Advice on an Ethos for high power observing

[Nicola Fletcher]

Hello all,

I'm looking for a (relatively) high power, 2”, widefield EP for my 12” dob primarily, but also for my new Mewlon 180C. Given their relatively narrow field of view, I think Ethos would be my preferred EPs for this. For the dob, I mainly use a 22mm Nagler and a Baader 8-24mm Zoom. The scope is f/5 and I don’t use a Paracorr. I’m not overly impressed with the zoom in the dob - it’s fine in my refractors but the image seems grainy in the dob, and not as nice as the views with the Nagler which are wonderful.

With the Mewlon, I’m planning on using a Baader 2” visual back, Baader 2” BBHS mirror diagonal, 22 Nagler and 41 Panoptic. To stay with 2” for both telescopes, I was deliberating between a 6, 8, 10 or 13mm Ethos. I could get a Powermate as well to maximise the value from one EP.

I’d really appreciate your advice on which to go for!

 

[The60mmKid]

Hi Nicola!

Do you have a strong preference for Tele Vue? I ask because the XWA eyepieces sold by various vendors (for example) give up little to an Ethos, cost less, and weigh less. Eyepiece weight is a consideration with dobs, especially with ultra-light ones on low rocker boxes like yours. Heavy eyepieces can create balance difficulties, which is why I wouldn't opt for powermate + heavy eyepiece.

Since your Mewlon has a much higher focal ratio, I'd keep the 41 Panoptic (or something similar) to use with the Mewlon, then put together 3-4 medium focal length eyepieces that work well with both the Mewlon (for medium to high magnification) and the dob (for low to medium magnification), then have one or two eyepieces of shorter focal length for high magnification with the dob.

So... A long FL eyepiece just for the Mewlon, a set of medium FL eyepieces for both, and a short FL eyepiece or two for the dob.

But that's just me 🐢

 

Edited February 19 by The60mmKid

[The60mmKid]

I'm also curious: When you notice the graininess from the zoom, have you compared it to a fixed FL eyepiece of the same (or similar) FL to which the zoom is set? The reason I ask is that I'm curious whether you're seeing optical shortcomings of the zoom or whether other variables are at play (e.g., the greater sensitivity of your dob to seeing vs. a smaller instrument, thermal acclimation of the primary mirror, etc.). When I started using a dob after years of using a refractor, I wasn't happy with the medium-high power views, and it took me a while to learn to manage the thermal factors that were actually impacting the view.

I also recognize that, unlike me, you aren't a garden-variety bonehead 🐒 So, please accept my humble apologies if all of this is already obvious.

Edited February 19 by The60mmKid

[AstroKeith]

I can see you are a TV user, so understand the inclination to stay with them. (Me too!)

I have 8,10,13 & 21mm Ethos. I used to have a 6mm Ethos but found I didnt use it. So I bought the 10mm and a x2 Powermate.

My 13mm is my favourite EP, often it stays in all session. The 10 is 2nd. When I had my 10" travel Dob, I once did 109 Messiers (WSP) without removing the 13mm Ethos. Al Nagler was on hand and made me write it up.

So, I'd suggest the 13mm, leaving a decent gap to a 8mm later.

[The60mmKid]

1 minute ago, AstroKeith said:

I can see you are a TV user, so understand the inclination to stay with them. (Me too!)

I have 8,10,13 & 21mm Ethos. I used to have a 6mm Ethos but found I didnt use it. So I bought the 10mm and a x2 Powermate.

My 13mm is my favourite EP, often it stays in all session. The 10 is 2nd. When I had my 10" travel Dob, I once did 109 Messiers (WSP) without removing the 13mm Ethos. Al Nagler was on hand and made me write it up.

So, I'd suggest the 13mm, leaving a decent gap to a 8mm later.

Yes, Tele Vue is fantastic, and it wasn't my intention to cast doubt on their quality or value. I've gone through phases of selling everything that isn't black and green!

[Louis D]

Calling @Don Pensack for feedback.  I believe he uses Ethos extensively at high powers in his large Dob, or at least used to.

