Which 80mm Refractor for Imaging

[Skuber]

Apologies if this question has been asked a million times before, but:

I'm slowly working my way up to start some astrophotography.

Hopefully, in a few weeks, I will have saved up enough to buy my first refractor for imaging.

Looking through the web, SGL and some books on the subject, it seems that the general consensus is that an 80mm doublet or triplet refractor would be a good place to start.

I'm thinking of a budget of maybe £650-£950 (for the OTA).

The scopes I've seen out there (at various price points) include:

The Skywatcher Equinox 80 ED PRO

The Williams Optics Megrez 80

The WO Zentih Star 80

TMB ED 80

Takahashi 80 (this was second hand for over £1000 so is probably out of my price range)

Meade Series 5000 80mm Triplet

Which of these scopes do you think is the best for imaging? Are there any others in my price range that would be suitable?

Some of the articles I've seen appear to recommend the Equinox 80 over the Meade 5000 - I would have thought the Meade should be better as it's a triplet and the Equinoxes are doublet?

Any help would be appreciated

[davew]

Hi Skuber,

Takahashi didn't make an 80mm scope that I know of. They made an FCT76. FC76 and FS78. The FCT76 is supposed to be very good with the reducer at f4.5 but I doubt this is what you were looking at. The FS78 is ok with it's reducer at f6 but is rather expensive for what you can get out there in the more modern world. Also if you insist on getting the correct connectors and other bits they will cost more than a good scope.

If you want a good talking point at a star camp get one. If you don't.... don't.

As an FS78 owner I can't advise on the others.

Dave.

[Skuber]

Hi Dave,

Yes, you are right - I checked again and it was a 'Takahasi Sky 90' I saw for sale.

I'm after the scope that gives me the best pictures for imaging in my price range - I'm inclined toward the Meade at the moment because it's a triplet (and it's had good reviews)

[ollypenrice]

I am a Tak fan but not really of the Sky 90 which is an old design and prone to throwing up blue haloes when imaging (at least that's the case with one that visited here. The owner has now sold it.)

I wouldn't get too hung up about triplet v doublet. You will be wanting a field flattener anyway if you go for the Equinox. I don't think the Meade 80 will will cover a DSLR chip without curvature, though the larger 127 does its best to do so. So the whole doublet-triplet thing is not what it seems.

If you look at the images posted here there are lots of gems from the ED 80 variations...

There has been adverse reaction to a new WO focus mechanism of late. Maybe someone will clarify which models this applied to?

Olly

[Skuber]

Thanks Olly, that's interesting.

Looking at all of the reviews on the net, I'd assumed that triplets were usually superior to doublets - especially in the case of the Meade 5000 vs the Equinox ED 80 Pro.

Something else for me to think about

[NickH]

The Meade is good...as a TMB owner I can vouch for them too...(105mm though), and a Tak SKy90, well just look at Greg Parker/Noel Carboni's work on those..

Good options you present, and I am sure you'll have fun with whichever

[ollypenrice]

The Meade is good...as a TMB owner I can vouch for them too...(105mm though), and a Tak SKy90, well just look at Greg Parker/Noel Carboni's work on those..

Good options you present, and I am sure you'll have fun with whichever

Re Greg and Noel - I know, Nick. Nothing to be said, you are right, their stuff with the Sky 90 is amazing. However, the one that came here was hard work. It went off for collimation but the owner still sold it. And I believe Ed Ting described it as the only Tak in which he had ever seen false colour.

You tested the Meade 80 I think. How did it cover the DSLR chip?

As you imply, the imager is spoiled for choice at reasonable prices in this aperture.

A triplet does beat a doublet all things being equal - but at the lower price end of things all is not equal. Do you spend the money on grinding more glass less well or less glass - not very grammatical - more well?? Either way seems to work in this case.

Olly

[NickH]

Coverage was okay, but I am not the best person for a review on the Meade with a DSLR, as I tend to use smaller cameras

For my money, get the TMB 80 which is on UK AB&S for £899...:-)

[RobH]

I'm with Nick...the TMB that's for sale will be a beauty....get it quick to stop me from buying it

Rob

[ollypenrice]

Sounds good.

Olly

[Skuber]

Coverage was okay, but I am not the best person for a review on the Meade with a DSLR, as I tend to use smaller cameras

For my money, get the TMB 80 which is on UK AB&S for £899...:-)

Thanks for the advice, I'll maybe take a punt at that scope and see if it's still for sale

[NickH]

Thing with a TMB is that it will hold that price... it's like an Aston Martin car...they don't really devalue that much once on the S/H market

[BlueAstra]

I have the single speed focusser 80mm Meade 5000 (new ones have a dual speed ). Having said that I've never had a problem focussing when using a mask. The camera rotation clamp also only works if you mount from the attached dovetail, so mounting from tube rings can be a problem if you use a camera. I usually rotate the camera and re-focus if necessary. I also use a Telvue 0.8 FF. This gives me pointy stars right out to the corners of my 1000D. Got the Meade after the S@N review and havn't regretted it!

[NickH]

5000 is indeed a good scope, that integrated dovetail is a royal PITA though....did anyone tell them about the EQ6? :-)

[Skuber]

Many thanks for all of your advice.

I've bought the TMB, so now I'm looking forward to getting it and trying it out (I bet we'll have cloudy skies for weeks now!)

Many thanks,

Skuber

[NickH]

Good good call...superb scope if it's up to spec...

Should come with a strehl report, which, whilst not definitive as to the quality of your specific scope, is a nice to have

[sgazer]

I have no experience with these particular scopes, but a few things I would consider would be the focal ratio and flatness of the field and what reducers/flatteners are available for them. I found the Celestron C80-ED to be very good for £200 (not on your list, but occasionally come up second hand), just needs a flattener/reducer. Then there's lots of money left for other goodies!

[NickH]

TMB's pretty flat, though the TV0.8X FF will make them faster and flatter still

[Skuber]

I saw a review on Cloudy Skies that suggested that the TMB 80 ED triplet was pretty flat out to about 80% of its field at least.

That's probably plenty flat for me to get started on imaging - when I start wanting to get that last 20% flat you'll probably get some more questions from me!