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prime focus new telescpe


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hello need a bit of help i have this telescope Revelation 16" f/4.5 M-CRF Truss Dobsonian (Black) it works perfectly when viewing but when useing my phillips spc900 it will not focus it will  with a barlow lens but not without. now i understand i need to push the primary mirror forward but can anyone help me with how to push it forward like what would the best way to go about it i was thinking of cutting the trusses down a little bit would that not put the primary mirror closer the the secondry and focuser but not sure of how much to do it and not long had the scope and dont want to kill it haha if anyone can help that would be great thank you

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Well you are trying to get the camera to the focal point of the scope, so you either mod the camera to be able to fit there, mod the focuser to allow more in focus or mod the scope to move the focal point outwards.

Cutting the truss legs down a bit is the latter and I would be loathe to do that on any scope let alone a new one.

If you can modify the camera housing to get it closer or even inside the focuser the problem will go away.

Some planetary cameras are designed with this in mind and slide into the focuser.

Modifying the focuser by either changing it for a low profile one or removing any extra bits would also do the trick.

What are you trying to image though? Planets are normally imaged with a Barlow anyway.

Be aware that if you do mod the scope you may then need extension tubes to reach focus on some EP's.

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Sorry didnt get back sooner Yer camera mod was best haha got a bit carried away i think cut the truss what was i thinking project box from maplin sorted cheers for your help mate do you know any good barlow lens i have a x3 rubbish one got with old sky watcher i seen a x5 on ebay but not sure do you think the scope could handle that it does get very dark here isle of wight

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I just have a baader one but it is very nice, I don't notice any loss of image quality with it.

You have a lot of aperture and putting a 5x in there would take you to f22.5, I don't have an spc900 so best to check with someone that does what type of focal ratio it works best at.

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Huh, cut truss legs on a fantastic telescope in order to make a 15 quid obsolete webcam work. In the words of Gen McAuliffe 'Nuts'! ;)

My SPC900 worked fine with f5 @750 + 2xBarlow. (and W/O)

You might need to physically pull it out from the draw tube a little in order to move the tube further in.

Remember this is hit n miss 'technolology' as the camera was only designed for taking and transmitting video of live people during.....

If this fails, post it over to me before you kill the telescope. I promise to give it a good and happy home. :)

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