Moving away from stock eyepieces for an 8 inch dobsonian

[alex1978]

Hi everyone, I could really do with some advice...

The time has come to move away from the stock eyepieces that came with my dob (8 inch Skywatcher 200p - 1200mm f5.9) . I sort of thought this would be relatively easy but as I research deeper into the eyepiece world, I seem to be more and more confused by the whole shebang! 

The second I started reading into exit pupils, apparent field of view, true field of view etc, it all began to be a little less clear. The theory is pretty sound in my mind but without any practical experience at looking through eyepieces other than my stock ones, I can’t really put any of that theory into meaningful experience. 

I bought an Orion Epic ED-2 3.7mm eyepiece a few years ago, my only foray into buying a better ep apart from a cheap 6.7mm plossl, and I have to say, it really put me off! It was horrid - I could’t really see anything through it. Seemed so narrow and dark. Now I’m sure it was utterly unsuitable for my scope, but that is where my confusion is coming from. Why?! 

So primarily I’m after something for higher magnification viewing. Budget would be around £100. It would make sense to get something that can be barlowed easily (and to that end, I will need a barlow as well). So maybe a 12mm or something around 9mm. 

At the higher end of budget, I’ve been looking at the Explorer 82 degree eyepieces and the lower end the BST Starguiders. Reading the reviews, the BST’s sound really great, but is the afov of an Explorer 82 going to be more fun to look through? I like the idea of immersive viewing but is that even possible on high magnification?

Any advice would be hugely appreciated as I’m going around in circles (circles of confusion - bad pun)! 

(Sorry to post this as I realise there are some very similar posts on this forum, but finding very specific answers has been hard and I want to try and get this right first time!)

 

[Gazabone]

Best advice is to try a few out if you have friends or a local Astro club/society you can link in with. My personal opinion is that you're doing the right thing to upgrade from stock ep. I'll never forget the first time I looked through a 2" ep, it really felt like I was falling into the scope. 

Again, purely personal recommendation; firstly my preference is the Baadar Hyperion range and I do 85% at least of my observing with the 24mm. Although I have a 16mm nagler which I love as well. A Hyperion is around your £100 budget though and would be my first choice. 

Happy viewing ??

[Littleguy80]

I have an 8mm Starguider that barlows well. It's a good step up from stock eyepieces. For planetary viewing, I also use a 6mm orthoscopic eyepiece which has 40 degree AFOV. I found lots of recommendations for sticking to a smaller AFOV for planetary viewing as it's the planet and any moons that are the focus of you're viewing. 

I think you benefit more from the widefield eyepieces at lower magnifications.  I have one of the 68 degree Explore Scientific eyepieces but that's a 24mm which is great.

The Starguiders are a good starting point as they're relatively inexpensive for a nice eyepiece. Start with 1 or 2 eyepieces and then see where you feel you're missing out

 

[darknight]

you know, i think you can’t beat the clestron x cell ones, excellent value, huge eye relief and very clear optics, and for the price you can’t go wrong

[rockystar]

I have the ES82 24mm and think it is a great EP, and if didn't already have a couple of Morpheus EPs, than I would get more from the ES82 range. If you are looking for higher power, then I would see if you can get an 8.8mm in that range. I have the same scope as you and my highest power is a 6.5mm which doesn't get a lot of use, and I feel I'm missing something in the 9mm range. My second choice would be a 14mm - my 14mm gets a lot of time in the scope, and this will barlow to (effectively) a 7mm.

I know what LittleGuy is saying about keeping the AFOV narrow for planets, but as you have a DOB you will really benefit from a wide EP and not having to nudge as often.

[alex1978]

Amazing, thanks so much everyone. I think what you say is right, Gazabone, about looking for an astro club - to get some real, first hand experience of the different ep's out there would be great. 

Thanks Darknight - I hadn't even looked at the Celestrons! Will look into them. 

Littleguy80, great to hear some good things on the BST's - they really sound like very good value for money and got me very tempted.

