High Power Eyepiece for 3" Refractor

[astro_al]

Evening all,

I bought a Tak FC-76 (F7.5) this week after being scopeless for over 5 years, and was wondering what eyepieces other owners of this scope (or similar) are using for high power viewing of planets and doubles in the UK.

I had a Tak FS-60 about 5 years ago and was regularly able to push it to 120x with a Nagler 6-3mm zoom. Seeing here should support pushing the FC-76 on a half-decent night so I am thinking a 3.5 or 4mm EP. I liked the Nagler zoom a lot but did have to nudge my mount along a fair bit so I am considering something with a larger AFOV this time around as my new mount is also un-driven.

I am using the Tak 1.25" prism diagonal and I am not sure how it will handle a large EP like a Delos or a Pentax XW. Maybe a Nagler 3.5 would be a good option. I don't wear glasses but the eye relief of the zoom at 10mm was comfortable compared to other EPs I owned at the time.

Any suggestions or first-hand experience with the same setup would be appreciated.

Thanks

Al

[Stu]

I had a Televue 76 for a while, very nice scope. I used a nag zoom, plus also a 3.5mm type 6 Nagler and also a 3.5mm Delos. The Nagler was a very nice, and compact eyepiece, depending upon your mount it may balance better than the Delos, although the Delos probably has a slight edge in performance.

EDIT Having re read your post, I also have a Tak Prism and do think the T6 Nagler would be better in it.

The Delites look good too but I don't think there are any in that focal length?

[astro_al]

Thanks Stu.

Good to get some info on the Delos. I have experience with Naglers but Delos and DeLite EPs came in while I was away from the hobby.

Al

[Stu]

3 minutes ago, astro_al said:

Thanks Stu.

Good to get some info on the Delos. I have experience with Naglers but Delos and DeLite EPs came in while I was away from the hobby.

Al

General consensus is that they and the XWs are about on a level. I've not used Delites but they are basically same performance as delis but narrower fov and more compact. Cheaper too!

I did also try a 3.7 Ethos SX. Superb views, I think 3.7mm is the perfect focal length for the 76 but I found myself too often looking at my eyelashes rather than the target. Eye relief a little short and I found the afov too big if anything.

[astro_al]

Looks from the Televue website that a 3mm and 4mm DeLite have just been released. I guess these are the replacement/upgrade to the Radians.

[nightfisher]

There is a Vixen SLV 2.5 in the classifieds on here at a rather tempting price

[Stu]

3 minutes ago, astro_al said:

Looks from the Televue website that a 3mm and 4mm DeLite have just been released. I guess these are the replacement/upgrade to the Radians.

That's good. Well worth considering except that the afov is a fair amount less than the Nagler, depends how much nudging you want to avoid!

[iPeace]

My INED70 won't measure up to a Tak or a TV76 (at least this is my assumption), but I have used the 3.5mm T6 Nagler, the 3-6 Nagler Zoom and the 3.7mm Ethos with it. They all worked very well indeed. I did have a slight preference for the Zoom over the T6 which I never could fully rationalize, but there you are. The Ethos came later, and has superseded the Zoom but for size, weight and, well, zoom! I have only ever used the Ethos with its 2" skirt and am so used to it that I am not sure I would be inclined to use it in a 1.25" diagonal - it's no small thing.

Nowadays, there's the DeLite in 3, 4 and 5mm. I'm curious about them, but still keep my Zoom.

[iPeace]

In fact, I liked my 3-6 Zoom so much that I got one of the last available new 2-4 Zooms as well.

[astro_al]

4 minutes ago, iPeace said:

Nowadays, there's the DeLite in 3, 4 and 5mm. I'm curious about them, but still keep my Zoom.

Thanks iPeace. I think I would probably favour the zoom over the Delite also. The convenience and the performance of the zoom was very good and the jump in AFOV moving to a DeLite is probably not worth it for me. I think it looks like the Nagler 3.5mm may be the best option.

Al

[Stu]

1 minute ago, iPeace said:

In fact, I liked my 3-6 Zoom so much that I got one of the last available new 2-4 Zooms as well.

I'm sure the 2 to 4 is a great little eyepiece, but I always found the 76 had just about run its course by around 3.5mm, sometimes a little higher, so no red for more temptation  

The 2 to 4 makes perfect sense in the Televue NP101 type scopes I think, short focal length with an aperture which can take the power, and needs a 2mm to get there.

I'm sure it's fun in the 120ED when conditions allow though.

[iPeace]

1 minute ago, Stu said:

I'm sure the 2 to 4 is a great little eyepiece, but I always found the 76 had just about run its course by around 3.5mm, sometimes a little higher, so no red for more temptation  

The 2 to 4 makes perfect sense in the Televue NP101 type scopes I think, short focal length with an aperture which can take the power, and needs a 2mm to get there.

I'm sure it's fun in the 120ED when conditions allow though.

Certainly, the 2-4 Zoom is a specialist, meant for splitting doubles with the biggun. Doesn't get much use, but it doesn't get in the way, either, tucked away in the EP case, and I probably won't ever find another so it stays.

 

[astro_al]

16 minutes ago, nightfisher said:

There is a Vixen SLV 2.5 in the classifieds on here at a rather tempting price

Thanks Jules, but I think that could be too much power for my aperture. May be OK for lunar though.

