John

I've owned and used the 2.5x 1.25 inch Powermate and the 2x 2 inch one. They are superb optical devices - practically invisible apart from the image amplification that they provide. I found little or no change to the focus position and they did not vignette eyepieces with larger field stops in the respective formats. 

I'm a visual astronomer only - no imaging experience with them.

I have not used the Tak extender I ought to add.

Edit: On the topic of eye relief, Powermates do not change that as far as I'm aware, unlike conventional barlows.

1 hour ago, Stu said:

Thanks for bringing this one to my attention John. I got it last night in the 128mm but it was TOUGH! My skies are a bit worse due to lights from a building site to the south east unfortunately, think I need to start heading out a bit more. I am 90% sure I got it with averted vision but it was right on the limit. I used a 7mm XW for x148, I wonder if going higher would have helped?

With the 120mm I found 180x-190x teased out the fainter points of light a little easier. XW 5mm / Ethos 4.7mm seemed best. I'm pleased that you got it though. 

Another one that I found challenging last night was getting M13 and the galaxy NGC 6207 in the same FoV. M13 is dead easy but the 12th mag galaxy (which is 1 degree away) needed a lot of averted vision, tube tapping etc to confirm with the smaller aperture. It was a piece of cake with my 12 inch dob of course but I am enjoying pushing these refractors as far as I can 🙂

I must give that deep breathing a try sometime, when nobody is around of course 🙄

28 minutes ago, Louis D said:

At higher powers, I'm generally looking at smaller objects, and 70 to 78 degree AFOVs seem plenty wide enough for my non-tracking observing of such objects.

For me, I like as wide as possible. The 110 degree AFoV Ethos SX 4.7 was (again) invaluable as I observed (un-tracked) the quasar 3C 273 tonight. For glasses wearers when observing, <15mm of eye relief is "no go" I appreciate 🙂

22 minutes ago, Epick Crom said:

Great stuff John! It's always fun investigating mysteries in the night sky 👍

Thanks Joe. Turns out that it's not so mysterious after all - Sky Safari shows a magnitude 12.6 star in that spot which Stellarium omits. Shows that it pays to consult more than one star atlas before jumping to conclusions ! 🙄

I've just had another go at the quasar 3C 273, this time with my ED120 refractor. At the same magnification that I was using with the 100mm last night (same eyepiece in fact) I could go about half a magnitude fainter so picked up a couple more stars in the field that 3C 273 is situated in, as well as the quasar itself. I've added the magnitude of those to the Stellarium-generated chart below. The odd thing though was that I have been picking up a further magnitude 12.5ish (est) pinpoint of light but there is nothing plotted there in Stellarium (my version goes down to magnitude 15). This "star" is definitely there (I've checked and re-checked about a dozen times over the past 30 minutes). I'm wondering if it is a variable star that has flared up tonight ? I'll do some more research on that one. I've marked it's position on my chart below with a ? and a magnitude estimate. Fun stuff ! 🙂

I've switched from the FC100-DL to the ED120 now that it is getting darker. It will be interesting to see the difference that 20mm of aperture makes to spotting that quasar in Virgo !

1 hour ago, Deadlake said:

You managed to use your TOE 4 mm yet?

Yes - this evening is it's 5th time out. I've yet to see any noticeable difference between it and the Nagler zoom at 4mm or the 3.5mm XW to be honest but I'll keep on trying 🙂

From previous experiences it may take a night of excellent seeing to spot any differences and I've not really had one of those for a while. 

Quite a few folks on CN are raving about the TOE's so there must be something about them  🙂

31 minutes ago, JeremyS said:

I’m going to pretend I didn’t see this

It's either that or we have to have a whip round to cover the costs of @Stu's sessions with an osteopath 😄

The FC100-DL observing an early evening Venus. Sun well above the horizon and the planet is nice and crisp. Maybe hints of cloud structure on the disk ?

Nice evening to be out 🙂

1 hour ago, DirkSteele said:

...... Heck of a price per inch in 1989. We should all appreciate  lucky we are with prices of good quality scopes in 2023 compared to those buying more than 30 years ago.

Yes, I noticed that. When you think about 34 years of inflation the price per inch today is really very reasonable, even for premium glass.

I was sad to hear of the death of Terence Dickinson back in February this year. I've read a lot of his books, articles and other publications and he seems to capture the wonder of astronomy really well.

