Eyepieces for new setup

[Jamesruss13]

Hi guys I’m currently just a bino observer with a pair of Olympus 10x50 and horizon tripod, have previously owned an evostar 90 but got rid of it as light pollution was horrendous at my previous address. Anyway I’m looking to fulfil my dream of getting a Skywatcher ED80 on an az4 mount ( possibly upgrade to an equatorial at a later date if I’m going to get into astrophotography and a Skywatcher 8” dob just to have some aperture in the arsenal. I want to stick strictly to 2” eyepieces for both the scopes and I’m looking for some recommendations on what eyepieces to purchase, id like a few different focal lengths but ideally stick with the same brand/range. Have considered the Hyperion range and would love maybe just one low power eyepiece from the televise radian or Delos range, my budget would certainly not allow me a full set of these! Any advice would be much appreciated. 

[Louis D]

2 hours ago, Jamesruss13 said:

I want to stick strictly to 2” eyepieces for both the scopes

 

2 hours ago, Jamesruss13 said:

would love maybe just one low power eyepiece from the televise radian or Delos range, my budget would certainly not allow me a full set of these!

You're self-contradictory here.  First you say you want strictly 2" eyepieces, then you yearn for strictly 1.25" eyepieces.  Care to clarify?  You can always add dedicated 1.25" to 2" adapters to 1.25" eyepieces to make them effectifly 2"-only eyepieces.  There's no real reason to restrict yourself to 2"-only eyepieces except at long focal lengths and wide true fields of view where the field stop exceeds the inner diameter of a 1.25" barrel.

[Ruud]

Hyperions are best for slower telescopes and even then there are better options for each and every one of them. Delos are excellent in all telescopes. A bit expensive though and the Delos range does not go beyond 17.5 mm. At least some of the Morpheus are as good as Delos for a third less.

Explore scientific 68° and 82° are good eyepieces. The 68° don't come under 16mm. 

What is the value of having all eyepieces of the same brand/range? I can't imagine that is possible without compromise. In the dark all that matters are optical quality and ergonomics. Brand or range really aren't that important

2 inch eyepieces only make sense for when the field stop requires it. That is the case for 'field of view' vs 'focal length' combinations above the blue line is the diagram below. For instance, an 82° 31mm eyepiece is above the blue line and cannot be made in a 1.25" barrel.

When the field stop fits in a 1.25" barrel there is no reason to fit the eyepiece with a 2" barrel. Two inch does not mean better quality. (Just like size 11 shoes aren't better quality than size 9.) The reason why retailers mention that 2" eyepieces are 2" is for customers who have a 1.25" focuser. A 1.25" focuser cannot accommodate 2" eyepieces. 

 

 

 

[ronin]

Why 2" eyepieces? To an extent you are restrictiong yourself. Simply there are a lot of good 1.25" eyepieces out there. My main concern of 2" eyepieces is have you used one previously? If not then go have a look at one, they are big. The step sounds small but it is 1.6x in increase and that has to be performed in 3 dimensions, and 1.6 cubed is 4x. So they are 4 times the size/mass. I have said previously that the box for the one 2" eyepiece I have will easily hold 4 boxes that the TV plossl's are supplied in.

Larger diameter glass also introduces more aberattions, and costs more proportionatly.

Most do not make a range all in 2", ES 82's are 1.25 up to 14mm then they swap to 2", so then comes the swapping out of eyepiece and eyepiece adaptors. The ES 68 series is similar, 1.25" to 24mm the 2" above that in focal lengths. So again you swap eyepieces and adaptors. It is likely the swapping of 2 components that is the main drawback. To me it seems too much trouble.

Hyperons are OK in slow scopes and slow can mean slow, many will say f/7 but a few argue slower still. I suspect they have tried to accomplish too much by haveing their "dual" focal lengths and so the basic performance is compromised a bit.

Problem is likely to be you can have a field of view or focal length but not both in a single format. As said the ES 82's stop at 14mm, a 60 degree BST goes to 25mm and would I suspect deliver a wider view to the eye as the 14mm 82.

If you want a mix, 1.25:2, and one set then the ES82's seem "best" as they go to 14mm and you could get a single 24mm or 40mm 2" format.

[Jamesruss13]

Thanks for the replies guys, you could say when it comes to the science of an eyepiece I’ve been quiet naive! I assumed 2” eyepieces Would generally have a bigger field of view/exit pupil therefore better eye relief than 1.25 which is obviously not the case, and big thanks to rudd for the explanation and diagram that has helped a lot!, my only experience with eyepieces has been the cheap ones that come with a scope, now  I understand something like a 4 or 5mm eyepiece will always have a smaller exit pupil than a 10 or 12mm but I really didn’t like just how small it was with the higher mag eyepiece my evostar came with, it was like trying to look through a pin hole!.  As with wanting to stick with the same range that just comes down to me being too organised in life in general lol. The ES I really like the look of but are quite pricey, I think I may have to just accept that decent eyepieces cost a fortune and maybe add a new one to the kit once a month or so, also I’ve heard good things about the BSTs if anyone has tried them?

