Barlow & T6 Nagler's ?

[Damo636]

Has anyone much experience of using the above ep's with a good Barlow? I had a great night last night mainly observing Jupiter with the Dob. I pushed the mag to 200X with the 6mm ortho and i was wondering how the 13mm and a decent Barlow would compare. I realise the BGO's won't be beaten on sharpness on planets but the wide field of the Nag's would be another option if they worked well barlowed. Of course in hindsight if i hadn't sold my Celestron Ultima a few months back i wouldn't have to ask advise on this

[MjrTom]

Hi Damo,

I use my 13mm T6 with the 2.5x Powermate and performance is very good.

In my scope the 13mm give a magnification of 38x. When paired with the powermate it is a 5.2mm EP with a magnification of 96x.

When comparing my Nagler 3-6mm zoom @ 5mm to the Powermated 13mm T6 the difference is negligible. I would say slightly darker and slightly less sharpness and contrast. however the FOV of the zoom is 50 degrees vs the Nagler T6 at 82 degrees aFOV so it includes loads more sky.

I especially like to use the Powermated 13mm on the Moon.

The whole disk fits perfectly.

[John]

I've barlowed T6's a lot as well - the Powermate 2.5x works superbly with them - you would not know you have the additional glass in there - you just get more power

Amazing to think TV can do this - all those glass elements and still wonderfull images

[Demon Barber]

HI Damo try and get a lend of an Antares 1.6 barlow they work very well with my fthos and 31nagler,well worth the investment and as its a 2"fits it really complimens the T/V lens``

Regards

Mike

[MjrTom]

One thing I forgot to say the Powermate does mess up the parfocal nature of my EPs.

All my EP's the 36mm Baader (a fluke) the Panoptic, the Nagler T6 and the Nagler Zoom are all parfocal to each other.

If I add the 2.5x powermate the focal point is all over the place.

Only a minor hindrance but thought worth mentioning.

[spaceboy]

Hi Damo,

I use my 13mm T6 with the 2.5x Powermate and performance is very good.

In my scope the 13mm give a magnification of 38x. When paired with the powermate it is a 5.2mm EP with a magnification of 96x.

When comparing my Nagler 3-6mm zoom @ 5mm to the Powermated 13mm T6 the difference is negligible. I would say slightly darker and slightly less sharpness and contrast. however the FOV of the zoom is 50 degrees vs the Nagler T6 at 82 degrees aFOV so it includes loads more sky.

I especially like to use the Powermated 13mm on the Moon.

The whole disk fits perfectly.

TBH I have only used my barlow and T6's a couple of times. From memory I would say I had a similar experience to MjrTom. I had no concerns about the darker image as this is often common with higher magnifications. The slightly softer stars I put down to the extra glass in the mix. The thing I did notice and was my main concern is that at times I could see internal reflections. Whether the powermate is any different I don't know but for me this has been a common occurrence in all the barlows I have used Tal, SW and now the TV. On paper it is said that the powermate and barlow are hard to tell apart when using short FL EP's, it only when you use longer FL EP's that the powermate comes into it's own as ER remains the as the EP manufacturer intended. Sorry I cannot offer any better advice but it's so long between clear nights that I cannot offer a more accurate assessment. When it is clear I'm always content just playing with the zoom

[MjrTom]

I never noticed any internal reflections when using the Powermate however now that you mention it I shall test it on some stars and Jupiter when its high enough.

Did you notice any colour cast? If I remember correctly it gives a slightly warmer tone when looking at the moon for instance.

[John]

One thing I forgot to say the Powermate does mess up the parfocal nature of my EPs.....

Thats interesting. I've only used a Powermate with Tele Vue eyepieces and with those it kept the focus point exactly where it was without the Powermate. That and maintaining (rather than enlarging) the exit pupil are supposed to be two of the main benefits of using a Powermate.

I guess TV can't maintain this with non-TV eyepieces.

Another vote for the Antares 2" 1.6x barlow here as well - I currently use one of those with my 8mm and 6mm Ethos with very impressive results.

[MjrTom]

Thats interesting, I was using TeleVue eyepieces when comparing how parfocal each configuration was.

Not miles out of focus but definitely a slight tweak needed I thought.

[spaceboy]

That and maintaining (rather than enlarging) the exit pupil are supposed to be two of the main benefits of using a Powermate.

.

DOH!! Exit pupil ? I knew it was one or the other.

I never noticed any internal reflections when using the Powermate however now that you mention it I shall test it on some stars and Jupiter when its high enough.

