zoom eyepiece

[bottletopburly]

Thinking of purchasing a zoom eyepiece ,are there or can anyone recommend one thats suitable for a 200p F5 

[Saganite]

I have only tried the Baader 8-24 zoom and can heartily recommend it, and it won't break the bank. The FOV is not so great at 24mm but that is all. They appear fairly often on the used market.

[bottletopburly]

thanks

[D4N]

I'd second the Baader zoom and the paired 2.25x Barlow is good as well.

[Dave In Vermont]

Don't be too concerned about the limited FOV of the 24mm setting. This narrow FOV is standard amoung all zoom-ep's of the 8 - 24mm range. And do steer clear of the 7 - 21mm-ish range. They tend to be inferior in most people's opinions/reviews.

Happy Skydiving-On-The-Moon,

Dave

[John]

Of the mid-range (focal length) zooms I've owned I liked the Baader 8-24mm the best I think. It performed pretty well in my 12" F/5.3 dobsonian. I did find the apparent field rather constrained and not too well defined either at the 24mm setting so I got a fixed length 24mm 68 degree eyepiece to use with the zoom and treated the latter as a 20mm-8mm. The actual apparent field of the Hyperion zoom has been measured at 42 degrees at the 24mm setting but widening to nearly 70 degrees at 8mm. My examples have matched this. So you get a bit less than specced at one end and a bit more at the other !. Nice eyepiece to use though 

[SonnyE]

I have the Celestron 8-24mm zoom. I like it fine.

Really makes it easy when you have one of those "What the heck is that" moments.

It was my main eyepiece for quite a while.

[Dave In Vermont]

The lower-priced Zooms, such as the Celestron that Sonny mentions above, are quite nice these days. They used to be considered as pretty bad, but this has turned out to be due to the narrow FOV found in the 24mm-ish settings. Now that this situation is better understood, they've miraculously "improved" over night! People are now writing very nice things about such low-cost entries as the Seben and Meade and, yes, the Celestron.

From the low-cost Zooms, the next price-jump will take you to the Baader 8 - 24mm, which are better indeed. I have a Vixen 8 - 24mm that I carry on me for outreach-work at local parks. It's not really inexpensive though. Vixen uses a lanthanum-glass element for a better, flatter field. And the price about doubles. But I'd buy a lower-cost offering if I needed a replacement. I also have a Baader for at-home, personal use.

The next price-jump from Baader takes you to such entities as Pentax. And they cost about 2X that of the Baader. I've yet to try one - being quite content with what I have now, and not wishing to tempt fate!

Enjoy -

Dave

 

PS - Here's a mnaual on the Baader 8 - 24mm Zoom you might find useful:

Hyperion 8 - 24mm Zoom Eyepiece - Instructions by Baader.pdf

[michael.h.f.wilkinson]

I have the William Optics Zoom II 7.5-22.5 mm which is pretty good. It has the usual narrow FOV at 22.5x but as my stock solar observing EP this does not really matter. It is no longer sold under the WO brand, but the same EP is sold by Orion:

http://www.telescope.com/Orion-75-225mm-Premium-Zoom-Telescope-Eyepiece/p/8238.uts

Opticstar

http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Telescopes-Opticstar.asp?p=0_10_5_1_8_331

and Omegon

http://www.omegon.eu/omegon-premium-7-5mm-22-5mm-zoom-eyepiece/p,33244

The long eye relief is particularly important for me. Paired with a MaxVision 24mm 68deg EP and a Vixen SLV 5mm it forms a neat travel set that covers most bases

[RobertI]

One annoying feature of my Seben zoom (which is fine in all other respects) is that it is not parfocal at when you zoom in or out, meaning refocusing is required. For the benefit of the OP are any of the other zoom eyepieces parfocal?  

[John]

40 minutes ago, RobertI said:

One annoying feature of my Seben zoom (which is fine in all other respects) is that it is not parfocal at when you zoom in or out, meaning refocusing is required. For the benefit of the OP are any of the other zoom eyepieces parfocal?  

I've tried quite a few zooms (Seben, Skywatcher, Celestron, Vixen, Baader and Tele Vue Nagler) but none were entirely par focal across the range of focal lengths. The Tele Vue Nagler zoom was very nearly so but even that needs a tiny tweak to the focusser when you alter the focal length. 

 

[YKSE]

I'd second Baader Zoom.

