jetstream

On 10/06/2023 at 15:52, Captain Scarlet said:

Head over to @jetstream’s, pretty sure he’s got a 120 he doesn’t want. You’re both in Canada so he’ll be just round the corner 😁

Lol! Right now my St Croix fishing rod has taken priority to the dismay of the local walleye population 😈 The sky is filled with forest fire smoke again, pretty bad actually and just started today. Big fire about 130 miles north of here rumour has it. And so my scopes sit idle...

2 hours ago, John said:

Why do well respected scientific organisations allow their branding to be used on such poor quality equipment ?

Not sure but my neighbour has a National Geographic branded "reflector" from years ago and he thinks its a nice scope.... asked me to set it up- but thankfully he lives 900 miles away and only visits in the summer- and forgot about it - it is a complete piece of junk.

This in contrast to the H130, that is a very good scope and nicely affordable.

Sometimes I start a thread and am not really sure where to put it lol the mods do a great job shuffling things into the right spot. I dont find an image posted in the obs section offensive personally.

1 hour ago, John said:

Thankfully this does not seem to apply on SGL but in some other places there is a sort of "if there are no pictures it did not happen" attitude creeping in 🙄

I think the odd snap / sketch / picture to illustrate an observation isn't an issue personally. It can be helpful for others.

 

I hear you, some visual observations can raise eyebrows including some of mine. Honesty is key IMHO. And this- I challenge any imager to a duel- I take one 5 second look at a DSO, say Pickerings Wisp with my 24" and the imager with any scope, anywhere on earth to a single 5 exposure, zero processing and we'll compare notes...😁

7 hours ago, SwiMatt said:

But I would disagree that spotting at this level remains a tick exercise

Well I agree with @Piero- I still do tick exercises, but eventually one starts to realize that the tick list is endless lol the bigger aperture and the darker the skies the list becomes so large ....

During my 'tick" phase I did discover some objects that have become favourite go to mainstays ie the IC1318 complex, the "Little Veil" nebula complex, SH2-94, the Foetus neb and Hickson 55 plus so many more.

As far as observing under LP skies and with small aperture, it really is a tick exercise IMHO.

6 hours ago, F15Rules said:

Q. "What are "bright" DSOs, really?"

A. They are easily visible small grey smudges, as compared to barely visible, wispy grey smudges.

🙂

Dave

Lol!👍

A faint fuzzy is a faint fuzzy no matter the aperture. Oddly enough I really enjoy bright DSO in my 24" ie ones that are bright in my 10" - the difference is staggering.

"Bright DSO" is only relative to the skies you observe from and the aperture you use IMHO. No matter how well my TSA120 does under very dark skies it cannot touch my 10" dob for DSO. Regardless of some opinions, a 10" dob, under LP skies will outperform a 100mm-140mm class scope every time.

Take a small scope, put it under dark skies and it will amaze wih the views it gives... our H130 gives a stupidly bright view of M81/M82...and M42...and...👍

46 minutes ago, Louis D said:

I'd have loved to have had a peek at the moon last night, but the mosquitos are swarming thanks to a very wet spring here.  I really need to move to a more arid climate to enjoy astronomy better.

My sky right now is a blurry seething mess fueled by 30c temps and the lake evaporation. This combined with massive hatches of blackflies and mosquitos...  I like you am taking a lunar break lol

Gerry

9 hours ago, nicoscy said:

I will also post something here, where I don’t expect to be crucified by AP fanbois: I had a second run AP Stowaway 92. I have had many scopes in that aperture so I feel I can make a fair estimate of its abilities. To bottom-line it, nothing special at all and a bit underwhelming actually

Many kudos to you Nicos !

Calling it like it is regardless of brand, I do the same.

Years ago I reported sub par performance in a SW120ED, eyebrows raised. After a long while I fixed it (with advice here) and it gives great views. It was then a side by side was done between it and the TSA120- the TSA120 showed contrast detail the 120ED did not- again eyebrows raised.

IMO, the only way to sort things out is from testing and real world reviews... honest, non biased reviews.I brought the TEC160 up in this thread for two reasons- to illustrate a recently made scope from a top maker that could be said to be sub par in blue and also to illustrate the hesitation for criticism of certain brands...which by default illustrates the willingness to criticize a particular one.

If SV puts out a bunch of sub par scopes or bs's their numbers I'll be in line to first report it should I have experience with it believe me.

We are all winners here IMHO, all the makers will ensure better consistency now that scopes can easily be called out through DPAC which is hard to argue with when done properly and with reasonable equipment. My next high end refractor will be DPAC'd no question.

