Does anyone have any experience with the bintel focussers? I find that on my C925 based scope, at high powers I do tend to chase the focus around quite a bit and final focus requires a very gentle touch with minute movements of the focus knob.
Some time back I upgraded to a 2" diagonal and went against advice at the time and bought the SCT style not the refractor style, I have found it a bit of a pain ever since as I find myself moving the EP around the back of the scope a fair bit as targets change and it means loosening the lock ring on the diagonal to rotate it then donig it up again, sometimes an issue in the middle of the night when things have cooled off and everything has tightened up. I was thinking about the combination of a crayfor style two speed focusser to make it easier to deal with at higher power and also eliminate mirror flop (Not a great issue but it is there) and get a refractor style 2" diagonal to go with it. Getting rid of two problems at one.
My issue is I have no experience at all with the Bintel focusser, I would want it to outperform the original in terms of smoothness and fine focus or is it just not worth doing.
And a further hypothetcal, does anyone know of a source for just the screw on nosepiece for the diagonal to convert the one I have (Which is in perfect condition) to a refractor type?
The Bintel focuser is a re-branded GSO. If you search for reviews on the GSO crayford, you should find plenty.
I remember reading such reviews when looking for a crayford for my 'scope. I eventually chose a more expensive brand, partly for payload, partly for upgradeabilty and partly to get the larger flange size for maximum FOV (which shouldn't apply to you due to the narrower baffle exit on the C9.25).
I don't recall anything particularly bad about the GSO reviews - some mention of cosmetic wear on the barrel comes to mind but that's about it.
Another option is a Feathertouch microfocuser in place of the main focuser knob - I'm pretty sure they would make one - but, personally, I prefer the Crayford approach.
As for the screw - there are plenty of sources online (eBay, hobby shops) if you know the exact size.
[QUOTE=does anyone know of a source for just the screw on nosepiece for the diagonal to convert the one I have (Which is in perfect condition) to a refractor type?[/QUOTE]
You might have to butcher an old 2" EP or something to get the bit you need. I would think it has the same thread and sleeve length. I assume you want to slip the diagonal it into the focuser, yeah?
Have you given your Bintel focuser a good going over since you bought it? When I got mine, & before I fitted it to my C8, I stripped it down and gave it a birthday. It didn't need much, but just the new grease and a firm up made it operate a lot smoother. I have the procedure for doing it if you want it. Can't remember if I got it of IIS or somewhere else. Let me know if you want it & I can email it to you. It's to big to attach here.
Yeah, that would be my intent, scope, focusser, diagonal.
I looked at the feathertouch but I recall they stick out further than the OEM focus knob and they would be likely to foul on the diagonal as it was turned and I have trouble justifying a high end crayford style, as you said, the baffle tube of the 925 would make the extra ID irrelevant anyway.
I will look into my 2" eyepieces and see if any have the same thread as the nose of the diagonal, looking at that never occurred to me. At the worst I might have to buy an older EP to scrap and scavenge a nose from.
Paul, I just had a look at mine. I have a GSO 2" 90° diagonal that I unscrewed the barrel off. I screwed the barrel from my 30mm Bintel (GSO) EP into it. They are a perfect match. I did a quick measure of both bits and they are identical.
The first picture is with the diagonal's own barrel. The second is with the one from the EP. Even the file size is the same.
... just the screw on nosepiece for the diagonal ...
D'oh! You meant a replacement nosepiece, not a screw on the nosepiece. I'm obviously having a blonde day!
If your diagonal is 2" GSO, then Agena Astro sells replacement nosepieces separately. Like Stewart says, 2" barrel GSO superview eyepieces (maybe others) use the same barrel.
Thank you both. I was going to try the nose from one of my 2" Meade eyepieces. The diagonal is Bintel supplied and branded so GSO made I assume. Then I just have to work out an attachment method to the scope.
