Can of worms opened: What APO?

[Dodge]

Got the AP bug, and I'm looking to buy my first APO - mainly for DSLR AP but with the potential to go with a dedicated CCD in future.

As I see it, I need the scope and a flattener - perhaps with a focal reducer if it has a longer focal length although it seems most APOs come around the 400-600mm focal length so a reducer is probably unneccessary. My budget is up to £1500, although I'd rather not spend that much where possible.

I've been reading quite a bit and have heard horror stories of pinched optics on TS APO's, slipping Crayfords, inconsistent cheap triplets, FPL51 vs 53 glass and spacing with sensors and field flatteners and frankly, the more I read the more confused I've become!

So, for £500-1500 what shall I put on my NEQ6 with a Canon 1100D on the back?

[Steve Ward]

Skywatcher Evostar ED80 Pro + the dedicated Field flattener would be a very good combination .

OK I'm slightly biased in that it's the setup I use but it's a great bit of kit and produces great results for the price.

Steve.

[ollypenrice]

£1500 would get you a second hand premium scope. It wouldn't get you a Tak quadruplet but it would put some fabulous apos within your range. The TeleVue 85 is lovely and usually fetches about £1K, then you need the reducer flattener. The TV85 has a superb R and P focuser, albeit single speed. While you are using a DSLR a fast f ratio is particularly important. This becomes less critical with a CCD since those are cooled and not time limited on subs length. At the other end of your budget you can now buy the ED80 OTA only from FLO. This does need the focal reducer flattener but they all do if they are anything but quadruplets. You can't have a flatfield refractor without a rear element. Focal reducers are important not because they reduce the focal length but because they reduce the focal ratio.

Olly

[Dodge]

Thanks chaps.

Olly - a quick question for you if I may: Have you had any experience with Altair Astro's 80mm triplets? I appreciate what you're saying about used premium APO's but I would generally prefer to buy new with support from the supplier / manufacturer.

Something like the Wave 80/480 triplet with the flattener would come in at £788. The focal length is fine, and it's F6 which is reasonable too. I read your review on the 115mm which seemed to fair well (and is in budget, but may be a touch slow for the DSLR at F7). The 80/480 has a 3.5" focuser which is a positive, although I'm unsure as to whether it's a Crayford or r&p.

A comparison would be the ubiquitous ED80 doublet (600mm/F7.5), focal reducer (510mm/F6.37) and field flattener which would come out at £575. I suspect this will require a focuser upgrade as it's non rotating and probably not up to snuff for a heavy load.

I'm not against spending £1500 on the right scope as I'll only be messing around with the DSLR for now, but the remaining funds from either of the above would be used for CCD equipment at a later date.

Any opinions much appreciated.

[cantharis]

Stellarvue is another high end scope builder, I am so pleased with mine. But they are hard to find this side of the pond.

[Earl]

This scope has had some good reviews

http://www.teleskop-express.de/shop/product_info.php/info/p2403_TS-Triplet-APO-90-600mm-Carbon-tube--2-5--PHOTO-focuser.html

[Dodge]

Thanks folks.

Something that confuses me slightly is the flattener to chip distance. Some quads have the flattener built in the tube, meaning the distance between the flattener and the sensor is variable - yet if I go for a triplet plus flattener, the flattener seems to attach to the focuser, meaning the distance between the flattener and focuser is fixed yet the flattener moves in relation to the front elements.

[Earl]

Thanks folks.

Something that confuses me slightly is the flattener to chip distance. Some quads have the flattener built in the tube, meaning the distance between the flattener and the sensor is variable - yet if I go for a triplet plus flattener, the flattener seems to attach to the focuser, meaning the distance between the flattener and focuser is fixed yet the flattener moves in relation to the front elements.

The built in type are Petzval http://en.wikipedia.org/wiki/Petzval_lens these are designed to be such, where as a triplet with a reducer is not the same thing.

[Dodge]

The built in type are Petzval http://en.wikipedia....ki/Petzval_lens these are designed to be such, where as a triplet with a reducer is not the same thing.

Thanks Earl, but it's not a reducer I was referring to. Forgive my amateurish ignorance here, but here's a couple of TS examples - other than that I would imagine the one with the built-in flattener may not be compatible with a reducer (should I choose to fit one) and the slight difference in focal length, one has the flattener built into the tube, one you would attach to the focuser:

http://www.teleskop-express.de/shop/product_info.php/language/en/info/p3881_TS-Super-Apo-80-480mm-F-6---Triplet-FPL-53-objective---colour-free---2--Crayford-f.html

http://www.teleskop-express.de/shop/product_info.php/language/en/info/p5194_TS-APO80Q---80mm-f-6-5-Quadruplet-Astrograph---44mm-field.html

[laser_jock99]

As well as the optics pay close attenion to the quality of the focuser some of the cheaper triplets may be let down by this.

