Ethos + power mate?

[Rob_UK_SE]

2 hours ago, Stardaze said:

Happy to report that the XW eye placement seemed absolutely fine last night, it all fell in place? A great steady night I found, it was excellent viewing conditions throughout. If anything, having spent most of the night flitting between 5/8/13, the 20 towards the end didn't work so well for me. Ah well, the winter season is approaching quickly, where I don't have to burn the candle both ends. 

That’s great news. 😀 I’m looking forward to those sociable 6pm skies too (let’s hope they are a little less frequently accompanied by cloud!).

[Dantooine]

5 hours ago, Stardaze said:

Happy to report that the XW eye placement seemed absolutely fine last night, it all fell in place? A great steady night I found, it was excellent viewing conditions throughout. If anything, having spent most of the night flitting between 5/8/13, the 20 towards the end didn't work so well for me. Ah well, the winter season is approaching quickly, where I don't have to burn the candle both ends. 

Glad the xw has worked out for you, see what you first wrote and thought oh dear. It was clear and I ended up outside until 0430, I’m like a zombie today. Mainly mars and it’s noticeably bigger now even in my scope. I can see dark patches well but wish I could get them darker. 

[Dantooine]

2 hours ago, Rob_UK_SE said:

It is a very lovely eyepiece to use and the additional magnification certainly benefits contrast. However, it is also very heavy and can cause all manner of balancing issues when observing around the zenith on a manual alt az mount. As long as your mount can apply some friction to the altitude bearing it should be ok. It’s not so much about balancing the telescope’s lens cells and eyepiece, but an issue of the uneven placement of the weight extending above the scope at the focuser end.

I recall once seeing an ingenious homemade solution bu Stu that added a counterweight on the opposite side of the focuser. I once tried to replicate this, but failed spectacularly!

Is it about the same weight as a es17/92 as my setup coped with that one?

[Rob_UK_SE]

6 minutes ago, Dantooine said:

Is it about the same weight as a es17/92 as my setup coped with that one?

It is indeed, in fact, I think the ES17/92 is even heavier than the 21E. You shouldn’t therefore have any issues. However, I was also trying to help you with a legitimate excuse for not buying it 😀.  Perhaps the 21E might be on the cards at some point? Alternatively, I could just lie and tell you that it’s ugly, has rubbish optics and is quite uncomfortable to use? 🤫

I am assuming that you may not be too far from where we are based.  You are welcome to try out mine on an evening’s session, if you don’t mind a bit of travelling?

[Louis D]

3 hours ago, Rob_UK_SE said:

I recall once seeing an ingenious homemade solution bu Stu that added a counterweight on the opposite side of the focuser. I once tried to replicate this, but failed spectacularly!

I have a 6" bolt that I screw into a threaded hole on my alt-az mount at 90 degrees to the OTA (on the bottom, rotating up to the front at high elevations).  I then hang a plastic grocery bag filled with a pound to two pounds of metal washers and bolts I had laying around to counteract the backward tilt of heavy eyepieces near zenith.  At lower elevations, it has little to no effect other than to bang into the tripod legs as I rotate in azimuth.  Being a plastic bag, it just moves out of the way.  I do have to dampen the swinging manually when that happens, though.  It works like a charm to prevent my rig from turning turtle near zenith, though.  It just looks literally trashy.

[Rob_UK_SE]

1 hour ago, Louis D said:

I have a 6" bolt that I screw into a threaded hole on my alt-az mount at 90 degrees to the OTA (on the bottom, rotating up to the front at high elevations).  I then hang a plastic grocery bag filled with a pound to two pounds of metal washers and bolts I had laying around to counteract the backward tilt of heavy eyepieces near zenith.  At lower elevations, it has little to no effect other than to bang into the tripod legs as I rotate in azimuth.  Being a plastic bag, it just moves out of the way.  I do have to dampen the swinging manually when that happens, though.  It works like a charm to prevent my rig from turning turtle near zenith, though.  It just looks literally trashy.

That sounds fantastic, Louis. I would very much like to see a photograph of this in action. Loving the plastic bag, in particular.

If you made the bag out of some sort of fancy material, with a suitably important looking logo, you could patent it and sell for a fortune! No one would know its filled with washers - they could instead be described as ‘aerospace-grade precision CNC’ed narrow cylinders’ with optimum weight balancing properties 😀.

 

.... quickly running off to the patent office.

