Fixed eyepieces for Helios Filedmaster ED60 (1 Viewer)

[MartinJ]

I am owner of a Helios Fieldmaster ED 60. I Think is a great scope for the price, very sharp and with good contrast.

Being a eyeglasses wearer, the provided zoom has the drawback of a limited ER, so I’m searching for fixed eyepieces that can offer more friendly view

There are two issues, first, how to attach the fixed eyepiece to the scope, and two, how to reach infinity focus. (The prism is far from eyepiece).

There are two methods for attach the eyepiece.

• First, the Helios Fieldmaster has an external T2 thread, so you can attach an T2-1,25 eyepiece holder and slide an 1,25 astro eyepiece. I use a low profile T2-1,25 eyepiece holder.

• Two, the Helios Fieldmaster has an 28 mm internal thread and you can attach an 1,25 astro eyepiece with an appropriate 28mm step ring.

In order to reach focus at infinity, you must shorten as much as possible the distance between prism and eyepiece, so it’s necessary to use astro eyepieces without the barrel. (Of course, without optical elements in the barrel)

I have tried with some affordable eyepieces and I want to share my experiences in the forum.

First eyepiece I tried is the Vixen GL 15, by 1,25 eyepiece holder (it’s possible you must sand a little the eyepiece’s holder internal side in order to attach Vixen eyepieces). I Think 14x with an Fieldmaster´s estimated focal length of 360 mm. Very wide FOV, better than provided zoom. 17 mm ER. Relaxed and sharp view.

Vixen GL 25W. (by eyepiece holder). I think 23 X. Better FOV than supplied zoom but blurry on edges. 13 mm ER.

Explore Scientific 15 mm. (by 28mm-1,25 step ring). Similar view to GL25W but more distortion on edges and really short ER.

WO Swan 9 mm. Think 40x. (by step-ring).Very short ER and too much distortion.

For now, there’s two affordable eyepieces that can do the job at low power, but I’m searching for a suitable 27x-30x.

Hope this can help for using fixed eyepieces in this scope. (and excuse me for my English).

 

[mayoayo]

MartinJ..Thanks for starting this thread..We started discussing the Helios/Saker In the Bosma 66 thread,but I think is worth a thread of its own..!

 

[woodhornbirder]

There are two methods for attach the eyepiece.

• First, the Helios Fieldmaster has an external T2 thread, so you can attach an T2-1,25 eyepiece holder and slide an 1,25 astro eyepiece. I use a low profile T2-1,25 eyepiece holder.

• Two, the Helios Fieldmaster has an 28 mm internal thread and you can attach an 1,25 astro eyepiece with an appropriate 28mm step ring.


can you show pics of these attachment methods? and one of an ep in place, thanks

 

[rmel66]

I am owner of a Helios Fieldmaster ED 60. I Think is a great scope for the price, very sharp and with good contrast.

Being a eyeglasses wearer, the provided zoom has the drawback of a limited ER, so I’m searching for fixed eyepieces that can offer more friendly view

There are two issues, first, how to attach the fixed eyepiece to the scope, and two, how to reach infinity focus. (The prism is far from eyepiece).

There are two methods for attach the eyepiece.

• First, the Helios Fieldmaster has an external T2 thread, so you can attach an T2-1,25 eyepiece holder and slide an 1,25 astro eyepiece. I use a low profile T2-1,25 eyepiece holder.

• Two, the Helios Fieldmaster has an 28 mm internal thread and you can attach an 1,25 astro eyepiece with an appropriate 28mm step ring.

In order to reach focus at infinity, you must shorten as much as possible the distance between prism and eyepiece, so it’s necessary to use astro eyepieces without the barrel. (Of course, without optical elements in the barrel)

I have tried with some affordable eyepieces and I want to share my experiences in the forum.

First eyepiece I tried is the Vixen GL 15, by 1,25 eyepiece holder (it’s possible you must sand a little the eyepiece’s holder internal side in order to attach Vixen eyepieces). I Think 14x with an Fieldmaster´s estimated focal length of 360 mm. Very wide FOV, better than provided zoom. 17 mm ER. Relaxed and sharp view.

Vixen GL 25W. (by eyepiece holder). I think 23 X. Better FOV than supplied zoom but blurry on edges. 13 mm ER.

Explore Scientific 15 mm. (by 28mm-1,25 step ring). Similar view to GL25W but more distortion on edges and really short ER.

WO Swan 9 mm. Think 40x. (by step-ring).Very short ER and too much distortion.

For now, there’s two affordable eyepieces that can do the job at low power, but I’m searching for a suitable 27x-30x.

Hope this can help for using fixed eyepieces in this scope. (and excuse me for my English).

