Nikon 21-9mm MC zoom

[Piero]

Thanks for reporting your story about the Huygens and SR with your Tasco 60mm   I always wondered how old the production was..

At F8 they were rather miserable instead.. Mine are not Japanese as far as I remember. I'll check next time.   At the time I replaced them with an Orion Sirius 10mm and Orion barlow shorty. The stock 25mm SMA was okay. The first observations are memorable whatever one uses I feel. I used to set my alarm at 2-3AM to observe Jupiter and then Saturn in 1997-1998. Also, nights were so quiet at the time compared to now at least. 

[Piero]

I finally completed my tests for this adapter.  

- Nikon MC zoom 21-9mm (13-30x) +/- 1.25"-to-0.96" adapter +/- Zeiss Abbe Barlow. 

- Telescopes: Tele Vue-60 (1.25" focuser), Takahashi FC-100DF (2" focuser). 

- Solar Herschel wedges: Lunt (1.25"), Baader (2"). 

 

The Nikon zoom reaches focus (all zoom range) with the 1.25"-to-0.96" adapter using the Lunt Herschel Wedge. The focuser is nearly all the way in. It also reaches focus when the Zeiss Abbe Barlow is added between the zoom and the Lunt. In this case there is more focus travel available, which is useful because this mean that some spacers could be still added to the Barlow lens. This result is very handy because the Zeiss Abbe Barlow nosepiece is not threaded and is as long as the nosepiece of a Powermate 2.5x. Therefore a 1.25" Solar Continuum filter cannot be attached to the Barlow nor left "free" on the ND3.0 inside the Lunt eyepiece holder. Using this adapter, one can simply screw the SC filter on the adapter and that's it really.

As the eyepiece holder of the 1.25" Lunt Herschel Wedge is rather tall to enable filter stacks onto eyepieces, the previous finding also means that the Zoom + this adapter will also reach focus in most 1.25" diagonals using the TV60. It certainly does using the 1.25" TV Everbrite diagonal. In this case, this adapter is less necessary as far as filters concern because these can be simply screwed onto the diagonal directly (which cannot be done with the Lunt Herschel Wedge!). 

 

There is no problem of focus for this zoom + the adapter +/- Zeiss Abbe Barlow using the 1.25" Lunt and the Tak. The Baader Solar Wedge offers a neater solution because the SC filter is mounted right before the ND3.0 and additional filters (e.g. single polarising filter) can be screwed onto a 2"-to-1.25" adapter. Therefore, using the Baader Herschel Wedge, there is no need for this 1.25"-to-0.96" adapter. The only small issue that one can have IF the 2"-to-1.25" adapter is medium-low profile (e.g. Baader #2408190 or #2956214) AND additional filters are screwed onto this adapter, is that the Zeiss Abbe Barlow (but also a TV 1.25" powermate) will hit the filter. One way to solve this issue is by adding a male M48 -to- male M48 adapter (like this:http://www.365astronomy.com/M48-M48-Positive-Converter-with-T2-and-M36.4-Negative-Threads.html) which adds those those 2-3mm preventing any touch. Alternatively one could also screw this additional filter onto the eyepiece, if a filter thread is provided.

 

This is my final Nikon. I added two rounds of electrical tape to the barrel underneath the large screw. This makes it very close to a 1.25" barrel. It is completely locked by the 1.25" Baader clicklock or any other 1.25" clamp I have. Then I added some rounds of electrical tape to the small barrel at the bottom, to make it very close to a 0.96" barrel. Now the eyepiece works great as if it had a dual 1.25" and 0.96" barrel size.  

 

 

Here is how it works with the Zeiss Abbe Barlow using the two combinations (left for my Tak-100, right for my TV-60): 

 

Here is the male M48 to male M48 adapter I use for screwing 2" filters onto the 2"-to-1.25" adapter so that the Zeiss Abbe barlow (but also a Powermate 2.5x) doesn't hit the filter: 

 

 

 

Here the Zeiss Abbe Barlow which doesn't hit the filter: 

 

 

 

.. and to add some chilli to the dish..  

Something that caught me with surprise  when I tested these combinations using the two wedges on the Tak, is that this Nikon zoom works noticeably better with the Baader than the Lunt Herschel Wedge, independently of the Zeiss Abbe Barlow. Whether this is due to the placement of the SC filter (between the prism and the ND3.0 in the Baader Wedge), the Zeiss prism, or a combination of the two, I have no idea.  The difference in granulation is rather striking. Same goes for the lines in the penumbra regions. To my eye the Nikon zoom on the Baader Wedge gives views that are a reminiscence of my Zeiss zoom or Docter. In contrast, using the Lunt Wedge, I've never been able to distinguish the views between this Nikon and my Vixen SLVs. I will continue testing this. 

After this finding, I am rather curious to check the performance of this zoom with the Baader BBHS. Even though this is not the Zeiss prism model, it might still reveal some improvement. Who knows.. 