Edited September 14, 2020 by Rob_UK_SE

[John]

3 hours ago, Rob_UK_SE said:

It is indeed, in fact, I think the ES17/92 is even heavier than the 21E. You shouldn’t therefore have any issues. However, I was also trying to help you with a legitimate excuse for not buying it 😀.  Perhaps the 21E might be on the cards at some point? Alternatively, I could just lie and tell you that it’s ugly, has rubbish optics and is quite uncomfortable to use? 🤫

 

The ES17/92 is indeed quite a bit heavier than the 21E. 1300g vs 1021g

I was using both last night

My counterweight "system" is a magnetic knife strip attached to the lower part of the scope tube and a couple of old iron counter weights that I can place in various positions along it.

 

 

[Dantooine]

14 minutes ago, John said:

The ES17/92 is indeed quite a bit heavier than the 21E. 1300g vs 1021g

I was using both last night

My counterweight "system" is a magnetic knife strip attached to the lower part of the scope tube and a couple of old iron counter weights that I can place in various positions along it.

 

 

When I think about it my 13E is about the same in my telescope as your 21E is in yours? Couple explain why I like it so much. 
 

when first see about the bag of washers as a counter balance I imagined a swinging pendulum. It must act as dead weight. 

[globular]

19 minutes ago, John said:

The ES17/92 is indeed quite a bit heavier than the 21E. 1300g vs 1021g

I'm thinking about the ES17/92. Is it really 1300g and not the 'official' 1175g?

[Rob_UK_SE]

41 minutes ago, John said:

The ES17/92 is indeed quite a bit heavier than the 21E. 1300g vs 1021g

I was using both last night

My counterweight "system" is a magnetic knife strip attached to the lower part of the scope tube and a couple of old iron counter weights that I can place in various positions along it.

 

 

I can see a whole new 100+ page thread of ‘Show us your low-tech counterweight system...’. 😀

Although I fortunately don’t have issues with balancing my current scopes, my old 12” Meade Lightbridge required taxi magnets with dumbbell weights attached.  I tried wrapping an old t shirt around them to minimise the painful ‘clunk’ that would resonate when moving near the zenith. After banging my shins against the weights, many times, I resorted to looping bright yellow guy rope around them to make them particularly unsubtle... it worked for most of the time. 

 

[John]

19 minutes ago, globular said:

I'm thinking about the ES17/92. Is it really 1300g and not the 'official' 1175g?

I've just weighed my ES17/92 and E21 on my kitchen scales.

I get 1150g for the ES17 and 1020g for the Ethos. Both with dust caps on.

Sorry about earlier confused figures - the ES17/92 is heavier but not quite as heavy as I originally thought

Here is my counterweight system:

 

[Dantooine]

36 minutes ago, globular said:

I'm thinking about the ES17/92. Is it really 1300g and not the 'official' 1175g?

I think you are correct. The 12mm version is lighter and is probably the quoted 1175g. I had them at one point and they were not the same weight. 
 

Edit..
sorry, I’ve just seen the above comment. Having a zombie day. 

Edited September 14, 2020 by Dantooine

[globular]

2 minutes ago, Dantooine said:

I think you are correct. The 12mm version is lighter and is probably the quoted 1175g. I had them at one point and they were not the same weight. 

Official figures are 1036g for the ES12/92 and 1175g for the ES17/92.  I trust John's scales more, but they are not far off.

[Dantooine]

4 hours ago, Rob_UK_SE said:

It is indeed, in fact, I think the ES17/92 is even heavier than the 21E. You shouldn’t therefore have any issues. However, I was also trying to help you with a legitimate excuse for not buying it 😀.  Perhaps the 21E might be on the cards at some point? Alternatively, I could just lie and tell you that it’s ugly, has rubbish optics and is quite uncomfortable to use? 🤫

I am assuming that you may not be too far from where we are based.  You are welcome to try out mine on an evening’s session, if you don’t mind a bit of travelling?

It may well be potentially bad if I get to see through one. I’d best not “see the light” just yet. My bank account is in a state of recovery from building up the set I now have 😱 and as you say, ethos are terrible eyepieces. 

Edited September 14, 2020 by Dantooine

[Louis D]

1 hour ago, Dantooine said:

when first see about the bag of washers as a counter balance I imagined a swinging pendulum. It must act as dead weight. 

That's why I have to dampen its swing when moving quickly in azimuth to a new target (by dampen, I mean grab it and stop it from swinging).  It is indeed a swinging pendulum.  Fortunately, moving slowly in azimuth to track doesn't induce the swinging motion to it.  Moving in altitude has no effect on its side to side motions no matter how abrupt.

[Don Pensack]

1 hour ago, globular said:

I'm thinking about the ES17/92. Is it really 1300g and not the 'official' 1175g?

