New APM "super zoom"

[Voyager 3]

On 30/03/2021 at 05:22, Littleguy80 said:

It has the potential to be a very good eyepiece. Would definitely consider replacing my Baader zoom if the reviews/reports are good. The Leica always sounded great but very expensive. 

How much do you use your BHZ Neil ? 

[Littleguy80]

3 hours ago, Voyager 3 said:

How much do you use your BHZ Neil ? 

I got it mainly for use with my 80mm Frac so not a massive amount. Most of the time I get the dob out. The zoom and frac are great for when you want grab a quick session. It was originally bought to be a travel setup but travel hasn’t been an option lately! The zoom has been getting a lot of muse recently for Solar Ha. I recently got a Daystar Ss60 and it pairs well with that. 

[Voyager 3]

Zooms and solar Ha are like sweet and honey ... You just can't seperate them 👍.

[Littleguy80]

1 hour ago, Voyager 3 said:

Zooms and solar Ha are like sweet and honey ... You just can't seperate them 👍.

Agreed. For WL Solar I always use the Nagler Zoom. Very tempted to get a Pentax XF zoom for Ha. That will be another test for the APM Zoom when it’s released 

[DesertSky]

7.7mm-15.4mm  is a very narrow range.

I have doubts...

I would wait for some reviews to be published.

[John]

7 minutes ago, DesertSky said:

I would wait for some reviews to be published.

So would I.

Welcome to the forum

 

[Mr Spock]

I don't know about limited range.  I can see 10-12" Newt users with a x2 Barlow seeing this as their only eyepiece. Interesting thought!

Let's see: 1200mm focal length = x78 to x156; + x2 Barlow, x156 to x312. So, x78 to x312 with just one eyepiece 

[Louis D]

I'm mostly concerned about eye relief as I've stated earlier in this thread.

The range actually covers my most used range of focal lengths.  Add a Barlow, and all I need is a good widest field eyepiece to cover most of my needs.

[John]

The estimated retail price seems to have edged much closer to $400 now according to the vendors section of the CN forum.

If the optical performance is in the Pentax XW / Baader Morpheus ball park then that would be good value.

 

 

Edited May 13, 2021 by John

[Virtus]

I was initially very excited about this zoom. If the 75 degree constant AFOV is true it will have a wider TFOV at 15.4mm than the Baader Mk IV at 24mm. 

I was going to get on the pre-order list but read a little more about it and it appears to be designed for daytime use with a lot of angular magnification distortion (AMD) present in the early prototypes. 

Not going to totally write it off but will definitely be waiting to read reviews once they're out before I will consider it. 

[Voyager 3]

2 hours ago, Virtus said:

I was initially very excited about this zoom. If the 75 degree constant AFOV is true it will have a wider TFOV at 15.4mm than the Baader Mk IV at 24mm. 

I was going to get on the pre-order list but read a little more about it and it appears to be designed for daytime use with a lot of angular magnification distortion (AMD) present in the early prototypes. 

Not going to totally write it off but will definitely be waiting to read reviews once they're out before I will consider it. 

They seem to have 2 types , one for spotting scopes and one for astro ..

[Piero]

11 hours ago, DesertSky said:

7.7mm-15.4mm  is a very narrow range.

Although there are zoom eyepieces with a much larger range, I would not say that a range of 15.4-7.7 is narrow. All depends on the telescope focal length.

In my dobson, f.l. = 1869.9mm with PC2, this zoom has a range of magnifications from 121x to 242x . When used with a VIP Barlow at ~2x, it can deliver something like: 259x - 519x . Using an spacer of 40mm, it would go from ~317x to ~614x . Yeah, I would possibly like something more for the "exquisite" nights, but I can always stick a Vixen HR if needed.

Anyway, my point is that zooms really kick when a very good Barlow can be added, in my opinion.

One could just use a low power eyepiece, a zoom, and a barlow, as "eyepiece" set. Minimalistic yes, but not necessarily less powerful.  

 

 

6 hours ago, Virtus said:

I was going to get on the pre-order list but read a little more about it and it appears to be designed for daytime use with a lot of angular magnification distortion (AMD) present in the early prototypes. 

Not going to totally write it off but will definitely be waiting to read reviews once they're out before I will consider it. 

 

Some users dislike AMD. There is this long living (and artificial) statement that astronomical eyepieces should not have AMD. Being optimised for nearly lack of AMD, means that they have a lot of RD. TeleVue is a brand which goes in this direction. One of the main reasons for this is the separation of double stars near the edge. If the eyepiece has positive AMD, the separation between a pair of stars decreases as this shifts towards the edge. RD is not free of defects either, though. If you look at the moon with a 24mm Panoptic, you will see an oval as our satellite moves towards the edge.

