Televue Eyepieces?

[iceblaze]

Hello,

According to this sticky:

http://stargazerslounge.com/beginners-help-advice/80772-eyepieces-very-least-you-need.html

I should go for the following eyepieces for my 90mm/F7 OTA (660mm focal length):

5.25mm (5mm) - high power (7 * 0.75)

8.75mm (9mm) - medium-high power (7 * 1.25)

14mm - medium-low power (7 * 2)

19.25mm (19mm) - low power (7 * 2.75)

35mm - ultra low power (7 * 5)

Which would turn out to be the following eyepieces from Televue:

5mm: Televue 5mm Nagler Type 6 Eyepiece - 1.25" - OPT Telescopes

9mm: Televue 9mm Nagler Type 6 Eyepiece - 1.25" - OPT Telescopes

14mm: Televue 14mm Radian Eyepiece - ERD-14.0 - OPT Telescopes

19mm: Televue 19mm Panoptic Eyepiece - EPO-19.0 - OPT Telescopes

35mm: Televue 35mm Panoptic 2" Eyepiece - EPO-35.0 - OPT Telescopes

What I would like to know is, am I correct in my math and in purchasing these specific eyepieces?

Also, all the other eyepieces except the 35mm are 1.25inch in that list. As such, I was considering not getting the 35mm eyepiece and instead going for the 32mm Televue Plossl:

Televue 32mm Plossl Eyepiece - 1.25" - EPL-32.0 - OPT Telescopes

This way, I can simply purchase the Baader semi-apo filter for the 1.25 inch eyepieces instead of both 1.25 and 2 inch eyepiece sets.

Any input is greatly appreciated!

-James

[GazOC]

Hi James,

Another option if the format size is important to you is to get a 24mm Pan (1.25 fitting) and scrap both the 19mm and the 35mm Pans. The 24mm will show as much sky as the 32mm Plossl.

Another take is that, TBH, you won't really need the semi-Apo filter on the 35mm Pan because the false colour shouldn't be much of problem at that magnification or on the kind of objects you are likely to use that eyepiece on, so you you'd be OK with just a 1.25 filter for the eyepieces in your list.

Gaz

[iceblaze]

Hi James,

Another option if the format size is important to you is to get a 24mm Pan (1.25 fitting) and scrap both the 19mm and the 35mm Pans. The 24mm will show as much sky as the 32mm Plossl.

Another take is that, TBH, you won't really need the semi-Apo filter on the 35mm Pan because the false colour shouldn't be much of problem at that magnification or on the kind of objects you are likely to use that eyepiece on, so you you'd be OK with just a 1.25 filter for the eyepieces in your list.

Gaz

Hello Gaz,

Brilliant suggestion with the 24mm Panoptic replacing both the 19mm and 35mm options! I think I now have my eyepiece list set in stone for this particular little scope. Thanks!

-James

[swamp thing]

Or... Replace the 19mm Pan with a 20mm Nagler same field as the 24mm pan but more power and therefore better sky contrast for DSO's. Plus the extra sharpness of the T5 design.

Am I just confusing the matter.

Regards Steve

[spaceboy]

I wouldn't waste your money on a semi apo filter full stop. I certainly didn't notice a significant enough difference in the views to warrant the hefty price tag. Agree with the others on the 24 Pan

[iceblaze]

I wouldn't waste your money on a semi apo filter full stop. I certainly didn't notice a significant enough difference in the views to warrant the hefty price tag. Agree with the others on the 24 Pan

Hello spaceboy,

The semi-apo filter I was thinking of is around $110 and the reason why I thought it would be a good purchase is because the Baader model claims:

"The Semi-APO works like it's name implies - delivering an amazingly neutral view, while cutting most of the annoying and contrast-robbing violet fringe that plagues all achromats."

(full description here: Baader Semi-APO Filter - 1.25")

So, if it can remove that violet ring around the planets I've been viewing as well as help with overall image sharpness, then it would be money well spent. However, you sound like you've had personal experience with semi-apo filters.. Did you have that experience with the Baader model?

Thanks!

-James

[Mr Spock]

I'm curious to know why you are spending so much on eyepieces for such an inexpensive scope. Even a modest scope for the price of the 35mm Pan with cheap eyepieces will outperform the 90mm achromat.

[Stu]

I would tend to agree with that. For the same, or less budget, you could get a better, apo scope plus some still very good lenses which would give better results. Tv's are good, but can't create miracles :-)

Stu

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[spaceboy]

I agree with Mr Spock & BMS I did think this but then realized the OP is in the US. I bet they practically give TV's away in the supermarkets over there. 2 for 1 deals and all that

Yes James I have owned a SA filter and found there was no noticeable improvement over purple halos. At the time the filter came up at the right price and figured I would give it a go due to all the hype. When researching the filter that gave the best improvement were said to be Sirius Minus Violet Eyepiece Filter MV20 (MV-20) - Warehouse Express but as with most fringe killers it will induce a yellow colour to the image in place of the violet.

HTH

[faulksy]

i agree with all the above as well

[iceblaze]

Hello guys,

Thanks for all of your replies. The reason why I am putting down the big bucks on Televue eyepieces is because I see them more of an investment that I can use in multiple OTA's later on down the line. The 5mm,9mm, and 24mm fits the math on so many tubes, why muck around with buying/selling lower quality pieces when I can start out the right way?

I figure I would just purchase them one at a time and use my current eyepieces until then.

-James

[iceblaze]

I'm curious to know why you are spending so much on eyepieces for such an inexpensive scope. Even a modest scope for the price of the 35mm Pan with cheap eyepieces will outperform the 90mm achromat.

Hello Mr. Spock!

