Televue powermate or explore scientific focal extender.

[djpaul]

Looking for people's thoughts on televues 2 inch x2 powermate vs explore scientific 2 inch x2 focal extender.

[Floater]

I have only the 2.5x Powermate so can’t compare anything. But my PM rocks! ?

[Kusanagi]

I  have got the ES 2" 2x focal extender but do not have the TV powermate so cannot compare, but I have found it to be an excellent addition to my collection as it gives nice and sharp images when in use with no apparent lose of light due to more glass and very well built ( but it makes it a little heavy ).

  I have read that the performance of the ES focal extender  is very  close to a TV powermate ( the TV is said to be slightly better performing ) but it is a lot cheaper and when I was looking for a barlow / focal extender and wanted one that did not change the eye relief, I could not warrant the extra cost of the TV powermate as it is at least a third more expensive than the ES focal extender and as I had read it was not a third better performing.

[John]

I have compared the 1.25" 2x ES Telextender with a 1.25" 2.5x Powermate and the difference was very slight indeed to be honest. I guess it's the same as is being found quite often these days ES have got within a few % of the Tele Vue equivalent performance for quite a lot less money.

While I've not used the 2 inch ES Telextenders I can't see any reason why they would not mirror this situation.

You can't mix ES products with TV in the eyepiece case though - they squabble when you close the lid !

 

 

[djpaul]

Hi John

I think it may have been you I spoke with a few days ago about a 2 inch x2 powermate. ?

My main usage would be with my william optics 73mm zenithstar and dslr firstly for lunar pics. 

[Ruud]

For imaging with the zenithstar it might be better to use a Barlow instead of a powermate or similar extender.

A Barlow will at least partially compensate for the field curvature of a refractor. (I'm not sure what a powermate does in terms of focal plane flatness.)

[bomberbaz]

On 11/05/2020 at 10:44, Ruud said:

For imaging with the zenithstar it might be better to use a Barlow instead of a powermate or similar extender.

A Barlow will at least partially compensate for the field curvature of a refractor. (I'm not sure what a powermate does in terms of focal plane flatness.)

Don't know if you realised Rudd but the post your answering is over a year old. Good information though.

Edited May 12, 2020 by bomberbaz

[Ruud]

1 hour ago, bomberbaz said:

Don't know if you realised Rudd but the post your answering is over a year old. Good information though.

I had no idea, Steve. It's weird, I wasn't doing a search or anything. Don't know why I ended up in this thread.

Stranger things have happened though!

[Don Pensack]

I have compared the 2 directly, visually, and the only things I note are:

--a (slightly) great amount of light scatter in the field of the ES FE

--additional in-focusing required with the ES FE versus essentially none with the PM.

This is a Zombie thread, but whether the differences would be noted would depend on a lot of other factors.

[Robindonne]

Its a very ancient but helpful conversation.   Luckily right on time before buying a 2”.   I read about the telecentric build of the Powermate.  The same build as the ES focal extender.   
thx.  Ill come back Next year to review here

[Stardaze]

Does the 2” ES version utilise a 2” and 1.25” EP holder?

Have been toying with trying one with an APM 13 and Delos 10. Whilst the APM can have the 2” barrel removed, I never do.

[johnturley]

2 minutes ago, Stardaze said:

Does the 2” ES version utilise a 2” and 1.25” EP holder?

Have been toying with trying one with an APM 13 and Delos 10. Whilst the APM can have the 2” barrel removed, I never do.

It has a 2" barrel, but comes with a 1.25 " reducer

John 

[Stardaze]

5 minutes ago, johnturley said:

It has a 2" barrel, but comes with a 1.25 " reducer

John 

Thanks John, that's how I read it. The Powermate provides both EP sizes from the look of it. Still, it could still give me an option for 8mm and 5mm?

[John]

Nice big stack when you use a Powermate 2x with a 20mm 100 eyepiece

 

[Don Pensack]

You should see that combination with a Paracorr.

My best lifetime view of Jupiter was with a 2X PowerMate + Paracorr + 8mm Ethos.

I think it stuck out of the focuser 15-16".

[niallk]

13 hours ago, Don Pensack said:

You should see that combination with a Paracorr.

My best lifetime view of Jupiter was with a 2X PowerMate + Paracorr + 8mm Ethos.

I think it stuck out of the focuser 15-16".

😁

tbh, I only use the 2x PM rarely for my 10E/8E/6E, and I tend to take the Paracorr out.

Interestingly, TV recommends the PM - Paracorr ordering depending on the EP being used (eg PM first in the pic above is not a mistake😀)

It's like sticking a small frac into the focusser!!

Edited August 16, 2020 by niallk

[Woking]

Weight should be a consideration too. My ES 2x FE pushes the mount to it's limit and I should really be rebalancing the scope everytime it's added or removed.

[billhinge]

forget everything else, you need one of these! (on special offer now 😀)

[John]

The long eyepiece plus Powermate stack can come in handy though

 

[niallk]

To the OP:

I can't comment on the ES, but can say that the 1.25" 2.5x PM and the 2" 2x PM from TV work beautifully. 

Edit: Oops - zombie thread!! And there was me worried about straying off topic 😂😂

Edited August 16, 2020 by niallk