80 vs 102 refractor

[Radman40]

Hello community. What do we thank about this one......

Is the extra weight, size and cost of a 102 mm APO refractor worth it when compared to an 80mm in terms their respective performance across a range of astronomical applications? I have never had opportunity to compare. 

 

🤔🤔🤔

 

[John]

Do you include imaging as a potential application for the scope ?

[Alan White]

I have owned both and liked both.
At present I have a 103mm Vixen, which is rather nice, but not as portable as the 80 was.
You win and loose with the change,
it depends on what you wish to use it for or how you wish to use it.

[F15Rules]

8 minutes ago, Radman40 said:

Is the extra weight, size and cost of a 102 mm APO refractor worth it when compared to an 80mm in terms their respective performance across a range of astronomical applications?

For visual use, yes, yes ,yes!👍

Dave

[ollypenrice]

In imaging the critical difference is in focal length and so field of view. In visual it's a difference in light grasp. Since neither is a light bucket it's likely to come down to issues like portability. While I might prefer to image with an 80 (depending on pixel size) I'd rather look through a 100.

Olly

Edited October 10, 2019 by ollypenrice
Typo

[John]

1 hour ago, F15Rules said:

For visual use, yes, yes ,yes!👍

Dave

I agree with Dave - for purely visual observing I would always prefer to have that additional 22mm aperture.

[joe aguiar]

Y not both lol I do 

My tak TSA 102 weight is 14 lbs compare I think to a skywatcher 100f9 apo which I think is 7.

But now I added the large format dual speed moon light focuser and the focuser is heavy and big. Its probably closer to 16 lbs now.

I also have a skywatcher pro ed gold version model with dual speed focuser. If I want lighter for quick view 80 is fine but views in 102 is better. 

If I had none and had to choose 1 then I would buy skywatcher 100 f9 ed evostar 

Joejaguar 

Edited October 10, 2019 by joe aguiar

[Radman40]

Thanks for all the replies so far. Interesting replys which have firmed up my thinking. I would be using it mainly for visual and the odd bit of dabbling with imaging. I may do some more serious imaging when time allows and I am not wreck on the sofa after work or chasing around after the family.  I am not even going to go down the doublet/triplet rabbit hole.

Does anyone think there is just too much choice with everything these days these days?  Buying Astro equipment is bad enough but buying buying a light bulb is like a punishment from the Greek gods.

[jadcx]

On 10/10/2019 at 18:58, F15Rules said:

For visual use, yes, yes ,yes!👍

Dave

Another agreement here.  Not that I have a 102 but I have been very aware of the visual improvement from 80 to 90, so if it fits, I'd go for it.

[mikeDnight]

An 80mm apo is a very enjoyable scope to use visually, but you'll notice a significant improvement in both brightness and detail through a 102mm apo. There's never been a better time to buy an apo refractor, particularly in the 80 to 100mm range. Whichever make you're thinking of, you'll be very unlikely to be disappointed.  For some, an apochromatic refractor of around 4" aperture is all the scope they need. The second hand market has some gems at times, so you may not need to buy new!

[F15Rules]

On 10/10/2019 at 18:49, Radman40 said:

 

I have used 80mm, 90, 100,103 and 128mm refractors, and I still have 80mm and 128mm scopes.

Firstly, as Mike says, an 80mm scope can be a wonderful tool to enjoy the night sky. When I was a teenager, Sir Patrick Moore taught us that a 3" (76mm) refractor or a 6" reflector were the minimum apertures that would give satisfying views and make worthwhile observations possible..(my first "proper" or "serious" (to me) scope was actually a 60mm Circle T Japan refractor, and it gave me some really wonderful views which spurred me on to get a bigger scope which would show me more).

In those days, though, refractors were nearly all F15 long tubes which weren't the easiest to mount, especially at higher powers: so, going from an 80mm F10 or F15 to a 100mm of a similar focal ratio was a real challenge in terms of mounting and portability.

Nowadays, however, thanks to modern, high quality ED glass doublets, it is possible to get a lightweight, relatively short F7 or F8 focal length refractor which performs as well as (and in some respects better than) the old long achromats, and yet can be easily mounted on a very portable altazimuth mount.

At different stages of our lives, different scopes will be best suited to our circumstances - family commitments, job, finances etc. I am fortunate to have recently retired and have made the choice for myself that a 5" (128mm) quality apo can almost be my "all in one" scope. (I say "almost", as I my 1970s  F15 80mm achromat is just a superb high power double star splitter due to its depth of focus), and so I keep it.

