A bit of power, tonight

[Piero]

As there was just a little breeze, I decided to push my TV60 a little bit more than usual. So, I used my vixen slv 5mm with barlow 2x (144x, 0.4mm exit pupil) and pointed to Jupiter and the Moon. This corresponds to 60in per aperture.

Jupiter

To me, the typical limit for Jupiter with this telescope was around 100x, a magnification that I reach using my Nagler 7mm plus Barlow 2x. Having said this, tonight Jupiter took 144x pretty well. The main north- and south- equator bands were clearly visible (as they are above 50x), but it was also possible to spot a third band in the south hemisphere. I am curious to see whether I am able to spot moon transits.. 

Moon

Well, the moon handles 144x very well. I sort of expected this. Instead, what always surprises me is how this little scope showed me a moon at 144x! Very nice and really rich in detail. There were so many details to capture, just starring and being patient. A lovely experience, a bit like flying over the moon!

A comment on the optics. They just transmitted the light as they have to. No aberrations. Just clear images. The Vixen SLV 5mm is a lovely eyepiece. I prefer the vixen slv to the nagler for planetary observation because to me the views are a touch cooler and crisper. To my eye this is more evident on Jupiter. Not that the Nagler behaves bad though! It is an excellent eyepiece and I thank a lot Alan and John for their reports and comments on the Nagler 7mm. Possibly, my opinion is a bit biased because of the larger eye relief of the Vixen SLV, which makes my view through it more relaxing.  

At this power per inch, you don't gain in resolution, but our eyes add something due to the increase in magnification. I am looking forward to seeing these targets again (wind permitting) and Saturn in the next few months 

Unless the seeing is very bad, this scope can be pushed at 144x quite often. The reason why I don't generally do it, is the wind, which shakes a bit too much my photo tripod. mm.. I should try to watch with retracted legs, but then I will have to curve myself as Galileo did on the paintings..

[Stu]

Nice one pdp. It's a very capable scope and small, high quality refractors are often capable of being pushed beyond normal limits.

In my WO SD 66mm I could see GRS and shadow transits, I no longer have this but will give the Tak 60 a go soon. It should be similar to your TV60

[Piero]

Yes, you are right! They are very capable instruments!

I remember your review about your WO SD66 (http://stargazerslounge.com/topic/161700-wo66-grab-and-go-setup/). It was very interesting and inspired me a lot! Not casually I opted for a photo tripod too. Very handy and total weight is kept below 6kg. 

The Tak60 is another gorgeous piece of design. I chose the TV60 vs the Tak60 because just because it was cheaper and on the reviews I read they were very similar. Plus I don't have or intend to use 2" eyepieces. I think these ones are incredible little but very powerful telescopes. 

I haven't seen the great red spot yet, but I believe it is possible. Just need an evening with better seeing than last night. 

[Stu]

Ah yes, I remember that thread, I'm glad it was useful. The 66 was a lovely compact and capable scope, but I think the optics in the 60 (both Tak and TV) are a little bit better corrected and allow higher mag.

Do you have any problems with floaters in you eye given the small exit pupil? I have a very annoying one which I have to look around/past to see Jupiter.

In many ways sticking with 1.25" makes sense, it keeps the weight down, makes balancing easier and you can still get a lovely wide field given the short focal length of the scope.

GRS is definitely possible in these scopes. It won't jump out at you, and does need patience and good seeing but it will be there! Perhaps a neodymium filter may help a little too?

Have fun, and let us know how you get on. Aperture is great, but there is a lot of fun to be had trying to squeeze the most out of a small and high quality scope.

Stu

[Piero]

Thanks Stu for the advise of the neodymium filter. I still have to try my variable polarising filter and move it by 90 deg. I will do some tests and then decide. Thank you very much! 

I haven't had any problems with floaters in my eye. The image is still very bright at 0.4mm exit pupil which is quite shocking...

I believe you could go beyond 144x, 0.4mm ep easily, although with no gain in resolution of course. 

I am not an expert in optics, but it seems that every one having FPL-53 + scott doublets is happy and does not complain about aberrations. Instead, these appear more visible on refractors having FPL-51 (e.g. equinox-66 and wo sd66 (?) ). Tele Vue does not reveal the name of its optics, but I would think that is something at least in the league of FPL-53+scott for the TV60. The same for Tak60 I would say. That's why I decided to go for one of these two telescopes. 