Taking up an earlier suggestion, does anyone have a c925 with a feathertouch micro focuser to measure how far out from the back of the ota they protrude so I can work out if one would fit without fouling my diagonal? Otherwise I will email starlight and see if they can/will tell me.
I reckon so, and the other adapter I would need to put it on my SCT was next to it on the page. $55 between the two of them.
I had a look tonight and the barrel of my celestron e-lux 2" ep's screws straight on in place of the SCT thread nose. So that is one problem solved.
Next is a focuser, I think that the feather touch needs a closer look, it should clear the corner of the diagonal but if it is any taller than the stock focus knob the ep barrel will foul it, have to look and think if I would ever rotate it that far, though the refractor diagonal setup is likely to increase clearance there by a few mm.
You could consider the 0.8" travel feathertouch crayford focuser which bypasses any problem with mirror movement and only adds about 5cm to the light path from the rear cell. There's one in the cosmetic seconds area for $331 (regular $390) and the adapter is another $50. http://starlightinstruments.com/stor...product_id=203
OK, have taken the plunge and got a new chrome barrel for my diagonal and an adapter for the baffle tube thread. Well, one of the two, they did not have the adapter in Melbourne so they are getting one sent to me from another store. There is one frustration ticked off the list.
Now to dig into focussers. I am a bit tempted by the feathertouch upgrade if I can find one in Asutralia. It probably makes more sense for me than to go strapping a crayford to it, the scope is pretty well exclusively used visually and on those nights where high power planetary viewing is possible a low speed focusser to really snap it in would be a very handy thing.
I am just a little reluctant to spend too much on the scope itself as I am still considering remounting the scope or replacing it completely. Problem with remounting it is I end up with a CPC mount and tripod that would be pretty well worthless at the end of it all.
You could add a helical focus adaptor to the existing focuser for that final bit of fine tune. Badder make on that has 10mm of travel. Cost around $50-60 US I think
The Feather Touch will never need adjusting though, the GSO's do need adjusting from time to time.
Just a thought
Matt
Part one of the problem solved, the adapter and chrome barrel to convert my diagonal to the refractor type so it is not such a pain to rotate. It has chewed up a little focus length as it is about 12mm longer overall now but there is plenty left. That also sits the diagonal further out from the back of the tube so a feathertouch micro focuser might not foul any more.
There is a cosmetic second on the starlight site, trying hard not to buy it.
I would love to fix all my issues by selling almost the whole lot and buying an AZEQ6 and a new Meade 10" F8 OTA! Not quite feasible though.
Argh, I only went online to buy a FLIRC (USB infrared keyboard dongle) for $30, spent $300 on the feathertouch microfocusser instead. They had a cosmetic second on the site, which will do me fine, the scope is a couple of years old now so is not comsmetically perfect itself. I am looking forward to being able to really snap in the focus. Now I guess I am committed to my current OTA, either on the standard mount on a wedge or remounted.
Standard on a wedge has some appeal, I am thinking of designing my own wedge to go on a pier and it can stay permanently set up once it is well polar aligned, leaving the scope free to go on the wedge in polar mode at home or on it's original tripod in Alt Az mode elsewhere.
Now to look at getting stainless steel bearing balls for the Az/RA axis, they use nylon ones out of the factory and they can take a set so the axis gets lumpy if unused for a little while, I have normally fixed that by rotating the scope on the Az axis a couple of times to warm the balls up and round them off again, you can hear the difference as they true up.
nothing beats a good quality focuser.It makes focusing so much easier for imaging or just viewing objects. You will not be disappointed. But remember a telescope wont perform well with crap collimation.
Yep, already got that aspect covered, the first mod to this thing was a set of Bobs Knobs for the secondary. It was not far off to begin with but after a tweak it was visibly tighter for star images. Then I fitted the new Collimation screws and fluked it almost perfectly on initial fit.
The factory collimation screws on these scopes are just silly! Imagine using a fine pointed, sharp screwdriver around the corrector plate!
You meant a replacement nosepiece, not a screw on the nosepiece. I'm obviously having a blonde day!
