First eyepiece upgrade - what you wish you had done

[DRT]

Interesting choice. The 40mm does not show any more sky than the 32mm - is there another reason that you have chosen that as well ?

Do you remember me mentioning the nice bottle of claret?

More seriously, after using the 11mm I decided to collect all of the 1.25" TV Plossls to put in a small case to accompany the small refractor I plan to buy sometime soon as a travel scope. I refer you to the obsession described in my first post in this thread!

I hadn't realised about the FOV issue with the 32/40. If it turns out I don't need both someone might be getting a cheap low power TV Plossl soon.

[John]

Oh, I see 

The 40mm is just as well made as the others of course but it's apparent field of view is 43 degrees rather than the 50 degrees that the rest of the range have. It's also not par-focal with the other TV plossls as I recall. I did the same a few years back you see - to complete the set !

[Owmuchonomy]

Interesting choice. The 40mm does not show any more sky than the 32mm - is there another reason that you have chosen that as well ?

Not certain but I believe the 40mm is pitched purely at spectacle wearers due to its long eye relief.

[John]

Not certain but I believe the 40mm is pitched purely at spectacle wearers due to its long eye relief.

Yes, thats my understanding too. 

[DRT]

Good info - thanks. I'll contact TH and try to swap for something else.

[RikM]

The 40mm is good for afocal lunar imaging as well.

[michael.h.f.wilkinson]

Not certain but I believe the 40mm is pitched purely at spectacle wearers due to its long eye relief.

The 40mm should have about 30mm eye relief, which I find uncomfortable (sold my 36mm Plossl for that reason). Your glasses need to hover at a large distance from the eye lens, which makes it hard to position the eye properly. A 25-32mm Plossl is fine for people with glasses, a 20mm OK. Anything well outside that range is awkward, I find. I think the 40mm would be most useful in non-modded SCTs (i.e. with just a 1.25" back end) to get to 4mm exit pupil (handy for some objects). I also used my 36mm for EP projection for lunar imaging, so the 40mm would suit as well.

[michael.h.f.wilkinson]

...

All my BST's cost me about £280 - just bought the new 3.2mm - and I have read of people wanting 1 "significant" eyepiece for more then that, and I have to wonder why.

Everybody must make up their own mind on this, of course. People have made great observations with kit that would not sell today, and my Plossls gave me much joy for many years. I do not go for sets very much, but I find 70-82 deg nicer than 60. I have simply used the rule to upgrade when I feel a piece of kit is limiting me, i.e. when I start seeing its limitations. Buying second hand helps keeping costs down too.

[russ.will]

Questions:

1. Where would you buy your eyepiece and why?

Second hand if you have the patience, but buying from America once the UK/EU price is north of £150, means you can land a new EP for near second hand money.

2. What is the first eyepiece you would have bought and why?

A really good SWA (68-72deg) rather than faffing with mid-market upgrades (BSTs, Panaviews, X-Cels, Hyperions, etc) and wasting yet more money later on massive UWAs.

For instance, the BST/Starguiders are a good upgrade over the stock EPs and a solid recommendation because of it. But they will not be your last EP and by the time you've lost £15 on each one (assuming you bought new) a year later - and anybody in this hobby for more than a year, WILL flog them a year later - You may as well just get second hand Meade Series 5000 SWAs or SW Nirvanas in the first place.

Maxvision have currently made this phase of EP buying simultaneously easier and a lot harder. Easier because they kick the butts of the regular budget recommendations. Harder because they've made a noticeable jump in quality at upgrade time a lot more expensive!

Next and this is very much down to personal preference, target preferences and scopes owned; I personally don't find the extra UWA FOV that much of an advantage - as opposed to the jump from 55/60 deg to 70deg which is - because you can't see a lot of that extra AFOV without snapping your eyeball tendons. The other point worth noting, is that staying SWA means you get up to 24mm in a 1.25" EP which is smaller, lighter and possibly sharper than it's UWA equivalent. You also use an EP a lot more when you don't have to faff with 2-1.25" adaptors and especially re-balancing the scope which is a real waste of time.

Focal length would be (again assuming typical first time scopes that you listed) probably something in the 11-15mm, or should I say 100x range. That is as opposed to the usual n00b mistake we all made of buying a either a very short FL for maximum magnification (hardly ever used) or a very long EP (because everybody is supposed to have a massive EP right?) shortly followed by frantic Googling of Coma correctors and/or counterbalance weights. 

Just my 2p, based on my own personal 'journey' of owning 27* EPs to date, so it is by no means exhaustive!

Russell

*If you meet my wife, it's 6 EPs to date. Clear?

[Myopicus]

Having just ordered the Baader Zoom and Barlow (and a SW RACI finder) i'm really glad I've read this thread. PHEW!!

Can't wait!

[Caldwell14]

A great thread may I say, Me if I had my time all over again, I would in all honesty have started off with a SW Skyliner Dobsonian, a 200p more than likely, I have spent quite a lot of money chasing optical perfection with APO refractors , they are indeed very good, especially during these summer months.