And they are unique! No way I would be able to go by bike on a field with an 80mm and a mount for it, unless this is really shaky. And if you want real wide fields with an 80 you should consider 2" accessories which increase weight. I think an 80 is a terrific telescope and a solid complement for a larger telescope. However, to me, it already belongs to the class of telescopes and not in the class of small-ultra portable telescopes (where 60-70s belong ;-) ).

Look forward to reading about your Tak60 too! In terms of performance, I don't have any doubt it is great! Possibly an advantage of the Tak60 towards the TV60 is a more standard focuser. The TV60 helical focuser is a nice idea and easy to use from my point of view. The tube going inside-outside (coarse focuser) is a bit weird and requires some practice. Once learnt, it works well though. 

[John]

The Schott company makes lots of glass types so what matters is that the correct one is selected to match with the ED element whether it's Ohara FPL-51, 53 or something else by another glass manufacturer. The figure and polish of the lenses is also very important.

Tele Vue have never revealed the glass types they use in their refractors. Neither have Vixen as it happens. I believe Takahashi used to use Flourite elements but have moved to FPL-53 although officially they don't specifiy the glass types used.

[Piero]

Thanks John for clarifying this. Let's take the SW Equinox 66 (FPL-51) and SW Equinox 80 (FPL-53). Is the Scott glass the same for these two reflectors?

[John]

Thanks John for clarifying this. Let's take the SW Equinox 66 (FPL-51) and SW Equinox 80 (FPL-53). Is the Scott glass the same for these two reflectors?

Probably not because the ED elements are different (Ohara FPL-51 for the 66 and Ohara FPL-53 for the 80) so the mating element (the other lens) will probably need to be slightly different glass type for each one. It may well be made by Schott in both cases though. Ohara are another glass manufacturer by the way.

[Piero]

Last night I observed Jupiter from 9 to 10pm (twilight).

Transparency and seeing were very good to me.

After watching it for a while with my 3.5mm Nagler T6 (103x, 0.6mm ex. pup., 0.80 deg fov), I decided to add the Bresser 2x SA. 

The idea started as a joke because I thought the image would have been too dark for discern any detail. Instead, it was possible to perceive a little amount of shades on the two major bands of the planet. The boundaries of the other two less visible bands (North and South hemisphere, respectively) were also there. At 103x I was able to see the boundaries of these two bands on the 'equator side', but not on the 'pole side'. At 206x these were noticeable. 4 moons vere detectable and one was just about to get closer to Jupiter. I agree with Gerry (jetstream) that watching Jupiter in twilight shows more contrast. I was also able to see some red-ish colour on the major two bands, which instead is less noticeable when watching Jupiter in the dark. Looking at a bright source before watching the planet did not help me instead. I found I had more difficulty to notice details. Although the exit pupil was only 0.3mm, floaters did not cause me serious problems. Interestingly, I found floaters to be a problem when watching the Sun at 103x. Could these be related to overall image brightness? 

Venus. Also observed in the twilight. Visible 60% of its phase. No cloud detail was detectable. At 206x, on one side of the focus, Venus appeared violet, on the other side green/yellow. When in focus, there was no colour aberration. Curiously, at this magnification it was still very bright suggesting to me that a variable polarising filter might be beneficial. 

Looking forward to reporting about similar tests on the Moon, Saturn and Mars.

[Piero]

Last night the sky was clear and so I cycled with the tv60+tripod to the field nearby my house. Luckily it is only 2miles away and 6kg can be easily carried if split into two parts: tv60+eps+diag (2.2kg) in a backpack and tripod (3.4kg) in its bag on a shoulder.

Anyway, I tested Jupiter and Venus with a single polarising filter (SPF) at 103x and 206x. The seeing was good, but not as good as it was in my previous observation. Time was between 9.30 and 10.45pm (twilight).

Jupiter

The SPF noticeably improved the view. Four bands and a moon transit were easily visible at both 103x and 206x. The use of a SPF seemed to stabilise the image and improved contrast. A fair amount of shades were also perceptible on the main two bands. The transit appeared as a crisp black dot on the planet atmosphere. Without the SPF it was only possible to see the two main bands and no shade on them. They simply appeared as two thick lines across the planet. Interestingly the transit shadow appeared a tiny bit better without the filter. To me, using the SPF requires a bit of experience in order to rotate the eyepiece to gain the best contrast. However this is feasible.

Venus

Visible about 60% of its phase. No cloud detail was detectable even with the SPF. Planet glare was reduced but it was very difficult to focus, likely due to the average seeing and high magnification. Unfortunately I cannot take all my eyepieces with me, but just three which fit in the tv60 bag. I am curious to test Venus at 144x + SPF using the Vixen 5mm SLV. 

