Bintel Dobs

[mickoking]

G'day cobbers

Just a quick question. Will Panoptics and naglers reach focus on the Bintel deluxe version Dobs, the one's with the Crayford focusers ? :confused:

[janoskiss]

I guess so, since Bintel sell both TV EPs and GS Dobs, and one of the prime reasons to get a Nagler or a Panoptic is because you want wide views through your fast Dob.

OTOH, in my 8" GS Dob (from Andrews), which I have converted from R&P to GS Crayford myself, Televue eyepieces will not come to focus in the standard 2"-to-1.25" adapter. I need to pull the EP out a few mm and retighten to reach focus.

I actually bought a 35mm focuser extender but the travel of the GS crayford is so short that this is too much for TV EPs, so I still can't reach focus. No biggie. Just got to remember to raise the EPs a few mm in the focuser. Bit annoying when mixing TV plossls and HD orthos (which are sweet in the GS cray).

[ving]

my TV 10.5mm plossl needs to be pulled out of the GS focuser a bit... but that doesnt help you.
I once used one of louies naglers and couldnt get it to focus. i cant remember which one it was tho, i used 2 naglers and only one of them foucsed.

[iceman]

I've had 27 Pan, 22 Pan, 13 Nagler, 16 Nagler and 31 Nagler all reach focus in my scope no problems.

[mickoking]

Thanx for your council Dave,steve and Mike :thumbsup: I presently own a 250mm gso standard and I have to move my Nagler/ Pan's out a few mills so that's no drama. I was just concerned if the models with the crayford would reach focus at all with the televue e/p's.

[janoskiss]

My GS Crayford does not have as much out-travel as the original R&Ps (about 1/2 inch less) so you might have a problem. My Crayford's travel is just under 1.5 inch, R&P is 2 inch.

[mickoking]

Did your scope come supplied with the crayford or did you retrofit it ?

[ausastronomer]

The crayford focuser has more focuser travel (and/or stands a bit taller) than the standard rack and pinion focuser (can't be bothered measuring). I previously had a R & P focuser on my 10"/F5 GS dob and I had to sit the 27mm Panoptic back about 6mm to reach focus. I recently upgraded to the GS crayford focuser and the 27mm panoptic easily reaches focus in the new crayford with several mm of travel to spare.

CS-John B

[mickoking]

Thanks John. Doesn't sound like I will have a problem when I upgrade :)

[janoskiss]

I've got my GS R&P (came with 8" scope from Andrews Jan 2005) and Crayford (from Bintel Sydney Jan 2006) side by side:

R&P:
travel: 37mm
height: 88mm

Crayford:
travel: 35mm
height: 73mm

height = minimum distance from OTA to edge of 2" barrel.
allow +/- 0.5mm on above measurements.

[ausastronomer]

Steve,

Something doesnt make sense there, unless it's the 2"/1.25" adapter thats differrent, but it can't be that much different. I will go check my bits tomorrow afternoon.

CS-John B

[janoskiss]

John, the measurements I posted above are for the 2" focusers alone with no adapters.

[johnno]

Hi All,

John,

I have also found a difference in the 2"/1.25" adapters,
My new 7mm UO ortho,WILL NOT focus in my ED80,with the standard adapter,(Not enough IN travel),however the 9mm GSO Plossl,I bought off Darren,(DHUMPIE),works fine.

I have to use the 2"/1.25" adapter,that came with the GSO 2" barlow,to get the 7MM UO Orhto to focus.
Ie, This adapter is recessed,and allows the eyepiece to sit lower.

Regards.
John

[ausastronomer]

John,

The 27mm panoptic is a 2" eyepiece hence there is no adaptor in place, all I know is it woudn't focus before and it does with the new GS crayford. I will measure things tonight, if I get home from work in time.

CS-John B

[johnno]

Hi John,

Thanks for explaining,I didn,t know the eyepiece in question was a 2",
Learn something every day on this forum.

Regards.
John