what have zoom eyepieces ever done for us?

[Piero]

The Zeiss zoom 25.1-6.7mm (advertised as Zeiss Vario D 15-56x / 20-75x) goes from ~45deg to almost 70deg and costs £600 with both the Baader 2" and 1.25" adapters.

That is less than 2 TV Delos (as sold new today at £330), and half more than a TV zoom 3-6mm (new at £390).

It literally gives razor sharp views on axis. Combined with a Baader VIP it becomes a lunar-planetary surgeon with scalpel sizes for all needs. It's also smooth in the zoom range. No EOFB and very well controlled light scattering. Colour tone is neutral. 

Under decent seeing, to my eye it consistently beats my Vixen SLV on DSO and planetary targets. The Docter is possibly on par in terms of image sharpness on axis but with a very slightly warmer colour tone. The Vixen HR..  that's a tough rival to me..

 

For more details about the Zeiss zoom 20-75x, see https://www.cloudynights.com/topic/542372-review-zeiss-20-75x-zoom-eyepiece-and-swarovski-25-50x-zoom-eyepiece/ .

[davehawkins]

Been considering a zoom for lunar observing for a while now and reading this thread has convinced me I need one. I've just got to convince the Mrs, or sneak it passed her !

[N3ptune]

I discovered with a Celestron 24 to 8mm zoom that +-40 degree AFOV is not really interesting to use for low power like 24mm... No more zooms for me.

[cloudsweeper]

5 hours ago, N3ptune said:

I discovered with a Celestron 24 to 8mm zoom that +-40 degree AFOV is not really interesting to use for low power like 24mm... No more zooms for me.

I have a Meade 4000 8-24, and yes - the low AFOV at low mag is the downside of a zoom. 

As many have said, zooms are very convenient in particular situations, but for general use cannot replace a set of fixed FL eyepieces.

Doug.

[John]

7 hours ago, N3ptune said:

I discovered with a Celestron 24 to 8mm zoom that +-40 degree AFOV is not really interesting to use for low power like 24mm... No more zooms for me.

It's closer to 60 degrees a the 8mm setting.

The vast majority of mid range zooms are just the same though in terms of field of view - even the Baader and Pentax ones.

[BGazing]

Been in the same situation like the OP. Had 127 Mak with the Baader Mark III zoom.

First, a lot of good advice from everyone, and pretty accurate assessment of the qualities of the respective zooms.

Baader Mark III pairs well with the Mak 127, with some caveats. First, 24 mm setting is too narrow for getting the maximum TFOV, so I bought ES 24/68. 32mm plossl would serve the same purpose. Views with the zoom in Mak were really sharp, Mak is F12 and there was no serious degradation on the edges. Mak is mostly for lunar/planets and the ability to vary the focal length and find that perfect magnification and exit pupil and tailor it to seeing is very useful. Zoom was not parfocal to my 40 plus eyes, but only small adjustments were needed. Once you figure out what are your favourite magnifications for certain objects, zoom might help you later choose appropriate fixed EPs for your telescope. And zoom is super handy during winter, when I just could not be bothered to switch eyepieces.

On the minus side, Mark III zoom was kinda heavy for my 1.25 diagonal (not the stock one). Diagonal could handle it, but the screws on Mak visual back are not the best. Perhaps different screws with nylon tips would do a better job. Mark IV zoom is lighter, so it might help.

I will probably never get rid of my zoom, although I am now indulging slowly into second-hand green-lettered nirvana. To compare Baader zoom with Televue offerings is unfair. But it is a very nice tool, and one I think is pretty good for 127 Mak. You will rarely push your Mak under 10mm, and 10-16 mm will be your most likely range. At that range, the zoom is not that narrow.

@vlaiv I think the 24mm setting on Mark IV is still at 42 deg TFOV, irrespective of declared. But, if you want to purchase my Mark III second hand, I will gladly purcase a new Mark IV so we can compare. I need something lighter for solar...

[YKSE]

As shown by the posts of zoom owners, it's very handy for a quick session between clouds, fun and easy to use for plantary for suitable seeing conditions, etc. The narrowing AFOV in low mag part are among the major drawback, a serious one for those hungers WIDE AFOV.

My main interest is faint DSOs, i.e. galaxies, with planetary with binoviewers mostly. I find a zoom is just as capable for these fazzies as fix focal eyepieces, if we're comparing apples to apples. In my mind, Baader zoom to BST, or Leica Zoom to Delos (XW) are more reasonable comparison, as the zoom with a barlow replaces some 6-7 of fixed focal EPs, with a cost about 3 fixed ones.

For threshold faint DSOs, an advantage of a zoom is that it ZOOMs, i.e. by zooming slightly in and out, the instance change of brightness and size of a faint galaxy becomes more apparent than tapping the scope (an old trick from some experienced observers).

[Louis D]

1 hour ago, YKSE said:

For threshold faint DSOs, an advantage of a zoom is that it ZOOMs, i.e. by zooming slightly in and out, the instance change of brightness and size of a faint galaxy becomes more apparent than tapping the scope (an old trick from some experienced observers).

