Time to get a 4” APO?

[jetstream]

@Cjg I'm super interested in the presentation that your A-P gives on M24, Delle Caustiche. This object can also dazzle and from the sounds of it your scope will be superb on it under dark skies.

@Littleguy80 sorry to wander off course 😁

[Littleguy80]

24 minutes ago, jetstream said:

@Littleguy80 sorry to wander off course 😁

Not at all. I’m interested too!

[jetstream]

8 minutes ago, Littleguy80 said:

Not at all. I’m interested too!

Thanks Neil, I find it strange (but true) how some scopes can give these exciting effects. When I hear comments like the one about the A-P I pay attention.

Forgot to add- in your pursuit of the 4incher it might be of interest to note the differences in the presentation of the planets. Many owners of high end scopes will say this brand shows Jupiter better than that brand or Saturn is better in this one than that one etc. I think it boils down to colour rendition but could be wrong.

I think the Tak doublets are known for their rich colours on the planets, whereas my TSA120 is a more neutral scope, wicked on Saturn, Vg on Jupiter. Mind you were splitting hairs here... but the effect is real. The TSA120 is also wicked in WL solar.

Edited February 10, 2023 by jetstream

[cajen2]

18 hours ago, Cjg said:

For a long, long time, I swore that the Tak would have to be prised from my cold, dead hands...but that extra 16mm...as the highly experienced dude on FB said;

"The view was 3D like with huge detail in its letter box core, suspended in space above pinpoint diamond like stars." 

The Feathertouch focuser, although is a joy to use too.

If you're heading to Cwmdu for the AstroCamp, I'll have it with me there.

Chris

Can I join the queue for a peek at Cwmdu? 😉

[Cjg]

On 10/02/2023 at 16:08, cajen2 said:

Can I join the queue for a peek at Cwmdu? 😉

Sure! 😁 

[Cjg]

On 10/02/2023 at 14:41, jetstream said:

@Cjg I'm super interested in the presentation that your A-P gives on M24, Delle Caustiche. This object can also dazzle and from the sounds of it your scope will be superb on it under dark skies.

@Littleguy80 sorry to wander off course 😁

That’s the star cloud above the Lagoon and Triffid? Well, from 52 degrees North, my viewing has been limited, but remember all of the Sagittarius area just enchanting. I’ll be sure to have a look later this year.

[Moonlit Knight]

On 07/02/2023 at 15:55, FLO said:

They can be removed, but only because what is assembled can be disassembled. Removal of the focuser and dew shield for travelling isn't a feature. 

HTH, 

Steve 

I don’t suppose you know how to take the dew shield off do you. I was considering getting it power coated black.
 

Proper old school me.. 

[Moonlit Knight]

I was an early adopter of these KUO refractors, I have owned mine for just over 3 years. I had the same dilemma re 51 or 53 glass. I stumped up the extra 300 quid in the end, I was fortunate enough to be able to do so. Well I still have the scope and no intention of getting anything else. I have always had my eye on the next scope, but that changed when I bought that refractor. I still think it’s incredible value for money. Altair has been out of stock for months, FLO bought 50 of them and now have 13 left. The Technosky badged version is 11 quid under a grand now and with the way things are (Skywatcher prices have jumped up again just this week) I would be surprised if they are all not a grand a piece universally when everyone restocks. There is a fpl 51 number on eBay for 350 quid right now if I remember right if you are interested. Now that is a bargain. The build quality is extremely good on these scopes and are, in my opinion one of the few scopes that no one has a bad word to say about them 

[Moonlit Knight]

https://www.ebay.co.uk/itm/155401860997?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=GPUltlyGSgG&sssrc=2349624&ssuid=913qj9xFSeS&var=&widget_ver=artemis&media=COPY
 

Actually it is the fl 11 number now that I look properly 

[Littleguy80]

So my first purchase is made and it’s not a telescope but a mount. A Giro-WR came up so I decided to go for it. It’s small and light enough to replace the Mini-AZ as my travel mount, can dual mount scopes and will very happily handle a 4” APO. It’s three wishes in one 😉

[Deadlake]

On 10/02/2023 at 15:13, jetstream said:

Thanks Neil, I find it strange (but true) how some scopes can give these exciting effects. When I hear comments like the one about the A-P I pay attention.

Forgot to add- in your pursuit of the 4incher it might be of interest to note the differences in the presentation of the planets. Many owners of high end scopes will say this brand shows Jupiter better than that brand or Saturn is better in this one than that one etc. I think it boils down to colour rendition but could be wrong.

