Explore scientific 9mm or sky watcher 100 degree ep

[blinky]

I have a 12 inch go to dob and have a few eyepieces but really want to purchase 1 100 degree or possibly 82 degree if somebody can persuade me, eyepiece. I'm thinking the most useful would be the 9mm one as opposed to 14 mm - would that be correct? I'm into deep sky observing not lunar or planetary.  I'm thinking the the 9mm will give my darker skies and most objects should fit in the fov.... so how does th sky watcher myriad compare to the es ones? Other than the myriad is £100 cheaper!

[blinky]

Or do you observer types feel the 20mm would be more useful? The scope is f5 btw

[John]

The Myriad eyepieces are pretty good. I did a review of them a while back comparing them with my Ethos and Pentax XW eyepieces:

https://stargazerslounge.com/topic/236613-skywatcher-myriad-100-110-degree-apparent-field-eyepieces/

If I had to pick one for use in my 12" F/5.3 dobsonian I think it would be the 20mm. I've quite often had galaxy chasing sessions where a 20mm 100 degree eyepiece is all that I've used. You might see some coma at the field edges in an F/5 scope but not that much. Coma comes from the scope optics byt the way, rather than the eyepiece.

The ES 100's are very good too and ergonomically closer to the Ethos with that soft rubber eye cup rather than the harder twist up and down one that the Myriads use.

There is a lot to commend a 100 degree eyepiece used in a 12" dob. The ones I've used (Myriad, William Optics XWA, Ethos and ES 100) all seem to be really good

I ought to add that I am a wide / ultra wide junkie so that adds to their appeal.

The cons with 100 degree'ers is that they are pretty tall, fat and heavy compared to some of the 82's around. And they are more expensive too !

If you wear glasses when observing both 100 degree and 82 degree eyepieces can pose issues due to their eye relief being shorter, on the whole, than 68/70 degree eyepieces.

[Mark at Beaufort]

I have a 12" f/5 Dob and currently use a 20mm Myriad, 13mm Ethos and a 9mm Myriad. I also have a number of ES82 EPs. The Myriad EPs are very good and I previously owned the 21mm and 8mm Ethos and there is not a huge difference IMHO.

I think your best choice would be the 20mm Myriad and depending on funds I think a 14mm ES82 would be your next purchase. I did buy a 9mm Myriad after the purchase of the 20mm but this was because I already had a 11mm and 14mm ES82.

[alanjgreen]

I agree with John. I would say your first 100 degree should be in the range 17-21 mm. I would say that 9 or 10mm is too much for galaxies.

ES100 seem to get good reviews. If your dob is not goto then you will really appreciate the 100 degree field as there will be less nudging needed.

I love my Ethos21 & Ethos13. Not tried the 17 but I dont need it as the 13 & 21 cover all the bases.

Televue recommend 21-13-8 or 17-10-6 as the two optimum spreads for 100 degree eyepieces. So have a ponder which three would work best in your scope, then target one from your ideal set (doesn't have to be a televue EP) then you have something to work toward ...

(Although having said all that, I am going for a 10mm next. 8mm will not get enough use to make me feel it was money well spent! My end game will be 21-13-10, thats 100 degree finished at that point, hope its not too long until the next Televue sale )

Alan

 

[blinky]

Thanks folks, 20mm myriad it is then!  Next years bonus will get a 14mm eyepiece

[Louis D]

3 hours ago, blinky said:

Thanks folks, 20mm myriad it is then!  Next years bonus will get a 14mm eyepiece

There's also the Lunt Engineering HDC 20 mm 100° Eyepiece which has a tapered top just like the ES and Ethos.  The optics are reportedly the same as the Myriad version.

[rl]

A final thought before you splash the cash. Do you need to wear glasses while observing? None of the standard 100 degree options have enough eye relief. Presumably you've had the opportunity to look through a 100 degree eyepiece already..

If you do then have a look at the ES 92 degree options which are glasses-compatible. IMHO the 92 degree 17mm can stake a claim to being the best eyepiece ES make ( I know, a difficult thing to judge, horses for courses) and so far has been the only one I have kept.

RL

[Mark at Beaufort]

6 minutes ago, rl said:

. IMHO the 92 degree 17mm is the best eyepiece ES make and so far has been the only one I have kept.

RL

Thanks RL I like ES eyepieces and I must admit I really fancy trying the 17mm ES92.

[rl]

Mark;

At the risk of taking the thread off-topic, the ES 92 degree is excellent. The edge correction holds up really well (Newtonian f/ 4.6 inc paracorr) regardless of whether you use glasses or not ( which is not true of all ES 100 degree offerings in my experience). If you use glasses, you might find that the AFOV is greater than your specs..I can see above and below my specs into unfocussed field! In fact, the optical quality of your specs might be the limiting factor...If find the CA control on the eyepiece almost perfect, but the specs actually contribute enough off-axis CA to be an SMALL annoyance through their own dispersion. .looking straight ahead into the centre of the FOV shows no CA. Keeping your head straight and looking at the field edge with peripheral vision shows the CA inherent in the specs..turn your head to face the edge and it goes!

I bought mine just before the pound fell after the referendum for which I am truly grateful..

RL

[Louis D]

I got a 17mm ES-92 for Christmas when they were 20% off, and I can attest that the top and bottom of my eyeglasses cutoff the field of view.  Side to side this isn't an issue.  I have low index plastic lenses for astronomical usage that introduce the least CA possible short of using glass lenses (which no one seems to sell anymore).  I haven't found CA to be objectionable with the combination.  It's nice to be able to see the entire FOV at once without having to cram in to the eyepiece like with the TV 17mm Nagler T4.  It's also not finicky about eye placement like the NT4.  I also could not detect any astigmatism or field curvature at the edge.  No ghosting to speak of either.  It is very heavy, so balance could be an issue.

[Mark at Beaufort]

Thanks RL and Louis D for that information.

We better go back to the original question for Blinky on 100 degree EPs.

[Louis D]

On 2/22/2017 at 04:53, blinky said:

I have a 12 inch go to dob and have a few eyepieces but really want to purchase 1 100 degree or possibly 82 degree if somebody can persuade me, eyepiece.

So blinky, would you be opposed to a 92 degree eyepiece splitting the difference between 82 and 100 degrees as rl and I suggested?

BTW, I checked your webpage and you have taken some wonderful astrophotos!

[blinky]

Was about to buy the 20mm myriad but now discover that it's out of stock everywhere!  

[Louis D]

1 hour ago, blinky said:

Was about to buy the 20mm myriad but now discover that it's out of stock everywhere!  

APM claims to have the Lunt Engineering HDC 20 mm 100° Eyepiece in stock.  It's the same optics as the Myriad/Williams in a more ergonomic package.  Check with them to confirm.

[TheLookingGlass]

The 9mm Baader Morpheus feels incredibly immersive. Feels more like an 80 degree EP with the nice eye relief. Not heavy either.

I highly recommend the 9mm and the 12.5mm too. I took the flimsy rubber eyecups off the Morpheus and exchanged them from two Explore Scientific EP's. Both exchanged over quite well and I also have tops caps for them all.