I think what Rockystar mentions about going for the wide afov kind of hits the nail on the head for me - I really quite like the idea of a more immersive experience (although yet to actually see what that's like first hand through a higher mag ep)! Sounds like the 14mm ES82 might be the way to go with a barlow.

[Buzzard75]

I am by no means an expert, but I was going through this same thing recently. I needed to replace the Plossl that came with my scope for something that didn't have a reticle in it. This is what I've learned. Let's start by looking at your scope and your eyepiece combination. You have an 8" (203.2mm) apperture and a focal length of 1200mm. Your focal ratio is 1200/203.2 or f/5.9, as you said. The eyepiece you're using has a 3.7mm focal length with an apparent field of view (AFOV) of 55deg. Your magnification with that eyepiece is roughly 324x. Your theoretical limit of useful magnification is your apperture (8") multiplied by 50, or 400x. While your eyepiece falls into that theoretical range, it's unlikely it will actually be useful based on seeing conditions. If you're blessed with excellent seeing conditions, you may be able to push your magnification to 250-300x. Your exit pupil is your apperture divided by your magnification, or 203.2/324= .63mm. That is an extremely tiny exit pupil. Once you get below 1mm exit pupil, you may start to see floaters and other junk in your eyeball fluid. Combine the tiny exit pupil with the small AFOV and you're just asking for a bad time.

What I decided to do was aim for something just below or close to half of my theoretical limit. I also knew I wanted something that had an exit pupil of 1mm or slightly larger. I have a 12" scope so my theoretical limit is 600x. I have no preconceived notions that I will be able to get anything close to that on any given night. Half of that though happens to be in that 300x range. At 300x my exit pupil would also be just a hair above 1mm. My focal length is 1500mm. So essentially I would be looking for something in the 5mm (1500/300) range. Rather than buying a 5mm eyepiece though, I decided to purchase a 2x Barlow so I could get some extra use out of some other eyepieces. So instead of a 5mm, I started looking for a 10mm. I also knew I wanted something that gave me some excellent eye relief so I didn't feel like my eyelashes were cleaning the lens. That and I have a few family members who were glasses, as do I from time to time. I also wanted something with an AFOV of 68 or larger to take in a bit more of the scenery around the objects I was looking at. I landed squarely on a Tele Vue Delos 10mm.

Using what I've just described for myself, you could do the same analysis. If you go to about half of your theoretical, you're looking at about 200x, which would also give you an exit pupil of just above 1mm. This would put you in the neighborhood of about a 6mm eyepiece. From there you need to determine if you want to just use a straight eyepiece or if you want to Barlow to get that low. You also need to determine how much eye relief you need and what sort of AFOV you want.

[vlaiv]

I have same scope, and my preference so far was: 32mm - finder/widefield, 17mm best for faint DSO based on my LP / exit pupil, 12mm as a secondary DSO with more mag, 7mm for planets / planetary nebula / trapezium and those object that require high mag. 25mm and 10mm never saw any use really (10mm was really crappy one, so 12mm GSO was used all of the time for this mag range).

6mm exclusively for planets. But most of my eyepieces are bad, with exception of 6mm BCO and 7mm TMB II clone (58 deg AFOV), which are fairly good but not top. Other include mix of GSO / SW plossls (interestingly enough they all show about same level of performance - 50% of field onward astigmatism sets in getting progressively worse at F/6 - edge is a real mess). So I'm in process of getting my collection of eyepieces "in order". I have couple of scopes, but this selection that I came up with, I tried to match to all of them - hence they will be matched to 8" f/6 dob as well:

3-6mm TV Nagler zoom (planets)

I might keep 6mm BCO for a while to compare to new eyepieces

7mm Delite (planets / planetary nebulae, some globulars)

11mm ES 82 (general high power DSO, and to try out big AFOV - never had a chance to go that wide )

18.2mm Delite (general lower power DSO)

24mm ES68 (widefield / finder)

And maybe, at some point I'll add 28mm ES68 for really wide field. I would also like to try out something in 14mm range with large AFOV (like Morpheus, but need more reviews to decide).

