Nikon 21-9mm MC zoom

[Piero]

About 10 days ago I ordered this adapter for £5.99 (inc. shipping) on ebay:  http://www.ebay.co.uk/itm/122589135237 . 

Although there are some mods to reduce the light path of my Nikon zoom 21mm-9mm (mostly known as Nikon zoom MC 13-30x, 20-45x, 25-56x) as well as to make it compatible with 1.25" adapters, my main issue was that I could not yet use filters with it. Of course this is not a problem with 2" focusers or even 1.25" diagonals, but the issue arises if you want to use this zoom with the Baader / Zeiss barlow (which isn't filter-threaded) and the Lunt Herschel Wedge.. 

This small adapter arrived today!   The barrel of the Nikon zoom is slightly smaller than 0.96", but the fitting can be improved with 3-4 rounds of black electrical tape.

As a side note, with one round of electrical tape on the top part (after removing the locking ring which is only necessary with the Nikon fieldscope), this eyepiece can also be successfully inserted into a 1.25" barrel, reducing the light path of about 20mm (which can be handy, particularly for binoviewing. With this configuration filters cannot be used though). 

Here some pics.

The 0.96"-to-1.25" adapter:

 

Nikon + adapter + 1.25" solar continuum filter:

 

Nikon + adapter (again):

 

Nikon + 0.96"-to-1.25" adapter + 1.25"-to-2" adapter:

 

Nikon fitting the 1.25"-to-2" adapter after some tape on placed on the top (see side note above): 

 

The above solution works with that baader adapter, but is not effective with the Baader 1.25" clicklock coming with the Baader Zeiss barlow. To make it work with this, one needs to tape the eyepiece barrel to an approx 1.25" thickness. Unfortunately, filters cannot be screwed at the bottom with this configuration. If this is not necessary, this might be the best solution.

[John]

All sorts of useful adapters out there !

 

[Louis D]

Great photos!  It really helps to visualize what you did.

Is this the Nikon zoom that folks over on CN rave about as being nearly as good as orthoscopic eyepieces?

[Piero]

3 minutes ago, Louis D said:

Great photos!  It really helps to visualize what you did.

Is this the Nikon zoom that folks over on CN rave about as being nearly as good as orthoscopic eyepieces?

Thanks Louis!  

I don't know! I didn't try it much in the night because of the long daylight. In white light it seems (at least) on par with my Vixen SLV. This adapter will allow me to use it more successfully with the Zeiss barlow and SC filter. I believe it should work very well with binoviewers given its ergonomics. 

[John]

25 minutes ago, Louis D said:

Great photos!  It really helps to visualize what you did.

Is this the Nikon zoom that folks over on CN rave about as being nearly as good as orthoscopic eyepieces?

I think it's the same one. Piero has posted in a CN thread on mods to a highly thought of Nikon zoom so I believe this is the same eyepiece ?

Edit: Sorry, I should have posted a link to the CN thread. Here it is:

https://www.cloudynights.com/topic/520490-nikon-13-30x20-45x25-56x-mc-7mm-21mm-zoom-eyepiece/

I hope that is the right one Piero

[Piero]

Yes, the CN thread discussing the mods is this : https://www.cloudynights.com/topic/520490-nikon-13-30x20-45x25-56x-mc-7mm-21mm-zoom-eyepiece/    

It was started by Dennis, who is also a member here on SGL. I don't remember the reference that this zoom is nearly as good as an orthoscopic , but maybe it is there..?  

Essentially, after the removal of the locking ring (Dennis' mod, https://www.cloudynights.com/topic/520490-nikon-13-30x20-45x25-56x-mc-7mm-21mm-zoom-eyepiece/#entry6927902) there are two nice alternative mods in that thread:

1) full tape (by Dennis): https://www.cloudynights.com/topic/520490-nikon-13-30x20-45x25-56x-mc-7mm-21mm-zoom-eyepiece/#entry6927982 

2) partial tape (by Tank): https://www.cloudynights.com/topic/520490-nikon-13-30x20-45x25-56x-mc-7mm-21mm-zoom-eyepiece/page-2#entry6947240 

Both reduce the light path considerably and work nicely with binoviewers according to them.  

 

1.25" filters cannot be screwed onto the barrel of the Nikon with any of these mods though, so if one really requires this, the only alternative I can see is to use a 0.96"-to-1.25" adapter. The downside is that this needs about 20mm inward travel.

[Floater]

Piero, you are an ocular alchemist. (And I claim copyright on that.)

I'm hanging on when I can and lovin the ride ... ??

[Piero]

21 minutes ago, Floater said:

Piero, you are an ocular alchemist. (And I claim copyright on that.)

I'm hanging on when I can and lovin the ride ... ??

 

[estwing]

I think Bomberbaz has one

[John]

It's very interesting how these excellent zooms, designed originally for top end spotting scope use, are being "discovered" by the astro community over the past few years and modded to make them suitable for astro use. The Nikon in this thread is much less expensive than the Leica, Zeiss and Meopta options and it's size makes it more binoviewer / travel scope friendly 

I wonder how many other really nice zooms are lurking out there for us astro nuts to re-purpose for our use ?