As far as I know it is not possible to correct both AMD and RD at the same time. Choices really. Personally, I like a trade-off between RD and AMD. 

The Docter UWA 12.5mm (nowadays called Noblex) does show AMD as well as some RD. Those who don't like AMD, tend not to like this eyepiece (not a surprise). To me, this eyepiece is one of the finest eyepieces in the market. I would call it a gem.

[Stu]

4 hours ago, Piero said:

RD is not free of defects either, though. If you look at the moon with a 24mm Panoptic, you will see an oval as our satellite moves towards the edge.

Indeed! I really dislike viewing the Moon in my 24mm Panoptic because of this issue. It is great for most other targets though.

Regarding doubles, I think most of us observe these on axis as much as possible, though obviously in a dob where you are nudging you need to be able to use as much of the field as possible.

I found this very useful link on the web for describing and explaining different optical Abberations, I’m sure you know it but useful for others perhaps (and me!)

https://www.handprint.com/ASTRO/ae4.html#distortion

[Piero]

19 minutes ago, Stu said:

Indeed! I really dislike viewing the Moon in my 24mm Panoptic because of this issue. It is great for most other targets though.

Regardung doubles, I think most of us observe these on axis as much as possible, though obviously in a dob where you are nudging you need to be able to use as much of the field as possible.

I found this very useful link on the web for describing and explaining different optical Abberations, I’m sure you know it but useful for others perhaps (and me!)

https://www.handprint.com/ASTRO/ae4.html#distortion

 

Yeah, the 24 Pan is another great eyepieces (currently my only TeleVue!), not ideal for observing the Moon, but lovely for other things (like star fields).

You made a good point regarding on/off axis. Both AMD and RD are off-axis. Not everyone observes planets or double stars off-axis.. In a dob at high power, one could end up observing the target at the edge to avoid constant nudging. 

 

I am aware of that link, but I am not sure whether it is fully correct regarding AMD / RD. In fact, the text calls RD as positive distortion, whereas AMD as negative distortion, letting one feel that they are kind of opposite. As far as I know, both can be positive or negative. For example, regarding AMD, if positive the image is "magnified" on-axis, and "minimised" off-axis, whereas negative AMD is the other way around. Not sure how common negative AMD is. Regarding RD, it is easier to think as if the image is projected on a sphere. If positive, you are looking at this image from the inside of the sphere, whereas if negative, you are looking from the outside. Not sure how common negative RD is.

What we see near the edge with common eyepieces having these distortions: 

- AMD: the moon pretty much remains round, distance between stars shrinks

- RD: the moon becomes an egg, distance between stars pretty much remains unchanged

 

Anyway, this is a bit off topic. Personally, I would not bother too much about the presence of some AMD in this eyepiece. To me, there are more important factors (e.g. how much back focus needs, how much the view remains sharp at the high-end of the magnification range, comfort, colour tone, etc). 

Very pleased to hear that this new zoom will be available in the astro market. If it has the optical quality of a Pentax XW / Delos, ~ £400 does not sound much to me. The Zeiss zoom I have is out of production, the Leica zoom costs nearly two times. Zooms are great not just for slimming down, but for the added practicality of getting your favourite magnification for a certain target without having to swap eyepieces.

[JeremyS]

1 hour ago, Stu said:

Indeed! I really dislike viewing the Moon 

Me too, Stu.

And the Pan 24 doesn’t help.

[Stu]

Thanks @Piero. I confess I did wonder whether the descriptions were exactly correct, thanks for your explanation. I’ll do some more research myself to familiarise myself with the differences.

[Stu]

4 minutes ago, JeremyS said:

Me too, Stu.

And the Pan 24 doesn’t help.

Tee hee. I can’t agree with you there because I do love observing the moon, just not through the Pan! 👍

[Don Pensack]

3 hours ago, Piero said:

 

Yeah, the 24 Pan is another great eyepieces (currently my only TeleVue!), not ideal for observing the Moon, but lovely for other things (like star fields).

You made a good point regarding on/off axis. Both AMD and RD are off-axis. Not everyone observes planets or double stars off-axis.. In a dob at high power, one could end up observing the target at the edge to avoid constant nudging. 

