John

55 minutes ago, Carbon Brush said:

@Zermelo has raised an important point.
As we age our ability to discern detail at low light level declines considerably.
I was told by an optician that by age 60 we have 1/3 the night vision of age 20.
So aperture will brighten an object to help compensate for old eyes.

 

The irony there is that it is often later in life that one can afford good quality equipment with high potential performance. I quite often wonder what I would have been able to achieve if I could have afforded the equipment that I have now back in my 20's 🙄

Back then though full time work plus bringing up children would have left me too exhausted to take advantage of it so probably no overall gain then !

11 minutes ago, DaveL59 said:

thankfully it's still alive and well and being picked up again 🙂

https://www.bbc.co.uk/news/world-66371569

6 hours ago, Louis D said:

Some folks over on CN have been using a 1.25" to 2" Step Up Ring screwed onto the 1.25" filter threads of their ASZ to prevent it from smashing into their diagonal optics, especially prism ones, when used in 2" mode.  The ring's 2" outer surface will stop at the diagonal's 2" safety lip that prevents 2" eyepieces from inserting too far.  It might also be useful for other hybrid eyepieces with extraordinarily long 1.25" barrels when used in 2" mode in diagonals without a lot of excess insertion distance.

Thanks Louis - that sounds a good suggestion. 

6 minutes ago, Mr H in Yorkshire said:

Hi John, your introduction of a sub-thread about the Starchair is interesting but I think it could do with a separate entry. Anyone searching for info on the Starchair will likely miss this if it's embedded in a different topic and that would be a pity. Unless you object I will ask a moderator to do that. Cheers.

No problem if that can be done. I don't want to distract from your original thread 🙂

I've seen spiral structure in M51 from my bortle 5 back garden with a 10 inch aperture on a dark night of good transparency. Not really "in your face" but it was there when my eye had adjusted and I had become fully dark adapted and I used some averted vision techniques. Subtle to be honest with you. I observed the same target with a 20 inch aperture from a darkish site a few years back and the view was like the images you see - wow !!!

It is difficult to guarantee what aperture will do this because observing conditions, observer experience and other factors have quite a bearing on what can actually be seen. 

Some observers have seen spiral structure with as little as 4 inches of aperture but not me, alas 🙄

13 minutes ago, Frenchastro said:

.... For example, when I was looking for a TSA102, one appeared for sale not far from London. It was much cheaper for me to take the eurostar between Paris and London,  go in the morning and return in the evening, rather than paying shipping and taxes....

 

Would you not still have to pay import taxes though ?

One thing that I can share is that, for me, the APM 7.7-15.4mm zoom has to be treated as a 2 inch eyepiece. Used in 1.25 inch mode it needs such a lot of inwards focuser movement that it will not reach focus at all in 2 of my scopes and only barely in the others. Used in 2 inch mode the APM zoom reaches focus at around the same position as the Delos 14mm.

Because I currently use refractors, I need to ensure that the 1.25 portion of the APM zoom's barrel clears the diagonal mirror when used in 2 inch mode. This has worked out OK in my Astro Physics and Tele Vue 2 inch diagonals. If I was to use a filter on the eyepiece barrel I think there might be problems though so any filtering of this eyepiece will be applied at the end of the diagonal barrel.

3 hours ago, Mr Spock said:

Shame you haven't got a SvBony 7-21mm in there. It has a good technical test ( http://astro-talks.ru/forum/viewtopic.php?f=32&t=1483#p41976 ) and it would be interesting to see how it performs as a planetary eyepiece.

I do have a clone of the Hyperflex 7.2mm - 21.5mm zoom. I'm not sure how close that is to the SvBony 7-21 zoom ?

3 hours ago, mr_belowski said:

looking forward to seeing your results here, any sneak previews / preliminary findings available?

Thanks for the interest. I learned a long time ago not to jump to any conclusions when comparing optical equipment. I need to have several decent sessions using the eyepieces on a variety of targets with scopes of different specifications. Due to the weather conditions I have managed just two short sessions under mediocre conditions which told me very little about the comparative merits of these zooms I'm afraid. 

I'm very glad that I don't review equipment like this for magazines where there are deadlines to be met. It must be very difficult to gather enough experience to compose something useful with the current UK conditions🙄

I think there should be longish thin bolts with wingnuts on them through those holes in the upper leg sections just above the top of the lower leg sections. These bolts go through those "loops" in the metal tray supports and secure it as well as enabling the tripod legs to push against the supports creating tension and rigidity.

Any DIY shop will probably carry them. 

2 hours ago, Frenchastro said:

What was essential for me was that I am lucky to have been able to import them from Japan thanks to a friend. They came back to me at 164 € (around £141) all taxes included.....

That is an excellent price. Does that include import tax / duty or does that not apply to Japan - France imports ?

2 hours ago, bosun21 said:

This thread is 7 years old 🙂.

It started before AI became so accessible 😁

14 minutes ago, ScouseSpaceCadet said:

A Stellamira 125 ED f7.8 refractor... The Oklop case is nice...

This telescope did not arrive with the advertised losmandy plate, rather a vixen dovetail bar. Perfect except I bought a vixen bar so will need to return it.

I have been destroyed by a virus this week so cannot really be bothered having a proper look... 🙄

Could it be that the losmandy bar is on the bottom of the tube rings ?

(sorry you are feeling unwell and apologies if you have already looked at the other side of the scope)

Edit: I realise now that you must have checked this so please ignore my suggestion 🙄

This group test by Bill Paolini is quite often posted but it is relevant so here it is again if you have not seen it:

Mirror vs. Dielectric vs. Prism Diagonal Comparison - Articles - Articles - Articles - Cloudy Nights

It also highlights the importance of effective baffling / blackening within the diagonal body. 