Not sure if Olly is allowed to coment on Altair Astro any more- a similar thread was brought an abrupt halt by the Admin a few weeks ago.........

[kirkster501]

There is a review of the Altair Astro Wave 80 by Badgers over at the member review section. It looks a cracker and I am thinking of getting one in due course.

[ollypenrice]

As well as the optics pay close attenion to the quality of the focuser some of the cheaper triplets may be let down by this.

Not sure if Olly is allowed to coment on Altair Astro any more- a similar thread was brought an abrupt halt by the Admin a few weeks ago.........

Quite so. For information, I have no commercial link of any kind with Altair Astro and certainly do not do any marketing for them. However, since they send me their scopes for magazine review Admin are entitled to see this as a back door way of using SGL for advertising, a view I've agreed to respect, and respect it I will. It's not an unreasonable view, after all. If you'd like my opinion of these telescopes I'm easy to find in the public domain and I'll give you as honest an answer as I can.

If you want my advice on which small apo to buy, that I will certainly give you since I have absolutely no doubt about it whatever. Go mad and buy a Takahashi FSQ85ED or, failing that, a used Tak FSQ106N, the fluorite version which does not suffer much from temperature affecting focus. I've just finished reading the reprint of Barnard's Photographic Atlas, as reviewed by Steve RIchards in S at N, and nearly a hundred years ago the great man was saying that his smaller Petzval held focus better than his larger one. Plus ca change!

For about a grand I'd look for a TV85 and TV reducer. I've had two very old TVs, one of which I still have, and they are mechanically superb and optically still darned good. My Pronto cost about £200. What can you say?

Olly

[swag72]

I was looking for something similar early this year and with a similar budget. I managed to find a second hand Pentax 75SDHF and although a doublet, it is a great scope capturing some great data. Accepting that these scopes are hard to find (only been 2 on ABS so far this year) I'd without hesitation go for a TV85.

I often say that an ED80 is a good scope for example, and bang for buck, it seems to be so. There are many people happy with theirs on this and many other astro forums. But I've had a SW scope before, and I wished I'd never bothered and gone straight for a quality scope from the off. It sounds very snobbish and I don't wish it to, but I'd never bother with a scope of that ilk ever again. The build quality of a premium brand is just so different to the likes of the mass produced scopes. The focusers just work and that is generally the weakest part of the scope.

I know that it is sometimes hard to justify such spends, but if you get a premium brand, then you'll never look back. In my opinion, if you buy a more budget brand, you'll always be looking forwards.

Just my 2p worth, based on nothing more than my Skywatcher and Pentax experience.

[ollypenrice]

Yes, in imaging the mechanical integrity of a scope is incredibly important and at the capture stage the number one thing is focus. That, too, is a mechanical issue. Budget optics can now compare pretty closely with the best but mechanically the budget scopes can have issues.

Olly

[MRAPO]

Got the AP bug, and I'm looking to buy my first APO - mainly for DSLR AP but with the potential to go with a dedicated CCD in future.

As I see it, I need the scope and a flattener - perhaps with a focal reducer if it has a longer focal length although it seems most APOs come around the 400-600mm focal length so a reducer is probably unneccessary. My budget is up to £1500, although I'd rather not spend that much where possible.

I've been reading quite a bit and have heard horror stories of pinched optics on TS APO's, slipping Crayfords, inconsistent cheap triplets, FPL51 vs 53 glass and spacing with sensors and field flatteners and frankly, the more I read the more confused I've become!

So, for £500-1500 what shall I put on my NEQ6 with a Canon 1100D on the back?

WHAT YOU HAVE BEEN TOLD ABOUT TELESCOPE SERVICE IS Rubbish AND PURE LIES

THEY HAVE AMAZING APO,S THE TS 90mm TRIPLET APO HAS BEAT OUT SOME

TAK APO,S LIKE THE TAK SKY 90 AND THE TAK FSA 102mm THE FOCUSER IS

SUPER SMOOTH AND STRONG ITS A MATCH FOR ANY FEATHER TOUCH THE

TS 90 APO IS BETTER THAN AND TAK OR ANY 90mm APO TODAY AND AT HALF

THE PRICE.

ANOTHER FPL-53 APO IS THE TS PHOTOLINE 102mm BUT THE FOCUSER IS

NOT AS GOOD I HAVE TWO TS APO REFRACTORS GREAT SHOP VERY CHEAP

I HAVE BOUGHT SO MUCH STUFF FROM THE THEY NOW GIVE ME 10% OFF

EVERYTHING THATS MENT TO BE A SECRET.

[hunterknox]

WHAT YOU HAVE BEEN TOLD ABOUT TELESCOPE SERVICE IS Rubbish AND PURE LIES...