I'll have to give that a try the next ime I'm trying to pick out faint fuzzies.  Usually, once the DSCs put me on the right spot, I use the sweeping method to try to pick out the slight sky brightening associated with the object.

[John]

YKSE's points about using the magnification change and tapping the scope to detect faint DSO's are good 

I just wish that the Baader zoom would transmit a little more light from such obects

[Stu]

13 minutes ago, John said:

YKSE's points about using the magnification change and tapping the scope to detect faint DSO's are good 

I just wish that the Baader zoom would transmit a little more light from such obects

You need to try a Leica John 

[iPeace]

On 05/21/2017 at 13:10, BGazing said:

Been in the same situation like the OP. Had 127 Mak with the Baader Mark III zoom.

First, a lot of good advice from everyone, and pretty accurate assessment of the qualities of the respective zooms.

Baader Mark III pairs well with the Mak 127, with some caveats. First, 24 mm setting is too narrow for getting the maximum TFOV, so I bought ES 24/68. 32mm plossl would serve the same purpose. Views with the zoom in Mak were really sharp, Mak is F12 and there was no serious degradation on the edges. Mak is mostly for lunar/planets and the ability to vary the focal length and find that perfect magnification and exit pupil and tailor it to seeing is very useful. Zoom was not parfocal to my 40 plus eyes, but only small adjustments were needed. Once you figure out what are your favourite magnifications for certain objects, zoom might help you later choose appropriate fixed EPs for your telescope. And zoom is super handy during winter, when I just could not be bothered to switch eyepieces.

On the minus side, Mark III zoom was kinda heavy for my 1.25 diagonal (not the stock one). Diagonal could handle it, but the screws on Mak visual back are not the best. Perhaps different screws with nylon tips would do a better job. Mark IV zoom is lighter, so it might help.

I will probably never get rid of my zoom, although I am now indulging slowly into second-hand green-lettered nirvana. To compare Baader zoom with Televue offerings is unfair. But it is a very nice tool, and one I think is pretty good for 127 Mak. You will rarely push your Mak under 10mm, and 10-16 mm will be your most likely range. At that range, the zoom is not that narrow.

@vlaiv I think the 24mm setting on Mark IV is still at 42 deg TFOV, irrespective of declared. But, if you want to purchase my Mark III second hand, I will gladly purcase a new Mark IV so we can compare. I need something lighter for solar...

What he said. Right on.

[John]

31 minutes ago, Stu said:

You need to try a Leica John 

Having sold a few bits and bobs recently it's a possibility. I'd prefer to "try before I buy" ideally though. I'm not sure whether the EFoB thing would be an issue or not for me

If (some hope ! ) a used one popped up I might take a punt on the basis that I could sell it again if it didn't suit.

 

[Stu]

12 minutes ago, John said:

Having sold a few bits and bobs recently it's a possibility. I'd prefer to "try before I buy" ideally though. I'm not sure whether the EFoB thing would be an issue or not for me

If (some hope ! ) a used one popped up I might take a punt on the basis that I could sell it again if it didn't suit.

 

I never had a problem with EOFB but I mainly used it for planetary and solar observing under not great skies. If you have much better skies then it might be an issue, not sure.

I certainly found it rivaled or bettered BGOs on axis, the edge of field is not as tidy as premium fixed focal length eps as far as I recall so using on an undriven scope may be less satisfactory. As you say, one to try out if unsure.

[Davey-T]

It's Stus fault that I've got the Leica, not planning to sell it any time soon 

Dave

[Peter Drew]

Depends also on what telescope you are using the zoom on, 24mm isn't a low power on a 16" SCT, an individual single wide angle eyepiece is certainly needed.  

[Piero]

A nice combo is a low power eyepiece, let's say 82deg 24-30mm for F5-F6 telescopes, AND a high quality zoom. If a nice barlow (e.g. the Baader VIP) is attached to the latter, an astro weapon is ready for use!

Plus, these two can be both 2" which is quite handy. Planetary nebulae are also handy with zoom eyepieces. 

 

If I understood correctly from reports on CN the VIP largely improves the EOFB in the Leica. 

Besides, the VIP basically improves all my eyepieces..

[jetstream]

To my eyes the Zeiss 25.1-6.7 shows faint DSO extremely well, checked against the 10mm BCO which has high contrast. The 10mm BCO might be a hair ahead of it but after many comparisons its hard to say.

This zoom is used very much here.

[John]

1 hour ago, jetstream said:

To my eyes the Zeiss 25.1-6.7 shows faint DSO extremely well, checked against the 10mm BCO which has high contrast. The 10mm BCO might be a hair ahead of it but after many comparisons its hard to say.

This zoom is used very much here.

Wow ! - when you think what the BCO 10mm costs, it's a stunning performer

[Highburymark]

On 20 May 2017 at 16:34, Piero said:

The Zeiss zoom 25.1-6.7mm (advertised as Zeiss Vario D 15-56x / 20-75x) goes from ~45deg to almost 70deg and costs £600 with both the Baader 2" and 1.25" adapters.