Now I'm aware that my lineup might not suit you in terms of quality / price, but I listed it just as a guideline into range of focal lengths that I use and plan to use, hope that helps a bit.

[Richard Hather]

Hi Alex if you are going to go with a ES14mm 82D there's one on the buying/selling thread here's the link 

My advice would be ES are good quality and the bigger FOV is brilliant.

Always by second hand as and when the eps come up and Barlow for that matter I've saved £100s this ?

Richard 

[alex1978]

Such a great forum - thanks everyone, incredible advice!

Buzzard75, amazing - thank you. That really helps to understand why that 3.7mm was such a disaster! Yours is a great formula to try and work out what I might need. Much like you, the idea of going for a wide afov is very appealing. I like the idea of a bit of scenery around what I'm looking at. 

Vlaiv - awesome list, thank you! I've actually also got my eye on the 32mm Skywatcher Panaview for a really wide field ep. It's great to hear from people with the same scope. I love it and am very looking forward to seeing what it's capable of beyond the stock ep's. Your list of potential ep's sounds good and pretty varied. It's a minefield out there with the options available! 

Richard, thanks so much for that link - I'll follow up on that. The barlow idea sounds almost too good to be true really. 2 eyepieces for the price of one! 

[Charic]

The BST Starguiders work very well, I have a 6mm William Optic in place of the non-existant Starguider, and the 32mm Sky-Watcher Panaview in 2" fitting. These all work very well for me, but most importantly, their comfortable and affordable. I've had more expensive glass in my system, with no improvement  over image quality, but the field of view differed, but I have found a liking for around the 60° mark.

Today, the minimum I would keep is the 8mm and 12mm Starguider and the Panaview, and a Barlow for the SG's.  I have a Plössl set too, was always going to get one, but did not acquire the intended Meade set? and the Revelations are very much cheaper than my Starguiders, and have 8° less afov. Their better value than other expensive Plössl's I have tried, and just as good if not better on some targets, with better eye-relief and afov. Don't discount them, their very good if your after a Plössl.

 

[alex1978]

Thanks Charic - interesting to hear more good things on the BST's. They really do sound like great value for money - I think it all comes down to afov now between them and the ES82. How do you find the 32mm Panaview with the 200p? 

[Charic]

23 minutes ago, Buzzard75 said:

I also wanted something with an AFOV of 68 or larger to take in a bit more of the scenery around the objects I was looking at. I landed squarely on a Tele Vue Delos 10mm.

I chose a similar option, but found no image improvement, only the wider field of view,  and as I don't wear my glasses at the scope, even 20mm eye-relief can be a little too much ( might regret that one day) and on the lowly f/6 focal ratio, the Delos was not being optimised to its best, but If I had managed to find the faster scope back then, the 12" sky-liner  solid classic or even the 10" solid classic, things may have been so different. I needed to try  for myself, a Delos,  for the same reasons, folk saying how great Tele Vue brand is.  On certain scopes, you pay for the quality  and need the quality of a corrected eyepiece, and may reap some reward,  but for my f/6 thats a very expensive EP for a little extra field of view. On the said scope, f/6 skyliner, you'll notice the larger field with the Delos and the longer eye-relief, but image wise, I get just the same from a £49 EP over a £300+ eyepiece, but, unless folk try for them selves, they won't know.
The Tele Vue Delos ( I had the 6,8 &10 ) is a great eyepiece, but not needed/practical on my f/6. You could buy four new Starguiders for less than one secondhand Delos! They work very well, they cost very little, their available here https://www.firstlightoptics.com/bst-starguider-eyepieces/bst-starguider-60-12mm-ed-eyepiece.html or on eBay, where I originally bought mine, take your pick.

For the OP, sticking with the  telescopes aperture size in mm is a good indication of the scopes practical use, same as  choosing an eyepiece to match the focal ratio of the scope, giving the 1mm exit and practical magnification. That said, I recently viewed the Moon at 800x, not spectacular, but conditions allowed, but I honestly doubt I could view ANYTHING else up there at that power, let alone keep up with the movement?

