ES 2x Focal Extender vs TV Powermate 2.5x?

[Vinnyvent84]

Can someone give me some advice / insight? I have a Nexstar 6SE living in a Bortle 8 zone in NYC. Would upgrading from a ES 2x Focal Extender to a Televue Powermate 2.5x show a worthy difference for lunar and planetary visuals?

[Mr Spock]

It will change the magnification of your eyepieces by 2.5 times instead of 2.0, that's all. 

So at 1500mm focal length and 18mm eyepiece with Powermate would give you x208 instead of x167 with the 2x Focal Extender.

[Vinnyvent84]

2 hours ago, Mr Spock said:

It will change the magnification of your eyepieces by 2.5 times instead of 2.0, that's all. 

So at 1500mm focal length and 18mm eyepiece with Powermate would give you x208 instead of x167 with the 2x Focal Extender.

Thanks Mr. Spock! I probably should have made a more apples to apples comparison. If I were to use a 2x Televue Barlow vs a 2x ES Focal Extender would there be a distinguishable difference in detail at the same magnification between the two? 

[bosun21]

5 hours ago, Vinnyvent84 said:

Thanks Mr. Spock! I probably should have made a more apples to apples comparison. If I were to use a 2x Televue Barlow vs a 2x ES Focal Extender would there be a distinguishable difference in detail at the same magnification between the two? 

No. I have owned both and can't notice any discernable difference between them.

[Ricochet]

9 hours ago, Vinnyvent84 said:

Can someone give me some advice / insight? I have a Nexstar 6SE living in a Bortle 8 zone in NYC. Would upgrading from a ES 2x Focal Extender to a Televue Powermate 2.5x show a worthy difference for lunar and planetary visuals?

Looking at your other posts your eyepieces are a 32mm TV Plossl, a 8-24mm BHZ and a 7mm X-Cel LX. With your f/10 SCT the only eyepiece that you can really use the 2X extender with for planetary is the 32mm Plossl, to emulate a 16mm Plossl, which is too low a magnification. For planetary you will want to be using the 8-10mm part of the range of the BHZ and (maybe!) your 7mm X-Cel LX. Setting your BHZ to 12mm and using it with the extender is almost certainly going to degrade a planetary image in an SCT, but might be useful for splitting double stars.

So no, you won't see any increase in planetary performance by upgrading to the TV Powermate, because either extender should remain in its box during those observations.

[John]

Given the eyepieces you already have I think I would be considering a good fixed focal length 6mm eyepiece for 250x which is likely to be the upper end that is useable reasonably often with the scope.

Something like a Vixen SLV 6mm would cost no more than an ES 2x focal extender (possibly less) and provide excellent high power performance.

 

[Vinnyvent84]

2 hours ago, Ricochet said:

Looking at your other posts your eyepieces are a 32mm TV Plossl, a 8-24mm BHZ and a 7mm X-Cel LX. With your f/10 SCT the only eyepiece that you can really use the 2X extender with for planetary is the 32mm Plossl, to emulate a 16mm Plossl, which is too low a magnification. For planetary you will want to be using the 8-10mm part of the range of the BHZ and (maybe!) your 7mm X-Cel LX. Setting your BHZ to 12mm and using it with the extender is almost certainly going to degrade a planetary image in an SCT, but might be useful for splitting double stars.

So no, you won't see any increase in planetary performance by upgrading to the TV Powermate, because either extender should remain in its box during those observations.

Thank you for clarifying that’s what I figured but just wanted to make sure it was more a scope / location limiter and not quality of product one. 

[Vinnyvent84]

2 hours ago, John said:

Given the eyepieces you already have I think I would be considering a good fixed focal length 6mm eyepiece for 250x which is likely to be the upper end that is useable reasonably often with the scope.

Something like a Vixen SLV 6mm would cost no more than an ES 2x focal extender (possibly less) and provide excellent high power performance.

 

Thank you! I was contemplating the TV Delite 7mm as I was told it’s actually more like 6.5. But it comes a decently high price before I was able to even see how my current Celestron X-Cel 7mm does. If I manage to get good views at some point depending on conditions this option you gave looks like a reasonable cost to give it a try if the 7mm happens to work out well. 

[Naughty Neal]

Although the Xcel - lx is listed as a 7mm it is in fact  6.5mm in line with the meade HD60 version which uses the same internal lense arrangement.

 

Edited December 27, 2023 by Naughty Neal

[Vinnyvent84]

2 hours ago, Naughty Neal said:

Although the Xcel - lx is listed as a 7mm it is in fact  6.5mm in line with the meade HD60 version which uses the same internal lense arrangement.

 

Didn’t know that thank you!