John

DPAC can deliver some surprises. Here is one that I don't think many saw coming:

Bench Test of a StellarVue SVX180 Apochromat - Refractors - Cloudy Nights

43 minutes ago, LDW1 said:

We started out with reasonable priced zooms and now the rarer, much, much higher priced ones are showing up as is usual, lol.

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).

5 minutes ago, cajen2 said:

On the subject of FOV, the Baader is 50°-68° and the two OVLs (which I believe are the same as the Svbonys) are 40°-60°, so there is a difference.

I have the OVL 7.2-21.5mm and it's optically very good but the FOV is a touch claustrophobic and mine has a very stiff action, needing two hands to change f/l. I'm getting a second-hand Baader shortly and I'm hoping that will be better.

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 !

16 minutes ago, Mr Spock said:

Back then it was all TV  Fads and cliques come and go, the TV one had its day 

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 🤣

35 minutes ago, Moonlit Knight said:

Why does every thread about refractors always end up turning into a conversation about about Takahashi’s. Seriously folks, what is the point of any one posting about any other brand of refractor when always heads in one absolutely predictable direction, it’s getting to be a waste of time. 
 

Nevermind…

Anyway I am still thinking about it, sorry it’s not a Takahashi chaps. 

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

10 minutes ago, Mr Spock said:

Already got  See the change in my sig 

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

23 minutes ago, Captain Scarlet said:

I must say ED102SS is a decidedly odd name for a reindeer 😄

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.

14 hours ago, bluesilver said:

Appreciate the replies,

It is the collapsible version of the Skywatcher Dobsonian,  and just looking back at the place where i originally got it from,  it is indeed listed as a f4.4

so my mistake there.

 

I will have to look into this comma a bit more,  I am thinking i may not possibly have any, but then again,  i only just recently heard about comma correctors and haven't noticed any weird shaped stars,  but as mentioned i haven't really been looking for it either.

I am mainly just using the standard 20mm eye piece that came with it and occasionally swap it out for e televue 10mm Delos

I will have to take another closer look next time i get it back out.

 

 

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.

38 minutes ago, mikeDnight said:

When I bought my Vixen 102mm F13 achromat from Peter Drew back in 1986, it came with a 40mm Kellner just like that one. Honestly, in that Vixen the 40K was wonderful. I'd love to be able to turn the clock back to see if the eyepiece and scope really were as good as I remember them. I had some very memorable views of some brighter DSO's using that eye piece and scope. Of course being only F13,  it was a comet seeker. 

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. 

8 hours ago, Astroscot2 said:

john, you never made comment on the OO you owned?

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 ?

13 minutes ago, Paul M said:

I gotta ask, what's a "kit tester"?

I've seen a number of member that just seem to churn over high end equipment but rarely add any other imaging or observing contributions. Is that them?

 

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..."

2 hours ago, mikeDnight said:

Nice podcast, although with a number of small errors from the presenter's. The FC series all have the same diameter tube; the DF has identical optics as the DC, and it's focuser is green or blue not black. The DL had the black focuser; and all of the new FC's are Steinheil and not Fraunhofer. Other than that it was nice to listen to.

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 🙂

3 minutes ago, Ratlet said:

I thought we figured out green a long time ago.

I seem to recall a documentary on the BBC in the 80's about an English courtier in Elizabethan times who created a sample of purest green.  I think he was trying to make gold, but his plan wasn't cunning enough...

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

7 hours ago, jetstream said:

Rumour around the campfire is the the earlier Sw120ED's labelled "Pro" had some excellent optics. Mine goes 300x on lunar, about 265x on Jupiter. Its not bad ...until you look through something with truly good optics- and I'm fussy....

 

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 !

11 hours ago, AstroKeith said:

I suspect that 'StarSense' technology will become almost standard fit within 5 years even for visual only equipment. Similar to integrated sat nav in cars and phones...

 

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 🙂

4 hours ago, Kon said:

I found with my manual Dob that using the full sensor frame is fine with the thick crosshair but it is becoming harder when i get down to 640x480 ROI. The centre of the crosshair is not square to the sensor any more and I need to re-align it. I have tried what John suggested above to offset but when you go to the tight ROI, it is even harder. For visual the RACI is perfect.

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 ?

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