Suggestions for upwards of 150x on f/5 12"...?

[furrysocks2]

Last week, I acquired a 2nd hand 12" f/5 Revelation.

I've got a few mismatched EPs:

• 2" Aero ED 35mm/68deg/44x - love it
• Andromeda 19mm/65deg/80x - not bad
• Nirvana 16mm/82deg/95x (coming) - hope I'll love it
• Altair Lightwave LER 12.5mm/55deg/122x - nice enough on the moon
• TMB II 6mm/58deg/253x - first even semi-decent view through it the other night

I'm looking for something to bridge the gap 150x and up... possibly replace the TMB.

I'm not sure I want to get a coma corrector yet, and have never had good results with a barlow. Happy to try one or two more EPs. Given the rate at which things move across the fov at higher mags, I'm drawn by the idea of 82 deg, 68 at least - I know FOV is not everything but untracked it must be something. Is it a reasonable effort to go for something wider at higher mag in this scope?

I plan to build an equatorial platform over the next year or two, and might like to do some afocal lunar imaging (have a Baader adapter to try out).

Read the Hyperion's don't perform that well at f/5, perhaps ok for planets centered in fov. The ES 82 Series perhaps... 11, 8.8, 6.7...?

[NGC 1502]

You have a good spread of eyepieces, but agree that there’s a gap between 122 and 253x that needs filling. From what you mentioned, the ES 82 degree 8.8 would do that nicely at 173x, and would be far more useful on more occasions than 253x.

There are differing opinions on the Hyperions, but they do have a comfortable eye relief if you need to wear glasses. The ES doesn’t have the long eye relief. If you don’t need to use glasses and if you are ok with the price, I’d go for the ES 8.8 myself, as you’ve mentioned, the 82 degree field is better for manual tracking.  I know an EQ platform is a possibility in your future.

One other thing, a coma corrector does help with the coma inherent in a fast mirror, but eyepiece off axis issues remain, even in very expensive eyepieces.

So many choices, including the second hand option.

HTH, Ed.

[Timebandit]

 

As ever with this hobby. It really helps if we have a budget . As we love spending other people's money?

 

But as there is no budget then here I go. The 7mm Pentax XW is a quality eyepiece. It has a fov of 70d and 20mm eye relief, with optics as sharp as a Ortho. Just a top class eyepiece. They do come up second hand so you can save a few ££. This eyepiece I use in my 14" reflector and at f/ 4.6 without any type of coma corrector. This eyepiece works really well and is one of my favourite for DSO , globs as well as lunar and some planetary 

In my Opinion the Pentax 7mm XW is a quality eyepiece that you will keep for life , so worth the initial investment ? 

 

 

[25585]

7 minutes ago, NGC 1502 said:

You have a good spread of eyepieces, but agree that there’s a gap between 122 and 253x that needs filling. From what you mentioned, the ES 82 degree 8.8 would do that nicely at 173x, and would be far more useful on more occasions than 253x.

There are differing opinions on the Hyperions, but they do have a comfortable eye relief if you need to wear glasses. The ES doesn’t have the long eye relief. If you don’t need to use glasses and if you are ok with the price, I’d go for the ES 8.8 myself, as you’ve mentioned, the 82 degree field is better for manual tracking.  I know an EQ platform is a possibility in your future.

One other thing, a coma corrector does help with the coma inherent in a fast mirror, but eyepiece off axis issues remain, even in very expensive eyepieces.

So many choices, including the second hand option.

HTH, Ed.

FLO does not state eye relief on the Hyperions, neither does the PDF sheet linked to, but Baader Planetarium web site states 20mm throughout. 

@John reviewed Hyperions against Vixen LVWs & IIRC the latter won by a slight margin. Ebay does have the shorter FL Vixens for sale still. 

[furrysocks2]

Thanks, both.

No glasses. Re: budget... I guess 2nd hand at £50-£100.

[25585]

12 minutes ago, furrysocks2 said:

Thanks, both.

No glasses. Re: budget... I guess 2nd hand at £50-£100.

Baader site has a Christmas sale on, putting their Hyperions in your budget € prices. 