[Charic]

26 minutes ago, alex1978 said:

How do you find the 32mm Panaview with the 200p? 

To see the Moon floating in a Sea of space is quite stunning, and sometimes when I'm in "lock-down" inside my Dob-tent, I won't have access to the finder scope, so in goes the 32mm, just great for searching the night sky. Not only that, M31 Andromeda fills the view when I'm away from home, but at home due to the pollution, M31 is a nothing to declare image? its there, just barely visible, the core most notable. Away from home, good conditions, mid Winter for me, M31 wow!

One of my guru's here ( he don't like that?) is @rwilkey......check this out, its this link and the advice here on SGL that got me to invest in my first Starguider the 8mm. http://www.swindonstargazers.com/beginners/eyepieces.htm I was also tempted to retail the Starguiders in the past, only wish I had now?

[alex1978]

1 minute ago, Charic said:

To see the Moon floating in a Sea of space is quite stunning, and sometimes when I'm in "lock-down" inside my Dob-tent, I won't have access to the finder scope, so in goes the 32mm, just great for searching the night sky. Not only that, M31 Andromeda fills the view when I'm away from home, but at home due to the pollution, M31 is a nothing to declare image? its there, just barely visible, the core most notable. Away from home, good conditions, mid Winter for me, M31 wow!

Ok, great to know! I am in the middle of light polluted London but do occasionally get out of town. I have a real love for Andromeda so might be worth scooping the 32mm up for those darker sky moments! Thanks for that. Also, good advice on the BST's  - I think I'm going to order up a couple of similar ep's around the same focal length, probably the BST and the ES82, and make a decision by actually looking through them and returning the one that doesn't come out on top! Only real way to understand what I might favour! 

[Buzzard75]

9 minutes ago, Charic said:

The Tele Vue Delos ( I had the 6,8 &10 ) is a great eyepiece, but not needed/practical on my f/6. You could buy four new Starguiders for less than one secondhand Delos! They work very well, they cost very little, their available here https://www.firstlightoptics.com/bst-starguider-eyepieces/bst-starguider-60-12mm-ed-eyepiece.html or on eBay, where I originally bought mine, take your pick.

For the OP, sticking with the  telescopes aperture size in mm is a good indication of the scopes practical use, same as  choosing an eyepiece to match the focal ratio of the scope, giving the 1mm exit and practical magnification. That said, I recently viewed the Moon at 800x, not spectacular, but conditions allowed, but I honestly doubt I could view ANYTHING else up there at that power, let alone keep up with the movement?

Agreed. I wasn't necessarily suggesting that Tele Vue was the only option. There are certainly a number of other brands and models available. I was just stating that after I narrowed everything down to what I wanted, the TV Delos 10mm was right smack in the middle of my sights and extremely hard to ignore.

And I think for those higher magnifications, the moon is the one exception since it's so close. You might get some waviness/distortion in the image, but you can see some pretty cool stuff.

[alex1978]

9 minutes ago, Charic said:

One of my guru's here ( he don't like that?) is @rwilkey......check this out, its this link and the advice here on SGL that got me to invest in my first Starguider the 8mm. http://www.swindonstargazers.com/beginners/eyepieces.htm I was also tempted to retail the Starguiders in the past, only wish I had now?

Great link - thanks! 

[Littleguy80]

10 minutes ago, Charic said:

One of my guru's here ( he don't like that?) is @rwilkey......check this out, its this link and the advice here on SGL that got me to invest in my first Starguider the 8mm. http://www.swindonstargazers.com/beginners/eyepieces.htm 

This was my starting point for looking into my first eyepiece upgrades. Fantastic amount of information and very well presented

[Charic]

14 minutes ago, alex1978 said:

..........make a decision by actually looking through them and returning the one that doesn't come out on top! Only real way to understand what I might favour! 

The eBay outlet offers just what your after, you still need to pay up-front, and any return postage.

