Advice needed Helios Fieldmaster scope ED60DS (1 Viewer)

Hello, I've just bought this scope second-hand. It seems pretty good on first impressions but I have a question about the focus wheel. I've previously used old spacemaster scopes which have a focus wheel conveniently located on the body of the scope but near the eyepiece. This scope has the wheel positioned along the scope tube which doesn't work for me as well. This is just a design issue and obviously there's nothing I can do about this but my question is: there appear to be two wheels, one on top of the other which is presumably for fast focus and the other for fine-focus. The problem is the (fine-focus?) wheel at the end slips off very easily and I know it's only a matter of time before it'll be lost, Can I loctite it onto the spindle or will this affect the focus of the inner wheel which is obviously on the same spindle? Or, is this outer thing that appears to be a wheel nothing more than an end cap that has no other function other than aesthetic ? I tried to upload a photo but couldn't work out how to do this
Many thanks in advance if you can solve this for me Andrew

Hi Andrew,
As you are in Southampton maybe ask Action Optics for advice.

They may also have eyepieces for it?

Regards,
B.

I should update my details! Now living in the west country so maybe Ace Optics in Bath is the best bet. Thanks for the advice. Actually I'm re-considering the whole angled scope thing and inclined to sell this on and look around for a good straight one with wider field of view

Hi,

first of all - besides the fine focus question which I will address below, the optics buffs in here would love to hear about how the views are in your example...

- can you get a nice and sharp view at its maximum magnification of 45x? How easy is it to find best focus at 45x - is there a clear point of best focus (aka the focus snaps) or do you have to search a lot to find the least blurry setting?

- how is control of chromatic aberration - observe a high contrast target (dark bird or branches against an overcast sky - should be easy to find at this time of year in britain ;-) Do you see color fringes at the edges?

Now to the matter of the dual focus drive (the model mentioned above has a 1:10 dual speed focuser) - traditionally a knob like this would be fitted to an axle with a flat side (sorry, don't know the proper term) using a grub screw in the side of the knob and pressing on the flat side. If that is the case, you need a small allen key fitting the grub screw to loosen it a bit (but don't remove completely), push the knob back on so the grub screw will press on the flat side and carefully tighten the grub screw.

If there is no grub screw, it might be friction fit and in theory could be glued, but you have to check where the 1:10 gears are found - they can be either in the knob (in which case the application of glue might have disastrous results) or it could be a fine drive axle running inside a hollow coarse drive axle and gears inside the body.

You can test this by turning the coarse drive a bit - if the axle end where the fine drive knob used to sit is turning quicker than the coarse drive, it's one axle inside another and you can probably glue the knob back on (just make sure not to glue the inner axle to the hollow one by using too much glue).

If the axle end turns at the same speed as the coarse drive knob, there are planetary gears inside the fine focus knob and gluing it back on is going to be kinda tricky as glue inside the gears will ruin it.

Regarding angled vs straight - it's a matter of taste but angled has a few valid points going for it:

- can be used easily by multiple peoples of different height while staiming aimed at some bird. This is next to impossible with a straight example without changing the tripod height and thus loosing the target.

- needs a less high tripod which matters as it allows you to use the tripod with the center column down or mostly so - which will increase stability.

A straight scope might seem easier to aim, but if you use Kimmo's cable tie sight on an angled one, aiming it will be even easier. The only reason I might consider a straight example is for use inside a vehicle with a window clamp or inside a hide with a hide clamp.

Joachim

Hi Joachim, thanks for your very detailed and helpful reply. I've only just bought the scope and I'm going to play around with it tomorrow and will reply when I've learnt a little more about it. This is my first experience with an angled scope and the way I'm feeling at the moment is that it's destined for ebay-I miss my straight scope which with a shoulder pod, could be aimed like a rifle allowing the tracking of birds in flight which I don't think this will ever allow me to do. More detailed response to your questions and the fix you suggest will follow............. Andrew

shearwater333 said:

I miss my straight scope which with a shoulder pod, could be aimed like a rifle allowing the tracking of birds in flight which I don't think this will ever allow me to do.

Click to expand...

Hi,

ok, I haven't tried to use a scope on a shoulder stock... it might well be that angled is not good for that.

Joachim

It worked! I removed the small rubber casing and there was the grub screw which I tightened up and it works 100% fine now, so thanks very your advice which prevented me from putting a drop of super glue on the spindle which could have been disaster had any seeped through to the gear mechanism. As far as the scope goes, I'm sure that these were an extremely good deal (they are now discontinued) and I paid a lot less for this second hand one. It is clearly well-made and has the advantage of ED glass which to my mind doesn't provide a hugely improved image than my old opticron screw in type eyepiece. Another issue for me is that the zoom gives such a narrow FOV. If birds kept still, this would be a fantastic scope but it seems to me that this would only be of benefit in bird watching when looking at nesting birds at a distance or possibly herons, roosting birds etc........so, some buyers remorse for me at the moment. I may keep it for a while and see if I can learn to love it but my hunch at the moment is that I won't. Anyway, now at least I can sell it in full working order so many thanks for that

Hi,

glad it worked - you're welcome.

Yeah, a narrow field of view (both true and apparent) at the low magnification end is the common gripe with almost all zoom constructions. At maximum magnification zoom EPs usually have a quite wide apparent field of view (this example has a tad over 60 deg) - the true field is of course not very wide due to the higher mag.

For the record - did you try it at the max magnification of 45x - an ed scope should have no problems with that - even a well made non-ed example should still be ok.

Joachim

No problem with clarity at all in fact it was crystal clear at 45x, very little loss of definition at the edges. I'm in an urban environment right now and I was looking at roof tiles about 50m away, individual lichens were all very easily seen in some detail but the field of view at this distance was only about five tiles.