[furrysocks2]

I've been turned off them by many reports, though. I think I'd have to see one to be convinced otherwise.

Which begs the question why I'd buy anything blind, based on the opinion of others, but there we are. I guess you read enough and ask questions to gauge the average.

Biggest decision is 82 vs 68, precise focal length will probably be determined by what turns up for sale and at what price.

[Paz]

I think an 8.8mm es82 would be a good fit between 12.5 and 6, and the es82s are good. The only problem is finding one second hand.

I have a 12, 8, and 6 in my set for my reflector and I find that the gap from 12 to 8 is the gap I notice most.

[furrysocks2]

23 minutes ago, Paz said:

I think an 8.8mm es82 would be a good fit between 12.5 and 6, and the es82s are good. The only problem is finding one second hand.

I have a 12, 8, and 6 in my set for my reflector and I find that the gap from 12 to 8 is the gap I notice most.

Not saying an ES 8.8mm 82deg (172x) would be sharp across the field, but it works out to a larger true field of view in that than my 12.5mm 55deg. The 6.7 at 226x would take exit pupil to 1.3mm, my 6mm being 253x/1.18mm or so.

I think with the 82 degree 16mm Nirvana coming (95x), and assuming something the likes of the 8.8, the 12.5 would likely get replaced, too. The 6mm I've got is 65 degree, but it would perhaps be a turn off to go from 8.8mm 82deg 172x to 6mm 65deg 250x, feel like hard work and warrant replacing too. Arg!

And thinking about the labour involved in narrow fov at high mags leads to thinking again about whether I'd prefer a dual speed focuser.

 

But I digress. What I'm really after is a relaxed lunar experience, the 12.5 is not quite enough, the 6 is too hard work. [Edit: add into that more afov to boot). The 8mm Vixen NPL I have is not enjoyable, too narrow not enough eye relief.

[25585]

More expensive, but would a zoom be the answer?

[furrysocks2]

9 minutes ago, 25585 said:

More expensive, but would a zoom be the answer?

I wouldn't mind the cost of that, but given "68 degrees FOV at 8mm, 50 degrees at 24mm" for the Hyperion IV, it probably wouldn't get a look in at lower mags if I'm sitting on a 16mm 82deg. And then I'm still toiling with whether 82deg is the right way to go... even if it's not sharp out the edges, longer duration presence in the fov must help to keep manual tracking going.

[ronin]

I suspect that one of the ES 82's are the obvious, they are about the same cost as the 68's so the 82's would seem to have the advantage. Baaders do have poor reports on fast scopes and it seems they need f/6 or slower - I half think that Baader have tried to mke an eyepiece do more then one thing and that usually means compromises somewhere. Equally if someone has an f/8 scope they get more then maybe expected.

 

[25585]

4 minutes ago, furrysocks2 said:

I wouldn't mind the cost of that, but given "68 degrees FOV at 8mm, 50 degrees at 24mm" for the Hyperion IV, it probably wouldn't get a look in at lower mags if I'm sitting on a 16mm 82deg. And then I'm still toiling with whether 82deg is the right way to go... even if it's not sharp out the edges, longer duration presence in the fov must help to keep manual tracking going.

With you there. I have a LVW 8mm which is very good, and they are still available. Only 65 AFOV but relaxed viewing, and near your budget. 

[alacant]

Hi. Absolutely no visual expert but I've one of these. On my 6" refractor, I honestly can't see much/any difference between it and one costing €silly; things like the M-clusters in Auriga are wonderful. But hey, I speak from a quick comparison one evening... HTH. 

**oh, and you don't have to have your eyeball right on the lens to see anything!

[Paz]

1 hour ago, furrysocks2 said:

Not saying an ES 8.8mm 82deg (172x) would be sharp across the field, but it works out to a larger true field of view in that than my 12.5mm 55deg. The 6.7 at 226x would take exit pupil to 1.3mm, my 6mm being 253x/1.18mm or so.

