8mm Ethos --Question

[Pig]

What is the purpose of the thumb screw that goes between the 1.25" & 2" barrels ? and is it ok to remove it ? I am guessing you have to so the eyepiece sits properly in the diagonal !!

[iPeace]

Yes you can remove it, especially if you only use it in a 2" diagonal. Just don't lose it! Replacements are not easy to find. Not sure what it's for, it doesn't seem to have any function in combination with any of my diagonals.

[iPeace]

BTW you can find the instructions for this eyepiece (including what the screw is for) on the Televue web site.

[Louis D]

I think it's so you can tighten it to the outside of a 1.25" diagonal so the eyepiece can be fully inserted into the eyepiece holder.  Of course, the better solution would have been a removable 2" skirt like the AstroTech AF70 eyepiece line.

[DRT]

I removed these from my 6, 8, 10 and 13mm Ethos as soon as I bought them as I just couldn't see a use for them in either 2" or 1.25" diagonals.

 

[John]

I've removed the scews from mine too. They live in the boxes along with the instruction sheet and Tele Vue stickers.

Interesting point Louis D makes - the SX Ethos have removable 2" "skirts".

[Pig]

Cheers guys..... I will remove it and make sure I don't lose it  

[m.tweedy]

when i bought mine i also got some Baader 28mm fine tuning rings and keep them attached at all times

https://www.firstlightoptics.com/baader-planetarium/baader-hyperion-finetuning-ring.html

Here is the article that i used

 

 

 

 

Before fine tuning rings

[m.tweedy]

Here they are with the fine tuning rings permanently attached.

[John]

I use the Baader FT rings with mine as well. I use the 28mm ones but I'd like to find something a little shorter - something around 20mm would be ideal. This would ensure that the eyepiece focal plane is closer to where Tele Vue intended when the eyepiece is used in 2" mode while still allowing 2" filters to clear the 1.25" barrel section.

 

[m.tweedy]

1 minute ago, John said:

I use the Baader FT rings with mine as well. I use the 28mm ones but I'd like to find something a little shorter - something around 20mm would be ideal. This would ensure that the eyepiece focal plane is closer to where Tele Vue intended when the eyepiece is used in 2" mode while still allowing 2" filters to clear the 1.25" barrel section.

 

i agree. I have not been able to find the solution either.

[m.tweedy]

this is the official expensive solution

http://www.televue.com/engine/TV3b_page.asp?id=41

[DRT]

2 hours ago, m.tweedy said:

this is the official expensive solution

http://www.televue.com/engine/TV3b_page.asp?id=41

I have two of those that I use with my 8mm and 6mm Ethos and I have to say that once you have swallowed the exorbitant cost and forgotten about it they are great to have around. The quality of the engineering that has gone into them is top notch and they feel extremely secure. Personally, I think the extra few quid is worth it when you consider the value of the thing you are planning to hang off the end of it

 

[John]

Having tried a Tele Vue barrel extension, I didn't think it was any better than the Baader 28mm Fine Tuning ring and even longer so further from the focal plane position that I would like to achieve. Not worth the £25 asking price IMHO, despite being a massive TV fan on most things 

 

[alan potts]

2 inch skirts reminds me of the late 60's.

I guess reading this the 8mm Ethos is already with you Shaun, which one's next?

Alan

[Louis D]

5 hours ago, m.tweedy said:

i agree. I have not been able to find the solution either.

Well, I found the Blue Fireball 2" Spacer Ring with 0.75" Extension # S-2C at 19mm long on this side of the pond.  If it doesn't screw all the way in to the 2" filter threads, it would be just over 20mm of extension.

[DRT]

Those look very good, Louis, and very similar to the Baader fine tuning rings we have over here.

[Pig]

4 hours ago, alan potts said:

2 inch skirts reminds me of the late 60's.

I guess reading this the 8mm Ethos is already with you Shaun, which one's next?

Alan

I am not sure Alan, if anything it will be the 3.7mm but the XW's I have are pretty hard to beat (3.5 & 5) and I not sure if 110 degrees are needed at such low power !  The sale ends today .......

[John]

9 minutes ago, Pig said:

I am not sure Alan, if anything it will be the 3.7mm but the XW's I have are pretty hard to beat (3.5 & 5) and I not sure if 110 degrees are needed at such low power !  The sale ends today .......

I've now picked a the 3.7ESX to go with the 4.7 but pre-owned rather than from TH. The 4.7 seems just as good as the 5mm XW to me with the exception of the eye relief so it will be interesting to see how the 3.7 compares with the 3.5 XW.

I guess you mean high power rather than low. You don't need 110 degrees at either of course but it's nice to have with my undriven, alt-az mounted scopes

 

 

 

[Pig]

Yes John I meant high power  ....  they are great with driven mounts too. Given the small difference in FL between the 4.7 & 3.7mm there is quite a difference in magnification. If a 3.7 came up second hand I would take it

[alan potts]

Not just saying this because I keep thinking of getting one but I feel the 4.7mm may get more use. I have seen a good few 3.7mm E's on the secondhand market since they came out but never a 4.7mm. I feel the lower power may get more scope time too on nights of less than idea seeing. Both of these are really too short for my 18 inch as they give good cricket scores magnification, I think it is the only reason I haven't pushed the boat out on them.

I do have the 4.5mm and 3.5mm Delos'ssss which I use in driven mounts on some of my other scopes. I have said it many times but the Ethos range are in a class of their own when used on a Dobsonian, well any 100 degree eyepiece really.

What I don't have an answer to is why I had 5 of them before I even had a Dobsonian scope.

Alan

 

[iPeace]

2 hours ago, John said:

I've now picked a the 3.7ESX to go with the 4.7 but pre-owned rather than from TH. The 4.7 seems just as good as the 5mm XW to me with the exception of the eye relief so it will be interesting to see how the 3.7 compares with the 3.5 XW.

I guess you mean high power rather than low. You don't need 110 degrees at either of course but it's nice to have with my undriven, alt-az mounted scopes

 

 

 

You will love the 3.7mm. I certainly do.

[iPeace]

2 hours ago, Pig said:

Yes John I meant high power  ....  they are great with driven mounts too. Given the small difference in FL between the 4.7 & 3.7mm there is quite a difference in magnification. If a 3.7 came up second hand I would take it

And well you should.

[iPeace]

10 hours ago, John said:

Having tried a Tele Vue barrel extension, I didn't think it was any better than the Baader 28mm Fine Tuning ring and even longer so further from the focal plane position that I would like to achieve. Not worth the £25 asking price IMHO, despite being a massive TV fan on most things 

 

Took my que from John on this one, these are fine kit and get it done in style.

[DRT]

1 hour ago, alan potts said:

What I don't have an answer to is why I had 5 of them before I even had a Dobsonian scope.

Were you in the Cub Scouts, Alan? If so, perhaps you just subconsciously acted upon the spirit of the Motto