 

I am aware of that link, but I am not sure whether it is fully correct regarding AMD / RD. In fact, the text calls RD as positive distortion, whereas AMD as negative distortion, letting one feel that they are kind of opposite. As far as I know, both can be positive or negative. For example, regarding AMD, if positive the image is "magnified" on-axis, and "minimised" off-axis, whereas negative AMD is the other way around. Not sure how common negative AMD is. Regarding RD, it is easier to think as if the image is projected on a sphere. If positive, you are looking at this image from the inside of the sphere, whereas if negative, you are looking from the outside. Not sure how common negative RD is.

What we see near the edge with common eyepieces having these distortions: 

- AMD: the moon pretty much remains round, distance between stars shrinks

- RD: the moon becomes an egg, distance between stars pretty much remains unchanged

 

Anyway, this is a bit off topic. Personally, I would not bother too much about the presence of some AMD in this eyepiece. To me, there are more important factors (e.g. how much back focus needs, how much the view remains sharp at the high-end of the magnification range, comfort, colour tone, etc). 

Very pleased to hear that this new zoom will be available in the astro market. If it has the optical quality of a Pentax XW / Delos, ~ £400 does not sound much to me. The Zeiss zoom I have is out of production, the Leica zoom costs nearly two times. Zooms are great not just for slimming down, but for the added practicality of getting your favourite magnification for a certain target without having to swap eyepieces.

With AMD the moon diameter closer to the edge shrinks and the moon becomes oval

With RD, the moon diameter stretches radially as the moon nears the edge and the moon becomes oblate.

Distortion is distortion, as the opticians say.

I suspect the best lunar eyepiece might only partially solve for either distortion if a wide field, but the best lunar eyepiece with the least distortion would be a narrower field eyepiece.

On the other hand, if sharpness at field edge is critical, and you always pull the lunar feature to the center to examine it, an excellent widefield can be a revelation.

My first view of the Moon through a 6mm Ethos was shocking--2/3 of the moon in the field in sharp focus to the edge.  At 304x.  Moving the edge to the center showed some shape changes, but didn't reveal any more details.

At low power the distortion of the shape of the Moon seems far more annoying than at higher power.

We need to wait to see what people think when using the eyepiece at 7.7-10mm.

 

[John]

One of the things that has always impressed me about the Ethos eyepieces is the way that aberrations / distortions are controlled in the outer parts of the field of view. Quite frequently I have enjoyed observing a double star or maybe Saturn with the 6mm or 8mm Ethos and let the target drift right across the field of view until it is obscured by the field stop edge. I've been constantly surprised how a tight double star stays nicely split right up to the field stop and equally how fine details such as the Cassini Division remain sharp right across the field of view. 

Obviously Tele Vue will have accepted some form of optical distortion in order to obtain the very wide and sharp field of view with low levels of astigmatism even in relatively fast scopes but whatever choices they made seem to be the right ones as far as my observing eye is concerned at least. Whether my wallet is so keen on them is another matter entirely

 

 

 

 

Edited May 14, 2021 by John

[DesertSky]

20 hours ago, Mr Spock said:

I don't know about limited range.  I can see 10-12" Newt users with a x2 Barlow seeing this as their only eyepiece. Interesting thought!

Let's see: 1200mm focal length = x78 to x156; + x2 Barlow, x156 to x312. So, x78 to x312 with just one eyepiece 

A barlow and a zoom makes 2 pieces not one  Also a good barlow can be costly like an eyepiece. Additionally attaching, removing a barlow and re-focusing is not easier than changing eyepieces. Denkmeier sells a powerswitch that can make it easy but it is not cheap.  

[Stu]

3 minutes ago, Don Pensack said:

At low power the distortion of the shape of the Moon seems far more annoying than at higher power.

I think that’s exactly right Don, and that’s the reason the 24 Pan stands out I think. The views are low power so the effect is very obvious. To be fair though, I’ve not noticed it as severely in other eyepieces so I guess it is more extreme in the Pan.

[Mr Spock]

45 minutes ago, DesertSky said:

A barlow and a zoom makes 2 pieces not one

One eyepiece I said 

[Voyager 3]

Your most unwanted update - 

" Available on date Friday, July 9, 2021 " 

[Space Hopper]

Paid and ordered mine mid June.

Marcus quoted me a 6 to 8 week delivery (from then) so possibly mid August, but hopefully a bit before.

Jupiter and Saturn should be nice targets by then.

 

[John]

18 hours ago, Space Hopper said:

Paid and ordered mine mid June.

Marcus quoted me a 6 to 8 week delivery (from then) so possibly mid August, but hopefully a bit before.

Jupiter and Saturn should be nice targets by then.

 

I'll look forward to reading your experiences with it.

I'm less keen on being an "early adopter" these days - must be old age