Eyepiece Dilemma

[John]

26 minutes ago, Rob Sellent said:

Ohh, this sounds like a good test for the Vixen. Clearly, I'm a very poor lunar observer for I've never seen the Rille, Stu . Do you know when the best time to do so would be? And here or elsewhere, it would be nice to hear how your 8" planet killer gets on and how you think it compares to your fluorite

I've yet to see the Alpine Valley rille in any of my scopes smaller than the 12 inch dob. Stu has done really well to get it in his 100 Tak

As this is the eyepieces section I'll add that my favourite fine detail lunar observing eyepieces are the 5mm pentax XW with the 12 inch dob and my 3.5mm XW with the refractors.

[Stu]

5 minutes ago, John said:

I've yet to see the Alpine Valley rille in any of my scopes smaller than the 12 inch dob. Stu has done really well to get it in his 100 Tak

Thanks John! Pretty sure @mikeDnighthas managed it too so I don't think I was imagining it!

[LDW1]

If you don’t already know or just haven’t done it, the next time you go to an optometrist or ophthalmologist have them measure your pupil diameter, they will gladly do it at least where I live. Then you will know, have a base to determine on and have both eyes checked, there are so many floaters in my right eye that I trained myself to view / use my left that has literally no floaters, works well.

[Stu]

17 minutes ago, LDW1 said:

I trained myself to view / use my left that has literally no floaters, works well.

I don't suppose that was so easy, but well worth it for you I'm sure 👍👍

Unfortunately I don't have that option. The views through my right eye are nowhere near as good as my dominat left eye. Whilst in daylight they are similar, in low light the right eye gives brighter images, but ones that are far more grainy, with less resolution. For planets, lunar and solar I either use binoviewers or have to look around the floaters.

One note on binoviewers, I tend to prefer using longer focal length eyepieces and barlowing to achieve the required magnification. It seems to work better and give images which are easier to merge and view.

[John]

1 hour ago, Stu said:

Thanks John! Pretty sure @mikeDnighthas managed it too so I don't think I was imagining it!

I don't think you were imagining it either

[Rob Sellent]

Thanks for the lunar links @Stuand your insights into the binoviewers. I can appreciate that Barlowing long focus length eyepieces would probably make life easier and probably double up quite well without the Barlow for solar viewing. I'll keep my eyes peeled on the secondmarket and if a pair come up, I'll probably go for it and have a little play .

Thanks for the eyepiece suggestions @John. I've been playing with the Orthos and feel I definately need something around the 5/6mm range. In my younger days I never had a problem with Orthos but either due to age or being spolit by more comfortable eyepieces, I find it difficult to use the shorter focal lengths. I'm split at the moment between the XW at 5mm or the Delos at 6mm. A nice position to be in

[mikeDnight]

On 19/09/2019 at 12:19, Rob Sellent said:

I wonder if anyone has any insight on what to do? I've been thinking whether it is worth purchasing an eyepiece around 0.7 exit pupil, 6mm, 150x for a 4" f8.8 (902 focal length) apo?

My eyepiece collection consists of a Baader Mark IV Zoom, a complete set of Baader Genuine Orthos (5, 6, 7, 9, 12.5 & 18mm), TeleVue x2 Barlow, Delos 10mm & 14mm, Panoptics 19mm & 24mm. This set up is fine for my f5 Dob and f6.3 apo and I feel a 6mm in either scope would be redundant but not in the f8.8.

Do you think it's worth spending quite a bit of money going for a 6mm dedicated eyepiece in the f8.8, or just stop fussing and and get on with the Orthos and Barlowed Delos ?  Again, finally, there's also the option of a Nagler 3-6mm Zoom but again, is that worth it when I already have some cracking, tip-top Orthos?

Any ideas/insights would be greatly received

I'd say that things are just starting to get interesting at X150 Rob. Personally I'd choose a 5mm over a 6mm for your excellent refractor. A 5mm Pentax XW would give stunning views, but I wouldn't leave it at that. I'd suggest you also buy the 3.5mm. Your scope will cruise along at 100X per inch on the Moon on a good night, because it is such a high quality instrument. I'm quite comfortable with short eye relief eyepieces, and so I'm fond of the Vixen HR eyepieces, and find even the 2mm comes in handy. I've even barlowed it on my Tak FC100DC with pleasing results. I never consider exit pupil or eyepiece calculators. If it works for me I'll use it!

I do like bino viewing though, and get amazing views using cheap longer focal length eyepieces along with a barlow, that are every bit as good as the views through high end mono eyepiece views. Stu mentioned above, that he'd seen the alpine valley through his 100mm refractor, and I too have seen it several times through my own 100mm scope. Your Vixen will definitely show it also Rob, when the lunation and a steady atmosphere allows. To me I appears as a subtle, broken white line, just slightly brighter than the mare floor of the valley. The best I ever saw it was when I was using a pair of 15mm Vixen Lanthanum eyepieces in my barlowed binoviewer. So don't be afraid of pushing your scope well over the 50X per inch limit. It will thank you for it!

[Rob Sellent]

@mikeDnightThank you for the great advice and information. I was out last night and noticed that in conditions of good seeing the frac wasn't running out of puff around 150x, so as you say, a 5mm would be a good bet here. I've read many posts and seen many sketches here on SGL and have noted that you don't appear to have a problem with short eye relief. You're either a brave man or have bionic eyes I think you're right to point out to not be afraid. As you say, if it works, use it. What I'll do it is either go for a dedicated 5mm XW or Barlow the 10mm and 14mm Delos I already have and purchse a 6mm Delos. I'll also see how I get along with higher magnifications and if I'm comfortable, I'll definately look into those Vixen HRs. Thanks again, Mike