John

7 minutes ago, Captain Scarlet said:

I can easily see Uranus as a disc, it's 3.5 arcsecs. I can just about detect that Neptune is a disc, at slightly over 2arcsecs, but that may be difficult because it's also so dim. But I reckon Ceres at <1" might be beyond my disc-detectability. I'll try with my 12inch at high mag the next time I try, and see what I see.

I've found Uranus and Neptune respond well to high magnifications, sometimes very high magnifications (ie: 400x or more). With my 130 triplet I've spotted Neptune's largest moon Triton at such high magnifications. Your 140mm should be able to spot that and maybe even a couple of Uranus's moons on a dark night 🙂

Well, nothing broke and the focuser seemed to handle it OK although it did start to creep a bit when I pointed the scope towards the zenith, without the tension knob tightened.

I've owned the Nagler T6 13mm (twice) the 17.3 and 14mm Delos (still have the 14mm) and the 13mm Ethos plus quite a few other 12/13mm eyepieces as well along the way.

It is a very useful eyepiece focal length in practically all scope specifications.

The only eyepiece of this focal length that I really had any issues with was the Explore Scientific 92 degrees 12mm which had way too much eye relief for me. Of course it is precisely this feature that makes it very popular with those who wear glasses when observing. 

All the eyepieces discussed in this thread are of very good or excellent optical quality so what we are discussing here are primarily ergonomic considerations and what suits individual observers, as @Alan White notes in his post above. Given that we are all different it is perhaps no surprise that there will not be all that much consensus.

Personally I slightly prefer using the Pentax XW's over the Deloi that I've owned but only by a small margin and I can get along quite happily with a Delos if that is what suits the task in hand best.

I did really love the T6 Naglers (I had a full set at one point) but gradually switched to the Ethos eyepieces once I had discovered how much I enjoyed those. A couple of years ago I bought another 13mm T6 Nagler for old time's sake but found that I had now got used to what the 13mm Ethos had to offer and the little 13mm Nagler seemed a little lack-lustre buy comparison so off it went to another home.

Sometimes we need to try a few eyepiece designs out to find out what suits our personal preferences. Thank goodness that the used equipment market enables that to happen. 

2 hours ago, Mr Spock said:

For my ultimate ultra-light grab and go I've gone the other way. I use a 60mm FS-60CB on a Slik photo tripod. It's something I can carry round a bird reserve when I'm using it in terrestrial mode.

That is the same tripod that I am using - the Slik Master Classic. A very good tripod I think although I'm no expert in these things. I did try my 70ED with the standard head you are using with your Tak 60 and it worked quite well but I think I prefer the AZT6 for astronomy use with that scope.

It is nice to have complete setups like these that can be carried with one hand 🙂

Hi,

I am relatively inexperienced in the world of small scopes but I have recently acquired a 70mm F/6 ED refractor and just this week a TS AZT6 alt-azimuth head which I am using on a Slik Master Classic aluminium photo tripod.

I've only used this setup a couple of times but I can report that the AZT6 copes quite well with the 2.2kg 70mm refractor and the total weight of the setup (including 1.25 inch diagonal, finder and a 20mm SWA eyepiece) is no more than 5kg, so really pretty easy to move about. 

Being realistic, I think an 80mm ED doublet type refractor might be pushing the mount too far without adding a counterweight and associated bar to the other side. Something I was keen to avoid to maintain maximum compactness. It would probably require a stouter tripod than I am using as well. 

I used the scope up to 140x magnification and, although there was some vibration for a couple of seconds after I had adjusted the focus, the view settled enough for me to split double stars down to 2 arc seconds separation.

My little refractor is just one of the Altair ones that uses an FPL-51 (or equivalent) ED element in the objective so there is a small amount of CA around bright targets in the F/6 optics but I feel it's reasonable for the price paid.  More importantly (to me) the objective seems well figured and polished and gives a good star test and shows tight star images even at 50x per inch of magnification. I don't image - I just observe.

I tend to agree generally with the views on small apertures posted by Don Pensack earlier in this thread but my little setup will at least ensure that I can have a telescope with me when I travel whereas before I've been limited to binoculars. 

