Pentax XW7mm

[markse68]

1 minute ago, John said:

Only one way to find out .....

I like mine 😂 But i haven't compared them to any other fancy equivalents...

The 7xw performs superbly btw- the quality of image of Jupiter is just as good as my ortho and this corneal reflection has only manifested itself on Jupiter so i’m not displeased with it generally and won’t be getting rid of it just yet.

[Littleguy80]

I've experienced the same thing with my 9mm Lunt XWA. I generally just use orthos for planetary but have just bought a 10mm Delos which doesn't have this issue. 

[jetstream]

7 hours ago, markse68 said:

yes. it happens with those too apparently 😂🤪

”Yes, it happens to me too and last night I was really thinking about it.  I was using Delos eyepieces but it happens with others as well.  I think it might depend on the curvature or lack of curvature of the eyepiece top lens.  It may also matter if your eyeball is too dry or too wet.  I forget which. “ from an interesting thread on it on CN.

several people suggested moving eye closer to eye lens than normal er helped- seems to be common issue with long er  eps with large eye lenses more so than eps with smaller lenses.

actually reading that thread made me feel a bit better- i had been thinking there must be something wrong with my particular xw7 and that i should have  bought a new one but now i’m reassured that it happens with a LOT of eps from all makers and seems to be fairly inherent in long er widefield eps so i’ll just tolerate it... or get fitted with some expensive multi-coated contact lenses which surely must be the next big  thing for visual astronomy! 🤔

 

I have tried piles of eyepieces and the Delos has never done this eye reflection- my 10mm Luminos was famous for it.  Do you have a link to the CN thread?

[markse68]

7 minutes ago, jetstream said:

I have tried piles of eyepieces and the Delos has never done this eye reflection- my 10mm Luminos was famous for it.  Do you have a link to the CN thread?

it’s an interesting thread that Don participated in- he must have the patience of a saint 😉 The conclusion i’m coming to is this can happen to any ep but especially those with long er and wide afov but seems to depend also on scope and eye characteristics combination 🤷‍♂️ Larger aperture (brighter image) seem to make it worse too. 

https://www.cloudynights.com/topic/572187-corneal-reflections-on-jupiter/

[jetstream]

30 minutes ago, markse68 said:

it’s an interesting thread that Don participated in- he must have the patience of a saint 😉 The conclusion i’m coming to is this can happen to any ep but especially those with long er and wide afov but seems to depend also on scope and eye characteristics combination 🤷‍♂️ Larger aperture (brighter image) seem to make it worse too. 

https://www.cloudynights.com/topic/572187-corneal-reflections-on-jupiter/

My 24" and the Delos do not produce eye reflections for me- YKSE, a respected member here mentioned lens cleaning in that CN thread- have you tried cleaning this eyepiece?

[Ricochet]

On 25/06/2020 at 02:33, markse68 said:

I recently picked up a s/h but supposedly  unused XW7mm but it seems to have a problem. Or maybe not... 

when I observe Jupiter with it the image is excellent- I’m getting just about as much sharpness and detail as a 7mm ortho I think but it does this strange and quite irritating thing. It’s hard to describe but it’s like Jupiter is forming a beam of light that swishes across my eye as the disk moves across the fov and if I move my eye it kind of dances around. The 5 doesn’t do it nor the 14 or any of the others I have (I don’t have the 10 yet) I’m wondering what could be the cause? The eye lens is clean and like I say the image it produces is excellent. Anybody own the XW7 noticed something similar? I guess it could be an interaction with my scope 🤷‍♂️ Maybe it’s a reflection off my eyeball? It’s fine with less bright objects and I didn’t notice it on the moon when I first tried the ep.

What about if you use the 14 with a 2x barlow? Do you see a similar effect then? 

[markse68]

1 hour ago, jetstream said:

My 24" and the Delos do not produce eye reflections for me- YKSE, a respected member here mentioned lens cleaning in that CN thread- have you tried cleaning this eyepiece?

i think the conclusion was that was for a different issue- a haze around bright objects? Yes the eye lens is spotless on mine.

[markse68]

24 minutes ago, Ricochet said:

What about if you use the 14 with a 2x barlow? Do you see a similar effect then? 

i’ll try that- good idea

[markse68]

Good news!

I sent the 7XW back for a full refund unhappy with a few things apart from this issue- namely that it had been advertised as unused for which i paid a premium but it had quite obviously been used... 

Anyway I just received a brand new one from FLO and have tried it tonight on Jupiter and there is no evidence of this issue at all 👍 In fact Jupiter looked great apart from AD smearing which i’m super sensitive to now 🤦‍♂️😂

The one with the issue was the original series in a Pentax rather than Ricoh/Pentax box so I can’t be sure that they haven’t just improved the coatings but it’s sorted now whatever so that’s nice and I’m much happier

 

 

Edited July 22, 2020 by markse68

[John]

Glad you are happier now Mark

My 5mm and 3.5mm XW's are older and have the green boxes. My 7mm and 10mm were purchased new from FLO a couple of years back and are in the grey Ricoh era boxes.

They seem to perform universally well.

Interesting that you have become AD sensitised now. I found that I became the same over scope generated CA and eyepiece generated astigmatism but coma I don't seem to notice, or at least it does not bother me. Others would simply have to use a coma corrector I expect

When I was testing eyepieces and the odd refractor for the forum I guess I was really looking out for these issues. Now I've "retired" from that, I'm more relaxed about them.

Yay ! - I'm enjoying cheap eyepieces again !

[markse68]

Thanks John . I was thinking it was a shame i couldn’t use it with the adc on Jupiter as it’s the perfect power with my scope but I will try it without the barlow next time. The 14 barlowed with the adc has the dancing corneal reflections so not so great. I should try the 7 barlowed with the adc on antares next time too though - been using the bco 6mm but at ~500x and the small fov you don’t get long after it settles before you have to nudge it again. The wider fov would be useful.

[John]

2 hours ago, markse68 said:

... been using the bco 6mm but at ~500x and the small fov you don’t get long after it settles before you have to nudge it again. The wider fov would be useful.

My 6mm is the Ethos, which helps with a longer drift time.