I think the Tak doublets are known for their rich colours on the planets, whereas my TSA120 is a more neutral scope, wicked on Saturn, Vg on Jupiter. Mind you were splitting hairs here... but the effect is real. The TSA120 is also wicked in WL solar.

Also Jerry the diagonal used, I find the red colours of Jupiter and Saturn come out more using a BBHS coated diagonal over say a max bright. Makes a real difference IMHO.

[jetstream]

8 hours ago, Deadlake said:

Also Jerry the diagonal used, I find the red colours of Jupiter and Saturn come out more using a BBHS coated diagonal over say a max bright. Makes a real difference IMHO.

In the case of the TSA120 I find the diagonal doesnt affect things as compared to straight through, it sure does with respect to my SW120ED however.

[Deadlake]

1 hour ago, jetstream said:

In the case of the TSA120 I find the diagonal doesnt affect things as compared to straight through, it sure does with respect to my SW120ED however.

prism or mirror?

[jetstream]

33 minutes ago, Deadlake said:

prism or mirror?

Either, eventhough Ive seen the reports of image degradation using prisms. Even if the TSA 120 is technically degraded a small bit with the prism, the neutral tone high spec optics dont reflect this in the eyepiece (to my eyes). It is a very forgiving telescope, at f7.5.

[IB20]

Just revisiting this thread whilst it’s snowing and I can’t get any scope out.

I’ve been thinking, do I need a 4” APO? I have two 3” inch refractors, an achromat and a super apochromat and am now a refractor convert. Now I’ve converted my 3” 76DC to a f12.5 scope and I’m missing a wider field but also have no 2” set-up at all.

What is the actual difference at the eyepiece between a 3” and 4” on say the moon, WL or planets? How does increased resolution and brightness actually translate? Is it subtle or incredibly obvious? I’ve found a great Japanese YouTube channel (BosqueRico Len’sKing TV) which compares resolution between Takahashi’s on Saturn. Are the images a fair representation of what one would expect in terms of improvement? 

What about lunar and solar? Has anyone any similar resources that could explain the at eyepiece differences? Being a white light junkie, having more resolution for granulation would be a great.

The f7 FPL53 Starfields or doppelgängers look like superb scopes and a real bargain, stick one of those on an AZ4 and I think it would be a fairly nice combination; not unobtainable either. Plus I desperately need another tripod and mount so I can set up more than one refractor. 

Maybe I’ve answered my own question…
 

[jetstream]

@IB20There should be no difference in sharpness for a given optic of different apertures IMHO. What I like about fast optics is that you get large image scale at bright eye illumination. I can say this- my 90mm SV gives sharper images than any of those posted.

We might be in similar pursuits- a 100mm frac that cool fast that allows maximum views for the seeing. A good doublet APO fits the bill IMHO.A 120mm on WL solar is much more sensitive to seeing IME.

[IB20]

11 minutes ago, jetstream said:

@IB20my 90mm SV gives sharper images than any of those posted.

 

It’s likely a compression issue from YouTube. I’ve also screen grabbed, enlarged and cropped but yeah, agree I see sharper images in the Tak 76 than those images. Interesting that you mention bright eye illumination. I have always found I prefer dimmer views, my eyes seem quite sensitive to brightness hence why I enjoy the 3” so much. In the 8” dob it is such that I really need to control it to be able to observe, especially when the seeing doesn’t allow the magnification to be pumped up to the max to take the edge off the brightness.

[jetstream]

8 minutes ago, IB20 said:

especially when the seeing doesn’t allow the magnification to be pumped up to the max to take the edge off the brightness.

This is the key!!

A scope should be picked based on the preferred eye illumination at the mag the the seeing usually supports, IMHO.ie dimming the planet at a mag that the seeing supports.

I do this all the time, with various scopes.

A binoviewer beam splitter does this at lower mags because the splitter "halves" the volume of light to each eye/ per conventional exit pupil. AKA "the false exit pupil theory".

This fact, IMHO, is why many find binoviewers provide a better view, combined with the idea of binocular summation.

[Stu]

2 hours ago, IB20 said:

What is the actual difference at the eyepiece between a 3” and 4” on say the moon, WL or planets? How does increased resolution and brightness actually translate? Is it subtle or incredibly obvious? I’ve found a great Japanese YouTube channel (BosqueRico Len’sKing TV) which compares resolution between Takahashi’s on Saturn. Are the images a fair representation of what one would expect in terms of improvement? 