BST Explorer 15mm (Astrotech Paradigm 15mm this side of the pond)

Rmel66.

 

[looksharp65]

BST Explorer 15mm (Astrotech Paradigm 15mm this side of the pond)

Rmel66.

Exactly my thought. The 12 mm was very nice with my previous scope, the Pentax 65 mm, but the WO SWAN 15 mm (72 degrees) was unusable on that fast spotter, having a tremendeous curvature of field.
I'm also considering the Helios as a spare, but will probably buy a spare ED50A body instead.
Again, I'm pretty convinced that the BST Explorer 15 mm would fit the Fieldmaster very well.

//L

 

[MartinJ]

There are two methods for attach the eyepiece.

• First, the Helios Fieldmaster has an external T2 thread, so you can attach an T2-1,25 eyepiece holder and slide an 1,25 astro eyepiece. I use a low profile T2-1,25 eyepiece holder.

• Two, the Helios Fieldmaster has an 28 mm internal thread and you can attach an 1,25 astro eyepiece with an appropriate 28mm step ring.


can you show pics of these attachment methods? and one of an ep in place, thanks

Yes, they are.

First, the external T2 thread.
Second, T2 external and 28 mm internal.
The eyepiece holder attached to T2 external
The GL 15 in eyepiece holder

 

[MartinJ]

There are two methods for attach the eyepiece.

• First, the Helios Fieldmaster has an external T2 thread, so you can attach an T2-1,25 eyepiece holder and slide an 1,25 astro eyepiece. I use a low profile T2-1,25 eyepiece holder.

• Two, the Helios Fieldmaster has an 28 mm internal thread and you can attach an 1,25 astro eyepiece with an appropriate 28mm step ring.


can you show pics of these attachment methods? and one of an ep in place, thanks

And now, the 28mm,1,25 step ring.

First, homemade 28-1,25 step ring. (Half 28 mm uv filter and half 1,25 filter)
Second, eyepiece attached to step ring.
Finally, eyepiece with step ring attached to internal 28 mm thread.

Let me know if you need more photos.

 

[mayoayo]

Hi Martinj...I mentioned these eyepieces to You in the other Thread,and then I saw that You already had already posted a link to them!...http://www.valkanik.com/oculares/extra-flat/p1/
As I mentioned these are the same eyepieces(the 16mm) that Zen Ray and Vortex sale for the ZEN ED82 and the Razor HD..I am totally sure because I had two of the Zen version,and was able to unscrew one from the adapter..The thread could very well be 28 mm ,In this case they come with an astro adapter ,but is removable..My concern with tha model,looking at the mount of the Helios is that the thread is inside the mount at least 5mm deep,so you need at least 1cm of thread to allow the eyepiece to sit on the mount AND reach the inner threads....for what I remember the eyepieces in the link only had a few turns of thread,so they might not engage in the Helios...once again ,Henry Link that the 16mm is a copy of the Nikon SE binoculars ocular!...
I have the distributor pretty close by and I will go next week,after the holiday ,to pay a visit and I can try those eyepieces...

 

[woodhornbirder]

http://www.birdforum.net/showthread.php?t=224588

probably too tall to come to focus

guess my nikon+adapter would work....not cheap option tho...

 

[MartinJ]

Exactly my thought. The 12 mm was very nice with my previous scope, the Pentax 65 mm, but the WO SWAN 15 mm (72 degrees) was unusable on that fast spotter, having a tremendeous curvature of field.
I'm also considering the Helios as a spare, but will probably buy a spare ED50A body instead.
Again, I'm pretty convinced that the BST Explorer 15 mm would fit the Fieldmaster very well.

//L

Thanks looksharp65.

I´ve been searching for the BST explorer, and, for, some pictures in the web, they seems that have an optical group in the barrel.

Do you have the eyepiece?. Could you tell me if is threre´s a optical element in the barrel.

 

[MartinJ]

Hi Martinj...I mentioned these eyepieces to You in the other Thread,and then I saw that You already had already posted a link to them!...http://www.valkanik.com/oculares/extra-flat/p1/
As I mentioned these are the same eyepieces(the 16mm) that Zen Ray and Vortex sale for the ZEN ED82 and the Razor HD..I am totally sure because I had two of the Zen version,and was able to unscrew one from the adapter..The thread could very well be 28 mm ,In this case they come with an astro adapter ,but is removable..My concern with tha model,looking at the mount of the Helios is that the thread is inside the mount at least 5mm deep,so you need at least 1cm of thread to allow the eyepiece to sit on the mount AND reach the inner threads....for what I remember the eyepieces in the link only had a few turns of thread,so they might not engage in the Helios...once again ,Henry Link that the 16mm is a copy of the Nikon SE binoculars ocular!...
I have the distributor pretty close by and I will go next week,after the holiday ,to pay a visit and I can try those eyepieces...

