When I had my 8" f4 newt I could fit my DSLR straight on & shoot. Now, I upsized to a 12" F5 dob and as some of you know I have no Prime focus with this model (BT302-b). So with advise from an IIS member the solution is to either shorten the tube by 50mm or raise the Primary mirror by 50mm. I decided not to cut and came up with a cheap solution to raise the mirror.
I went down to the local Cabinet maker and had him cut me two perfectly round 300mm diameter x 25mm disks of chipboard for $5 each. While he did that I went to the bolt shop & bought 6x 85mm matching thread bolts also $5.00. So I have my $15 Primary adapter. All assembled perfectly, re did the colmination & I tested it all out on a road sign 3 km away. See Pic.
It works, I have Prime focus with the DSLR however NOW I've lost all Eye Piece focus completely! I can't use the reflector for eyeball viewing unless restored to original.
Since you've pushed the focal plane 50mm further out, your focused probably doesn't have enough travel. Try an extension tube between the focuser and the eyepiece.
Since you've pushed the focal plane 50mm further out, your focused probably doesn't have enough travel. Try an extension tube between the focuser and the eyepiece.
Now you need a 50mm extension tube???? for eyepieces, get a pair of bino's and get viewing two eyed with zero problems with focusing…hopefully
My Newt needs a 50mm extension tube for mono and no extension for binoviewing. Just a thought. It is an imaging Newt supposedly.
Matt
Hi Pinwheel, Just hold an EP up to the focuser [not in it] and move back from the focuser until the view comes into focus, which will show you how
long the extension tube needs to be; and add a bit extra because
different EPs require the focuser to be further out than others.
Glad you're getting it sorted.
raymo
Hi Pinwheel, Just hold an EP up to the focuser [not in it] and move back from the focuser until the view comes into focus, which will show you how
long the extension tube needs to be; and add a bit extra because
different EPs require the focuser to be further out than others.
Glad you're getting it sorted.
raymo
Raymo, I've worked that part out & guess what, My 2" to 1.25" ep adapter has a filter thread behind it, so I just need a 2" tube with a filter thread and it's all done. Getting closer now!
