Choosing between 4" ED Refractors for visual

[quasar117]

I'm looking to move away from a Dob to a refractor setup as I have a young family and time spent observing is precious. 

 

Interested in the 4" ED f/7 fracs for purely visual but don't know if a slower scope such an F/11 would be more enjoyable for solar system, lunar and double stars.

 

My budget for the OTA is £900.

Mounting on, either Skytee 2 or AZ4 on Berlebach uni28.

Would the 4" F/7 still provide satisfactory views coming away from a 10" dob?

 

Thanks.

 

[rl]

ED is the important bit. Just choose your eyepieces appropriate to the OG focal length.

Very slow scopes like f/11 or f/12 allow the use of cheaper flint glass for similar levels of chromatic aberration, and possibly cheaper eyepieces for the same off-axis aberrations. The views can be excellent; the tradeoff is cost for  compactness and the mount. The ED scopes with shorter focal length will do both high magnification for solar system and wide field for deep sky, but the OTA will be more expensive, as might the eyepieces if you go as low as f/5

In my book a halfway decent 10" Dob will beat any 4" refractor providing all four "C"s are met at the same time; Conditions, Collimation, Cooling, Coatings.

But they are bulkier and more temperamental...which is why you raised the post!

Edited February 18 by rl

[mikeDnight]

An F7 4" ED will be much easier to handle, give a wider/richer star field when needed, and will power up for lunar, planetary, and double star observing like the best of them. I'd not hesitate to say grab yourself a 4" F7 ish ED apo doublet or triplet. The Askar 103 appears to be a stunning piece of kit that would last a lifetime. But you've also got the Starfield and many others to choose from, not forgetting second-hand scopes too.

Edited February 18 by mikeDnight

[Mr Spock]

41 minutes ago, quasar117 said:

My budget for the OTA is £900.

Starfield 102mm f7 is £899. Don't hesitate, just buy it. It's one of the best 4" scopes out there. I could barely separate it from my Tak.

[Elp]

The SF 102 is extremely good, you'd want the speed for that faint DSO stuff so would be more useful for visual use rather than just using for solar system objects. For the faint stuff it'll depend on your surrounding LP, doesn't really affect planetary viewing.

Edited February 18 by Elp

[quasar117]

40 minutes ago, Mr Spock said:

Starfield 102mm f7 is £899. Don't hesitate, just buy it. It's one of the best 4" scopes out there. I could barely separate it from my Tak.

I am very tempted to pull the trigger on it however, I have seen a used one (different brand label) for sale that is a few years old for 70% of the price of a new one. Is it worth the risk to save the extra cash for a diagonal and some eyepieces? 

[Elp]

Buy the seller, not the item. An item which has been used well and looked after will be talked about with a passion by the seller, we like to waffle a lot as we don't get to use our stuff that often due to the weather.

[quasar117]

2 minutes ago, Elp said:

Buy the seller, not the item. An item which has been used well and looked after will be talked about with a passion by the seller, we like to waffle a lot as we don't get to use our stuff that often due to the weather.

Sound advice!

[quasar117]

Just now, quasar117 said:

Sound advice!

They haven't used it much apparently. Now is that due to dissatisfaction or just utilizing other equipment more?  A question I should probably ask. 

[dweller25]

I would suggest you buy a new Starfield 102 F/7.

It has a proven track record and will have a guarantee for peace of mind.

 

Edited February 18 by dweller25

[Mr Spock]

Just now, dweller25 said:

I would suggest you buy a new Starfield 102 F/7.

It has a proven track record and will have a guarantee.

Agreed. Plus service from FLO is second to none.

[Elp]

15 minutes ago, quasar117 said:

They haven't used it much apparently. Now is that due to dissatisfaction or just utilizing other equipment more?  A question I should probably ask. 

If you can, always see scopes in person as you can ask to view through them and check over the mechanics. My SF was bought fairly blind, nothing wrong with it as per the item description. In fact most of mine have been bought used not in person barring the C6 which I wanted to check the corrector plate and focusing mechanism and the 130pds which I wanted to check the overall condition nothing was bent or rattling, never had an issue with them.

You should ask them to describe the visual experience, what eyepieces they've used, was there chromatic abberation or astigmatism. If they've used it for AP even better as you can request images but you'll have to put some faith into the images being theirs. Did they buy it new, why are they selling. As mentioned, they'll describe it in detail if they are passionate about it, if you meet them in person you'll get a vibe immediately whether they're passionate amateur astronomers, something difficult to determine via text.

Edited February 18 by Elp

[quasar117]

Since I'm looking at this in the view of a "lifetime" scope it would probably be wise to buy new, as you say it will be peace of mind with a guarantee.

I will also ad that I posted a wanted ad on astrobuynsell for this OTA and was contacted by chap from Epsom who appears to be a reseller of Altair astro. He says he could sell me a brand new OTA with some discount as he apparently now's the owner of Altair..sounded a bit dubious to me. Anyone had dealing like this before?

[Mr Spock]

Buyer beware as they say. I'd always buy from a well known reputable retailer. That's why FLO gets so many recommendations.

[Elp]

If it feels wrong always listen to your gut

[Elp]

The good thing about this scope it comes in many guises, Tecnosky, TS, Altair, Starfield so you have choice.

[quasar117]

If I do buy from FLO, will they check collimation before it is send out?

[MartianHill]

3 minutes ago, quasar117 said:

If I do buy from FLO, will they check collimation before it is send out?

Probably not, but if there is an issue they are VERY good at sorting it out 👍

[Nik271]

15 minutes ago, quasar117 said:

If I do buy from FLO, will they check collimation before it is send out?

I think FLO don't normally check the collimation of doublets, simply because doublets very rarely arrive out of collimation. I am sure if there is any issue with the scope they will take care of it.

[mikeDnight]

27 minutes ago, quasar117 said:

If I do buy from FLO, will they check collimation before it is send out?

It would be rare for a refractor, especially a doublet, arriving out of collimation. It is one of the beautiful things about refractors, that they can take a knock many times and yet be as good in a hundred years as they were on the day of purchase. Don't panic over what will almost certainly not happen. Refractors stay sharp!

[quasar117]

Just now, mikeDnight said:

It would be rare for a refractor, especially a doublet, arriving out of collimation. It is one of the beautiful things about refractors, that they can take a knock many times and yet be as good in a hundred years as they were on the day of purchase. Don't panic over what will almost certainly not happen. Refractors stay sharp!

Indeed another reason from moving away from my Dob!

[quasar117]

Would the Starfield benefit from being mounted on Skytee2 rather than AZ4? I'm aware I'd be losing the slomo control on the AZ4. I'm just concerned under high magnification vibration might be handled better with the Skytee2.

 

[mikeDnight]

13 minutes ago, quasar117 said:

Would the Starfield benefit from being mounted on Skytee2 rather than AZ4? I'm aware I'd be losing the slomo control on the AZ4. I'm just concerned under high magnification vibration might be handled better with the Skytee2.

 

Yes! You'd have slow motion control of your scope when using high power.

The AZ4 is solid if on the right tripod. 

Edited February 18 by mikeDnight

[quasar117]

2 minutes ago, mikeDnight said:

Yes! You'd have slow motion control of your scope when using high power.

The AZ4 is solid if on the right tripod. 

Berlebach uni28 

[mikeDnight]

12 minutes ago, quasar117 said:

Berlebach uni28 

Should be good but pricey. A tubular steel SW tripod would be solid too, or an older aluminium Vixen tripod. Many of the cheap Chinese aluminium tripods have plastic guides through which the lower leg section slides, and that flex, are weak, and at times break.