How heavy is too heavy?

[Dunkster]

Folks, bitten by the bug, clouds are a dangerous thing

I'm interested in options for an 82* or higher EP that won't overwhelm the 6SE.

Looking at the specs for Meade UWA, ES82, Nagler... they're all around the 800-1000g mark. Factoring in a 2" diagonal, that leaves almost 1.5kg hanging off the end.

How heavy is too heavy?

[MjrTom]

Balancing is the issue more than the actual weight

try these: Baader 1kg Laufgewicht mit Vixen Level Prismenklemme

[CGolder]

no such thing on a 6SE, i used 41 panoptics and ethos in these scopes with the screw on 2" and had no issues at all

[Rob_UK_SE]

There are lots of options available to you, however, you need to be mindful about the size of the field stop.

Balance wise, I found using Baader Hyperions on a 6SE was about as much weight as was workable to avoid any sort of strain on the motors (I used to have a 6SE). In this case, the OTA was positioned on the mount quite close the the end of its dovetail.

The baffle opening on the back of your SCT is going to be the limiting factor for you. In the case of the 6SE the baffle size is 27mm. Therefore, anything beyond a field stop of 27mm is going to show some vignetting. You can use a 2" diagonal, but you will loose some light. Please see the link below:

I want to use 2? eyepieces with my Schmidt-Cassegrain telescope (SCT) and or Maksutov (Mak). Will there be vignetting from the telescope optical tube assembly (OTA) itself?

I would suggest sticking with the 1.25" star diagonal and looking at some 82º field of view eyepieces. For example, you could go for the 16mm Tele Vue nagler. This would give you a magnification of 93x (your scopes focal length is 1500mm?). The 13mm Nagler T6 is a wonderful eyepiece and would give you 115x magnification.

Alternatives could include the 14mm / 11mm Explorer Scientifics - both eyepieces are highly regarded.

Careful though, the wide field bug is dangerously addictive!

Rob

[CGolder]

I had a 6SE and found it extremely good with 2" eyepieces and certainly worth the upgrade, the results even in a 41mm 68 degree were very pleasing and provided nice views ( how do they do that )

not sure if my mount was better than most be counterweighting didn't even cross my mind as it wasn't struggling in any way with extremely large/heavy eyepieces and a 2"

[Luke]

I think the T6 Naglers are under 250g:

Tele Vue Nagler Eyepieses - Telescopes UK: Telescopes & Telescope Accessories in your only London shop

[John]

...The baffle opening on the back of your SCT is going to be the limiting factor for you. In the case of the 6SE the baffle size is 27mm. Therefore, anything beyond a field stop of 27mm is going to show some vignetting. You can use a 2" diagonal, but you will loose some light. Please see the link below:

I want to use 2? eyepieces with my Schmidt-Cassegrain telescope (SCT) and or Maksutov (Mak). Will there be vignetting from the telescope optical tube assembly (OTA) itself?

.......

Thats exactly my understanding too. You can certainly stick a 2" eyepiece with a large field stop on the back of a C6 or a C5 for that matter and the view will look OK but not all the light gathered by the primary will be reaching the eyepiece.

I think Celestrons own advice needs to be heeded on this.

[Dunkster]

Thanks chaps, inspirational as always!

So... if I understand this correctly, I shouldn't try for anything more than a 27mm EP?

I'm looking for the widest I can get, at practical size, weight and cost

options so far....

1. ES82 24mm (1.3 deg) 725g $199/$299
   
2. ES100 20mm (1.33 deg) 964g! $399/499
   
3. TV Nagler 20T5 (1.09 deg) 482g $495
   
4. TV Nagler 22T4 (1.2 deg) 680g $525
   

The Meades seem to be about the same weight as the ES. I've used US$ as I'm going out there on business shortly and can get it dropped to my company's office

How would I know if I'm stressing my mount? (with or without counterbalance) And would I miss the FOV if I treated myself to the TV? Is the 22T4 really better than the 20T5? Am I wasting my money on my little SCT?

Sorry for all the questions... the end of the ES sale is approaching

Play safe, or take the chance ...

[John]

So... if I understand this correctly, I shouldn't try for anything more than a 27mm EP....

No, its the field stop diameter that should be around 27mm max. Trouble is, many eyepiece brands don't publish the field stop diameter. Predictably, Tele Vue do though. The longest focal length TV's that fit within this limit are:

TV 32mm Plossl: field stop = 27mm

TV 40mm Plossl: the same - so no more sky visible

TV 24mm Panoptic: the same

TV Nagler 20mm: 27.4mm so OK

TV Ethos 17mm: 29.4 so nearly OK but costs £630

Other eyepieces of similar specs to the above (ie: focal length and FoV) would be OK too.

[Ian123]

Came across this, don't really know how reliable it is but might be worth a look, you can of course change whatever parameters you want to view including the field stop for various EP's

ep.xls

[Dunkster]

Thanks again, chaps, great spreadsheet too, it's... erm... illuminating

Basically that puts paid to my ideas of a wide EP for now at least, but takes care of most of my weight worries so long as I ignore the Ethos...

1. TV Ethos 17mm 750g ~£500
   
2. TV Nagler 20T5 482g ~£300
   
3. ES 82 18mm 396g ~£100
   

Are the TV really worth the extra £££? Hmm. I could essentially have the 11, 14 and 18mm ES82 for the price of the 20T5 at the sale prices. But it's my birthday soon and I deserve a treat

Anything else I should consider? (sorry, probably over thinking this!)

[Rob_UK_SE]

IMO The Ethos might be a little overkill in your scope - although it would provide exquisit views.