Al

[Louis D]

I use a 3.5mm Pentax XW in my AT72ED occasionally.  The view seems sharp across the field with great contrast, but the floaters in my observing eye become really bothersome at 0.6mm for me, so I don't use it nearly as much as my 5.2mm Pentax XL.  It is a long eyepiece, so you want to make sure you have a sturdy diagonal with that one.  I use my 2" diagonal with it although I think my 1.25" would also handle it since it handles my binoviewers just fine.

[Stu]

14 minutes ago, Louis D said:

I use a 3.5mm Pentax XW in my AT72ED occasionally.  The view seems sharp across the field with great contrast, but the floaters in my observing eye become really bothersome at 0.6mm for me, so I don't use it nearly as much as my 5.2mm Pentax XL.  It is a long eyepiece, so you want to make sure you have a sturdy diagonal with that one.  I use my 2" diagonal with it although I think my 1.25" would also handle it since it handles my binoviewers just fine.

Floaters are a very valid comment Louis. I can handle them down to about 0.5mm, but even then then are distracting, especially for planetary viewing. I have one right in the middle of my observing eye which I have to do my best to look around.

I guess the OP has used the nag zoom down to these levels (3mm)and feels ok with them though, so should be ok at 3.5mm focal length.

[John]

My high power eyepieces are Pentax XW 5mm and 3.5mm, Ethos SX 4.7mm and 3.7mm and the Nagler 2-4mm zoom for good measure. They all perform excellently but I start to have issues with floaters at around 3mm and find them distracting at 2.5mm and shorter.

I find that I use the Ethos SX's in their 1.25" mode more than with their 2" skirts on. They are tall eyepieces but actually not a lot larger or heavier than the XW 5 and 3.5.

 

[Louis D]

25 minutes ago, Stu said:

I have one right in the middle of my observing eye which I have to do my best to look around.

I find that if I rapidly flick my eye to the side (or up or down), I'll get a second or so of clear vision before the floater drifts back into the center.  Annoying.

[Stu]

18 minutes ago, John said:

My high power eyepieces are Pentax XW 5mm and 3.5mm, Ethos SX 4.7mm and 3.7mm and the Nagler 2-4mm zoom for good measure. They all perform excellently but I start to have issues with floaters at around 3mm and find them distracting at 2.5mm and shorter.

I find that I use the Ethos SX's in their 1.25" mode more than with their 2" skirts on. They are tall eyepieces but actually not a lot larger or heavier than the XW 5 and 3.5.

 

That sounds like exit pupils of 0.4mm and below (assuming your 120ED John), which is probably better than most! Your eyes must be pretty good still then  

[scarp15]

I have a TeleVue 76, F6.3, which has seen various ownership including one time I believe Stu. I would like to include one day a DeLite 4mm to provide x120, I also use a 5mmXW. This recent addition focal length is listed on Telescope House but stocks are not I expect as yet available.

[Stu]

1 hour ago, scarp15 said:

I have a TeleVue 76, F6.3, which has seen various ownership including one time I believe Stu. I would like to include one day a DeLite 4mm to provide x120, I also use a 5mmXW. This recent addition focal length is listed on Telescope House but stocks are not I expect as yet available.

Nice to know it is still in good hands, it is a lovely scope  

[Highburymark]

I'm putting together some lightweight eps for my 4" Tak - Already have a Nagler 3-6 but want some wider options - it's between Delite 4mm (nice, pricey, bit narrow), Nagler 3.5 (nice, very pricey, bit too much power), ES 82 4.7mm (nice, not quite enough power), and SW Nirvana 4mm (great value, 82 degrees, same as William Optics costing almost twice the price). 

[John]

I'd get the very best optically that I could for the Tak. The ones you list are very nice but I suspect the Delite is the best in pure optical performance terms.

I didn't think I'd use my Nagler 2-4mm zoom much with my 900mm FL Tak but it's in the diagonal very often. These darn Taks can soak up power like anything

 

[Stu]

6 hours ago, Highburymark said:

I'm putting together some lightweight eps for my 4" Tak - Already have a Nagler 3-6 but want some wider options - it's between Delite 4mm (nice, pricey, bit narrow), Nagler 3.5 (nice, very pricey, bit too much power), ES 82 4.7mm (nice, not quite enough power), and SW Nirvana 4mm (great value, 82 degrees, same as William Optics costing almost twice the price). 

I would agree with John, Delite if you can live with the afov, Delos or Pentax XW if they are not too big, otherwise Nagler 3.5 t6 might just be the best compromise; such a lovely compact eyepiece, always surprised me how they squeezed 82 degrees into it!

[astro_al]

1 hour ago, Stu said:

Delite if you can live with the afov, Delos or Pentax XW if they are not too big, otherwise Nagler 3.5 t6 might just be the best compromise.

Sums it up nicely!

[Highburymark]

14 hours ago, Stu said:

I would agree with John, Delite if you can live with the afov, Delos or Pentax XW if they are not too big, otherwise Nagler 3.5 t6 might just be the best compromise; such a lovely compact eyepiece, always surprised me how they squeezed 82 degrees into it!

Thanks chaps - appreciate the advice