53 minutes ago, RobertI said:

One annoying feature of my Seben zoom (which is fine in all other respects) is that it is not parfocal at when you zoom in or out, meaning refocusing is required. For the benefit of the OP are any of the other zoom eyepieces parfocal?  

As John has commented, no zoom is exactly par focal throughout the range. My measurement of Baader Mark III is focus difference about 0.7mm across the range. If you focus on the high mag end, you'll be about to go down a couple of clicks ( focus on 8mm, down to 16mm e.g.) without refocus.

There's not much diffference to the fixed focal length EPs, some tweek to the focuser is need too when you change an eyepiece, the excel file in the link is Tamiji Homma's measurement of some EPs,

http://www.cloudynights.com/topic/310666-master-eyepiece-focus-distance-chart/?p=3990093

As we can see, Pentax XW's need very small tweek (max 0.28mm) for 1.25" EPs, while Televue plössls (8mm to 32mm) may need over 1mm tweek, depite that all are named as par focal.

[Paul73]

Hi

Zooms are atractive. But, f5 is really on the cusp of their capabilities (unless you go really really expensive).... They still work but the quality does drop off if you use faster scopes. But what else should we expect?

They also have moving parts which can make sixth hand purchases more risky than purchasing 4 carefully chosen fixed length eyepieces for the same price (the BST Starguide would be good in your scope).

As others mention. The Baader MkIII is a good choice with a 24 or 28mm 68° (eg. the MaxVison).

Paul

ps. The Baader is as Parfocal as it gets! I've just spent an hour using one and YKSE is right focus at 8mm and you won't have to touch it again you get to the other end.

[michael.h.f.wilkinson]

My WO Zoom II is very, very close to parfocal too. Only the tiniest tweaks needed.

[bottletopburly]

Thanks for the Input food for thought

[N3ptune]

I wish to share my experience, taking the risk of going against the popular vote, again.. (But my influence came from various major people from SGL, nevertheless)

I had the Celestron zoom which gave 24mm, to 8mm  (41x to 125x) + a  Xcel LX 2x Barlow. And, But, It turned out I had the chance to get a refund on the zoom and replace it with 2 fixed focal length EPs: Xcel LX 25mm and 18 mm to get 40x, 80x, 55x, 111x. (with the barlow) almost the same magnifications has the previous zoom.

I already had a decent Barlow, plus a refund on the zoom , I only had to spend 130$ to pay for 1 Xcel LX EP.. It was an easy move to do..

--> But the thing is, I am behaving like a baby and I am not going back to 45 degrees @ 25mm, especially. I have no more moving parts, 60 degrees AFOV always, much better views even with my F5 scope, there is almost no coma, the amount is really negligible. (Now I guess the Pentax zoom or the Baader Zoom, they probably easily outperform the Celestron )

I think it's relevant to have a wider AFOV at around +-25mm and maybe less  at higher power to watch the the planets for instance.  (The zoom seems to do the contrary of logic) It's just an alternative option, which is inexpensive for the quality.

If you already ordered the zoom.. it's ok too, I had a good time with mine it paid for itself many times. 

 

 

 

[RobertI]

Slightly off topic, but I was out using my Seben zoom with my 72mm frac last night, and as usual It was very useful for finding the right magnification for the object, depending on its size and faintness and the sky brighness. The ET cluster and most small open clusters were able to take the max magnification available, but M31 needed lowest mag, despite the sky background brightening considerably. On previous sessions the smaller bright  galaxies such as M51, M81 and M82 were best somewhere in the middle. So the zoom is not only useful, but also educational to see the effect of magnification on different objects.

[YKSE]

27 minutes ago, RobertI said:

Slightly off topic, but I was out using my Seben zoom with my 72mm frac last night, and as usual It was very useful for finding the right magnification for the object, depending on its size and faintness and the sky brighness. The ET cluster and most small open clusters were able to take the max magnification available, but M31 needed lowest mag, despite the sky background brightening considerably. On previous sessions the smaller bright  galaxies such as M51, M81 and M82 were best somewhere in the middle. So the zoom is not only useful, but also educational to see the effect of magnification on different objects.

Exactly, that's the strength of a zoom, because it zooms

The real time change of magnification/brightness enables we to find most focal length for the object, let it be a few seconds of good seeings in planetary viewing, or different details on the Moon, or threshold faint galaxies. I've been able to see some faint mag 13 galaxies by fairly quick zooming in and out in averted vision.