I hope that helps a little with your decision making 🙂

Nice report Magnus, great looking scope in a wonderful location too 🙂

On the apparent diameter of 1 Ceres, Stellarium gives a figure of .83 arc seconds which is co-incidentally similar to the apparent diameter of Jupiter's moon Io.

With the Galilean moons I have found that it is possible to notice differences in what appears to be their apparent diameters with scopes of 100mm or more aperture and from this I have been able to work out which was which on a particular night without looking up their relative positions.

The challenge with 1 Ceres is that there are no nearby objects in the sky with which to directly compare it's apparent diameter with, in the same field of view, so it may well be rather difficult to work out if what you are seeing is it's true disk or something more akin to an airy disk as you get with stars. Maybe that is also the case with the Galilean moons but there are definitely visual differences in apparent size between them whether though varying airy or true disk diameters.

I guess that does not really answer your question - I would be very interested to hear what others think 🙂

Thanks for posting your report and that lovely photo 👍

I have a 31mm Nagler. It weighs a touch under 1kg so a little lighter than the ES 30mm. I use it most frequently in my Vixen 102mm refractor which has a Vixen R&P focuser and the scope / focuser seems to cope with it quite well.

I uses to use the Vixen and 31mm Nagler combo with an AZ4 mount as well. 

I'll have to try the mighty Nagler with my newly aquired 70mm F/6 ED refractor - it will give a near-6 degree true field in that !

You might need to move the scope a little bit forward in the tube rings to get a better balance with heavier eyepieces in the diagonal.

2 hours ago, Rusted said:

Has optics become Hifi? Where only subjective nuances of "golden eared reviewers" are the accepted measuring stick?
 

 

That is just where I think things might be heading 😒

54 minutes ago, jetstream said:

DPAC will tell us both how good our scopes are

Well that is the interesting thing isn't it. I've been very happy with my ED120 for the near decade that I have owned it. Let's say that someone (it won't be me) DPAC tests it and the results show that it is a mediocre scope.

This could have 2 effects:

- my enthusiasm / enjoyment for the scope is dampened, which would be sad.

- my confidence in my observing ability would be dented, which would also be sad and might even lead to me pulling out of the hobby.

But I guess that "knowing the truth" is more important than anything else 🙄

5 hours ago, tim22 said:

Hi John.  I've used the laser and also the Cheshire to confirm that the focuser draw tube alignment to the lense is good.  But I don't know how I should use the Cheshire for the objective tilt?  I can see no way of adjusting objective tilt so I was anticipating putting some tilt on the focuser to straighten the image out.  thanks Tim

The view through the cheshire (no diagonal) when it's diagonal face is illuminated reveals either objective tilt or focuser tilt as per the illustration below. If your laser eliminates the latter then the former may apply if you see the misaligned cheshire circles:

5 hours ago, 900SL said:

It will certainly lead to higher prices, and people returning perfectly useable scopes because their test results were less than ideal.

 

I wonder if it might also lead to the situation where used scopes that have not been DPAC tested will be harder to sell or will need to be priced at a lower level ?

2 hours ago, jetstream said:

I wouldnt pay $18000 to get fringing on Jupiter - I paid a lot less to get it with my SW120ED.

You ED120 is clearly at one end of the performance scale for the model and mine must be closer to the other end !

1 hour ago, Deadlake said:

I think that’s another thread…

I'd like to see more independent tests of Orion Optics UK optics, but that really is another thread (or two !).

£159 seems outstanding value for a 20mm 2 inch 80 degree AFoV eyepiece 👍

Great looking scope Dave - congratulations 🙂

Has that Unitron look but probably with even better optics !

1 hour ago, Deadlake said:

Well if you knew SV was testing red you might. The colour band was not on SV’s site until this blew up and you would of only got a hint if you looked at SV’s Facebook page.

What wavelength of light is hindsight best tested with ? 😁

I think it's been accepted for a while that the most exacting light to test scope optics in is green. 