[Piero]

Hello @Stu, could you change the title of this thread from "new-096-to-125-adapter-arrived" to "Nikon 21-9mm MC zoom", please? 

[Stu]

Sorted  

[Highburymark]

Interesting Piero. How do you rate your two different wedges with other eyepieces, particularly the Zeiss zoom? Just wondering if you only see a noticeable difference between the two with the Nikon?

[Piero]

3 hours ago, Highburymark said:

Interesting Piero. How do you rate your two different wedges with other eyepieces, particularly the Zeiss zoom? Just wondering if you only see a noticeable difference between the two with the Nikon?

That would be a good test. I didn't try the Zeiss zoom with the Lunt on the Tak essentially because the eyepiece is rather big for that diagonal. 

The Zeiss zoom with the Baader on the Tak was very good and at low power the views were more or less compatible with the same zoom + VIP nosepiece + Lunt + TV60 (without VIP nosepiece the Zeiss zoom doesn't reach focus on the TV60+Lunt). This is not a good comparison of course but the level of granulation at low power seemed to be proportionally similar. 

The Vixen HR works well with both the wedges. I didn't notice any particular "boost", apart from resolution in the Tak, but that is due to aperture.

This is a weird finding because when I tried the Nikon + Lunt +/- Zeiss barlow on the Tak the seeing was very good, possibly even a bit better than when I tried the this combination with the Baader wedge.

I also checked that the Lunt Wedge was cleaned properly and it was.

The Nikon + Lunt on the TV60 gave very similar performance to the Nikon + Lunt on the Tak (except for resolution), and the views are very comparable (if not identical) to my Vixen SLV 9mm or 5mm when the Nikon is used with the Zeiss barlow. 

I wonder whether the Nikon is somehow optimised with prism. It shouldn't make a difference I guess, but who knows.. it was invented for a spotting scope. The weather is not helping much.. a proper test on the Moon, Saturn, and some star cluster using the Baader BBHS would be really interesting. 

I should also test my Vixen SLV 9mm with the Baader Wedge. That would also be a good test. 

[jetstream]

I'm thinking that the Baader Coolwedge might be a bit better optically than the Lunt wedge?

[John]

26 minutes ago, jetstream said:

I'm thinking that the Baader Coolwedge might be a bit better optically than the Lunt wedge?

All the reports that I've read point in that direction Gerry.

The Lacerta Brewster Angle Herschel wedge also looks to be a strong performer at around or less than half the price of the Baader.

[Stu]

5 hours ago, John said:

All the reports that I've read point in that direction Gerry.

The Lacerta Brewster Angle Herschel wedge also looks to be a strong performer at around or less than half the price of the Baader.

It would be interesting to know how the two compare at high power. The Zeiss definitely has a strong edge over the Lunt when at say x150 or x200 for granulation cells, which I have always put down to the accuracy of finish on the Prism. If the Lacerta keeps up at these mags then it is a good deal  

[John]

It's often at high power that optical differences become apparent. Similarly with scope optics.

That said, when I have observed the Sun with my Lunt HW and even the Kendrick filter that preceded it, I've not had any particular problems seeing granulation. Presumably we are talking about the degree of definition of the granulation here ?

With my Tak FC 100 and the Lunt HW I can see the "eye lash" structure in the pre-numbra of larger sunspots, which I thought was quite impressive. Not that I'm a regular solar observer though, so that might be commonplace

 

[Stu]

7 minutes ago, John said:

It's often at high power that optical differences become apparent. Similarly with scope optics.

That said, when I have observed the Sun with my Lunt HW and even the Kendrick filter that preceded it, I've not had any particular problems seeing granulation. Presumably we are talking about the degree of definition of the granulation here ?

With my Tak FC 100 and the Lunt HW I can see the "eye lash" structure in the pre-numbra of larger sunspots, which I thought was quite impressive. Not that I'm a regular solar observer though, so that might be commonplace

 

I think we often talk about 'seeing granulation' whenever the mottling effect is visible on the surface. After a discussion with Ken a while back, it is clear that the actual granulation cells are very small, I think 2 to 3 arc seconds, so to see them properly you need high power. At lower power I think you can say you are seeing 'macro granulation' for want of a better phrase. I've had a couple of occasions when the seeing is so good that I could observe the changes in the granulation cells over a period of 15 to 20 mins.

I did a side by side test of a Lunt 1.25" and Baader CoolWedge under very good seeing conditions and the difference at high power was clear. I don't know how the 2" Lunt would compare.

Seeing the petal structure in the penumbra is fairly normal although it really depends upon the seeing conditions. I find that the view can look quite ordinary, then the seeing steadies and it knocks your socks off! That's one of the things I love about white light solar, apart from the very high mag images, the visual view beats most of the images I see on the forum, the fine detail is amazing.

[Piero]

The difference at high power between the two wedges is noticeable to my eye too. At low power there is less light scatter in the Baader and this is also noticeable to my eye. 

The Lunt does show granulation and eye lash structure in my Tak and TV60. The image delivered by the Baader on the Tak is a bit crisper though. 