The 20mm Nagler would be ideal for utilising all of the available light from the baffle, without any problem with vignetting. However, this eyepiece has quite a limited amount of eye relief so you do have to get very close.

If you stayed with the 1.25" barrel you could look at: 24 Panoptic, 16mm Nagler and 13mm Nagler.

With a 2" barrel I would still recommend the 24mm Panoptic for your wide field, then 17mm Nagler (excellent eye releif) and 13mm or 12mm Nagler.

Are Tele Vue worth it, well, this all comes down to personal preference and opinion. Your 6SE is quite a slow scope being f10, so it isn't to critical about the eyepieces you choose. Whereas in very fast f4-5 ish Newtonian it is much more important.

I am a big Tele vue fan, however, with the recent price increases my recommendation would be to either explore the used market for Tele Vue, or alternatively strongly consider the Explorer Scientific set. The 82º model performance is very close to the Nagler and in last months Sky at Night the 100º was considered to be very close the the Ethos. In both cases they are nitrogen filled too!

Rob

[John]

IMO The Ethos might be a little overkill in your scope - although it would provide exquisit views....

They look even more OTT in a 1.25" diagonal and this is just the Ethos 13mm

[Rob_UK_SE]

but...I bet you smile like the cat that just got the cream every time you use it.

A lovely grab and go setup there John.

Rob

[Dunkster]

LOL John you're going to cost me dear showing me that!

[Dunkster]

OK hopefully last query

What makes the 24 panoptic better for wide than the 20t5, they'd show pretty much the same amount of sky? Optics or just a cost consideration?

From reading other threads, I got the impression that for a given view, higher magnification is better because of the sky magically be moving darker. Just curious, I'm like that

[Rob_UK_SE]

They are both great eyepieces. The 20mm Nagler will possibly have better contrast as the sky will be darker due to a slightly increased magnification.

Some say that it is difficult to take in the whole field of view in an eyepiece much above 70º. Personally, I don't find this an issue, but some do.

The 20mm Nagler has 12mm of eye relief so it is a little tighter than the 24mm Panoptic with a more generous 15mm. If you wear glasses, or might in the future, this could be an issue.

The Nagler and Panoptic should both be tack sharp. The main selling points of the Nagler are the slightly wider field stop, the 82º field of view and the increased magnification which is good in light polluted areas.

The benefits of the Panoptic are that it is very easy to use, flat right accross the whole field (although I am sure the same can be said for the Nagler), you don't need to upgrade the diagonal and it is also considered one of the best eyepieces available for a binoviewer - should you ever decide to move in this direction. Lastly, it is cheaper too!

Rob

[RikM]

Just to throw another one into the mix, my Pentax 20mm XW is a lovely EP. If you are after the widest field then it comes up short at only 70° but when looking through it, it's almost like it isn't there. I was truly torn between this and the Pan 24 and in the end went with the XW because I already had a couple of other focal lengths. This spends a lot of time in my focuser.

[Dunkster]

Thanks Rob - I do wear glasses, but not for observing. My ES82 8.8 has arrived, and I'm just waiting for the clouds to shift to have my first 82 degree experience and take it from there.

Thanks Rik - I've seen some good things written about the Pentax, and isn't indecently priced either.

[swamp thing]

What makes the 24 panoptic better for wide than the 20t5, they'd show pretty much the same amount of sky? Optics or just a cost consideration?

It isn't. They are both great eyepieces. They are pretty close on most things but AFOV. You could argue that the pan is flatter but the Nagler is more contrasty.

Too close to call IMO

If I had my 24mm pan back again, I would exchange it for the Nagler every time but I won't change my 20T5 for the Pan.

I just prefer the AFOV of the Nagler.

Regards Steve

[John]

..If I had my 24mm pan back again, I would exchange it for the Nagler every time but I won't change my 20T5 for the Pan. I just prefer the AFOV of the Nagler......

I've been down the same road as Steve and my feelings for these eyepieces are the same as his

[Ian123]

I would exchange it for the Nagler every time but I won't change my 20T5 for the Pan.

Is this what they call a 'Paradox'

[Dunkster]

Thanks to all for your help, hoping to get out with the 8.8 over the weekend if the weather stays anywhere near the forecast then will decide... doing my sums, the Ethos looks a thing of beauty but v pricey.... There's always a tomorrow, I hope

[Dunkster]

Folks,

Sorry to reopen this one, but indecision has struck with too much choice at this critical juncture

I've been erring in the direction of the Nagler 20t5 and either a 11 or 13 t6 - any reason the 12t4 would be better?

But then, after reading the S@N of the ES100 I'm tempted... it's less than the price of either Nagler if ordered now, but then the FOV is so wide it shows almost as much sky as the 20t5. Yet it's very heavy compared to the 82(TV or ES). Any disadvantage to the 14 instead of the 20t5 besides weight?

Alternatively I could and add to the 8.8 with the 11, 14 and 18 ES82 for $400. Too many FL?

Or any mix of the above...

As you can see, I've way over complicated it. Any tips to mitigate the risk and/or find the best balance?

[cs1cjc]

It is all too easy to spend money on astronomy hardware!

I am becoming cynical about the value of eyepieces wider than about 68* AFOV, nor I do not like bulky heavy eyepieces like the Hyperions, nor do I want to use 2" while 1.25" still serves the purpose. But then I have never liked heavy engineering...

I am also trying to minimise focal lengths and currently generally use only ES82 4.7mm, 8.8mm, Hyperion 17mm (tuned down to 15mm) and and ES24 68*. I have a 38mm SWA which I rarely use and all my filters are 1.25". I do have a GSO screw-in 1.5x Barlow to fill gaps when I (rarely) need to. In reality the Hyperion is also seeing little use.