As for eyepieces green is gold, TeleVue all the way. You don't however have to pay a fortune for quality. If you can live without an ultra wide field of view their is nothing, and I am happy to be challenged here, nothing of a higher optical quality that a TeleVue Plossl, available second hand for a mere 50 quid a pop. Their are tons of eps out their that are really good ep, Celestron have X-Cel XL. BST explorer are ace, amazing for the money, really amazing. With respect the fore mention eyepieces are part of the journey, I have owned both, a TeleVue may very well be for life.

[Joves]

The 40mm should have about 30mm eye relief, which I find uncomfortable (sold my 36mm Plossl for that reason). Your glasses need to hover at a large distance from the eye lens, which makes it hard to position the eye properly. A 25-32mm Plossl is fine for people with glasses, a 20mm OK. Anything well outside that range is awkward, I find. I think the 40mm would be most useful in non-modded SCTs (i.e. with just a 1.25" back end) to get to 4mm exit pupil (handy for some objects). I also used my 36mm for EP projection for lunar imaging, so the 40mm would suit as well.

I completely agree, Michael. I just purchased a 32mm Plossl to use in my Quark, as it is apparently the best performing EP in this application. I must say, the abundance of eye relief was quite a surprise and, to be honest, plain uncomfortable. I haven't used it at night (and probably won't bother doing other than purely to see how it performs, as I have better eyepieces), but I found having to keep my eye hovering over the eyepiece in the light of day whilst viewing the sun to be quite counterproductive. I can only imagine what the 40mm is like. Will not be purchasing that one, that's for sure. My Vixen LV 25mm EP is a lot more comfortable for my needs.

[John]

The long eye relief of longer focal length plossls should be expected as the plossl design (as in the orthoscopic) dictates eye relief will be 70%-80% of the focal length. What makes them comfortable (or not) is the approach the manufacturer takes to the provision and positioning of the eye cup in relation to the position of the top surface of the eye lens.

The older "smooth side" designs without an eye cup and with the eye lens right at the top of the eye piece body can be difficult to use as there is no guide to positioning your eye - you have to basically "hover" over the eye lens which can be tiring and tricky to maintain.

Vixen use a twist up eye cup and a recessed eye lens in their NPL plossls and that I've found makes the 30mm in that range comfortable and easy to use. With the eye cup twisted up I just rest my eye socket gently against the soft rubber around the eye cup and, voila, the field of view is fully visible with no black outs or other such issues.

Thats my only gripe with the Astro Hutech and Fujiyama 25mm orthoscopics - the eye lens is right at the top of the body, the eye relief is 22.2mm and "hovering" is required !

Ergonomics in eyepiece design do count as well as optical prowess in my opinion     

[Moonshane]

I completely agree, Michael. I just purchased a 32mm Plossl to use in my Quark, as it is apparently the best performing EP in this application. I must say, the abundance of eye relief was quite a surprise and, to be honest, plain uncomfortable. I haven't used it at night (and probably won't bother doing other than purely to see how it performs, as I have better eyepieces), but I found having to keep my eye hovering over the eyepiece in the light of day whilst viewing the sun to be quite counterproductive. I can only imagine what the 40mm is like. Will not be purchasing that one, that's for sure. My Vixen LV 25mm EP is a lot more comfortable for my needs.

you could always get one (or even two) of these http://www.televue.com/engine/TV3b_page.asp?id=158#.U6_6EMtOWP8

I made a small tube of neoprene foam which does the same sort of job. 

[YKSE]

The long eye relief of longer focal length plossls should be expected as the plossl design (as in the orthoscopic) dictates eye relief will be 70%-80% of the focal length. What makes them comfortable (or not) is the approach the manufacturer takes to the provision and positioning of the eye cup in relation to the position of the top surface of the eye lens.

The older "smooth side" designs without an eye cup and with the eye lens right at the top of the eye piece body can be difficult to use as there is no guide to positioning your eye - you have to basically "hover" over the eye lens which can be tiring and tricky to maintain.

Vixen use a twist up eye cup and a recessed eye lens in their NPL plossls and that I've found makes the 30mm in that range comfortable and easy to use. With the eye cup twisted up I just rest my eye socket gently against the soft rubber around the eye cup and, voila, the field of view is fully visible with no black outs or other such issues.

Thats my only gripe with the Astro Hutech and Fujiyama 25mm orthoscopics - the eye lens is right at the top of the body, the eye relief is 22.2mm and "hovering" is required !

Ergonomics in eyepiece design do count as well as optical prowess in my opinion     

Excellent general information about plössls and orthos for beginners to consider with their first uppgrade.

[Joves]

you could always get one (or even two) of these http://www.televue.com/engine/TV3b_page.asp?id=158#.U6_6EMtOWP8

I made a small tube of neoprene foam which does the same sort of job.

That is excellent, thanks mate. I'll definitely get one of these. With shorter eye relief, I think the 32mm Plossl will be a very nice eyepiece.