Focusers

[Solanum]

I have the standard GSO Crayford 2" focuser with my scope and find that getting fine focus can be a bit of a pain. I was thinking of the GSO/Andrews/Bintel 10:1 fine focuser, and figure it'll be an easy upgrade as the mounting screws will probably match those of my existing focuser.

Is this a sensible upgrade, or should I go for something more fancy. I don't really have any fancy needs, just want finer adjustment.

Comments?

[PCH (Paul)]

Everard,

I have the 10:1 style of focuser, and believe me the difference is huge. You'll wonder how you managed once you get the 10:1

Cheers,

[Tamtarn]

Hi Everard

We have fitted Bintel 10:1 Focusers to both our scopes and have certainly noticed the difference with finer focusing.

There are several higher grade units available, but they come at a much higher cost. We are very happy with ours for what we use them for.

David

[erick (Eric)]

Everard

I had the same goal - replace my standard Crayford with a 10:1, but then got a good deal on a used Orion Accufocuser. A bit of ATM work later and I had it fitted - see here:-

http://www.iceinspace.com.au/forum/s...ad.php?t=10782

Now I don't have to touch my scope to focus at high magnifications. I was having trouble avoiding vibration as I focused. And the fine control is excellent.

But if you were starting with a new electric focuser and factored in your time, the 10:1 is certainly cheaper (and you can probably sell the replaced Crayford) - unless you want no touch focusing at high mag.

Eric

[Omaroo (Chris Malikoff)]

Yep - another vote for the Bintel 10:1. I fitted one to my 8" Newtonian a while ago and it's a pleasure to use. One thing to note is that you can undo the small hex grubscrews at the base and rotate the entire focuser throat around its axis so that your focusing shaft is set to be near-parallel to the ground for most viewing. A nice feature in such a well-priced unit.

Just be aware that the four holes in the square base are set at 70mm - which fits most 8" units up front - but I believe the 10" and up Newtonians typically need wider spacing. Be sure to mention this to Bintel and they'll give you the appropriate base plate that they've recently produced.

Oh - one more thing.... you'll probably find that you also need either a 35mm or 50mm 2" extension tube to reach focus again.

Cheers
Chris

[erick (Eric)]

Originally Posted by Omaroo

....One thing to note is that you can undo the small hex grubscrews at the base and rotate the entire fucuser throat around its axis so that your focusing shaft is set to be near-parallel to the ground for most viewing. A nice feature in such a well-priced unit....

Yes, this is a good idea. The photos in the thread I referenced show my focuser rotated 45deg. Just remember to do the grub screws back up firmly. As far as I can tell, that is all that holds the focuser to the base plate - you wouldn't want a big 2" EP plus barlow plus focuser come crashing down. Less likely on a dobsonian mount, but if you had your tube on a equatorial mount with the focuser pointed downwards at some stage

[bojan]

My 5 cents worth...
This is not Crayford, but it can be (and probably will be one day)...
And since motor is mounted in eccentric cylinder, by rotating it with the knob I can dis-engage the focuser for manual use..

[Alchemy (Clive)]

The fine focusing helps for sure, buy the standard one and not the low profile one. the low profile got mine to work with a webcam but put any weight on it and the 2" tube will rock off axis. im going to get the large standard one and do the angle grinder thing and lop off a bit of the scope tube.(only needed for imaging with DSLR)

[Solanum]

Originally Posted by Alchemy

The fine focusing helps for sure, buy the standard one and not the low profile one. the low profile got mine to work with a webcam but put any weight on it and the 2" tube will rock off axis. im going to get the large standard one and do the angle grinder thing and lop off a bit of the scope tube.(only needed for imaging with DSLR)

I was thinking of that, for dSLR lunar photography (have to use a Barlow at the mo to get focus). Are you saying that the low profile one won't take the weight of a dSLR?

Are there any other downsides to the low profile focuser in general - effects on focus with any eyepieces?