That is less than 2 TV Delos (as sold new today at £330), and half more than a TV zoom 3-6mm (new at £390).

It literally gives razor sharp views on axis. Combined with a Baader VIP it becomes a lunar-planetary surgeon with scalpel sizes for all needs. It's also smooth in the zoom range. No EOFB and very well controlled light scattering. Colour tone is neutral. 

Under decent seeing, to my eye it consistently beats my Vixen SLV on DSO and planetary targets. The Docter is possibly on par in terms of image sharpness on axis but with a very slightly warmer colour tone. The Vixen HR..  that's a tough rival to me..

 

For more details about the Zeiss zoom 20-75x, see https://www.cloudynights.com/topic/542372-review-zeiss-20-75x-zoom-eyepiece-and-swarovski-25-50x-zoom-eyepiece/ .

I really advise buyers of high end zooms to shop around before they part with their hard earned. With so few astronomy retailers out there, there's not much competition in the market, so the manufacturers tend to control prices. But because the top brands (Leica, Pentax, Zeiss etc) design their zooms for spotting scopes, they're available from hundreds of camera shops across Europe, and many do very good deals. The Zeiss quoted above can be bought for around £460 from Park Cameras for example, but I would expect that even better deals can be found. The RRPs of these top rank zooms are very high indeed - always look for the best deal!

[Stu]

5 minutes ago, Highburymark said:

I really advise buyers of high end zooms to shop around before they part with their hard earned. With so few astronomy retailers out there, there's not much competition in the market, so the manufacturers tend to control prices. But because the top brands (Leica, Pentax, Zeiss etc) design their zooms for spotting scopes, they're available from hundreds of camera shops across Europe, and many do very good deals. The Zeiss quoted above can be bought for around £460 from Park Cameras for example, but I would expect that even better deals can be found. The RRPs of these top rank zooms are very high indeed - always look for the best deal!

Great advice there, I certainly paid more than that when I bought mine!

[YKSE]

2 hours ago, John said:

Wow ! - when you think what the BCO 10mm costs, it's a stunning performer

It certainly is Even in average seeing, to my eye, it shows noticeable better scatter controls on the Moon and Jupiter than many other multi-lens EPs, Maxvisions, some of Nikons, e.g. let alone to other low cost multi-lens EPs.

[jetstream]

On 2017-05-22 at 14:04, John said:

Wow ! - when you think what the BCO 10mm costs, it's a stunning performer

This eyepiece (10BCO) offers similar scatter levels and contrast as the Leica Aspheric but the Leica does not go as deep as this eyepiece, no question. The Zeiss beats both in the scatter department and also for on axis sharpness and DSO depth and color and...

The Leica Aspheric is a fantastic eyepiece offering sharp lunar/planetary detail and is the zoom for clusters. This eyepiece is top notch and it possibly slides into a bigger niche for the observers corner than the (Zeiss, which is my sharpest, on axis eyepiece.)

Excluding the HR2 2.4mm.
 

Thoughts John?

[John]

3 hours ago, jetstream said:

This eyepiece (10BCO) offers similar scatter levels and contrast as the Leica Aspheric but the Leica does not go as deep as this eyepiece, no question. The Zeiss beats both in the scatter department and also for on axis sharpness and DSO depth and color and...

The Leica Aspheric is a fantastic eyepiece offering sharp lunar/planetary detail and is the zoom for clusters. This eyepiece is top notch and it possibly slides into a bigger niche for the observers corner than the (Zeiss, which is my sharpest, on axis eyepiece.)

Excluding the HR2 2.4mm.
 

Thoughts John?

Very interesting Gerry.

If I had a Leica zoom I'd mainly use the magnifications that it produces for deep sky observing. My planetary observing usually starts at 8mm and shorter. I guess I'd need to consider an equal quality barlow as well if I wanted the Leica zoom to become my mainstay planetary eyepiece.

 

[Stu]

1 hour ago, John said:

Very interesting Gerry.

If I had a Leica zoom I'd mainly use the magnifications that it produces for deep sky observing. My planetary observing usually starts at 8mm and shorter. I guess I'd need to consider an equal quality barlow as well if I wanted the Leica zoom to become my mainstay planetary eyepiece.

 

Exactly that John, the Leica with a Baader VIP Barlow or similar (I have a very nice Zeiss Abbe Barlow too) gives the kinds of magnifications which are good for planetary. I considered the Leica more for Planetary/Solar than Deep sky and rarely used it without a Barlow.

[GavStar]

2 hours ago, John said:

Very interesting Gerry.

If I had a Leica zoom I'd mainly use the magnifications that it produces for deep sky observing. My planetary observing usually starts at 8mm and shorter. I guess I'd need to consider an equal quality barlow as well if I wanted the Leica zoom to become my mainstay planetary eyepiece.

 

I use my Leica zoom with the Leica 1.8x extender permanently attached - effectively turns the eyepiece into a compact 5-10mm zoom which gives 100 x to 200x for my 140mm frac - great for planetary viewing.