[Don Pensack]

Because of needing glasses down to 8mm, my longer focal length Ethos eyepieces went to other observers.

I discovered I used the 7mm APM XWA a lot more than the 8mm Ethos, so the 8mm went, too.  I simply preferred the 9mm>>7mm jump a lot more.

But I still use the 6mm, 4.7mm and 3.7mm.

The 6mm Ethos is special--it's as sharp as eyepieces can get and has superb contrast.

The 3.7mm is similar, but gets more limited use because of seeing conditions at 500x in my scope.  When seeing allows, it is my favorite eyepiece for planetary nebulae.  It makes seeing M57's central star no challenge.

The 4.7mm is my Uranus/Neptune eyepiece and I value the in-focus longer drift time of the 110° field.

Some nights, I want to leave my glasses on, so I do use a 4.5mm (actually 4.8mm) Baader Morpheus, and it is as sharp as the Ethos SX, but the much narrower field means I move the scope a lot more.

 

In a long focal ratio scope, the needs are different.  A 13mm Ethos would see a lot of use.  I think the 10mm might be just a bit better eyepiece, but it might see less use than the 13mm in the Mewlon.

In the dob, though, the 10mm and 6mm make a powerful pairing.  The 10mm would spend a LOT of time in the focuser.  The 6mm could be a "planet/moon" eyepiece--it's that sharp.

[John]

I have used Ethos eyepieces for high (and low) power observing for a decade or so with dobs and refractors.

Personally I think they are superb eyepieces in both these roles. I currently have the 21mm, 13mm, 8mm, 6mm and the 4.7mm in the series. I would like to get the 3.7mm again - I rather miss it 🙄

There are excellent alternatives of course so you have good and less expensive options as well if they are of interest.

@JeremyS has discovered the virtues of Ethos eyepieces relatively recently and I believe is really enjoying them as well 🙂

NB: I have used the 2x Powermate with the 13mm and 8mm as well in the past and the performance was still exceedingly good. The resulting "stack" in the focuser gets rather long though. 

Edited February 19 by John

[Don Pensack]

I've done PowerMate + Paracorr + 8mm Ethos ( a LONG stack, with 18 elements!) in the dob and had my "lifetime-best" view of Jupiter in full technicolor.

456x and absolutely perfect seeing.  I'll never forget it--like a Christopher Go or Damian Peach image, only with a sharper focus.

[JeremyS]

I’m a late adopter on Ethos. I find them excellent in my TSA 120 and Mewlon 210. 
I have 17, 13, 10, 8, 6, 4.7, 3.7
The FL of the M180 is also long so you won’t need the shorter FL Ethos. Their wide FOV means long drift time with an altaz mount. Optically they are excellent though fairly short on eye relief.

I find the Leica Zoom excellent with my M210. Can really tune in the seeing.

 

[Nicola Fletcher]

Thank you all very, very much for the replies. This is absolutely brilliant.

I think I am pretty much sold on Ethos. I really like Televue and all of my other EPs (apart from the Baader zoom) are Naglers and Panoptics.

@The60mmKid, interesting question about the zoom. I’ve definitely used it at 24mm and I think I still didn’t like it compared to the 22mm Nagler, but I haven’t compared it to any of the 1.25 higher power TVs that I have. I’ll do a proper comparison next time.

I appreciate the very different focal lengths of the two scopes which will have different requirements. I’ll try to sort out the dob first. Thank you @Don Pensack for your advice - I’ll go for the 10mm and 6mm first, then treat the Mewlon to the 13mm!  I KNEW this was going to be expensive!

 

[niallk]

The 10E was my first Ethos in my 15" f4.5.  I followed with a 6E ... then a 17E 🙈  I do leave a P2 in the focuser at the cost of weight.

Great EPs - enjoy!

[AstroKeith]

On 19/02/2024 at 23:42, Nicola Fletcher said:

Thank you all very, very much for the replies. This is absolutely brilliant.