Dude, turn your CAPS LOCK off.

It's not hard to find reports of the TS 65mm quadruplets with pinched optics. I have no doubt TS also do some very decent scopes, but just because someone else's experience doesn't match yours from your sample of two doesn't mean that they're lying.

If someone gets a lemon and reports it on here in a strictly factual way then they're doing us all a favour, something which is not to be discouraged.

[John]

Why are we SHOUTING ?

I think any feedback on Telescope Services (both good and not so good) is given in good faith, like all contributions to the forum. Personally I've had mixed experiences with TS but I've not bought anything as large as a scope from them.

Anyway this thread is about the different scope options available to the OP rather than a supplier review.

[Cjg]

Olliy how do you rate your Pronto? Am sorely tempted by a TV 76, which is the newer version ( I think).

would be used visually as my grab and go travel scope that I could take as hand luggage.

cheers

chris

[Dodge]

To MRAPO,

Thanks - I've done my own research and I appreciate your comments. It's not difficult to find reports on duff TS scopes here, and I'm not saying it's premium scopes or nothing. I've owned, and continue to own several Chinese scopes and I'm very happy with them. I may or may not buy something from TS - but I will research it carefully before doing so and for someone vigorously defending their products and admitting they get a discount, you'll forgive me if I take your opinion with a large pinch of salt.

I'm not a member of Cloudy Nights, and I don't read their forum so it's all a bit of a wasted point - but I do thank you for your opinions and your defence of TS products is admired, but not particularly helpful in this instance.

Perhaps the mods would be kind enough to just delete this thread?

[admin]

Perhaps the mods would be kind enough to just delete this thread?

MRAPO is no longer a member at SGL. Not because of his passionate support for TS but because of his fondness of controversy and because bad-mouthing other astronomy forums is not accepted at SGL.

Please feel free to continue your thread. Unfortunately threads discussing APO refractors often attract strong opinions but if people follow our CoC and afford each other courtesy and respect then we don't see why they should become a "can of worms"

[Islander]

Common sense prevails as always

It would be a shame to lose this thread as there's so much useful information in it.

Now, does anyone have a view on the Skywatcher Equinox Pro 80?

[ollypenrice]

Olliy how do you rate your Pronto? Am sorely tempted by a TV 76, which is the newer version ( I think).

would be used visually as my grab and go travel scope that I could take as hand luggage.

cheers

chris

I love it. I bought it because I missed my Genesis so much when I sold it. I like wide field views from short focal lengths of around 500mm because I just like curuising the stars and also some objects, like the Rosette and whole Veil, need a very short FL.

Mechanically the TV is quite unlike the optically excellent refractors from China. It is heavy, strong and built to last at least one lifetime and probably several. It takes 2 inch EPs and can be collimated at home should that ever be ncessary. The weight is not ideal for transport (though it is a small scope so not that heavy) but the build quality is just what you want if a bit of bumpy handling lies ahead.

Optically it is excellent with short FL eyepieces (which is how I use it) but its 'semi apo' qualities show at high magnifications. They are very mild though. This is almost an apo in visual use and certainly more apo than my ZS66 which claims full apo-dom. It has to be the best couple of hundred quid I ever spent on optics. (They seem to fetch £200 to £300 second hand.)

Another member reviewed the Pronto alongside an ST80 and felt the ST80 came close. I have two ST80s and I have to say that I take a totally different view. The ST80s, bargain that they are, give a rather milky, low contrast image with huge coma and pretty invasive false colour. My elderly Pronto is in an entirely different league with bright, sharp optics and minimal coma. Given that it cost about a grand nearly twenty years ago you can say that so it should!

The Pronto lives by the front door so we can catch the wildlife at the drop of a hat. It makes a good spotter with accurate colour.

Olly

[Rossco72]

As a long time owner and user of a TeleVue 85 I can heartily reccomend it.

With some patience you should be able to get the scope and reducer for around £1000. I also splashed out on the TV Focusmate 2 speed upgrade to the excellent R&P, this was about £175 new I think.

Starlight do a Feathertouch upgrade for around £300 which would give you a killer scope and flattener/reducer with a bees knees focusser for around £1300.

Cheers

Stuart

[Cjg]

Thanks Olly and Stuart for your input

Chris

[Bukko]

Hi, Islander,

I have the Equinox Pro 80 and have been really happy with it.

To help Dodge, who started this thread, it is a good VFM Apo, shows little signs of CA and the focuser is strong enough to hold a Canon DSLR firmly. If you plan to move over to a big CCD, OAG and filter wheel, then it would most certainly need a focuser upgrade. But for around £500 new, you could do worse.

But I bow to Olly's advice, if you can find a Tak in your budget and it fits in with your imaging plans, then I would get that in a heartbeat.

Good luck with your search.

Gordon.