[Louis D]

Another option to consider is the Celestron Zoom Eyepiece for Regal M2 Spotting Scopes.  I have two that I use in binoviewers with the eyecup removed (it unscrews completely).  They are very well corrected across the field and are very close to parfocal.  The field of view increases linearly from 24 to 8mm and the fieldstop is always sharp, unlike the Baader zoom.

[marcus_z]

A lot of people like the Leica 9-18mm Zoom, but that's about 650€ and needs an adapter.

[Mark at Beaufort]

I have owned three zoom EPs over the years -  Baader 8-24mm Mark 2, Pentax SMC  XF 6.5-19.5mm and currently  the TeleVue 8-24mm. Of the 3 the TeleVue is the best but unfortunately it is no longer available. I use my Zoom mainly for solar in the PST but also as a double star EP because of the zoom facility. It is used in a 12" f/5 Dob and an Orion VX8 f/4.5 Newt - no problem.

If I was starting out (TeleVue not available) I would buy the Baader 8-24mm Mark 3 together with the 2.25x barlow.

[Dave In Vermont]

I have a Vixen LV 8 - 24mm Zoom, which incorporates a lanthanum glass lens. These look just like the current Seben, and several others - but is quite pricey: $200US. And these were the same 8 - 24mm that TeleVue® used to sell. Made in the same place, but 'branded' TeleVue®. When this was reported, it wrecked TV's claim that they made everything they sold. So TV's 8- 24X was taken off the market.

So, Mark, if you ever want another zoom that is as nice as your old TV - the Vixen LV is still available. I love mine and use it for my scope during public-outreach. It's better than hauling a case of eyepieces about town. They're not quite parafocal, but pretty close.

Zoooooooooooooooooooooooooooom!

Dave - Skydiving on the Moon

[Mark at Beaufort]

5 minutes ago, Dave In Vermont said:

I have a Vixen LV 8 - 24mm Zoom, which incorporates a lanthanum glass lens. These look just like the current Seben, and several others - but is quite pricey: $200US. And these were the same 8 - 24mm that TeleVue® used to sell. Made in the same place, but 'branded' TeleVue®. When this was reported, it wrecked TV's claim that they made everything they sold. So TV's 8- 24X was taken off the market.

So, Mark, if you ever want another zoom that is as nice as your old TV - the Vixen LV is still available. I love mine and use it for my scope during public-outreach. It's better than hauling a case of eyepieces about town. They're not quite parafocal, but pretty close.

Zoooooooooooooooooooooooooooom!

Dave - Skydiving on the Moon

Thanks Dave I was not aware of the reason why TeleVue stopped selling the zoom. I have looked at the Vixen and yes it looks identical to the TeleVue so this is a good buy for £129 - https://www.telescopehouse.com/vixen-zoom-eyepiece-8-24mm-lv-40-60-degree-1-25.html

I also notice that the Vixen is being sold for $182.50 in the States - http://agenaastro.com/vixen-3777-1-25-lv-8-24mm-zoom-eyepiece.html

which is more than the current price in the UK using the current exchange rate..

[Louis D]

5 hours ago, Mark at Beaufort said:

Thanks Dave I was not aware of the reason why TeleVue stopped selling the zoom. I have looked at the Vixen and yes it looks identical to the TeleVue so this is a good buy for £129 - https://www.telescopehouse.com/vixen-zoom-eyepiece-8-24mm-lv-40-60-degree-1-25.html

I also notice that the Vixen is being sold for $182.50 in the States - http://agenaastro.com/vixen-3777-1-25-lv-8-24mm-zoom-eyepiece.html

which is more than the current price in the UK using the current exchange rate..

And in the US, we don't pay VAT, so the price would be £107.50 ~= $135 plus shipping.  This has been happening a lot lately.  I picked up a Baader Morpheus from the UK post-Brexit for $185 shipped vs. $239 (MSRP) or $199 (current sale price) here in the states.  The US doesn't charge import tariffs/duties on shipments under $200, so no problem getting that deal for me.

[Mark at Beaufort]

Louis I did not appreciate that situation on VAT. I have a Son living just outside San Francisco - permanent resident. Must keep that in mind as future reference especially as we see each other about twice a year.