John

The OP didn't specify a budget and had already owned a Nagler zoom, which is hardly a low cost item (it is more expensive than the APM zoom for example).

I use the 7.2-21.5 quite often and it is a very sharp eyepiece. The AFoV at the long end is rather off putting though - sub-40 degrees I reckon. The action on mine is quite loose really - I guess they vary. The Baader 8-24 AFoV has been measured at 44 - 68 degrees by owners. The Nagler zooms are something else - I'm not surprised that the OP regrets disposing of one !

Two companies who have been manufacturing astronomical equipment for 46 and 77 years respectively and are still regarded as leaders in their field. Fads and cliques 🤣

That's a fair point. A decade or so back they were hardly ever mentioned on this forum.

So the eulogising did not put you off for too long then ? 😁

He was the short, dumpy but slightly faster one 😁

I wanted a TV Genesis many years ago. I found one for sale but the seller simply would not budge on price and then my Vixen ED102SS popped up for sale at quite a bit less from a trusted SGL seller, so I opted for that instead. The Vixen is "slower" at F/6.5 but a doublet that uses an FPL-53 ED element. I can get a 4 degree true field with the scope and it also seems to be figured well enough to deliver sharp views at 200x plus as well. CA in the Vixen is really pretty low, comparing well with the F/9 ED100 that preceded it. No rock band name in the scopes title though - Vixen is named after one of Santa's reindeer, apparently ! I can see the appeal of owning a scope with the sort of history attached to it that the Genesis has though 👍 Edit: one further thought, a rock band name that might not be so popular for refractors would be Rainbow I reckon 😁

I used to use the longer version of the William Optics DT bar with my 130mm F/9.2 triplet. I attached it to the tube rings using 4 M6 bolts. It was pretty stable even with that long 9.4kg scope on board. I've since moved to a Losmandy bar though for even more stability. I would think that a 102mm F/7 would be very stable on the WO bar.

At F/4.4 coma will be there but may not be too noticeable depending on what eyepieces you are using and how hard you look for it. It does not affect the central part of the field of view. Toward the edges of the field you might notice stars take on a shape like small comets with their "tails" pointing away from the centre of the field of view. On the other hand, if you are not noticing it then it's probably not an issue that bothers you.

If it is the Skywatcher Skyliner 16 inch (the 400P model) then it has a focal length of 1800mm and the focal ratio is F/4.4. If you are using wide angle eyepieces with the scope, coma, will be an issue in the outer parts of the field of view so a coma corrector would make sense in such a scope. Planets are generally observed in the central part of the field of view so coma is probably not going to be an issue there. For star clusters and other more extended targets coma is likely to be seen and can be distracting. Some people are more tolerant of it than others.

I used to have a .965 inch Vixen 20mm Kellner with my Astro Systems newtonian and that was a great little eyepiece. Not the widest of views of course but very sharp and contrasty.

I don't want to take the thread off topic so I will just say that the OO 12 was a little better optically than the GSO or Skywatcher ones and, more crucially for me, weighed about the same as a 10 inch GSO / Skywatcher so was much easier to setup and move about than the GSO made 12 inch (which was a Meade Lightbridge). Back on topic, it looks like @Carbon Brushis gradually and thoughtfully moving towards a decision now 🙂

Good to see that GSO have upped their game now 🙂 I've owned 2 older GSO made dobs (8 inch and 12 inch), 4 Skywatchers (3x 8's and a 10) and one Orion Optics 12 over the years. The GSO's were OK but their mirror coatings degraded quickly and their mirrors were 1/4 wave PV at best I reckon (and that was what GSO claimed back then). The Skywatchers performed better and the coatings seemed more robust. But it is good when a major producer improves their products over time and maybe even as a result of user feedback on forums sometimes ?

It is a term invented by Paul who runs the UK Astro Buy & Sell website. This is from the site FAQ's: "Kit Testers: This is a category for those individuals (not businesses) who like to buy and re-sell for profit. I came up with the label "Kit Tester" to describe people who buy equipment, fix it or improve it, test it and then re-seller at a profit. But it also applies to anyone whose goal is to sell for profit, regardless of their approach. Kit Testers cannot have a banner ad, rather they pay a fee (based on the price of each item) for each ad..."

Having listened to it a few nights ago, I felt the same Mike. Nice enthusiasm with a few bloopers in the details. The first run (100) of DL's had the black focuser as I recall . The 2nd run (which I also thought was limited to 100 but maybe not ?) had the blue focuser. I think I would be very happy to own any of the FC 100's 🙂

"So what you are telling me Percy is something you have never seen, is slightly less green than something else you have never seen" 😁

That would be the difference then - I'm not really fussy 😀

I have a Tak FC100, a Skywatcher ED120 and a LZOS 130 triplet. I am purely a visual astronomer. The 130 performs just like a bigger version of the FC100 doublet - no false colour at, or either side of sharp focus and an ability to handle "stupidly" high magnifications with some ease. My Skywatcher ED120 is a good one and performs somewhere between the 2 although, as an F/7.5 doublet, it does show a little false colour either side of sharp focus around bright targets plus a small splash of it around Sirius and Venus at focus. My ED120 seems to have an excellent optical figure to the objective (just as important as false colour control IMHO) and the star test is as good as the more exotic refractors. The chinese ED120's can vary sample to sample as @jetstream's example seems to show. Plus the stock focusers might not prove entirely satisifying. My only word of caution is to be prepared for the step up in size, weight and mounting requirements if you choose to go above 120mm in aperture, even if a doublet, can be more than you might expect !

Interesting thoughts 🙂 I wonder if this poll was re-run in, say, 5 years time, the 70:30 split would be more like 90:10 ?

Just managed this here with my wife's compact digital at 20x optical zoom at around 18:30 hrs. The planets were separated by around 40 arc minutes at the time of this shot. Solid cloud mostly though, just got a lucky clear patch in the right place.

Many thanks for the continued interest in this topic even if you felt that you could not cast a vote. Through the comments posted I understand much more about the various approaches that people use to acquiring targets to observe / image now 🙂

Those are good points. I'm visual only so my solution is based on that. It's probably off-beam for imaging application.

Tracking is something that can be "fettled" with dobs although many these days are well designed and work out of the box. 10 inch is a great step to make from 5.1 inch - the views of the bright globular clusters at 100x-150x alone will make you instantly forget the physical size change / money spent I think. Things that are hard / on the edge with the 130mm will become straightforward and more detailed and many other fainter things will be within reach. Even though 2 inches / 50mm does not sound much, there is a lot of difference in physical size and weight when you go to a 12 inch so think carefully about that, if tempted further. I'll leave others to suggest brands / models etc because it's been a long time since I owned one but I think you are definitely thinking along the right lines for your 40th 👍

Could you adjust the on target position of the finder so that the target lies just inside the apex of the cross hairs rather than behind them, and note that position ? Like this:

Sounds ideal 👍 I had a GOTO system back in the mid 1980's (Vixen Skysensor) which did similar things, so they have been around a few years. Their function and capability has been improved a huge amount today though 🙂