A big thank to Gerry (jetstream) for suggesting to use a single polarising filter in the twilight. I like this a lot!    

[damnut]

Hi Piero,

Nice report and how you achieved it. look forward to reading more.

[Piero]

Thanks, Damian. 

I am curious to test on Saturn too. I have already tried, but I believe it is still too early due to its low position in the sky in the evening (~15 degrees above the horizon when I tried). So far I've managed to see Titan the rings but not the Cassini division (103x, 206x). The rings are well marked though and in a good angle so the Cassini division shouldn't be impossible (I think at least!). I haven't seen bands on the planet either. 

I also want to test narrow and line band filters at high power. So far, I found out that 103x + OIII filter is just too much (tested on the Ring Nebula) whereas 72x + OIII was at the limit (tested on the Eskimo Nebula) suggesting that an exit pupil of ~1.0mm is about the usable limit for an OIII filter. This at least for a small telescope. Although I would not consider the view of the ring nebula at 103x, 0.6mm exit pupil appreciable (too dim for my taste!), the 'ring' was clearly there and visible. The UHC can be regularly pushed a bit more, but I haven't found an upper limit for this. I plan to test it at 103x on the Ring Nebula next time. 

Piero

[Stu]

Piero, it's great to read of your exploits pushing your lovely TV60 to the limits. I do enjoy similar tastes in getting the most from small , high quality scopes.

Saturn looked quite nice later on last night, around midnight in the 4". Cassini was very well defined. There was also subtle shading on the surface.

One annoyance I have is that using the Leica zoom with Barlow and spacers to increase the power, I have no idea on the exact mag I'm using. Must find a way to work it out.

I will give the 60 a go and see if Cassini is visible.

[Piero]

Thanks, Stu! Yes, midnight is the earliest time to start watching Saturn 'reasonably', but that is also the time I have to pack as it takes me a bit to cycle home and then write a report to not forget details of what I saw.

However, next weeks will be promising as it is getting g higher and twilight longer, perfect for planets!

Even if you cannot determine the exact magnification, you could infer a range of magnifications for each step of the zoom ep, I believe.

I actually have a question for you about floaters. I remember you mentioned that floaters were an issue for you at small exit pupil (<0.5mm). What about if you go below 0.3 or 0.4 with your tak?

I wonder this because to me floaters are an issue with small exit pupil when the object is very bright. For instance the sun at 103x shows me huge distracting floaters. I don't have serious problem at 0.3mm watching Jupiter instead (206x).

Quite curious.. If so, they don't increase linearly depending on the exit pupil, but are also dependent on image brightness.

[Qualia]

Lovely set of reports, Piero and really inspiring.

Regarding Saturn: I usually don't start observing till after midnight so by the time I get round to the planet it's pretty well placed in the southern skies. I've been out this week with the 10" and 76mm and have failed to see Casini's Division with the smaller scope. I find the sharpness of Saturn breaking down a little once I start pushing 130x and although the seeing has been forgiving, my eyes and/or scope just can't resolve the feature - even with this type of magnification. In this light, it would be really interesting to hear if you or Stu can get a hint with your 60s, then I'll really know my eyes are 'up the spout'   

The main challenge with these kind of richfield fracs is getting planetary magnification which makes me wonder that perhaps it would be an idea to sell on your Vixen and 7mm & 3.5mm Naglers and look out for a 3-6mm Nagler Zoom? You'll free up weight and space and quite possibly have an ideal addition to your gorgeous frac. 

Thanks again for the lovely reports and I look forward to hearing how you get along with Saturn and other celestial wonders

[Piero]

Lovely set of reports, Piero and really inspiring.

Regarding Saturn: I usually don't start observing till after midnight so by the time I get round to the planet it's pretty well placed in the southern skies. I've been out this week with the 10" and 76mm and have failed to see Casini's Division with the smaller scope. I find the sharpness of Saturn breaking down a little once I start pushing 130x and although the seeing has been forgiving, my eyes and/or scope just can't resolve the feature - even with this type of magnification. In this light, it would be really interesting to hear if you or Stu can get a hint with your 60s, then I'll really know my eyes are 'up the spout' 

The main challenge with these kind of richfield fracs is getting planetary magnification which makes me wonder that perhaps it would be an idea to sell on your Vixen and 7mm & 3.5mm Naglers and look out for a 3-6mm Nagler Zoom? You'll free up weight and space and quite possibly have an ideal addition to your gorgeous frac. 

Thanks again for the lovely reports and I look forward to hearing how you get along with Saturn and other celestial wonders

Hi Rob, sorry, I completely missed your post.  