Are you aware of these guys/gals........http://www.bakerstreetastro.org Central London is the place to be? I tried to visit last time I was in London, but back again this August maybe, have some folk to catch up with, members here at SGL? 

If you try and visit, get a peek through their equipment , may be a good excuse to try something your looking for, or even find something different that you've not discovered yet!

[Charic]

7 minutes ago, Buzzard75 said:

TV Delos 10mm was right smack in the middle of my sights and extremely hard to ignore.

With you all the way.
 

I liked the offer of 20mm fov, 72° afov and Dioptrx© what more could you want? sadly though, all gone, but one day I may regret the sell.

[alex1978]

3 minutes ago, Charic said:

The eBay outlet offers just what your after, you still need to pay up-front, and any return postage.

Are you aware of these guys/gals........http://www.bakerstreetastro.org Central London is the place to be? I tried to visit last time I was in London, but back again this August maybe, have some folk to catch up with maybe, members here at SGL? 

If you try and visit, get a peek through their equipment , may be a good excuse to try something your looking for, or even find something different that you've not discovered yet!

Ah yes, heard of them! Yet to go along to a gathering but am keen and will try to get to the next one. Would love to see some other options and that could well be the time to do it. Always wondered about binoviewers but that's a whole new ball game! 

[Charic]

For me now, so far North (57°) its the land of twilight, so less use, if any from the Skyliner, using mounted binoculars when conditions allow, even the main constellations are hard to find when the sky is so bright, come Winter time, can't think of better skies, apart from those just a short drive away 

[alex1978]

17 minutes ago, Charic said:

For me now, so far North (57°) its the land of twilight, so less use, if any from the Skyliner, using mounted binoculars when conditions allow, even the main constellations are hard to find when the sky is so bright, come Winter time, can't think of better skies, apart from those just a short drive away 

Those winter skies sound idillic - London, not so much! 

[John]

I'm giving a short talk to my astro society this evening on this very topic

Having tried and reported on many eyepieces I reckon the best upgrades to stock eyepieces that I've tried are (in cost order, low to higher):

- GSO / Revelation plossls (£25 each or even less used)

- Vixen NPL plossls (£35 each approx)

- Tele Vue Plossls (£45-£50 used. The 8mm and 11mm can seem tight on eye relief)

- BST Starguiders / Explorers (£49 each from First Light Optics)

- Baader Classic Orthos in the 6mm, 10mm or 18mm focal lengths (around £50 each)

- Maxvision 68 degrees wide angles (around £60 new or as low as £40 used)

- A Baader 8-24 zoom (Ok it's £180 but it's the equivalent of 3-4 good quality fixed focal length eyepieces)

The above are ones which, to me, give the best performance boost over the stock eyepieces per £ spent during the years that I've been testing eyepieces. There are many other options out there of course but I've personally tried the ones that I've listed so can vouch for those.

You can pay a lot more of course but the performance gains start to follow a law of diminishing returns. Not that small gains are not sought after and welcome - you only have to look at the "Show us your eyepiece case" thread to see that

https://stargazerslounge.com/topic/57027-show-me-your-eyepiece-cases/

 

[Charic]

Charic  said: One of my guru's here ( he don't like that?) is @rwilkey.

John too.....

As John says, in order of price, the GSO,Revelations ARE the cheapest, but don't let that detract the fact their still  very good, for the price, as are all the others if they suit you and your needs.
I have used but  discounted the Tele Vues, and  Baader's and some Meade's, not listed above.

There is one fact that's true, John would not know how good/bad these eyepieces were/are without trying himself,  the same for you and I, and although John is fortunate enough to have a pile of EP's to be testing for the rest of his Years, we will never know until your hands on, and looking through!
Yes its expensive buying, some folk have  even loaned me eyepieces ( thanks again, you know who you are ) but reports alone are only half the battle,  and so far, enjoying the fight,  and to some extent have reached an end to my eyepiece collection, but not put off buying more to evaluate for my self, despite some small losses if/when I sell them on?