Did you notice any colour cast? If I remember correctly it gives a slightly warmer tone when looking at the moon for instance.

Maybe I'm doing something wrong but every barlow I've used I've notice it at one point or another.

As for colour cast..... In general and with out barlowing I have found the T6's & my T4 to offer slightly coffee coloured stars. The 16, 20 and 31 T5's are the exception, offering more of a cleaner white star. I guess the darker image of a barlowed T6 could be put down to a slightly harsher hue but I wouldn't want to say unless I'd had another look.

[MjrTom]

Yeah I suspect you are right here.

I imagine the slight colour cast of the T6 is accentuated when paired with a barlow/powermate due to the darkening of the image.

[Damo636]

Thanks guys. The 1.6X Antares would give me a nice range of mags. The Powermates are impressive pieces of kit but didn't really want to spend as much as that. I was thinking ULtima or TV 2X standard Barlow range but the Antares looks good. I don't think it comes with a 2''/1.25'' though so would have to source one of those.

[spaceboy]

Just a note Damo. The ultima is thumbscrew where as the TV is brass compression ring. Got to look after those EP's

[John]

Just a note Damo. The ultima is thumbscrew where as the TV is brass compression ring. Got to look after those EP's

So is the Antares 1.6x in the 2" fitting but you can put a compression ring 1.25" - 2" adapter in of course.

The Antares 1.6x is notoriously difficult to find for sale - it's listed by a few dealers but often seems to be out of stock. Mine was bought used.

This person had one for sale not so long ago:

U.K. Astronomy Buy & Sell

[Damo636]

Good point about the thumbscrew. It would have to be the TV though, there's no way an imposter with orange writing could sit in beside all the green and black

As it turns out i have been pm'd with a great offer on a mint 6mm Radian and now have to make my mind up which way to go. Decisions, decisions

[spaceboy]

Personally I would think twice about the Radian but that's only my opinion

[Damo636]

Personally I would think twice about the Radian but that's only my opinion

Do you not rate it? I have experience of the 14mm Radian and thought it was equally as sharp as the 13mm Nagler although i kept the Nag for the extra fov.

[Moonshane]

I really like my Radians. They have excellent eye relief, decent field which is flat and sharp and the contrast and sharpness generally is superb. They are reasonably light too (or no worse than Panoptics/Naglers in 1.25" fitting anyway).

I have a 10mm and an 8mm and previously had a 14mm and an 18mm.

No doubt they have a slightly yellow tinge to them but so do most TV eyepieces in my experience, certainly mine do compared with my BGOs.

[spaceboy]

Do you not rate it? I have experience of the 14mm Radian and thought it was equally as sharp as the 13mm Nagler although i kept the Nag for the extra fov.

As I said it's only my opinion but as we have a similar scope you might come to the same conclusion I did. While it was great on globulars I found it wasn't so good on bright planets. If you can get one at a good price it may pay to see what the general consensus is on the shorter FL Radians. It may work for you??

[Damo636]

Ok, appreciate the feedback guys.

[John]

Shows how personal the choice of eyepieces is

Personally, the Radian is the one Tele Vue design that I've not, so far, tried. Hopefully at the next star party I go to I'll be able to change that if someone will let me have a peek through theirs.

It will be interesting to see if the arrival of the Delos and any further focal lengths of that (which there surely will be) results in a shake up within the Tele Vue ranges, in due course

[spaceboy]

Don't get me wrong they are a nice EP. I considered them a bit on the heavy side but the large lens was comfortable to use and the adjustable eye guard was perfect for getting eye placement just right. Yes they have a more noticeable hue to the views than the others in the TV range but it was the problems I noticed in the 6mm when viewing Jupiter that I felt were unacceptable. I kept hold of mine for a while as the FOV & magnification was just right for globular clusters in my scope but when I got the Nagler zoom it never got used again.

[Damo636]

So is the Antares 1.6x in the 2" fitting but you can put a compression ring 1.25" - 2" adapter in of course.

The Antares 1.6x is notoriously difficult to find for sale - it's listed by a few dealers but often seems to be out of stock. Mine was bought used.

This person had one for sale not so long ago:

U.K. Astronomy Buy & Sell

It's still listed as for sale John. I sent an email in the off chance its still available.

[John]

It's still listed as for sale John. I sent an email in the off chance its still available.

Hope you get it Damo

[Damo636]

Thanks John, its unlikely at this stage but fingers crossed.