What about lunar and solar? Has anyone any similar resources that could explain the at eyepiece differences? Being a white light junkie, having more resolution for granulation would be a great.

Specifically on WL solar, I have used both 76 and 100 with my CoolWedge and can say that there is a noticeable, probably fair to say significant difference between them in visible detail.

For granulation, to me it is visible with the 76, but can be dramatic with the 100. At high powers it is obvious and opens up to show the cells themselves on occasion. The 76 doesn’t approach that in my experience.

Don’t mess around, get yourself an FC100  

[Littleguy80]

I’ve been playing the dangerous game of putting combinations of things into a FLO basket just to see how much it costs.

With regards to FC100DC, how good is the focuser if I wanted to use a 2” diagonal with something like the APM HDC 20mm eyepiece or an entry level Canon DSLR? Not sure if I need the more expensive version with the stronger focuser? If the DC is ok with that, I think I need this to use the 2” diagonal?

https://www.firstlightoptics.com/takahashi-adapters/takahashi-2-inch-eyepiece-holder-for-fs-60-and-fs-78fc100dc.html

I mentioned my hopes and dreams of a Tak to my lovely wife who has made her opening counter offer of some bathroom refurbishment should she agree. We’ll see where the negotiations go from here 😂

[jetstream]

4 minutes ago, Littleguy80 said:

how good is the focuser if I wanted to use a 2” diagonal with something like the APM HDC 20mm eyepiece

Could you change the focuser down the road if need be Neil?

I dont like big, long hvy eyepieces in a frac- the 42mm LVW is pretty light for what it is however. The lightweight 16T5 is great in my fracs for M42 etc as a higher power option on them.

Oddly , I hardly ever use the 20mm APM in my fracs.

[Sunshine]

40 minutes ago, jetstream said:

I dont like big, long hvy eyepieces in a frac

I would have to agree, which is why as much as I love my XW's I wish I had lighter and shorter eyepieces, and equally as good of course.

[JeremyS]

3 hours ago, Littleguy80 said:

I mentioned my hopes and dreams of a Tak to my lovely wife who has made her opening counter offer of some bathroom refurbishment should she agree.

That’s kind of her Neil, but I’m not sure the bathroom is the best place to store a telescope. Especially a Tak 🤔

[JeremyS]

6 hours ago, IB20 said:

Just revisiting this thread whilst it’s snowing and I can’t get any scope out.

I’ve been thinking, do I need a 4” APO? I have two 3” inch refractors, an achromat and a super apochromat and am now a refractor convert. Now I’ve converted my 3” 76DC to a f12.5 scope and I’m missing a wider field but also have no 2” set-up at all.

What is the actual difference at the eyepiece between a 3” and 4” on say the moon, WL or planets? How does increased resolution and brightness actually translate? Is it subtle or incredibly obvious? I’ve found a great Japanese YouTube channel (BosqueRico Len’sKing TV) which compares resolution between Takahashi’s on Saturn. Are the images a fair representation of what one would expect in terms of improvement? 

What about lunar and solar? Has anyone any similar resources that could explain the at eyepiece differences? Being a white light junkie, having more resolution for granulation would be a great.

The f7 FPL53 Starfields or doppelgängers look like superb scopes and a real bargain, stick one of those on an AZ4 and I think it would be a fairly nice combination; not unobtainable either. Plus I desperately need another tripod and mount so I can set up more than one refractor. 

Maybe I’ve answered my own question…
 

Having both a FC76 DCU and FC 100DZ (and FS 102), the detail visible in the 4-inch scopes on Jupiter is noticeably better. And resolution in globulars as well as what can be seen in extended DSOs. Sorry!

One caveat though. Make sure your mount can handle a 4-inch. My ScopeTech Zero and SW AZ GTi are fine for the FC76 but not really for the DZ….

[JeremyS]

13 hours ago, Sunshine said:

I would have to agree, which is why as much as I love my XW's I wish I had lighter and shorter eyepieces, and equally as good of course.

Agree. I generally use lighter, 1.25 inch EP with my 3 and 4-inch Taks. Especially for travel. This is where the TV Naglers come in - and the Tak LEs for even lighter use. This is not that the focuser can’t take it, by any means - just my usage preference

Edited March 9, 2023 by JeremyS