Gerry

@Jim L I read a lot of those reports a good while back and others and yeah its an eye opener... IMHO.

3 minutes ago, nicoscy said:

Gerry, I would agree re doublets and long focal ratios, but triplets can afford well corrected optics at shorter focal lengths.

For sure and at some point fast and larger aperture triplet figuring gets much harder I think which of course makes the lenses deadly expensive. I'm still considering a TEC 160, but like you, my exchange rate is not that great. With regards to f ratio, my own preference is around f7.5-f8 for a frac, triplet or otherwise. My new DM6 is fantastic, very easy to carry, great in use and can handle a largish frac, plus Tom Peters is great to deal with. Who knows what other frac I'll end up with on it, but I know this- if I drop a wad of cash I want the scope to be right up there optically.

There should be zero question about optical quality at these high prices from any maker.

@Jim L Having owned many dobs- my preferred telescope type- I would seriously look at this scope

https://www.firstlightoptics.com/bresser-telescopes/bresser-messier-10-dobsonian-telescope.html

I think they are available in the USA from Explore Scientific. They have excellent bearings and carry very easy. A vg focuser too and the optics are up there from what Ive heard.

Had these been available years ago I would not have purchased my OOUK VX10.

Gerry

9 minutes ago, nicoscy said:

I have a feeling that the whole SVX180 bruhaha has been a wake up call for SV

Definitely and rightly so- that scope should have never left SV - multiple levels of QC should have caught this and prevented shipment. I think but dont know that certain lenses might not be able to be figured for the very high level of quality that we are talking about, and so would have to be rejected, a very costly proposition.

The fast f ratios that the market demands is a huge challenge for the makers IMHO, ie LZOS 130 f 6 vs the 130 f9.2 - Id take the slower scope any day for my visual planetary/lunar observing, the latter a very well known top performer. The TSA120 was chosen by me for the apparently consistent optics they have, eventhough most samples Ive seen test in the mid 90's Strehl wise, but with balanced colour correction and faster cooldown than the superb TOA130.

All in all I think we are in the glory days with regards to telescope choices- a lot of the makers are getting long in the tooth however and who knows how long some of them will be around, this in reference to dobs as well.

I'm really glad all those guys are doing DPAC tests, I like looking at the results- the very long banter not so much, but it is my choice to read or not lol

Gerry

On 26/05/2023 at 21:21, nicoscy said:

Consistency is key.

I 100% agree.

I wonder if the other top makers have offered a very high level of consistency or is it taken for granted that they do? Is the TEC160 mentioned in this thread is an example of their consistency?

These DPAC tests are very revealing thats for sure and personally I love them. The tests will have all the makers on their toes IMHO. I'm pleasantly surprised at how well some SkyWatcher fracs tests actually. In their case the weak point might be the assembly of the scopes and the errors this can introduce like the example I have (120ED, gross focuser misalignment, fixed with a Moonlight).

Gerry

Dobs are great- I have 4 of them lol My favourite though is the 15" f4.8 truss dob from Astrosystems. This scope just glides through the sky effortlessly. I hope you guys get great views through yours coming up.

2 hours ago, Jim L said:

I don’t know the answer, but given the sensitivity of laser interferometry I’d be surprised if an optical element tested vertically and horizontally would yield the exact same Strehl number.

They dont... vertical interferometry is preferred I believe. Getting different interferometers to agree totally is near impossible and even individual fringe pictures dont 100% agree with each other from the same interferometer- hence the need for many averaged pictures to get a complete "final picture" of the optic.

I believe you are right in the sense that properly set up interferometers will give close numbers so the relative differences show the direction the optic is going for the optician.

With regards to SV having random SA correction in the other colours- could it not be said of other brands too? Or is the mentioned TEC160 an anomaly? Or other brands including A-P or Skywatcher? and LZOS??

Is this an indication of a lack of control like SV is being accused of? Ive looked at many test reports over many years and if any of these test reports are to be believed most if not all brands show sample to sample variation. IMO this variation is normal, but should be constrained within certain bounds or the optic rejected.

I'm thinking after all the scrutiny that SV is receiving they will, in the end, put out some of the best, most consistent optics around, if they are not already doing so.

I sure wish someone would tell me if the camera taking DPAC pictures can influence the look of the bands lol

Gerry

20 hours ago, barkis said:

I did return some time ago, but  I have  suffered some setbacks

Hello, excellent to see you back here!

