an extension is put the telecentric on the scope without the filter , cut a plastic or paper tube 220mm long and tape a piece of paper on the back end as a screen. Now hold it on the back of the telecentric and move the focuser out till you see the solar disk focus on the paper screen.
Now measure how far you needed to move the focuser out. I like to have the focuser out no more then an 1" and make up the rest of the distance with an T2 tube.
If it is the back then, the TZ4 can be focused with an back focus of 150mm to 250mm and still work fine.
Mark W
What scope are you using where you need 100mm extension? Is this for the back side or the front of the telecentric?
The front, then the TZ4 sits about 48mm in front of prime focus. The best way to see what you need for an extension is put the telecentric on the scope without the filter , cut a plastic or paper tube 220mm long and tape a piece of paper on the back end as a screen. Now hold it on the back of the telecentric and move the focuser out till you see the solar disk focus on the paper screen.
Now measure how far you needed to move the focuser out. I like to have the focuser out no more then an 1" and make up the rest of the distance with an T2 tube.
If it is the back then, the TZ4 can be focused with an back focus of 150mm to 250mm and still work fine.
Mark W
- marktownley
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Re: Source for LongerT-2 Extension?
Join 2 together?
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Re: Source for LongerT-2 Extension?
Thanks all.
I will put the telecentric in and use the cardboard tube to find focus.
The need for a longer tube ( I can use more than one if needed) was a result of confusion about where the 4x telecentric should sit relative to the original focus. I had read original focus should be 93mm from the front lens which didn’t seem to be the case as I was messing with it. Mark’s suggestion of 48mm sounds more like what it wants.
I will put the telecentric in and use the cardboard tube to find focus.
The need for a longer tube ( I can use more than one if needed) was a result of confusion about where the 4x telecentric should sit relative to the original focus. I had read original focus should be 93mm from the front lens which didn’t seem to be the case as I was messing with it. Mark’s suggestion of 48mm sounds more like what it wants.