1159g on my gram scale for the 17x92 and 1017g for the 12x92

The 9x120 is 1295g, and the 21mm Ethos is 1021g

[Dantooine]

6 minutes ago, Don Pensack said:

1159g on my gram scale for the 17x92 and 1017g for the 12x92

The 9x120 is 1295g, and the 21mm Ethos is 1021g

So the 9/120 is their heaviest. What is that like to actually use as I’ve not seen or used one?

[John]

Your mileage may vary but I've used a few 110 degree eyepieces and found those just a touch too much even for my hyper wide tastes. Don't fancy a 120 myself but I'll be interested to hear what Don says.

ES also have the 25mm 100 which apparently seems to push the design a little too far.

You can start to see why Tele Vue have stopped where they have.

 

[Louis D]

And first 10 units of the 9mm ES-120 didn't have their field stop inserted, so they actually have a 140 degree AFOV.  The observers who got them aren't letting them go from what I can tell.

[Dantooine]

1 hour ago, Louis D said:

And first 10 units of the 9mm ES-120 didn't have their field stop inserted, so they actually have a 140 degree AFOV.  The observers who got them aren't letting them go from what I can tell.

So you can almost see behind you 🤣

[Dantooine]

1 hour ago, John said:

Your mileage may vary but I've used a few 110 degree eyepieces and found those just a touch too much even for my hyper wide tastes. Don't fancy a 120 myself but I'll be interested to hear what Don says.

ES also have the 25mm 100 which apparently seems to push the design a little too far.

You can start to see why Tele Vue have stopped where they have.

 

I have to agree. The 4.7, I actually pull back a tad to see less. Personally I think I’d have preferred a 4.7E with 100 degrees like the rest of them. I’m sure others opinions will vary. 

[Stardaze]

10 hours ago, Rob_UK_SE said:

That’s great news. 😀 I’m looking forward to those sociable 6pm skies too (let’s hope they are a little less frequently accompanied by cloud!).

Must say, it’s not a great hobby for a morning person like me. Was going to get out tonight, but it’s not going to happen. Recharge for Thurs night, providing the forecast doesn’t change...

[Dantooine]

33 minutes ago, Stardaze said:

Must say, it’s not a great hobby for a morning person like me. Was going to get out tonight, but it’s not going to happen. Recharge for Thurs night, providing the forecast doesn’t change...

I did last night until 4.30 this morning and don’t think I can manage tonight either. 

[Don Pensack]

I reviewed the 9mm 120° elsewhere, but I'll recap:

--the eyepiece is sharp enough, but a bit darker than the 8mm or 10mm Ethos on either side.  Is it the 12 elements?  Or the coatings?  I don't know, but it's obviously darker.

--the curvature of the eye lens is such that ALL peripheral light coming into the eyepiece from around your head reflects directly into your eye.  The eyepiece requires you cup your hands

around the eyepiece to block peripheral light, or use a cloth over your head, or a hood that blocks peripheral light.  Otherwise, the eyepiece is impossible to use.

--the 120° field is simply too wide, not because 120° is bad, but because looking at the edge of the field toward the front of the scope has the sky in your peripheral vision, actually covering about

40% of the field you see.  To use the eyepiece while looking at the edge of the field requires blocking the light of the sky with a black cardboard or plastic sheet because you are actually looking

more in the direction the scope is pointed than you are perpendicular to it.

--correction at the very edge was very good, but not perfect (at f/5.75, coma-corrected).

 

An interesting eyepiece, sort of a collector's item.

 

In contrast, I have almost no reservations about the 92° series.

[Dantooine]

45 minutes ago, Don Pensack said:

I reviewed the 9mm 120° elsewhere, but I'll recap:

--the eyepiece is sharp enough, but a bit darker than the 8mm or 10mm Ethos on either side.  Is it the 12 elements?  Or the coatings?  I don't know, but it's obviously darker.

--the curvature of the eye lens is such that ALL peripheral light coming into the eyepiece from around your head reflects directly into your eye.  The eyepiece requires you cup your hands

around the eyepiece to block peripheral light, or use a cloth over your head, or a hood that blocks peripheral light.  Otherwise, the eyepiece is impossible to use.

--the 120° field is simply too wide, not because 120° is bad, but because looking at the edge of the field toward the front of the scope has the sky in your peripheral vision, actually covering about

40% of the field you see.  To use the eyepiece while looking at the edge of the field requires blocking the light of the sky with a black cardboard or plastic sheet because you are actually looking

more in the direction the scope is pointed than you are perpendicular to it.

--correction at the very edge was very good, but not perfect (at f/5.75, coma-corrected).

 

An interesting eyepiece, sort of a collector's item.

 

In contrast, I have almost no reservations about the 92° series.

Reading this I’m not surprised they are still in stock everywhere. The asking price is still holding firm though.