Looking for a good 3mm

[rowan46]

I have a 80/480 refractor and I am looking for a good 3mm with a decent eye relief and fairly wide field as its an undriven mount. I am hoping to take it up to the scopes theoretical max. This will be used mainly on planets. I will at some point be getting a 3.5mm pentax for high power dso work. Any suggestions?

[John]

There is a 3mm in the William Optics SPL range. They seem to get good feedback on here. Pushing the boat out a bit more (quite a bit !) there is the 3mm Tele Vue Radian.

An alternative suggestion altogether would be the Tele Vue Nagler zoom 3-6mm or even the 2-4mm. The field of view is just 50 degrees but they are superb quality and replace a number of high power eyepieces.

[E621Keith]

A 3mm Radian will go well with your scope. I used one with my 80/480 for planets. Sharp, 60deg AFOV, 20mm eye relief.

They are about £100 used.

[Ben Ritchie]

Budget?

The 3mm Radian springs to mind, the AFOV isn't huge but reasonable, eye relief is good, and planetary performance is good too. The WO SPL 3mm is a decent enough budget option too, and again has good eye relief.

[Ben Ritchie]

Aha, see Keith and John beat me to it

Definitely would second the Nagler zoom option, hugely flexible eyepieces for max-power work, although eye relief is a bit tight compared to the other options mentioned

[rowan46]

Would a powermated 6mm delos give a better view?

[RikM]

I have just this evening been given a 3.5mm Hyperion. I had a quick look at the Saturn with it in the Pronto. The planet was a good size at 128x but there was no detail visible beyond a slightly yellow disc and rings. Don't know if that was the night or the eyepiece or 128x just too much for a 70mm scope. Will try it out on the moon in a week or so but comfortable eyerelief and 68° field and you can unscrew the barlow bit to get a 2" fit 21mm Going to try that for public observing evenings.

[rowan46]

I used to like hyperions until you introduced me to delos and xw

[RikM]

I used to like hyperions until you introduced me to delos and xw

If it's clear tonight I will do a side-by-side (or at least one-by-one) 10mm XW + 2.5x TV Barlow | 3.5mm Hyperion | 7mm XW + 2.5x TV Barlow. That is equivalent 4.0 | 3.5 | 2.8mm, so still quite significant differences, but it might show if the Hyperion is way out of sequence i.e. if the 7mm + Barlow beats it!

[alan potts]

Though I have never had this one for me the 3mm Radian is one of the few in the frame or with a little less magnification either the 3.5mm Pentax XW or the Delos. I don't think any will disappoint.

Alan.

[John]

Would a powermated 6mm delos give a better view?

I've been using my 6mm Ethos with a 2x Powermate occasionally and it works very well if your focuser can handle the sheer size and weight of the resulting combination. The 6mm Delos weighs just a touch more than the 6mm Ethos I think.

[Stu]

The PowerMate is an amazing bit of kit. I was trying my new to me 6mm BGO in mine last night and it doesn't degrade the image at all, it's just like using a 3mm BGO, eye relief tight but quite manageable.

Stu

[alan potts]

Stu,

Very pleased to hear that it was something that I was wondering.

Alan.

[Schorhr]

I have used the 2.5 & 3.2mm planetary (58 deg afov, 40gbp) and they are great for the price... Though a 6mm+66deg+barlow wold cost the same and work fine, too, plus gives more flexibiity. If you are able to spend more, go for the Hyperion instead. Sharp, wide angle ep.

[alan potts]

Not that I think the Hyperion is a bad eyepiece but for me they don't deliver in fast scopes. The original questioner was thinking of a Pentax 3.5mm XW as a purchase at a later date, there is some difference in the performance of these two at around F 6. I also do not believe Baader still do a 3.5mm Hyperion, it seems to have been withdrawn, then there is a 5mm and an 8mm.

Alan.

[RikM]

Not that I think the Hyperion is a bad eyepiece but for me they don't deliver in fast scopes. The original questioner was thinking of a Pentax 3.5mm XW as a purchase at a later date, there is some difference in the performance of these two at around F 6. I also do not believe Baader still do a 3.5mm Hyperion, it seems to have been withdrawn, then there is a 5mm and an 8mm.

Alan.

I had a very quick, literally 5min, with it last night between clouds in the f/4.7. At 3.5mm it was actually better than I expected. Way too much magnification for a still warm 10" Newt but I think it could be ok. With the barlow element removed it was quite unusable. Not just poor or bad...quite impossible to use. Apart from the middle 15-20% the stars were all streaks and lines or wedge shapes, anything but round.