I can see the Cassini division on the 'wings' of the planet, as you called them in another post, if the seeing is good. Of course this requires some attention as it is not obvious. Observing more carefully, it is the distinction between ring A and B that is quite noticeable and therefore one can get the intuition where the Cassini division is. I have never seen it at 103x with the Nagler 3.5mm though.

At 28x with the Nagler 13, one time I managed to see Rhea as a very faint object. This was a total surprise and I discovered this later at home by searching potential moons right at the position where this faint object was located. All this answer is less informative for you though as these findings were quite later than your post. 

Nagler zoom 3-6mm. I believe it is a nice zoom eyepiece and there are many positive reviews about it. I have three concerns though:

1) tight eye-relief. The eyepiece lens seems so small that reminds me of one of my first eyepieces I have got (and still have in Italy), the orion plossl sirius 10mm. Also this has 10mm eyerelief, and although it was a fine eyepiece, I never liked observing in that narrow hole. I am not talking about field of view here, but just the small diameter size of the lens. Maybe I am wrong, but from the pictures, the nagler zoom seems to have a very narrow diameter lens. Sure, this is the case of orthoscopic eyepieces, but that is why I do not own any, despite their excellent performance. 

2) field of view. You are right that the zoom 3-6 would replace my 7, 5, and 3.5. However, I also use the 7 for dso, and although dim, having 1.5 degrees of sky at 50x is quite nice. I am not a mega-wide field addicted, but 50 degrees is a bit little for my tastes. Ideally I would be happy with a 70 degrees. I thought to get pentaxes for a long time. The only thing is that they don't often appear in the second market (and they don't last long either!) and they are just too big. The naglers are a powerful compact package and checks all my boxes. The vixen slv is a bit of an exception to what I just said.. However, it has a lovely eye-relief and it is so comfortable that I often forget the field of view. The lens is large and the eye is simply relaxed when observing. Plus the optics are fabulous to me. I bought nagler 3.5 second hand and it was a bit of a gamble. The reason was that my barlow lens requires a substantial inward refocus and on the tv60 this is quite annoying because you need to move the coarse focuser, risking to lose the target due to the rough movement. Therefore, I was looking for something around 3mm to avoid barlowing the 7mm. Honestly, if there were a vixen 3.5mm or 3mm, I would have bought it straightaway, but this does not exist. On the other hand there were a couple of 3.5 Nagler second hand and so I picked one up. It is a good eyepiece to me, but not at the level of the vixen 5mm. A bit less sharper and the tone is not as pure and clear I would say. Nevertheless, it is nice, also for double stars. Again.. even though the image is quite dark, having 0.8 degrees of sky at 103x is quite nice! 

3) lack of confidence that I would like it. It is a fairly expensive piece and I am not so confident that I would enjoy it. This is the weakest reason of course, but I wouldn't buy one, even second hand, just for trying it. It might sound coward, but since I do not feel the need for it and the points above are a bit tricky to by-pass, I wouldn't get one. Of course I could change my view, but for this, I believe I would need to see through one at the telescope. 

Have you ever tried one? If so, what do you think of it? 

[John]

I've owned 2 of the Nagler 3-6mm zooms and I've just never really warmed to them, despite their undoubted qualties

I bought the 2nd one about 2 years after I'd parted with the 1st one on the basis that I might not have given the 1st a real chance to shine and that my experience had grown a bit. They are really great little eyepieces and an impressive optical achievement but just didn't appeal to me (again !) for some unfathomable reason.

I didn't think the 3-6 Nagler zoom was quite as good as the Baader GO / University Optics HD orthos that I compared it to. Very, very good given it's zoom function of course and the ability fo just instantly fine tune the magnification is not to be sniffed at. The Vixen SLV 6mm would be at least as good as the zoom and maybe a little better from my experiences with that one.

[Piero]

Thanks John for your reporting your experience.

I see that the zoom feature as well as the parfocality during the shift can be highly desirable particularly on planetary targets.

Said this, considering your comment about the optical quality vs the Baader GO or UO HD, and after seeing the performance of the vixen slv with my eye, possibly you added a fourth point to my list of concerns..  

Of course mine is only a personal view and I believe that other members can be very happy with it. Therefore, I hope not to cause an argument for my opinion about this eyepiece. Everyone has personal tastes and I can see that for other users the nagler zoom can tick all the boxes in terms of power, compactness, and money too.

If they much cost less and I felt in the need of those focal lengths, I might get one, although I am concerned that I would not like it.