I suspect this will turn out to be more of a "why I love binoviewing" thread than in any way dissuade you from doing it 🙂

It may highlight where the technique has the most, and least, benefits so that might be useful 👍 

I've tried binoviewing quite a few times over the years with my scopes. I just didn't get on with them. I got the images to merge OK but I'm just more comfortable observing with the one eye. Also, my eyepiece tastes are for hyper-wides and super-wides such as Ethos and Pentax XW's so it would get expensive to have to double up on those.

I'm not a huge user of binoculars for astronomy generally actually although I do have some nice 11x70's.

Shame really because I read quite a lot about how many folks do find binoviewing extremely rewarding. It's just not for me, alas 😔

This is the last time I tried it - my 130mm triplet with William Optics binoviewers which FLO loaned me with another scope:

I use the Baader 1.25 inch twist lock adapter with my Baader T2 prism and it works exceptionally well I feel. No snagging on eyepiece undercuts because of it's longitudinal nylon tension rods.

On 30/07/2023 at 14:56, Don Pensack said:

The problem comes when someone gives a review of an eyepiece in an f/8 refractor and only cares about the sharpness in the center 1/3 of the field.

The person who has an f/4 dob and is looking for sharpness from edge to edge who reads that review has not read a review relevant to his scope or requirements.

And perhaps the reviewer hasn't looked through hundreds of eyepieces and doesn't have the experience to really review the eyepiece.

Merely stating that it was good doesn't carry any weight, in that case.

So some form of a review that contains measurements, even if it is above the heads of most readers of the review, is really essential.  We just don't get that 95% of the time.

I want to see at LEAST the following in a review.  We won't get it, though, because there is too little profit in eyepieces to pay for the necessary testing and too little interest

in knowing the results of such testing.:

1.       spherical aberration_________________________________________________________

2.       coma_____________________________________________________________________

3.       astigmatism________________________________________________________________

4.       field curvature______________________________________________________________

5.       distortion--type and amount___________________________________________________

6.       chromatic aberration--axial and lateral___________________________________________

7.       apparent field_______________________________________________________________

8.       eye relief___________________________________________________________________

9.       light scatter control--field and star outside field (glare)______________________________________________________________________

10.   SAEP_______________________________________________________________________

11.   CAEP_______________________________________________________________________

12.   Tint or spectrum of transmission________________________________________________________________________

13.   Vignetting___________________________________________________________________

14.   Transmission_________________________________________________________________

15.   thermal issues________________________________________________________________

16.   field stop focus_______________________________________________________________

17.   impression of contrast_________________________________________________________

18.   EOFB_______________________________________________________________________

19.   Sharpness on axis/50%/edge____________________________________________________

20.   Presentation of field: close, medium, distant________________________________________

21.   Presentation of field: concave (bowl), flat, convex (globe)_____________________________

Other comments about eyepiece_______________________________________________________________________________________________

We can work as a team Don - you handle points 1 - 21 and I'll contribute the "other comments" 😁

I do use a Baader T2 prism diagonal in 1.25 inch mode my F/9 100mm refractor and it works well but I use 2 inch diagonals (AP and TV) with my other refractors even though I mostly use 1.25 inch eyepieces with them. Quite a few of my eyepieces are on the large side so the security of the 2 inch format diagonals is good to have I feel. The TV's are made from a single block of alloy which seems particularly robust and secure.

Towards the end of August for a possible improvement ?:

UK weather: When will it stop raining and the summer improve? - BBC News

Look at where the eyepiece sits in Suiters "wobbly stack" of factors that impact the quality of the view - way down the list.

How could any image indicating possible eyepiece sharpness take account of all the other things, external to the eyepiece, that will impact that ?

It would be a nightmare for vendors as well - so many returns when observers views are not quite what the advertised image fidelity seemed to promise.

I agree that consistently accurate information on eyepiece specifications would be good though. So often AFoV and actual eye relief figures (even focal length occasionally) are inaccurate and field stop diameters are often missing altogether.

Anyway, this is straying off the topic of the new Takahashi eyepieces so I'll leave it there and wait for some reports from those who are actually using them under the stars. There are some starting to filter through on the CN forum.

The "standard" for eyepiece performance has to be how they perform for their intended purpose, with a human at one side and a telescope at the other, observing celestial targets, surely ?

Other data is of interest of course and fuels discussion during unfavourable conditions but the practical experience must have primacy I feel.

Otherwise forums like this will become little more than technical / theoretical interest discussion groups which might appeal to a few but I suspect the majority would much rather be out there "doing it" as often as possible.

Given the weather we have had in the UK lately, practical testing of eyepieces under the stars is getting rather hard to carry out. I have a couple of very interesting eyepieces on loan currently and but it is clearly going to be a long time until I get enough practical experience with them under my belt to write anything meaningful about them on SGL 🤔

With optical standards edging closer and closer between the best and the rest, you need some sessions under good conditions to spot the often subtle but consistent differences between them.

Its getting a bit academic as to whether eyepiece X has a tiny % better light scatter, sharpness or contrast than eyepiece Y if the chances of using the darn things at all is so slim 🙄

12 minutes ago, WolfieGlos said:

Fairly clear all day here, I was really thinking it might be clear like the BBC app says.

Now? A big, grey cloud has just rolled over the whole area. Hopefully the wind picks up and blows it away, or else Clear Outside will sadly be right 😪

Same here 40 odd miles south of you 😒

Sigh .... another evening tweaking my backlash 🙄

2 hours ago, John said:

Are zooms allowed ?

 

Assuming they are not:

Ethos 21, 13, 8, 6 and 4.7mm