While the Skyscout may be a humble little refractor, it is my first telescope and I'm just not over it enough to justify the purchase of a new OTA yet. I really like the little performer. However, I just bought a manual CG-5 today brand new for only $200, and what a beauty she is!

So, I am future proofing my gear for the OTA upgrade down the line.

-James

[pvaz]

I see where you are going with the future proof EP set but I have to agree you could get much better views with a larger aperture scope and mid range EPs.

Some of this EPs are heavy, specially the 35 Pan, so they may be too much stress for your focuser. The focuser on my 8" haves a hard time with both my Nagler 32 and Ethos 21mm.

If you have never used a top quality EP you can expect pinpoint star to the edge, unless your scope optics have distortions. You can also expect a bit more contrast and a wider and confortable FoV.

To put things in perspective (and this is a rough guess), this EPs on your current scope may add 25% in view quality. A larger scope (say an 8" dob) with mid range EPs will improve the views 300 to 400%. You'll actually be able to see structure in the Orion Nebula, more detail on planets such as the GRS, solve individual stars in M13, etc..

[iceblaze]

I see where you are going with the future proof EP set but I have to agree you could get much better views with a larger aperture scope and mid range EPs.

Some of this EPs are heavy, specially the 35 Pan, so they may be too much stress for your focuser. The focuser on my 8" haves a hard time with both my Nagler 32 and Ethos 21mm.

If you have never used a top quality EP you can expect pinpoint star to the edge, unless your scope optics have distortions. You can also expect a bit more contrast and a wider and confortable FoV.

To put things in perspective (and this is a rough guess), this EPs on your current scope may add 25% in view quality. A larger scope (say an 8" dob) with mid range EPs will improve the views 300 to 400%. You'll actually be able to see structure in the Orion Nebula, more detail on planets such as the GRS, solve individual stars in M13, etc..

Hello pvaz,

The difference in view quality sounds amazing on that dob! I currently have a set of decent Zhummel Plossl's which I use on my telescope. I have a pretty decent dual speed focuser, and a CG-5 mount, so I think it should be OK to use those eyepieces. However, the way you described the view quality difference does put things into perspective.

Perhaps I will hold out on the eyepieces until I get nice OTA first, then work out the math for those eyepieces with the new scope. I don't expect to ever get rid of the Skyscout as I want to use it as a benchmark for all other scopes I purchase, so I'll pop another scopes TV eyepiece into the little refractor from time to time

Thanks!

-James

[pvaz]

BTW another option for the wide field EP, staying in the 1,25" format is a Nagler 16mm or a Skywatcher Nirvana 16mm (half price, some say it's about as good).

With 82º AFOV they will show almost the same amount of sky as a 32mm Plossl or a 24mm panoptic. Only a grenade like 2" EP will show a considerably wider FOV.

[MjrTom]

Hmm I kind of agree with the comments in this thread however you could argue that nobody need Televue eyepieces unless you are using them on fast newtonians as the optical perfection is wasted on slower scopes.

Looking at the signatures of various people there are quite a few people using them with APO refractors and SCT's

I am also of the same thinking that it's a lifelong investment and when space dictates a big Dob is on the cards.

Also should I choose to sell any of them they command a high price and sell in minutes as a recent for sale thread on SGL shows

[pvaz]

I started with my 8". I then gave my little sister a 90mm refractor for her birthday. I was all smiles trying to point at M13 to show it on her scope, when I had it in view I must confess it was quite a disappointment for me.

I was used to see it as a big ball of countless stars, on her scope it was but a smudge with just some individual stars towards the edge.

I would say aperture is what really improves the views, while quality EPs improve the cosmetics on those views: better contrast for elusive details, sharper pinpoint stars and a wide and confortable FoV.

[MjrTom]

Yes nothing can trump aperture but there is merit in futurproofing your investment

[pvaz]

Yes nothing can trump aperture but there is merit in futurproofing your investment

True no doubt about that, it's a tough choice.

[iceblaze]

Hmm I kind of agree with the comments in this thread however you could argue that nobody need Televue eyepieces unless you are using them on fast newtonians as the optical perfection is wasted on slower scopes.

Looking at the signatures of various people there are quite a few people using them with APO refractors and SCT's

I am also of the same thinking that it's a lifelong investment and when space dictates a big Dob is on the cards.

Also should I choose to sell any of them they command a high price and sell in minutes as a recent for sale thread on SGL shows

Hello MjrTom,

Thanks for that. I tend to look at the OTA's as variable, where the accessories/mounts are the place to invest most of your beans. Perhaps the semi-apo filter is not a good purchase, but I do think I will still buy the 5mm, 9mm, and 24mm eyepieces (holding out on the 14mm), since I think those will be spectacular investments for future OTA's, as well as give some little boost to my current OTA.

-James

[swamp thing]

Hi

If you intend to change scopes regularly TBH the eyepieces focal length that seem to compliment most are 30mm 20mm 12mm and 8mm give or take a couple of mm either way.

These are the focal lengths I seem to come back to time and time again.

Regards Steve

[MjrTom]

playing Devils Advocate a little

The EP's I chose fall into the focal length ranges suggested with the exception of the following:

The Nagler zoom is suited to high power viewing on short tube refractors.

The 35mm Panoptic is my finder EP. I am aware that the exit pupil is a little large for newtonians but still usable. It should be perfect with an SCT for instance.

[Stu]

I use tv's in an f6.5 apo and an f20 mak. Very different results but as has been said on other threads, the benefits of contrast and fov are still worth it in long fl scopes.

If the OP is planning on buying further ota's in future then I guess investing in the best ep's from the start will be worth it in the end

Stu

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