 

My experience with optics is limited, but I have noticed that there are some combinations that work better and others that work worse. For instance, seeing permitting, the Baader VIP tend to improve the views of my Vixen SLV, whereas a TV powermate transformed my Docter into a Delos on steroids. This is something that puzzles me because:

1. people tend to evaluate eyepiece performance near the field stop rather than on axis;

2. to reveal any inaccuracies in (1), these tests are run on fast telescopes;

3. to test on fast telescopes (2), people use coma correctors (mainly TV). 

However, this assumes that coma correctors don't affect the view negatively, As the same is very often said about TV powermates (and to my eye this seems true for eyepieces of quality <= TV!) and it is against my finding with the Docter, I wonder whether one might actually spot a difference between a docter and a delos on a F4 eyepiece using a TV coma corrector. Possibly, the combination FastTelescope+CC for testing eyepiece is well worth off-axis, but not suitable on-axis.

The previous example is off-topic, but I preferred to add it because it seems to me that the Nikon is not working as well as it can when used with some other optical component. My Zeiss zoom seems less affected by these wedges. I also noticed less light scattering on this eyepiece when combined with the Baader, but any major difference in view detail passed unnoticed to my eye. The view was very good on both (up to 6.7mm, ~110x. No barlow). The Nikon was different instead and this was between 35x and 82x (=zoom with no barlow). Again, less light scattering was visible with the Baader, but the intensity of (macro-)granulation was clearly different. It looked like a huge amount of sand throughout the surface. I don't know how to explain this, but it was the kind of view that I had with the Docter on my TV60 at 28x or with the Zeiss zoom through the magnification range on both the telescopes. Eyelash-like structure on the penumbra regions was razor sharp. They were authentic tight, well defined lines, whereas what I was expected to see were slightly larger lines popping up and down depending on the seeing. 

I'm off for Italy on Thursday so won't be able to test for a couple of weeks. Hopefully the sky clears up this evening or tomorrow evening so that the Vixen SLV 9mm can be tested against the Nikon zoom on the Sun with the Baader wedge. 

[John]

I've regularly fallen into traps 1 and 2 above Piero but not 3. Just as well I've given up testing and reviewing eyepieces !

Enjoy your Itallian visit

 

[Piero]

3 minutes ago, John said:

I've regularly fallen into traps 1 and 2 above Piero but not 3. Just as well I've given up testing and reviewing eyepieces !

Enjoy your Italian visit

Thank you John! Hopefully the sky stays clear for some good observing time!  

I spoke a bit broadly on those three points above. On the other side of the pond it seems to me that CCs are used more frequently even at F5. Nothing wrong with it really. I just felt the need to express a doubt about the assumption that a CC only affects coma. 

Testing and reviewing eyepieces is fascinating, as long as it doesn't distract one from the hobby itself, I think. One thing I like of zoom eyepieces is that they just let me observe without thinking about which eyepiece f.l. is the best, what is the best eyepiece to frame the target, and so on. The zoom is just there on the focuser to be rotated as one feels. Amazing concept! 

[John]

I've certainly read reports that using a CC sharpens up the performance of certain eyepieces beyond just dealing with coma. I've never owned or used a CC though so I can't comment on that from personal experience.

I agree that the freedom that a zoom provides to just adjust to preference is very nice. I'm all for the optics just appearing to "get out of the way"

[jetstream]

The SW120ED/Baader wedge show the granulation as "cell" like to my eyes and this level of detail needs good seeing to allow high mag-which for me is 200x-300x with this scope.

18 hours ago, Stu said:

the visual view beats most of the images

I totally agree with this Stu.

[Piero]

6 hours ago, jetstream said:

The SW120ED/Baader wedge show the granulation as "cell" like to my eyes and this level of detail needs good seeing to allow high mag-which for me is 200x-300x with this scope.

I've seen those structures at 308x with the Vixen HR 2.4mm, but currently don't have an eyepiece giving 200x-300x here with the Tak. I need my Baader 40mm extension which is in Italy ATM. The Zeiss barlow used with this 40mm extension plus 1 or 2 15mm extensions borrowed from the VIP, will give me a 2.86x or 3.09x Zeiss barlow respectively, or mags of 235x or 254x using this Nikon zoom. It'll be fun!  

[Louis D]

On 8/22/2017 at 13:50, John said:

I've certainly read reports that using a CC sharpens up the performance of certain eyepieces beyond just dealing with coma. I've never owned or used a CC though so I can't comment on that from personal experience.

My cheap GSO CC really cleans up lowest power views in particular, even at f/6.  However, I think it should be removed at high power on low contrast objects like planets observed on axis.  I've not yet done a definitive comparison, but it seemed like my views through the Newt were slightly mushier than I remember them being without it.  It was only weeks later that I realized what might be going on.  CCs may introduce some spherical aberration on axis.  It's been too hot and steamy this summer to bring out the Newt for further comparisons.  It's on my to-do list for the fall/winter/spring observing season here.