[laowhoo]

Not familiar with the BST, but consider that a slower Newt (as mentioned for the Hyperions) will be more forgiving on mediocre EPs, easier to collimate, and possibly offer a better figure on the primary. Also, even though we went with a 12.5" Dob and insisted on 2" focuser, there were many who said it was unnecessary. They were probably right, and we can only "adequately" use our 31mm and 36mm Hyperions (we're f/6) under better skies than we have at home 90% of the year. Also, had we gone strictly 1.25" we'd be enjoying a smaller secondary which planet enthusiasts like to do. You'd also be able to swap your EPs to your refractor (just can't imagine 2" EPs on the ED80). Our f/6 is sort of the dividing line b/t slow and fast, but even an 8" f/7 is very manageable size-wise and will let those "lesser" EPs better shine for some substantial savings. Also consider a Barlow to double up your EPs. We followed Clark's formula (Google Clark OMVA) and went with a 1.5x, and others are available at 1.4x and 1.6x which, coincidentally, follow most mfrs EP line progressions. Like you, we have to conserve b/c we binoview and had to double our EPs.

[Charic]

16 hours ago, Jamesruss13 said:

Delos range, my budget would certainly not allow me a full set of these!

Take your time, buy second hand as/when they arrive, and you could afford the full set, eventually.
I had the 6mm 8mm &10mm Delos but felt they were no better ( apart from a wider field of view ) for my needs than my already affordable  BST Starguiders. 

[Louis D]

15 hours ago, Jamesruss13 said:

I’ve heard good things about the BSTs if anyone has tried them?

I have the similar Meade HD-60 line.  From 9mm on down, they are fantastic.  There's very little to distinguish them from the high end offerings.  The 12mm is very good in the center, but shows noticeable astigmatism toward the edge, but it's still quite good.  The 18mm and 25mm are decent in the central portion, but rapidly fall apart as you near the edge with astigmatism.  I would not recommend them.  I would assume the BST and Celestron XCel LX are similar.  Summarizing, best at short focal lenghts where the addtional apparent field of view (AFOV) and generous eye relief are welcome compared to simple eyepiece designs at those focal lengths; worst in the mid to longer focal lengths where there are better options available.

[Jamesruss13]

Thanks guys I’ve had a good look on a few sites I’m tempted by the 2.5, 4 and 6mm skywatcher UWA planetary eyepieces giving 240x, 150x and 100x for lunar and planetary viewing and would like a few low power eyepieces like perhaps a skywatcher panaview 26mm giving 23x and a decent 40mm eyepiece giving 15x for deep sky and star hopping. 

 

[John]

I assume that we are talking about the ED80 here ?

You might find 200x a more useful highest power so that would be a 3mm eyepiece or possibly a decent quality barlow lens used with the 6mm ?

You will probably find yourself wanting something inbetween 100x and your low power eyepieces so maybe a 12mm of some sort ?

If it was me I would probably go for a 32mm in place of the 26mm and 40mm as a general purpose "low and wide" eyepiece.

 

[Louis D]

I rarely go above 125x in my AT72ED because color starts to become visible and distracting.  That, and the exit pupil is becoming quite small at about 0.6mm.  At that size, the floaters in my eye become distracting as well.  For the ED80, I would think about 150x would be as high as I would want to go for similar reasons, so skip the 2.5mm eyepiece.

I would keep the 40mm if you can find a TMB Paragon clone or spring for a 40mm Maxvision SWA if you can find one.  Keep an eye on the classifieds to see what turns up.  I would skip 32mm and head right for something yielding a 2mm exit pupil, a 15mm or so eyepiece for 40x as John suggests.  Having just picked up a 12mm ES-92 and already having the 17mm version, I can highly recommend either.  However, more realistically, you could look into getting a 15mm BST Starguider.

[Louis D]

Thinking about it some more, I would recommend adding an eyepiece yielding about 75x since that power nicely frames many DSOs.  For the ED80, that would be about an 8mm eyepiece.  Again, you're in luck.  There's an 8mm BST Starguider.  I would compromise on getting both a 4mm and a 6mm eyepiece and get a 5mm BST Starguider instead.  Thus, 5mm, 8mm, 15mm, and 40mm.  Those 4 eyepieces would cover 90% of all your viewing needs.  You can add more later to fill in anywhere you feel a gap in powers needing filled.

[Jamesruss13]

Thanks guys much food for thought, I will probably ditch the 4 and 6 idea and go with a 5, I’ve loved observing with just my binoculars for over a year now limited to just 10x mag so even just a couple of eyepieces to start with will keep me occupied for hours! 

[laowhoo]

Honestly, one of O'Meara's books included his sketches (Messier objects?) w/ the accompanying mags and about 90% were b/t 200x-250x for what I think was a 10" scope (and his super-human eyes). Maybe it was Clark's book Visual Astronomy I'm thinking of. But yeah, those 4 EPs will stand you well, and the mag spread up high (medium to high) is where you'll want some diversity. We began with a 24mm, an 11mm and a 4.7mm (with a 1.5x Barlow) and used only these our first 5 years. The 4.7mm rarely got used b/c our seeing just couldn't support it, and it wasn't that often the Barlow got used either. (We have a 12.5" so that's 79x and 173x, sometimes barlowing the 24mm for 119x.) Granted, we had to learn to observe and have since added some, but only recently at Christmas.

It was Clark's Visual Astronomy of the Deep Sky. He includes his observations and drawings of 65 deep sky objects, and over 90% were drawn with 117x and 188x (he used both on all the objects) with an 8" scope. The only times he went higher (maybe 5 times) were after he'd used the other two. He also had dark Hawaii skies that could support that mag. You don't need much, but you have to make it count.

[marcus_z]

Here's something to discuss:

30mm explore scientific 82°

8-24mm Baader Hyperion Zoom

5mm TeleVue Delite

What do you think about that?