Still, at 3.5mm it might well have a use and it was a gift, so I can't complain can I ? I will still compare to the more expensive glass as the gaps in the cloud closed up completely in the 1min it took to pop into the house and grab my EP case.

[Stu]

Just as an observation, I find 3.5mm far more useable in both TV76 ( which is 480mm fl) and Astrotech 106 (690mm fl) than 3mm. It seems to deliver maximum useable power far more often. I rarely use my nag zoom at 3mm so have a 3.5t6 nag as a dedicated high power ep.

Ultimately a 3.5mm Delos, or perhaps if my numbers come up, a 3.7 Ethos SX would be ideal.

Stu

[alan potts]

Stu,

I guess if we are talking icing on the cake here we are really only left with the two you mention and I would have thought the Pentax 3.5 XW. I have been having sleepless night wondering whether to get one while I am here and still can't make up my mind. I could also Powermate to this with the 7mm Nagler

I think the thing that is throwing the spanner for me is it will be used on the APO mainly giving about X230 and I am really troubled as to if it will get enough use given the magnification and the fact I have the same Nagler zoom as you. They also don't come free with Cornflakes.

Alan

[rowan46]

I already have a 7mm xw which I could powermate but with a theoretical maximum of 160x I would like a 3mm. As you know with a faster smaller scope all the really useful magnification is done at the top end. I have a 24mm as a finder really, although it seems quite good on open clusters. A 12mm delos for low power, A 7mm xw gives me a high low power and a 4.7mm es 82 for higher power. I was thinking of a teleextender for the 7mm and something for that last little bit. My thinking is that I am pushing at the boundaries of what is possible on my scope and better glass is more likely to achieve it than something not so good. Or is 160x on a triplet apo 80/480 only theoretically possible.

[RikM]

I have used my 7mm XW plus a 2.5 TV Barlow on the Pronto (70/450mm) but the 10mm XW + 2.5 gets a lot more use.

[Stu]

I would think x160 is usable on a triplet when well cooled and seeing is good. I been using x137 (3.5t6) on my 76mm and it would probably take more under good conditions. I keep struggling to get decent views of Saturn and then realise it is still very low, and I'm often observing over houses and central heating flues.

Stu

[Deano1]

Someone mentioned the WO SPL 3mm, I've got one. I've never looked through a top of the range Tele vue or anything, but seems great to me, especially for the money. Nice build quality. I'd like to have a look through a Delos or something just to see the difference.

[alan potts]

I think if you have a powermate and a 7 mm XW then I would use these to get to 3.5mm. I do this at the moment with a 7mm Nagler, though now you have the gifted 3.5mm Hyperion.

I have thought very long and hard about either a Delos or Pentax XW for this slot but my magnification is much higher and used less, so far I have resisted. I still think that the 3mm Radian is about the only eyepiece at the same quality level to do the job you are asking. I use a 4mm Radian which gives me X202 in my APO and I have to say that is performs very well indeed, as does the 5mm Radian, I have no reason to believe the 3mm will let the side down.

The other thing you could do is buy a 6mm Delos and powermate that, the results are nothing short of stunning, sadly mine was not shock proof but no doubt died to save the APO as it fell from the mount, how many eyepieces can do that!

Alan.

[RikM]

I had a bit better compare with the eyepices in the TV Pronto last night. The 3.5mm Hyperion is totally outclassed by the Pentax / TV Barlow combinations. I looked at the thin crescent moon, Saturn and a couple of double stars. The edge correction was loads better in the fancy glass, sharp right out to the edge but the Hyperion started showing quite obvious astigmatism in the outer 15% of the view. The light throughput wasn't as high as the 7mm XW + 2.5x (2.8mm equivalent) so although the magnification was quite a bit higher, the image wasn't much dimmer with the barlowed XW. If you are going to get a 3.5mm Delos or XW anyway, then I would go for a 2.5x Powermate if you want that little bit extra. Could also be used with your 12mm Delos to give you 4.8mm so you might be able to ditch the 4.7mm EP.

[rowan46]

Someone mentioned the WO SPL 3mm, I've got one. I've never looked through a top of the range Tele vue or anything, but seems great to me, especially for the money. Nice build quality. I'd like to have a look through a Delos or something just to see the difference.

You really don't. I was like you, happy with what I had got then RickM showed me his delos and xw's at a star party leaving me with this unsatisfying itch that I had to scratch. Once you look through alpha glass you realise how second rate the rest truly is compared to it. I have 2 es 82 eyepieces which everybody tells me are excellent eyepieces but the delos and xw totally outclass them. That's the problem with star parties somebody has always got something better and you come away with this feeling of I want. God I wish I was as rich as Alan Potts