Helios Apollo 15x70 CA Question

[Tyr]

Good evening all,

I was hoping I could ask some advice from other owners of these binoculars about what I should be seeing with them and how I should be adjusting them as I've been having a little trouble with my new pair, which I recieved last week.

It's been clear over the weekend here and I've had a chance to use them for a few nights now. On the whole the view through them is good, much better than my old Helios Fieldmaster 10x50s, they feel like a quality instrument. The moon is great and deep sky objects like the double cluster, orion nebula and the pleiades are all nicely well defined with pin point stars (at least as much as in my 127 mak).

From what I understand these binoculars are achromatic (not ED glass) and have a focal ratio of about F5 making them fairly fast, meaning that some chromatic aberation should be expected.

When looking at the moon I can see some chromatic aberation (blue halo one side yellow halo the other), however adjusting the possition of the eyepieces improved it to the point where it's not noticable. However when looking at jupiter I see a significant blue halo about half the size of the planet I think, is that normal for these binoculars?

It occurs to me either

* This is normal and my expectations from reading other reviews was just a bit too high in this respect.

* I've not got them adjusted right.

* Theres a problem with them.

* The problem is with my eyes.

I do wear glasses for astignatism in both eyes and now with prism lenses (without them I can however drive and read what I'm typing now), I don't normally wear my glasses for observing however, but I did check and I can I think get away with it with these binoculars (I've bought all long eye relief EPs for my scopes as I don't think my sight is going to get any better in the future).

My inter pupilery distance as measured for my glasses is 62mm, I'm wondering if this is a bit small given the size of the eye pieces, I cant get the eyecups right up to my eye sockets the binoculars sort of balance on the bridge of my nose.

I did previously have the binoculars set wider than this for more comfortable viewing, but I tried this evening measuring the distance between the eye cups to get it set exactly, the eye cups are 4.5cm wide so with my 6.2 cm that means the outer edges should be 10.7cm appart at the widest point (assuming the lenses are centered in the center of the eyecups).

I've tried adjusting the focus but as far as I can tell it's ok at the default markers for +- 0, and the moon, orion nebula etc all seem to be in focus ok.

Any thoughts? does everyone see this much CA with them.

Thanks for reading

ps They were delivered straight from the importer

[BinocularSky]

I don't get that much CA on Jupiter, but my IPD is 67mm, and CA is usually much worse if your eyes are not on axis.

On the batphone, so expect weird autocorrect

[spike95609]

I get a bit of blue flaring on Jupiter through mine and slight yellowing on one side of the moon, but that only really happens if I have the view far off-centre where the image quality starts to distort. Could it be a problem with the angle of the eyepieces? When I got mine I set them at a fairly wide angle as it seemed to fit into my eye sockets comfortably, but I had problems focusing and soon realised that although it felt comfortable I was in fact looking at an object in the centre of one lens and on the edge of another - consequently everything was a little blurred. I've since narrowed the angle to almost its minimum so both lenses are looking at the same thing and everything looks much sharper.

[Tyr]

Thank you both for the replies.

I'll check again with the adjusted position of the eye cups. It was slightly better when I just looked through one eye piece.

I don't really plan on using these much as a planetary observing instrument, but I'd like to make sure I've got them adjusted right.

[Tyr]

I've had a couple more goes at Jupiter specifically, with a combination of both my glasses and the eye cups set at the closer measured distance the amount of "flare" I see from Jupiter is reduced, I'm thinking it's a combination of my eyes and the position of the eye pieces, so I'll just not worry about it any further and just get on with enjoying looking at everything else.

Last night I caught the moon rising behind a shifting curtain of low clouds, which was a very pleasing view with these if not very educational in terms of observing anything specific on the lunar surface.

I'm still looking forward to getting these to a darker site next time I go on holiday in this country, I think I'll have to plan another trip down to Exmoor.

[spike95609]

It might help more if you fold the eye cups back. My eyes are closer together than I thought they were and the cups do get in my way a bit. I'd also like to try these binos out under a proper dark sky, I don't think I've seen a fraction of what they can do yet.