Explore Scientific 82 Degree vs TeleVue Nagler at F/5

[crazyjedi]

The shorter your FL the bigger the differences between the best lenses and the next best lenses will appear. Shorter FL scopes are real tests for eye pieces

[Moonshane]

The shorter your FL the bigger the differences between the best lenses and the next best lenses will appear. Shorter FL scopes are real tests for eye pieces

I agree if you mean for a certain aperture - in other words, the lower your focal ratio, the bigger the differences?

[Damo636]

Below f5, Televue eps "might" outperform equivelant ES in terms of the amount of astigmatism present, not in the amount of coma! Coma will be present in a fast Newtonian regardless of what eyepiece is used. As far as I am aware, neither Televue or ES have any coma correction built into their eps, so the use of a coma corrector will even things up in this regard.

[Moonshane]

the irony of better eyepieces is that they often reveal the coma previously hidden by the astigmatism or other defects. I suspect this applies to both TV and ES eyepieces.

[John]

Astigmatism is just one optical issue of course. There are a bunch of others such as pincushion distortion, field curvature, light transmission, light scatter etc, all of which add up to make the viewing experience.

All eyepieces trade these issues off against each other in varying degrees and folks have their own tolerances for them too.

We (me included !) probably ought to pay more attention to this wider range of issues as they will have an impact in slower scopes too.

[Naemeth]

I think I've noticed astigmatism in most of my eyepieces, but then again, my prescription has changed (I've become less astigmatic in both eyes), so my glasses will effectively be over-correcting astigmatism. I doubt I'd notice it with new glasses, but I don't know.

Coma is an aberration of the telescope design, not the eyepiece, or I believe that is the case.

Light scatter can be incredibly annoying when looking at Jupiter or the Moon, with bad EPs I can sometimes know they are outside the field of view because of the glare I get. This may also be due to the scratches on my glasses.

[John]

...Light scatter can be incredibly annoying when looking at Jupiter or the Moon, with bad EPs I can sometimes know they are outside the field of view because of the glare I get. This may also be due to the scratches on my glasses.

I totally agree with this. Eyepieces that control light scatter and glare well, have no ghosting and maintain black sky backgrounds around bright objects make spotting subtle features, faint planetary moons and close but faint stars in binaries quite a lot easier.

[Naemeth]

I totally agree with this. Eyepieces that control light scatter and glare well, have no ghosting and maintain black sky backgrounds around bright objects make spotting subtle features, faint planetary moons and close but faint stars in binaries quite a lot easier.

Ghosting is the aberration where what looks like mist surrounds a bright object, like Jupiter right? That doesn't bother me as much, but I'd love to get rid of it too .

[crazyjedi]

I agree if you mean for a certain aperture - in other words, the lower your focal ratio, the bigger the differences?

Yes sorry meant focal ratio. Suffering snow blindness

[andrew63]

I totally agree with this. Eyepieces that control light scatter and glare well, have no ghosting and maintain black sky backgrounds around bright objects make spotting subtle features, faint planetary moons and close but faint stars in binaries quite a lot easier.

I think that's the real strength of the range of eyepiece that you're putting through the ringer at present!

andrew

[Daveyfitz]

with good margins you can lose a fair percentage of customers before it becomes critical. with smaller margins, every single customer is critical to achieving break even point so I doubt TV will reduce prices dramatically. I suspect most would be surprised how relatively small a business TV is so their overheads are relatively small too I expect. don't forget that it is TV that generally invent the types of eyepieces that we are talking about.

brand loyalty is I think still quite strong but this may of course change as you say. personally, I doubt it.

This seems counter-intuitive. Lesser margins are used to increase sales. Increased sales means more customers. More customers REDUCES the impact per customer. Larger margins and less customers = LARGER impact per customer.

[Moonshane]

it is counter intuitive but basic economics. see the attached. assuming they both sell 1000 units to start with and have the same costs, it's about break even point really. the company with the 3% margin only has to lose 10% of it's customers and has to work harder to avoid going into a loss making situation. the one with 35% margin can 'afford' to lose more than half of it's customers before even approaching losses.

I'll not say any more as we are off topic in a way but it does explain why I feel TV will not (and should not) reduce their prices markedly - it's a dangerous strategy.

margins.xlsx

[crazyjedi]

it is counter intuitive but basic economics. see the attached. assuming they both sell 1000 units to start with and have the same costs, it's about break even point really. the company with the 3% margin only has to lose 10% of it's customers and has to work harder to avoid going into a loss making situation. the one with 35% margin can 'afford' to lose more than half of it's customers before even approaching losses.

I'll not say any more as we are off topic in a way but it does explain why I feel TV will not (and should not) reduce their prices markedly - it's a dangerous strategy.

A little off topic - but very interesting and informative