Hi Mayoayo.

In that case, for reach the innner threads, it´s possible to take a 28 mm photography filter, remove the filter and attach it to the eyepiece´s thread and use it as a little extension tube. The eyepice will attach, but i don´t know about to reach focus.

Please, let us know about your visit to the distributor.

 

[looksharp65]

Thanks looksharp65.

I´ve been searching for the BST explorer, and, for, some pictures in the web, they seems that have an optical group in the barrel.

Do you have the eyepiece?. Could you tell me if is threre´s a optical element in the barrel.

Yes they do. I'm sorry I didn't realise that before recommending them.
But I think they would be usable even without the mini barlow, but their FL will be different and you may encounter problems finding an appropriate empty 1.25" barrel.

//L

 

[woodhornbirder]

http://www.ebay.co.uk/itm/151009590527

is that correct? for adapter t2 m42

 

[MartinJ]

http://www.ebay.co.uk/itm/151009590527

is that correct? for adapter t2 m42

I think that is it not. Is an adapter M42-Canon mount.

There´s two possibilities for obtain a "low profile"t2 eyepiece holder.

Buy an standard eyepiece holder T2-1,25, in an astronomy´s shop and cut the top.

Or, combine an photo adapter ring t2 female (to the Helios external thread) -m42 male and a very low profile M42 eyepiece holder (as used in Russians MTO). This gives a very low profile eyepiece holder without work.

 

[woodhornbirder]

`(as used in Russians MTO)`

no idea what you mean by that...you do like your jargon! Ive heard that chap gollum use less riddles

 

[MartinJ]

`(as used in Russians MTO)`

no idea what you mean by that...you do like your jargon! Ive heard that chap gollum use less riddles

Hello.

It´s an russian catadioptric tele-lens, used for photography and also for visual observation with adapters. Has a M42 thread.

Popular some years ago. I used mine a lot as a telelens.

Here´s one link.

http://www.russianoptics.com/page6.html

 

[mayoayo]

Hi Mayoayo.

In that case, for reach the innner threads, it´s possible to take a 28 mm photography filter, remove the filter and attach it to the eyepiece´s thread and use it as a little extension tube. The eyepice will attach, but i don´t know about to reach focus.

Please, let us know about your visit to the distributor.

Martinj..Good Idea..depending on the eyepiece to adapt ,a step-up ring can be also used,..I see in your photo that above the 28mm threads the mount has a couple of flanges and probably a can accomodate a 28-30 step-up ring...That might held Nikon Fieldscope eyepieces ,for users that ,like LookSharp,already own some of the eyepieces and want an inexpensive ,quality back-up scope..

I definitely will comment on my visit to the dealer..JUST called them ,and the scope is Sold-out, now waiting for a shippment ,probably next week..It suits my schedule,because I am bit busy for the rest of this week, after the "Semana Santa" Holiday...

It is nice to be able to buy the scope in person,.. to test minimally, and choose ,if they have few units available...This can make a difference ,specially in this price point..
You seem to be an astronomer,and I am sure You are familiar with Star-test as a way to test the quality of Your optics...Can You comment about the particular Characteristics of Your Unit..?
Thanks
M.

 

[woodhornbirder]

Am just wondering if i can use your adapter setup on this:

http://www.birdforum.net/showthread.php?t=237466

it has a m42 external thread i believe. Suspect it will work with short eps ~80mm in height.

 

[Ysterkvisten]

I can't wait for an easy set-up with fixed eye-piece on my Fieldmaster, a scope that I am very pleased with by the way.
Will follow this thread until that happens, be sure of that.

 

[MartinJ]

Am just wondering if i can use your adapter setup on this:

http://www.birdforum.net/showthread.php?t=237466

it has a m42 external thread i believe. Suspect it will work with short eps ~80mm in height.

Maybe you can, but the issue is reach focus at infinity.

If you are sure that the thread is m42 you can use this device:

http://www.widescreen-centre.co.uk/Products/BAADER_31_7MM_EYEPIECE_HOLDER.html

But, if you don´t know if external trhead is M42 or T2, maybe this option could give you more flexibility (and lower profile for reach focus):

First, an T2-M42 adapter:

http://www.ebay.es/itm/360479635405?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

And a low profile M42 eyepiece holder like this:

http://www.ebay.es/itm/Raccordo-42x...62844?pt=Strumenti_ottici&hash=item20d11b06dc

With the second option you sure can attach the eyepiece holder to the external thread, but i don´t know if the eyepiece will reach focus.