 

 

[Piero]

6 hours ago, John said:

It's very interesting how these excellent zooms, designed originally for top end spotting scope use, are being "discovered" by the astro community over the past few years and modded to make them suitable for astro use. The Nikon in this thread is much less expensive than the Leica, Zeiss and Meopta options and it's size makes it more binoviewer / travel scope friendly 

I wonder how many other really nice zooms are lurking out there for us astro nuts to re-purpose for our use ?

I agree! 

As far as I can see there have been two main obstacles: 1) the lack of more defined standards in the spotting scope industry, 2) a `philosophical vision running over years` that astronomical eyepieces require different optical specs from terrestrial eyepieces  used in spotting scopes. The former issue can complicate our lives as we often don't have adapters to port those eyepieces to 1.25" or 2" formats. The latter obstacle was substantially carried on by OCD dedication of having a clean field of view near the field stop with almost zero AMD.

I am not against a clean field stop. My only point here is that not every observer cares about a hyper clean field stop or desires eyepieces with minimal AMD. For all these observers, reasonably good terrestrial eyepieces should be completely fine. Basically, what I am trying to say is that a distinction between astronomical and terrestrial eyepieces seems rather artificial. It is more down to personal tastes to me. An example.. is it better the Docter UWA 12.5mm (another eyepiece historically used for terrestrial observation) or Delos12/Ethos13?  To me, the Docter is sharper on axis and I actually like the fact that it shows a balance between RD and AMD. For people with strong aversion for AMD, there is no doubt that what TV offers is better.

On my TV60 (which shows substantial FC given its short f.l.) the last 10% of the fov of this Nikon zoom is slightly imprecise at 21mm, but improves when zooming in. The Zeiss barlow also improves its performance. I didn't have time to test it with the Tak as the latter just arrived. The fov goes from ~39deg to ~58deg and its eye relief is about 10mm (it's comfortable though). It is a small powerful eyepiece in its own and incredibly powerful when used with a decent barlow. On axis at the highest power it is at least as sharp as a Vixen SLV 9mm. Now that I have this new threaded adapter, I can better test it with the solar continuum filter and Zeiss barlow. 

[John]

Perhaps our obsession about the outer parts of the field have blinkered our appreciation of otherwise fine performance ?

It's all Al Nagler's fault !

[Louis D]

18 hours ago, Piero said:

I don't remember the reference that this zoom is nearly as good as an orthoscopic , but maybe it is there..?

I think this is the thread started by Levine that I was thinking of.  Yes, he was using a bit of hyperbole.

[Piero]

2 hours ago, John said:

Perhaps our obsession about the outer parts of the field have blinkered our appreciation of otherwise fine performance ?

It's all Al Nagler's fault !

 

Well, I do think the amateur astro community is a bit biased towards Televue. To be fair, Al Nagler and Televue have been doing a lot for astronomy, no doubt. They do deserve recognition. The other good thing of TV is that they produce extended lines of eyepieces to cover many options.  

It's just that there are also other eyepieces with different specs and features, which can be very interesting and potentially better for certain users. I think it's a good thing to have multiple choices. 

[Piero]

2 hours ago, Louis D said:

I think this is the thread started by Levine that I was thinking of.  Yes, he was using a bit of hyperbole.

Thanks for the link, Louis! I was not aware of that thread. Strange that I missed it as there aren't many threads about this eyepiece. Most of the comments I have read are on birds forums.

[John]

1 hour ago, Piero said:

 

Well, I do think the amateur astro community is a bit biased towards Televue. To be fair, Al Nagler and Televue have been doing a lot for astronomy, no doubt. They do deserve recognition. The other good thing of TV is that they produce extended lines of eyepieces to cover many options.  

It's just that there are also other eyepieces with different specs and features, which can be very interesting and potentially better for certain users. I think it's a good thing to have multiple choices. 

Another good thing about Tele Vue is that I've never had to send one of their eyepieces back to Portugal to get an internal lens element cleaned

But I take your points about multiple choices, and prices, being a good thing 

[jetstream]

Could it be that owners of some brands are more open to report problems than others? It might seem like some astronomers don't want to jeopardize the value of their equipment IMHO.Wandering quality control could hit anywhere really.

https://www.cloudynights.com/topic/574698-delites-never-seen-this-before/

[Piero]

mm.. mm.. and here too: 

  

[John]

24 minutes ago, Piero said:

mm.. mm.. and here too: 

  

They do sneak through occasionally

 

[John]

1 hour ago, jetstream said:

Could it be that owners of some brands are more open to report problems than others? It might seem like some astronomers don't want to jeopardize the value of their equipment IMHO.Wandering quality control could hit anywhere really.

https://www.cloudynights.com/topic/574698-delites-never-seen-this-before/

I think this is the case sometimes.