I think I am pretty much sold on Ethos. I really like Televue and all of my other EPs (apart from the Baader zoom) are Naglers and Panoptics.

@The60mmKid, interesting question about the zoom. I’ve definitely used it at 24mm and I think I still didn’t like it compared to the 22mm Nagler, but I haven’t compared it to any of the 1.25 higher power TVs that I have. I’ll do a proper comparison next time.

I appreciate the very different focal lengths of the two scopes which will have different requirements. I’ll try to sort out the dob first. Thank you @Don Pensack for your advice - I’ll go for the 10mm and 6mm first, then treat the Mewlon to the 13mm!  I KNEW this was going to be expensive!

 

Nicola, did you see someone has just posted some Ethos for sale!

[JTEC]

I’ll just point out that I have an effectively brand new 7mm APM XWA 100 degree eyepiece listed here in the SGL For Sale section 🙂

[Highburymark]

Ethos do seem to come up in the classifieds pretty often, particularly on ABS. I had a couple of Delites that weren’t getting used, so recently swapped them for a 6mm Ethos, which gives 150x in my TSA, or 225x with the Tak extender. Stunning views of the Moon this week. And an added bonus - it’s a relatively light eyepiece.

[Mumia]

Hi, I have both the 13 and 6 mm ethos. These are great eyepics, with very good self-correction. I also had other focal lengths before, but these were the two I used most often. Especially the 13mm seems to be special. I filled the remaining gaps with delos and naglers. In my opinion, when it comes to eyepieces with a field of around 100 degrees, only the HW Nikons seem to be better. They are even more expensive, but we get two focal lengths for the price of one eyepiece thanks to the included branded barlow.

Edited February 22 by Mumia

[John]

2 hours ago, Highburymark said:

....a 6mm Ethos, which gives 150x in my TSA, or 225x with the Tak extender. Stunning views of the Moon this week. And an added bonus - it’s a relatively light eyepiece.

Thats true. The 8mm and 6mm Ethos are actually a little lighter than their Delos counterparts. 

[Nicola Fletcher]

15 hours ago, AstroKeith said:

Nicola, did you see someone has just posted some Ethos for sale!

Thanks @AstroKeith! The price is very close to the new price - plus I have a voucher for FLO so I don’t think I’d save anything from new. I appreciate you letting me know!

[Louis D]

5 hours ago, Nicola Fletcher said:

Thanks @AstroKeith! The price is very close to the new price - plus I have a voucher for FLO so I don’t think I’d save anything from new. I appreciate you letting me know!

Especially when you consider you need to subtract the 20% VAT from the new price.  It's highly unlike the seller is going to collect it again, so you really need to work from the pre-tax price to establish the tax-free used price.

[John]

17 minutes ago, Louis D said:

Especially when you consider you need to subtract the 20% VAT from the new price.  It's highly unlike the seller is going to collect it again, so you really need to work from the pre-tax price to establish the tax-free used price.

Over here we tend to work on the basis of around 60% of the retail price, including VAT for private sales of pre-owned equipment. 

If we knock the VAT off before that calculation we would be looking at used price expecations which are perhaps unrealistically low ?

 

 

Edited February 23 by John

[Don Pensack]

£100 + VAT = £120

60% of £120 = £72

It effectively means the eyepiece is being sold for 72% of the pre-tax cost.

That's not abnormal in the US, either.  It still represents a significant reduction from the new price.

A lot of used prices in the US run even higher, at ~80% of the new pre-tax price.

It explains why I've always sold used eyepieces in only a few minutes, as I use a 50% calculation for pre-tax price.

[Louis D]

Ultimately, it comes down to what the market will bear.

I always laugh when I see ads saying "Final price reduction!" as if that makes any difference to most buyers.  Generally, it's sellers who way overprice in the first place on non-in-demand items who do this.  I especially chuckle when they're trying to sell at a higher than new current price when the same item goes on sale or the price has come down drastically since new.  I've contacted some to point this out, and they get all indignant saying they sticking to their guns asking 75% to 80% (or more) of the price they paid.