I came across this piece that he wrote back in 1989 for the magazine "Sky and Telescope" through a link on the Astro Physics website. I can recall reading this when it was first published in S&T and enjoying it so it is nice to read it again and share it 30+ years on 🙂

The article mostly mentions AP refractors but the general thoughts on the appeal of fine refractors are interesting I think:

adventures-in-refractorland.pdf (astro-physics.info)

51 minutes ago, Louis D said:

I know you briefly had the 12mm ES-92.  How did the engagement differ between it and the 13mm Ethos?  I vaguely recall you had difficulty holding the exit pupil of the ES-92.

Wearing glasses, the ES-92s feel to me like the Delos/XW/Morpheus/Hi-FW taken up a notch in engagement without losing any of the ease of taking in the entire view at once.  There's no comparison to the 12mm/17mm NT4s which are both very difficult to hold the entire view while wearing eyeglasses.

I found the 12mm ES-92 optically extremely good but ergonomically very difficult. The eye relief for me, as a non glasses wearer, meant that I needed to "hover" my eye well off the top of the eyecup which is not a relaxed position and let stray light onto the eye lens of the eyepiece, which reduced contrast. I moved the eyepiece on to a new owner quite quickly. I found the 17mm ES-92 a bit easier in this respect so held onto it for longer. The only NT4 that I have owned is the 22mm which is reputedly the easiest Nagler for glasses wearers to get on with.

Having read many accounts of experiences of eyepieces from folks who wear glasses when observing I have come to the conclusion that the experiences of glasses wearers vs non glasses wearers is very often going to be different where eyepieces are concerned.  

2 minutes ago, Mr Spock said:

All gone now. The mist has become so heavy The sky is blank.

That is happening here now. It's an odd feeling to look at a sky where you can barely see any stars but just an hour or two ago you were looking out 1000's of light years 🙄

Interesting report and I can understand the "rollercoaster" analogy.

Not a good day for the mouse though 🤢

Interesting "factoid" on the quasar 3C 273 from the ESA / Hubble website:

If it was located 30 light-years from our own planet — roughly seven times the distance between Earth and Proxima Centauri, the nearest star to us after the Sun — it would still appear as bright as the Sun in the sky.  

I used the 14mm Delos and the 13mm Ethos tonight. Both really nice but I find the Ethos view the most engaging. I don't wear glasses when observing though.

Well I got the quasar !

Quasar 3C 273 is the brightest visible I believe although still faint at magnitude 12.85 or thereabouts. Plenty enough challenge for my 100mm refractor this evening ! After quite a bit of searching (the quasar is in the "bowl" of Virgo) and allowing my eyes to get dark adapted, I managed to spot the quasar using 191x (Ethos 4.7mm). I used the Ethos to give me as wide a view as possible to show guide stars. Allowing for a bit of atmospheric extinction 3C 273 was probably around magnitude 13 - pretty much at the limit for a 100mm aperture under my skies which are probably around mag 5-ish NELM tonight. Quasar 3C 273 is also one of the closest quasars to us at around 2.4 billion light years. 

Nice to get this result 🙂

Here is a refractor-view close up chart with the guide stars that I could see marked with their magnitudes according to Stellarium:

Phew !!! - going to try some easier stuff now ! 

16 minutes ago, Stu said:

Same here John! 

That is good to know - I was starting to think that it was only me !

I'm quite good at detecting faint targets but not so good at subtle contrasts I think. Why the heck I have 5 expensive refractors, goodness knows ! 😌

8 minutes ago, Mr Spock said:

Just been looking at Venus with the FC-100D and 4mm TOE. I've never been one for filters but the 80A really does help reveal the clouds. I might try and get a darker blue or violet to see what they do.

Nice 🙂

I've tried all sorts of filters with my 100mm - 130mm refractors and still not seen a hint of clouds, or at least anything that I would be certain of. Must be my eyes 🙄

8 hours ago, JeremyS said:

That’s just as well as there are one or two on here 👍🏻

Have we any idea how many FS 128's were made ?

2 minutes ago, Stu said:

Which one are you aiming for John?

The brightest - 3C 273 in Virgo.

Another chance to spot a quasar with my 100mm refractor hopefully 🙂

There is a curious pleasure in seeing how deep and far you can see with a small scope 

1 minute ago, Pixies said:

OK - found one at last.

Nice !

A lot of performance in a compact package.

I used to have all the Nagler T6's a few years back 🙂

My skies are bortle 5 here. I used to have a good quality (Astronomik) H-Beta filter when I had a 12 inch scope. That filter did help me to see the Horsehead Nebula (just !!!) but frankly very little else under my skies.

Under darker skies I might have got more from the H-Beta of course.

Excellent !