As I've posted before, when I've done reviews of equipment it's been easier because the stuff I've been reviewing has been loaned to me by FLO so I've not invested in it myself and FLO have always made it clear that I can be totally open about what I find during the testing.

There have been some new Tak's reported on CN recently that have arrived with dust on the objectives and badly painted internal baffles so problems can affect any brand at all.

[Piero]

Anyway, failing a quality control is fully acceptable. Nobody is perfect. However, it's important that there is a good customer service to tackle the issue successfully within a reasonable time.

[John]

BTW Did you ever manage to get into the 20mm TV plossl and try reversing one of the lens elements ?

I've been thinking back to eyepieces which I've used that had surprising issues and 3 more spring to mind (all brand new):

- a 30mm Pentax XW which was supplied on loan but I returned for a replacement because it showed loads of astigmatism in the F/6 and F/6.5 scopes that I had at the time. Don't think many of those were returned !

- a Baader Genuine Ortho, again on loan, which had a mysterious zone in the centre of the FoV where a sharply focussed object would suddenly go completely out of focus. I put this down to touching lens elements but didn't take the EP apart to find out because it wan't mine.

- a 4mm Celestron Omni which came, boxed and unused, with a scope. I could not get this little so and so to deliver a sharp image so I did take that one apart. In on of the lens groups, the cemented lens elements were not centered squarely by quite a large margin. That one went in the bin.

So "stuff happens" to the best of them

I've got an older Meade 26mm plossl somewhere which I just can't get to provide a sharp image - I've tried reversing the lens elements, cleaning, changing the lens spacing etc, etc but all to no avail. Another one for the bin in due course

[John]

Piero - I've gone a long way off topic with the above so feel free to keep on the topic of the Nikon zoom and adapter, where the thread started. Sorry about that !

[Piero]

47 minutes ago, John said:

BTW Did you ever manage to get into the 20mm TV plossl and try reversing one of the lens elements ?

I've been thinking back to eyepieces which I've used that had surprising issues and 3 more spring to mind (all brand new):

- a 30mm Pentax XW which was supplied on loan but I returned for a replacement because it showed loads of astigmatism in the F/6 and F/6.5 scopes that I had at the time. Don't think many of those were returned !

- a Baader Genuine Ortho, again on loan, which had a mysterious zone in the centre of the FoV where a sharply focussed object would suddenly go completely out of focus. I put this down to touching lens elements but didn't take the EP apart to find out because it wan't mine.

- a 4mm Celestron Omni which came, boxed and unused, with a scope. I could not get this little so and so to deliver a sharp image so I did take that one apart. In on of the lens groups, the cemented lens elements were not centered squarely by quite a large margin. That one went in the bin.

So "stuff happens" to the best of them

I've got an older Meade 26mm plossl somewhere which I just can't get to provide a sharp image - I've tried reversing the lens elements, cleaning, changing the lens spacing etc, etc but all to no avail. Another one for the bin in due course

 

36 minutes ago, John said:

Piero - I've gone a long way off topic with the above so feel free to keep on the topic of the Nikon zoom and adapter, where the thread started. Sorry about that !

No problem John , I like open conversations , and anyway this thread was just a rather silly one as I simply got excited for receiving an adapter that I've never seen!  

Unfortunately, no, I didn't manage to open the eyepiece. It was strongly cemented. Maybe it is possible, but not with the minimal set of tools I have over here. It should have been replaced at the time in '98, but due to complete lack of experience on my side, communication (e.g. this forum!), and use of the slow telescope (F8), I didn't know that it was faulty. At least nowadays, a bit of reading and text on the Internet can help make a good purchase and understand whether our equipment is good or not! I didn't throw it in the bin because after so many years, it has become a little piece of history. In Italy I still have the 20mm Huygens and 4mm SR in 0.96" format coming with my first Newton. (Hey! Now I can test them with the dob with this 0.96" adapter!). Although optically bad, it is interesting to compare the technology and understand the imperfections! 

mm.. as we are off-topic anyway, do you know when the H20 and SR4 started being supplied with mass produced telescopes?  80s, 70s.. ?

 

So, you received a faulty 30mm Pentax XW! That's really bad, they are so rare!   Did you receive it on loan for a review or because you were interested in getting one? 

[John]

I have H20mm and H6mm .965" eyepieces with my 1960's Tasco refractor. At F/13 they are not as bad as might be thought and, back then, were Japanese made. Maybe I'll try them with my 12" F5.3 one day for fun !. I picked up an SR4 shortly after I bought the scope. That was too much magnification for the 60mm objective really (200x !) but I used it occasionally on double stars. Those were the days - everything was a new discovery and exciting

The 30mm XW was for review. It was the 1st review I did as it happens. Steve at FLO was surprised but arranged a replacement straight away and that was much better - a lovely eyepiece and one I'd like to own but the prices have gone through the roof since Pentax stopped producing the 2" XW's