I sold my superb 103mm Japanese ED refractor simply because I can't now afford to have 2 similar quality scopes, one of which won't get much use because the bigger scope shows me significantly more. And I don't need the portability that some do, as I am lucky enough to have reasonable skies in rural Lincolnshire. Twenty years ago it was very different and I couldn't have afforded more than a decent 4" achromat. And it was great for me at that time..if I live another 10 it 15 years, the balance may well swing back to lighter, more portable as I get older and weaker 😱🙄..

So, in summary, it is much easier these days to upgrade from an 80mm to a 100mm class scope whilst still having great portability: one of my favourite ever setups was an excellent Vixen ED103s on a Porta II altaz mount. Lightweight, portable, and optically excellent. And I know there are many SGL members using a good F7 on a nice Porta, AZ4 or Skytee type mount who would agree on just how satisfying such a setup can be.

If you can afford it, I would say do it!😁.

Dave

[Paz]

I would go for more aperture if visual, but I would only go for the biggest you can afford and handle on your own

[mikeDnight]

I know its a 80mm to 102mm under consideration, but perhaps the 120ED Pro should be thrown into the mix. They are no longer physically than the 102ED Pro and are terrific visual refractors! 

[Radman40]

Thanks Dave....a very interesting tale of your journey with all the different scopes. A 4 inch does seem like a good trade off between portability and aperture. It’s all about ease of use for me at the moment. 

Mike....your eyepiece box is a thing of beauty. Extremely pleasing on the eye.

[timwetherell]

Yeah, my experience is similar. A 4" will begin to resolve globulars and give some quite decent views of brighter DSOs - I'm not saying an 80mm couldn't do that, but I've always found it much more of a struggle with a 3" refractor than a 4".  Back in the day when many of us had the ubiquitous 60mm,  a 4" refractor was classed as a "big" telescope!  

[mikeDnight]

17 hours ago, Radman40 said:

Thanks Dave....a very interesting tale of your journey with all the different scopes. A 4 inch does seem like a good trade off between portability and aperture. It’s all about ease of use for me at the moment. 

Mike....your eyepiece box is a thing of beauty. Extremely pleasing on the eye.

It was my decision to down size slightly that prompted me to move to simpler, but still high quality eyepieces. I was very happy using my Equinox 120, but after buying a Equinox 80ED,  I found myself using the 80mm far more often because of its ease of use and set-up. The 80ED was superb, especially with a binoviewer installed for lunar and planetary observing. At times it even gave a better view than the 120ED. So after considering the advantage of the smaller scope, I thought it would probably be a good move to go for a scope that was somewhere between the two, giving a little more resolution than the 80ED but retaining its light weight easy set-up.  When I heard that Takahashi were offering a light weight 100mm fluorite apo, I couldn't resist and have never looked back. The 100DC is just as comfortable as a grab and go scope as it is as a great observatory instrument.

Simplifying my eyepiece collection has also liberated several thousand pounds that had been trapped in a the form of Televue and Pentax eyepieces. In my FC100DC F7.4, my collection of excellent but old five element super plossls give me just as much joy with their piercingly sharp images. ☺ 

 

 

[Trikeflyer]

20 hours ago, mikeDnight said:

I know its a 80mm to 102mm under consideration, but perhaps the 120ED Pro should be thrown into the mix. They are no longer physically than the 102ED Pro and are terrific visual refractors! 

+1 for the Ed 120. I have an equinox 120 and it’s nice. I only do visual. Second hand you could get one for the price of a new 80mm if you look out and are not in a rush to get one.

steve 

[Adam J]

On 13/10/2019 at 13:30, mikeDnight said:

 

Is that an observatory or a dining room?

[mikeDnight]

On 14/10/2019 at 17:05, Adam J said:

Is that an observatory or a dining room?

It doubles as a bit of a man cave. Whenever the wife gets fed up with the repetitive banter between me and my friends, the observatory offers a clean and somewhat cosy retreat even in the cold of winter, as its electrically heated. And yes, it has been known to act as a dining room of sorts on occasion. 😊

[paulastro]

10 minutes ago, mikeDnight said:

It doubles as a bit of a man cave. Whenever the wife gets fed up with the repetitive banter between me and my friends, the observatory offers a clean and somewhat cosy retreat even in the cold of winter, as its electrically heated. And yes, it has been known to act as a dining room of sorts on occasion. 😊

Mmm, I seem to recall that the last time I came to visit you Mike your wife banned us to the observatory - I didn't feel we had any choice but to leave your lounge!  🤣

Also you're wife accused me of trying to sell you the tripod I brought along that you were going  to do a mod on for me, her actual words were 'he's not trying to sell you that pile of junk is he'.  As if I ever would!   By the way, that equatorial mount I offered to sell you at a great bargain price is still yours if you want to buy it .

I have to admit though, your good lady does have an awful lot to put up with, she should be made a saint!

By the way, the modified tripod works a treat - thank you my friend 👍.