9 replies to this topic

[Minuam]

I have 13 mm Ethos(weight – 590 gms) which I have used few times on my Celestron 127MAK, alt/az, goto.
I am wondering if is too heavy for the scope and too heavy for the tracking?
Thank you.

[SeattleScott]

Are you having issues? Is the scope losing the target when you swap it in? Is it affecting Goto accuracy?

 

Potentially adding some "counterweight" to the opposite end, maybe in the form of a dew shield if you aren't already using one, would help balance it out.

 

Scott

[Minuam]

Are you having issues? Is the scope losing the target when you swap it in? Is it affecting Goto accuracy?

 

Potentially adding some "counterweight" to the opposite end, maybe in the form of a dew shield if you aren't already using one, would help balance it out.

 

Scott

 

Thank you very much.

No I have not noticed any loss in tracking.

So its all right to use heavy EP for 5" scope with GoTo for long term?

Edited by Minuam, 26 November 2022 - 02:31 PM.

[Mike B]

I think there may be more glass in my 13-Ethos than in my 6” Mak!?   I don’t generally mix the two, but I can…. Might have to slide the OTA forward in the clamp to help maintain balance with such a heavy load in the tail? But then when reverting to normal-weight EP I’d be sliding things back again…. Lotta fuss for an EP!  I dunno… maybe I don’t love the Ethos enough to jump thru those hoops? Plus I can use any normal-weight 70-78* EP having full-field eye relief of 14mm to 17.5mm FL & get the same viewable field as I can comfortably see in the 13E with eyeglasses. 

[Minuam]

I think there may be more glass in my 13-Ethos than in my 6” Mak!?   I don’t generally mix the two, but I can…. Might have to slide the OTA forward in the clamp to help maintain balance with such a heavy load in the tail? But then when reverting to normal-weight EP I’d be sliding things back again…. Lotta fuss for an EP!  I dunno… maybe I don’t love the Ethos enough to jump thru those hoops? Plus I can use any normal-weight 70-78* EP having full-field eye relief of 14mm to 17.5mm FL & get the same viewable field as I can comfortably see in the 13E with eyeglasses. 

Thank you very much. My main concern is the tracking. Very helpful and much appreciated.

[Starman1]

Thank you very much.

No I have not noticed any loss in tracking.

So its all right to use heavy EP for 5" scope with GoTo for long term?

The issue is the strength of the diagonal.

If you have a 1.25" diagonal with a plastic body, I've seen a number of those break, and I wouldn't want to trust the diagonal when the scope points up and the eyepiece

is applying a lot of bending force.

An aluminum body shouldn't be an issue.

[Mike B]

Understood- indeed a valid concern! Depending on the mount in question, if the payload mounted is anywhere near its limit, you’d want to be wary. Otherwise, I’d think if the OTA+EP was a lot for it, you might hear motor strain? Or if it’s an EQ-type mount you might get some unwanted slop when, after chugging the load uphill, it reached the meridian-flip point & transitioned to the downhill side? In any even, getting the OTA load balanced for weight is always a good goal! Who needs mount trouble?  

[Spikey131]

It depends upon the Mak.

 

It looks absurd, but the 13 Ethos works in this 90mm Mak, and with the Questar’s built in Barlow, provides a FOV wider than a 24mm Brandon at 100x at the low end, and 200x at the high end - basically the only eyepieces the Q would ever need.

 

I tried it with my Q, but it is a bit unbalanced, and messes with the Questar feng shui.  The 13mm Nagler T6 makes a lot more sense.

 

This is from the TV website.

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[SeattleScott]

If you have a solid diagonal I wouldn’t be afraid to give it a shot. If you notice problems with tracking or GoTo accuracy, then stop using it with that scope. But the 13 Ethos really doesn’t seem extremely heavy for eyepieces these days, so it’s probably fine.

Scott

[Minuam]

The issue is the strength of the diagonal.

If you have a 1.25" diagonal with a plastic body, I've seen a number of those break, and I wouldn't want to trust the diagonal when the scope points up and the eyepiece

is applying a lot of bending force.

An aluminum body shouldn't be an issue.

Thank you all and thank you very much Mr Starman,
Your knowledge help to beginners is amazing, priceless and very helpful.