4mm Ortho

[mikeDnight]

Regarding the LV's, if the rubber eye cup is an issue, you can remove the entire rubber sleeve quite easily. Beautiful!

[25585]

3 minutes ago, mikeDnight said:

Regarding the LV's, if the rubber eye cup is an issue, you can remove the entire rubber sleeve quite easily. Beautiful!

Never knew that! I just leave the cup peeled back which leaves a good flat surface. 

[Littleguy80]

On 22/04/2018 at 11:14, Littleguy80 said:

Your reports on seeing Titan last year are the inspiration for this eyepiece purchase! A 4mm gives me 300x in my dob which should be enough...I hope! 

Edit: This should been Triton not Titan. Don’t think I need 300x for Titan  

[F15Rules]

On 22/04/2018 at 13:13, alan potts said:

I don't have the BGO version but I have the Hutech brand, may even be the same, at 5mm, I find this tight and like John, find I have to be in the right mood, or maybe farme of mind to use it. I find the shorter two I have, 5mm and 6mm tire me quickly. I can only imagine the 4mm will be hard work with shorter ER and smaller eye lens.

Alan

I always find that using a winged eye guard helps in eye positioning and comfort with short FL eyepieces. Much as I really liked my BGO's and especially Antares Elite orthos, I did find them tiring to use for any length of time without an eyecup or guard. Hovering intently over a tiny eyepiece hole isn't my idea of relaxation!

I recommend the Celestron Ultima/ Antares Elite Plossls/ Orion Ultrascopic/ Parks Gold "Pseudo Masuyama" ranges - Ortho like sharpness but a 52deg field and slightly better eye relief than Orthos..these are mainly 5 element units, with the shorter 3.8mm and 5mm (where available, and excluding the Celestron 5mm) being 7 elements due to their design, see below.

If you use an Ultima Barlow 2x (which I reckon is nearer 2.2x), or the excellent Baader Q Barlow (which is advertised at 2.25x), in a 10mm Parks Gold for example, you will get nice eye relief and comfortable viewing at c4.4mm focal length.

The Parks and I think Orion version is also available in a 3.8mm which has pretty good eye relief and is actually the 7.5mm version with a Barlow lens built in to the bottom, hence the larger size, see photo.

But whatever Ortho or similar you use, try a winged eye guard. They are a bit marmite, but I for one am a big fan of them?☺

Sizw comparison of GS 3.8mm 7 element and 7.5mm 5 element

[Alfian]

1 hour ago, mikeDnight said:

Regarding the LV's, if the rubber eye cup is an issue, you can remove the entire rubber sleeve quite easily. Beautiful!

We live and learn! Thanks Mike.

[25585]

There is a 10mm Baader Eudiascopic on ebay currently. 

 

[Littleguy80]

In the end I managed to pick up a 4mm Circle T Ortho for £40. Not a lot of money for what should be a nice sharp eyepiece. If it allows me to see Neptune’s little moon, Triton, then I’ll be very happy! 

[F15Rules]

On 23/04/2018 at 16:06, 25585 said:

There is a 10mm Baader Eudiascopic on ebay currently. 

 

Not any more, there isn't!

Dave

[F15Rules]

On 27/04/2018 at 18:56, Littleguy80 said:

In the end I managed to pick up a 4mm Circle T Ortho for £40. Not a lot of money for what should be a nice sharp eyepiece. If it allows me to see Neptune’s little moon, Triton, then I’ll be very happy! 

Cracking eyepiece in great condition..And no wretched barrel undercut to snag up!!☺?

Dave

[Littleguy80]

19 minutes ago, F15Rules said:

Cracking eyepiece in great condition..And no wretched barrel undercut to snag up!!☺?

Dave

Thanks Dave! Can’t wait to give it a go  

[Saganite]

Well done Dave, I have been trying desperately to ignore that 10mm Baader  for a while now 

[John]

The 4mm "volcano top" orthos are ergonomically easier to use than the flat top HD types IMHO. Not a lot of difference optically either.

I have my Tak FC100 out this evening so I might give my HD 4mm ortho a bit of star time, if I'm in the mood for it's quirks !

 

[Timebandit]

 

Nice 4mm hope you like.

Even though I am a "BIG" fan of the Ortho. I do find the 4mm MRG Ortho hard work. By this the eye position has to be "accurately placed " and" So Close" you are almost sticking your eyeball to it. Lovely sharp views and very well priced though.

Maybe I am getting to picky in my old age, or more discerning ? ☺

 

 

 

[Littleguy80]

9 minutes ago, Timebandit said:

 

Nice 4mm hope you like.

Even though I am a "BIG" fan of the Ortho. I do find the 4mm MRG Ortho hard work. By this the eye position has to be "accurately placed " and" So Close" you are almost sticking your eyeball to it. Lovely sharp views and very well priced though.