Gerry

From the land of ice and snow and bugs...lol lots of bugs

@Maciek_Cz I'm intrigued by your program actually. I'm not sure you ran the mentioned TEC160 through all three colours- can you do the green and red as well and post them for me?

@Sunshine got me the DPAC EP holders and now I'm searching for a good flat and hope get the camera lens sorted out -if it is even an issue, not sure yet.

I had previously expressed interest in a TEC 160FL hence my questions about it and potential sample to sample variation here as well. The fact that SV made that particularly good SVX127D to a level that beats this TEC 160 and many other triplets is amazing to me- and my feeling is it was no fluke.

That particular SVX127D would have better numbers than my TSA120 I bet.

In the end, the ability to take very high mag and not breakdown on the moon and planets is the real test IMHO.

@Maciek_Cz I appreciate your contributions in this thread and the knowledge you bring 👍

Gerry

1 hour ago, Maciek_Cz said:

I will only add that this analysis takes into account only spherical aberration.
Please tell me if the focal ratio is correct because I found information about the TEC 160 f/7 but also f/8.
The given focal length significantly influences the result. If it's f/8 then we're dealing with an even better result around ~0.89.

Excellent.

Looking at the bands I was guessing .80ish strehl but I basically know nothing about all this. I hope to test in the future and want all my ducks in a row. The camera lens distortion deal vs distance to focal plane needs to be sorted out in my mind first so I dont add or subtract error in the images.

So I guess we can say this TEC 160 "only"  has .80ish strehl in blue- not too good really as was insinuated for the SV127D at the same level.

2 hours ago, Maciek_Cz said:

Clearly, the manufacturer may not have had any idea about the situation for green and blue

This ^^ in reference to SV- I wonder if this idea applies to this particular TEC160?

23 minutes ago, Maciek_Cz said:

the other has such a good correction only for red light, green is at the level of 1/6-1 /7 lambda, and blue 1/4 lambda.

These are still vg numbers, not as good as the other sample but vg IMHO. I have no bias just a weakness for good optics. Out of curiosity regarding the TEC 160ED tested Mar16/2019 what would your program assign for numbers? Would it be similar to the first, lesser spec SV or better?

One thing that interests me is the possibility of distortion in the camera taking the pictures of the fringes, for any test not just the ones of the mentioned scopes.

Heres the blue outside focus for the mentioned TEC 160ED.

14 hours ago, Jim L said:

I wish I could be more helpful.

This is great info Jim- a 4" class refractor punches through challenging seeing better than any other scope IMHO. I'm fortunate to observe under Pickering 8-9 frequently and 7 most of the time. Im up here in NW Ontario.

I can observe at low exit pupils but my sweet spot is around .8mm exit pupil, which my 15" provides at a very useable 300x mag.

Eagerly waiting observing reports Jim!

Gerry

17 hours ago, Captain Scarlet said:

Gerry @jetstream already has a great (SV) 90mm, and of course the TSA120. No, he needs to fill the gaping void between his TSA120 and the 15”. Namely an SVX152T 😈 

I would love one Magnus...

The Hb is my least used filter and so its strange I'll pick up the new Baader CMOS when the exchange comes around. In reality I think most people would benefit upgrading their OIII or UHC to top quality Televue or Astronomik filters, IMHO.

Gerry

16 hours ago, Jim L said:

 The optics, fit and finish, and mechanics are all extraordinary. It is in every way the equal of my Taks and my Astro Physics 92 Stowaway, and is in some ways their superior. I would expect no less from the SVX127D, and with 55% more light gathering objective area views through it should be brilliant.

Excellent and congratulations for owning a fine telescope Jim. I think in the end the optical quality of the SV refractors will have some critics not saying much.... All the testing is a good thing IMHO- the price we are paying for these telescopes should mean we all get what we are paying for.

My hats off to SV for weathering the storm.

The old SVR90CF still puts up a great view after years of harsh dark site trips and was the first to show me IC434 when I was burrowed up on a logging road north of here in -30c.  I would try the SVX150 but if its a wide spaced air triplet keeping up to my temp drops here will be an issue, even the TSA120 will struggle at times.

How much mag will your SVX102 take on the moon and not breakdown? My 90mm SV supports 262x easily with a Vixen 2.4HR and more with the VIP barlow.

Gerry

18 hours ago, Highburymark said:

though whether you’d see any benefits over the TSA is another matter

I agree- best case scenario would be no difference to my TSA120- the Tak is a superb telescope. I am curious about the SVX127D's performance in comparison to the Tak..

I just have a weakness for good glass lol

Actually I just remembered a member here who knows collimation extremely well- @Piero can run through it for us possibly.