Another eyepiece advice/suggestions thread

[dreamstation]

Evening all. Just after some advice from the more knowledgable folk. I know there's a lot of eyepiece advice threads already but I didn't want to hijack anyone elses.

The eyepieces I currently have are: 6 Delos, 13/17/21 Ethos, 31 Nagler all used with a Paracorr type 2. The two scopes the eyepieces are used in are both 10" Sky-watchers.

The 13 is definitely the most used eyepiece in the lineup with the 21 and 31 also coming out quite regularly. I'm very happy with the performance of these 3 and they all have their time and place in my collection. The 17 I'm not so sure on. When I bought it I wasn't sure I would get any use out of it but I wanted to give it a go anyway. I just don't think I really need it but if someone can convince me otherwise then I may just hold onto it. What do you guys think?

Lastly, the 6 Delos is a great eyepiece but often the seeing conditions aren't good enough to use it. Just this past Saturday evening I wanted to get some time with Jupiter but I couldn't get close with the Delos and I had to use the 13 Ethos. I've been contemplating getting something in the 8-10mm range because I've got a large gap between the 6 and 13 that needs filling. Does anyone have any suggestions? What would be the most useful FL in that range in my scopes?

Thanks for the help and clear skies!

[Wavytone]

I'll suggest 9mm:

6mm x 1.5 = 9mm
9mm x 1.5 = 13.5.

As for what's available near that... there's a Nagler 9mm, Delos 8 or 10, ES 82 degree 8.8mm or a monster 100 degree 9mm, Pentax XW10, Nikon 10SW, Vixen LVW8 or Vixen SSW 10.

Spoiled for choice I suggest. Your call.

[janoskiss]

You don't need EP advice, you need financial advice! OMG look at the collection you already have! Each EP is worth nearly as much as your scope!!

Seriously though, sell the 17mm Ethos and get the 8mm Ethos. 9mm would be better but Ethos come in 8 or 10mm only, and you'll likely find any other 100-deg-FOV EPs lacking in comparison with Ethos (with few notable exceptions that cost more still and do not have anything to offer at these FLs afaik). I don't recommend the 9mm Nagler T6. The Ethos is a much better EP imo.

Anyway, it's better to have more closely spaced magnifications at high powers than at low powers. So 13, 8 and 6 are a good mix.

If you're willing to do more selling and buying, keep 21mm Ethos, sell the 17 and 13mm and get a 10mm Ethos and a 7mm DeLite. Along with your 6mm Delos, that would be probably the ideal TeleVue package for your scope (I assume we're talking about a 10" f4.7-5.0 Dob).

[Allan]

With your current lineup, yes I would suggest you sell the 17 Ethos. I have one that I don't use often, but I bought it to use in a scope coming later this year. Otherwise I wouldn't own it either.

Use the funds to buy a 10mm and 8mm to fix up the gap you've got there. You may want to keep the 6mm for nights of good seeing, your choice.

I've used the Delites, and as dedicated deep sky eyepieces they are a backward step for someone who already owns Ethos/Delos eyepieces.

[ausastronomer]

Hi Allan,

That depends entirely on what you're trying to achieve with your deep sky observing. If you own a large aperture telescope and are trying to hunt down and tease out extra detail in dim threshold galaxies and planetary nebula, where the need is to maximize light transmission and contrast, as opposed to maximizing the Field of View, I would have said they are a step forward over Delos and Ethos, not a step backwards.

That all having been said I think with a small scope like this (8") the 17mm Ethos needs to go and be replaced with both an 8mm and a 10mm eyepiece, if that fits within the budget.

Cheers,
John B

[Allan]

John, a lot of what you say is very true. I just spent 4 nights observing with Al Nagler and all the Delites, including the yet to be released ones. On planetary nebula we observed, I could see slightly more detail with the Delites than the Ethos. But I've seen the same advantage using Delos vs Ethos. So in my mind the Delos is the goldilocks eyepiece, and the only reason one would choose a Delite is to save a bit of cash, or size and weight. Otherwise Delos still has the ideal combination of FOV and optical quality.

I'm not sure someone would see the extra detail in a 10", when comparing Ethos and Delites, at any rate it would be very subtle, so I still consider the Ethos a better option as a dedicated deep sky eyepiece.

Re-reading the OP with mention of planetary observing in the mix, then Delos is the easy suggestion, as that and the Delite make better planetary eyepieces.

[dreamstation]

Thanks for the suggestions all. I had all but convinced myself that the 17 had to go, so it's good to have some confirmation that I'm doing the right thing. It really wasn't getting much use. I will definitely get more use out of an 8 and 10.

I did touch on this in my first post but I have been doing all of my observing using the paracorr, even when viewing planets. It's probably more out of convenience as changing things in the dark all the time can get tiresome. Will using the paracorr while observing planets degrade the image in any noticeable way? I understand that it increases power by 15% so when I've used the 6mm it's probably closer to that of a 5mm and could be why I can't always get results.

As for which 8 and 10 to get I've been leaning towards the Delos, simply because I love the 6 that I have when viewing is favourable. I enjoy the wide fields of the Ethos and Nagler lines at low power but I'm not sure if I would at higher powers. Has anyone had the pleasure of comparing the two side by side and could give their thoughts?

Thanks again for the help. It's very much appreciated.

[janoskiss]

If you're happy with the Delos for higher powers then get that. I have not tried one but I'd be very surprised if it lacked anything in comparison with the Ethos except the FOV. I expect it's also a more comfortable EP to use (more eye relief and adjustable eyeguard). The specs read like they're TV's answer to the Pentax XWs.

I failed to register before that you're using a Paracorr. In that case 13mm Ethos, and 8 and 6 mm Delos sound like a good set.

Whether you lose anything to a Paracorr on planets: you can always try and see what works best. I'd ditch the Paracorr at high magnifications though. It's very difficult to avoid a bit of stray light reflecting here and there. It's not so much about the optical elements but about light reflected from the barrels when viewing bright objects (even properly blackened barrels will reflect some), and then getting secondary reflections from the glass surfaces (even the best coatings don't work for light entering far off axis).

One way of combating that is by having baffles between your EP and coma corrector (rings of blackened barriers around the inside perimeter of the barrel) --- talking ultra-low-tech here: matte black paint (I use black chalkboard paint in a spray can - you can probably do better) and bits of carefully cut and placed cardboard. It's amazing how much such simple things can improve performance with little effort and at virtually no cost.

But however it works out in practice I see nothing wrong with trading in your 17mm Ethos for an 8mm Delos and taking it from there.