Maybe I am getting to picky in my old age, or more discerning ? ☺

 

 

 

Thank you. I’m gonna go with discerning  

It’s going to be more of a specialised eyepiece for me. It won’t be often I can use 300x so I can live with it being a trickier eyepiece to use. I think the sharp views will be worth it  

[John]

Well I gave up with my HD 4mm ortho after about 5 minutes . The TV 2-4mm Nagler zoom is much more comfortable to use and delivers matching views as far as I can see, at least of tonights binary star targets. Plus you can zooooooom .....

The HD ortho is optically excellent of course but finding and holding that tiny eye lens / eye relief set into a slightly dished flat top is hard work.

I expect your volcano top will be easier to use Neil - hope it delivers for you

[Littleguy80]

35 minutes ago, John said:

Well I gave up with my HD 4mm ortho after about 5 minutes . The TV 2-4mm Nagler zoom is much more comfortable to use and delivers matching views as far as I can see, at least of tonights binary star targets. Plus you can zooooooom .....

The HD ortho is optically excellent of course but finding and holding that tiny eye lens / eye relief set into a slightly dished flat top is hard work.

I expect your volcano top will be easier to use Neil - hope it delivers for you

Haha thanks John. I’m sure it’ll get the job done! The Nag zoom sounds like a great eyepiece though. 

[Littleguy80]

The little Ortho had a quick test run on Venus and, later on, Izar. Didn’t have any issues with eye relief or placement. I remember being more taken aback by the short eye relief on my 5mm BGO when I first used that. The difference here may be that I was expecting short eye relief. Could also be down to the Volcano top design versus the flap top of the BGO. Either way, off to a good start. Will have to wait and see how I get on with more prolonged use.

[jetstream]

3 hours ago, Littleguy80 said:

The little Ortho had a quick test run on Venus and, later on, Izar. Didn’t have any issues with eye relief or placement. I remember being more taken aback by the short eye relief on my 5mm BGO when I first used that. The difference here may be that I was expecting short eye relief. Could also be down to the Volcano top design versus the flap top of the BGO. Either way, off to a good start. Will have to wait and see how I get on with more prolonged use.

How was Izar in the 4mmVT?

[Littleguy80]

30 minutes ago, jetstream said:

How was Izar in the 4mmVT?

Nice clear split as you’d expect at 300x with the blue colour of the secondary coming through well. The sharpness looked to be as good as the 5mm BGO. I’m planning on hitting a few more doubles with it over the next few sessions for a more thorough road test  

[jetstream]

Excellent Neil. Izar is a favorite of mine, what color! The VT is easier for me to use in these short fl's and I find no issues with it.

[Littleguy80]

12 minutes ago, jetstream said:

Excellent Neil. Izar is a favorite of mine, what color! The VT is easier for me to use in these short fl's and I find no issues with it.

Agreed. In my old scope it was particularly challenging being quite tight. Much easier in the dob allowing me to enjoy the colour more! 

It’s also been a good test of my dob mount. Manual tracking at 300x with a small TFOV was something I was concerned about but managed it with relative ease. 

[Timebandit]

 

Well done getting on with the 4mm Ortho.?

Not everyone's cup of tea , with the narrow fov and tight eye relief. But having a 5mm Ortho already, at least you have had a bit of practice .

With a Dob I find the 4mm Ortho really hard work. Tight eye relief, narrow fov and you have to have eye placement correct. Its a bit of a juggling act while trying to track with a manual dob also. 

That's probably why I prefer the XW at high mags, just easy to position the eye and a larger fov helps with manual tracking. Those Orthos at high mags, you are so close due to eye relief, that you are almost hugging the Dob.

Maybe you love your Dob a lot ,so are happy to be a Dob hugger ?

 

 

 

[jetstream]

The 2.4mm HR Vixen easily tracks the moon in the 15" dob- I find the truss dob easier to track with than the tube models.

[Littleguy80]

More fun with the 4mm Ortho last night. M57 was the target. Located with the 9mm Lunt and then worked my way through my Ortho collection. 7mm Meade RG, 5 and 6mm BGO and finishing with 4mm Circle T. All of the Orthos showed the mag 13 star next to the ring with averted vision. It seemed brightest with the 4mm to me but still required averted vision. This felt like a good test run for Neptune and Trition later on in the year. A couple of weeks back, I had a look at M57 through an 18" dob and the mag 13 star was easily held in direct vision with that. No central star though. I also tried all the Orthos on Albireo last night for fun. I can confirm it's still one of the prettiest doubles no matter what the magnification is!

[Dave1]

Very interesting Neil. 

As you push the magnification up the exit pupil gets smaller and therefore the image should get dimmer. The fact you say it seemed brightest with the 4mm Ortho is very interesting indeed. You must have a great 4mm eyepiece there! Hang on to that one.

I've just purchased a 7mm Fujiyama orthoscopic eyepiece, to add to my collection! To fill a gap for viewing the planets. Should work well with my 80mm telescope and 102mm telescope!