I think with the 82 degree 16mm Nirvana coming (95x), and assuming something the likes of the 8.8, the 12.5 would likely get replaced, too. The 6mm I've got is 65 degree, but it would perhaps be a turn off to go from 8.8mm 82deg 172x to 6mm 65deg 250x, feel like hard work and warrant replacing too. Arg!

And thinking about the labour involved in narrow fov at high mags leads to thinking again about whether I'd prefer a dual speed focuser.

 

But I digress. What I'm really after is a relaxed lunar experience, the 12.5 is not quite enough, the 6 is too hard work. [Edit: add into that more afov to boot). The 8mm Vixen NPL I have is not enjoyable, too narrow not enough eye relief.

I wasn't thinking about that issue but you are absolutely right, if the 8.8 matched or beat the 12.5 for true field of view then the 12.5 would be pretty much be cut out of use.

I had a spell where I had a 10mm plossl and 67mm es82 with my st120 and the plossl rarely got a look in.

[furrysocks2]

On 02/12/2017 at 13:05, alacant said:

Hi. Absolutely no visual expert but I've one of these. On my 6" refractor, I honestly can't see much/any difference between it and one costing €silly; things like the M-clusters in Auriga are wonderful. But hey, I speak from a quick comparison one evening... HTH. 

**oh, and you don't have to have your eyeball right on the lens to see anything!

I recently remembered that I have an unbranded "80 degree 11mm" EP - similar appearance. Not saying they are in any way comparable (other than perhaps price). But, I thought so little of it in the past that I think it's somewhere on the garage floor. I'll try and find it and give it a look through.

I've put up a wanted for an 8.8mm ES - they're "only" £127 from FLO, so perhaps if I can sell some kit or see what Santa says...

[25585]

To me TFOV at high mags seems more a paper exercise when using unguided viewing as the area being viewed is so small any slight unwanted off-target movement is going to lose your viewing area. Zooms, in theory at least, would help de-magnify & expand the FOV some for getting back.

[furrysocks2]

2 minutes ago, 25585 said:

To me TFOV at high mags seems more a paper exercise when using unguided viewing as the area being viewed is so small any slight unwanted off-target movement is going to lose your viewing area. Zooms, in theory at least, would help de-magnify & expand the FOV some for getting back.

I hadn't thought of a zoom in those terms, but yes it's the frustration of losing an object and spending time relocating that I was thinking about. I can see how a zoom could help there.

[25585]

1 minute ago, furrysocks2 said:

I hadn't thought of a zoom in those terms, but yes it's the frustration of losing an object and spending time relocating that I was thinking about. I can see how a zoom could help there.

Only other easy way is a turret, but for high mags parfocal eps must be the best. You could choose your own range then, but others who have used turrets can advise on their ease & effectiveness. 

[Moonshane]

I always enjoy a 9mm eyepiece in most of my scopes, including one I had previously like yours. In your scope it would give 167x which is usable almost always and I find it useful to have one at 7mm which would be usable less often but at 214x would just sit nice between. In my current scopes it gives 204x, 178x, 149x and 100x. So in some ways, one eyepice and four scopes is the way to go!  

Personally I have gone for Delites but cheaper options are also worth it.

[Moonshane]

ps on the issue of losing an object, I just put the object to the right of field before the swap and it's generally a minute or so before it drifts out of field.

[furrysocks2]

1 minute ago, Moonshane said:

ps on the issue of losing an object, I just put the object to the right of field before the swap and it's generally a minute or so before it drifts out of field.

I lose it when I'm looking at it... stiction and cack-handedness.

[25585]

1 minute ago, furrysocks2 said:

I lose it when I'm looking at it... stiction and cack-handedness.

Same here. A twitch, sneeze etc at high mags. 

Worst when your viewing object is too dim to find in a guidescope! 

[furrysocks2]

Learning about DSOs and exit pupils... perhaps the ES 11mm, giving 138x and 2.2mm exit pupil would be better. Or a zoom, as suggested above.

Can't afford another EP though.

[25585]

I like 10mm, just because it's easy to remember or calculate a magnification knowing the scope's focal length (5mm ep = 2x, 20mm = half of 10s etc). 

The 12 F5 is 1500mm fl so a 10mm ep will give you 150x.