Hi Vincent
Read in the yahoo groups that the stellarvue nighthawk is not able to focus using the William Optics 2" diagonal with Barlow on.
Seems that there is not enough "infocus", and that the WO diagonal is too long. Did you encounter this during your eval? (if you have the said diagonal). I am thinking of gettting the WO 2" diagonal.
Photos of White NightHawk
that's interesting. I didn't come across this problem with my 1.25" TV diagonal. I don't understand what they mean by "too long". Most diagonals front (the chrome part where you insert into the drawtube) is around the same length.sojourn88 wrote:Hi Vincent
Read in the yahoo groups that the stellarvue nighthawk is not able to focus using the William Optics 2" diagonal with Barlow on.
Seems that there is not enough "infocus", and that the WO diagonal is too long. Did you encounter this during your eval? (if you have the said diagonal). I am thinking of gettting the WO 2" diagonal.
The only time I couldn't focus is with the eyepiece directly into the drawtube.
I think the problem does not lies with the diagonal. What barlow is that guy using? Could it be that the barlow require more infocus?
I think it is not the problem of the physical size.. I think what they mean is the light path is longer for the WO 2" diagonal, compared to the 1.25", which has no problems. It is the optical design of the WO 2" diagonal. Not sure too what is the barlow they were using.
I have the Celestron Ultima barlow, and planning to get the WO 2" diagonal. Just got to test the combination out..(the diagonal, barlow, and ep).
It is strange too that you cannot focus when ep is directly in the drawtube.
I have the Celestron Ultima barlow, and planning to get the WO 2" diagonal. Just got to test the combination out..(the diagonal, barlow, and ep).
It is strange too that you cannot focus when ep is directly in the drawtube.
I have tested the scope last night with a 2" WO diagonal, SCT type (same diagonal except that it has SCT threads in the front) and there is no problem focusing with the 21mm and 14 mm Pentax and 2X Ultima barlow. I am not sure why people say they can't focus...sojourn88 wrote:I think it is not the problem of the physical size.. I think what they mean is the light path is longer for the WO 2" diagonal, compared to the 1.25", which has no problems. It is the optical design of the WO 2" diagonal. Not sure too what is the barlow they were using.
I have the Celestron Ultima barlow, and planning to get the WO 2" diagonal. Just got to test the combination out..(the diagonal, barlow, and ep).
It is strange too that you cannot focus when ep is directly in the drawtube.
As for eyepieces can't focus direct from the drawtube, that's quite normal for a low-end refractor. The drawtube has a 2" backfocus and that's not enough for most eyepieces. The reason they make the drawtube short is because they didn't want to compromise the quality of the focuser...the longer the drawtube, the more difficult to make the focuser smooth and steady. Furthermore, not many people view it straight-through. Anyway, it's not a difficult problem to solve if you must view it straight (I never had to view a refractor straight in my entire astro life). Just get an extension tube will do. SV sells that but you can easily make one yourself. But I really doubt you need that at all.
Note : The canon 10D has no problem focusing using prime-focus mode...meaning straight through without any eyepiece. With eyepiece and diagonal, it shouldn't be even a problem at all.
i have the older version, at1010. tube was made too long, so if i use a wo diagonal, i can't reach focus with most eyepeice 12.5mm and below. televues eyepiece doesn't have this problem. using a normal 1.25inch diagonal solves this problem as the diagonal is much shorter.
not too sure about the at1010 nighthawk, heard from vic that the tubes are made slighty shorter so that there is no more infocus problem.
~MooEy~
not too sure about the at1010 nighthawk, heard from vic that the tubes are made slighty shorter so that there is no more infocus problem.
~MooEy~
i only have problems with eyepieces below 12.5mm. televue eyepieces require u to rack the focuser all the way back in most scopes, so i managed to reach focus with abt 1cm left. the entire line is parfocal, so no problem even with the shorter fl.
but i think a better choice is to use a 1.25" diagonal. it's smaller, lighter and can reach focus. at least being lighter doesn't give the focuser too much stress.
~MooEy~
but i think a better choice is to use a 1.25" diagonal. it's smaller, lighter and can reach focus. at least being lighter doesn't give the focuser too much stress.
~MooEy~