When I'm checking refractors I use a well collimated laser to check the focuser is aligned with the the optical axis and then (after making changes to focuser tilt if they are needed) use a cheshire to check the objective tilt. 

9 hours ago, jetstream said:

Me neither!

But hey this could be my last chance to manage one

That's one of the challenges isn't it - by the time we get the means to acquire the equipment that we have dreamed about, old age catches up and actually using it becomes quite a challenge 😁

9 hours ago, jetstream said:

Rohr seems to be a resource many quote eventhough some question his results as is bound to happen espc the interferometer results. Apparently interferometer results are hard to duplicate between units and the conditions they test in ie horizontal vs vertical, atmospheric concerns and type of interferometer used.

DPAC appears to be an easy and accurate test to use and can be easily repeatable. Good opticians use many tests to evaluate optics as they are being made including testing in multiple wavelengths of light.

I think the future will bring many many test results for us to view and this will tell the tale.IMHO.

Judging by the DPAC threads on CN, I think that technique will get a fair share of results scrutiny as well and some of it quite "lively". Only to be expected I guess - people can get very sensitive when the soundness of their prized possessions are questioned, even if it is not their particular example 🙄

3 minutes ago, jetstream said:

@John Do you think or have you heard if the AZ100 would hold the likes of a TEC 160 steadily?

It's difficult for me to say - I've never used a TEC 160. @Stu would be a better person to ask I think - he has a lot more experience of the AZ100 than I have had.

@GavStar has a TEC 160 but he went for the TTS 160 from TrackTheStars. 

1 minute ago, jetstream said:

I have a funny feeling there are going to be many samples of one tested as DPAC really catches on...

I can recall Herr Rohr testing quite a few ED120's (or clones) and the results were really rather better than many expected. My own example seems a cracker 👍

I have not used a Diskmount but they do look very impressive and seem to have some very satisfied customers judging by remarks on here and that other forum 🙂

I have used a couple of the Rowan AZ100's though and even though they were beta-test versions the quality of engineering and operation were very apparent to me. With the further testing by @Stu and others and improvements made by Rowan on the back of that I reckon the production Rowan AZ100's are truly superb high capacity alt-azimuth mounts. 

As it happens, personally I ended up with a T-Rex mount though for my largest refractor (130mm F/9.2 triplet). These are long out of production now but I've no doubts that the AZ100 does an equally good job and of course Rowan are still around supporting and improving their products.

One of the issues with this, it seems to me, is that a single example of a scope gets a less-than-great DPAC test which gets posted online and then is dissected by dozens of posters of varying degrees of experience, leading, possibly, to the impression that the model is generally poor, which might be completely inaccurate - the test sample being just one of possibly 1000's.

If , say, a dozen randomly selected samples of varying ages had been tested, the results might be slightly more interesting ? 

With the SV 180 I understand that the situation is different with just 50 or less having been made. My point above refers to mass-production instruments.

2 hours ago, SuburbanMak said:

....My only slight glitch packing was in getting the Tak twist ring to let go of the diagonal, in the end I had to take the visual back off and unscrew all the bits separately & then put it back together.

 

 

Excellent report 👍

I have exactly the same issue with my Tak FC100-DL that you describe above. At some point I guess I will change from the Tak twist ring adapter so something that grips well when needed but also lets go when asked to !

Luckily I don't need to remove the diagonal from my scope very often 😏

A good test of how faint a star the scope can pick up is the mag 13 star just outside the ring nebula. On a decent night I have seen that one with my Tak FC100.

1 hour ago, Carbon Brush said:

.... my preference is to put the finder much nearer to the eyepiece.

When looking for an object an RDF (any type not just telrad) gets you somewhere near.
Then the x9 or similar finder gets the target centred.
Then look through the scope eyepiece.
If things don't seem to be working out you can easily swap your eye between finder scope and main scope without moving far.....

That is just the way that I like to have things as well. The ability to be able to move the observing eye smoothly between finder(s) and eyepiece is quite important I find, particularly between the optical finder and the eyepiece.

In my case Rigel Quikfinder plus 9x50 RACI: