Refractor for astrophotography

[blueskies123_89]

Im looking for a refractor to replace my meade SN8 as an imaging scope, going on the EQ6 with an ED80, with price cap of ~$2500

The ones I'm looking at are:

North Group 127ED APO (waiting for quote, but I imagine on the $1000 area)
Astrotech AT111EDT 111mm f/7 ED triplet ($USD1895 astronomics)
Astrotech AT106 106mm f/6.5 FPL-53 ED triplet ($USD1885 astronomics)
William Optics FLT110 ($USD2899 OPT) - stretching the budget...
William Optics FLT132 (second hand, if I can find one).
Any other suggestions? (I've read a lot about the RC8", but I've got my mind set on a wider field refractor, unless someone can convince me otherwise.)

I am so very tempted by the NG 127ED, but a bit scared by it's low price. I know a few people own it on this forum, and I've seen the photos they produce. My questions are:

1) Does it have baffles inside
2) Does the "promoted focuser" work well with a DSLR (or QHY8/9 eventually), or does it need an upgraded one.
3) Ive seen the photos, but I don't know if they are cropped, so does it have a flat frame / any flattners needed?

I originally had my eye on the FLT110 before I saw the 127ED, is the extra $$$ really worth it?

Thanks guys
George

[Gallifreyboy]

Hi George,
have you looked at the WO online shop that has free shipping? It has same price as OPT but free shipping is a big bonus. I have the WO FLT98 carbon fibre which is a beautiful scope. The standard focusser is untroubled by a canon 1000d pointing vertical.

Peter

[AlexN]

Theres an FLT132 for sale 2nd hand on the forums for $2900... Thats what I'd be doing...

Out of your list, if I had the money to spend right now, this is how I'd have it ordered...
1 - FLT132
2 - AT 111 F/7 triplet
3 - AT106/FLT110 ~ The FLT110 might have a slight edge here depending on what focuser is on the AT106... If its got the 2.5" FT, then the AT106 is a winner, if not, then the FLT... It would also depend on what FLT110 is available these days... Earlier on, there was two versions, one with a TEC lens, the other with a TMB designed lens.. From what I read online the TEC model displayed much better correction, however this was some time ago...

The FLT132 is a TMB designed lens I believe, I know a few of them are for sure, I don't know if there is other ones with different lenses around..

Jump on Astromart and have a look around... I saw a TMB 130 Signature Series go for around 2K USD recently...

I don't know enough about the 127ED to make any valuable comment..

[rally]

If you want wide field spend the extra few hundred dollars and get a Tak FSQ106

There was one on Astromart (now gone) earlier this week for $3000 US with everything you would need inc 1.6x extender in a scopeguard case.

For similar money you could also buy a 2nd hand Tak Epsilon 160 or 180 on Astromart, these are astrographs, but they dont come up as often as the FSQ's

[blueskies123_89]

Thanks, yep if I am to buy one I'll buy it from them.


Yes I saw that, but the funds won't be available for a while (a month or two), if that is still up then...


It's interesting how on the astronomics website, they had the AT106 priced higher than the AT111 before discounted... Also the ATs are rack and pinion, that should throw me off.


Yes I've been surfing astromart, fingers crossed theres something up when the $$$ arrives.

George

[Waxing_Gibbous]

I can't comment on the AT106 or 111. I've seen real no complaints, but seen no raves either.
The "North Group" Apo is sold under several different labels:
Meade, Astro-Professional, Astronomica, Explore Scientific, Tech2000 etc. etc. Basically any cheapish 127mm Apo. is likely to be a Nanjing(North) Group refractor, same glass, (slightly) different tubes.
It was reviewed last year by Sky at Night who found it well corrected for colour, but not so good for SA.
The focuser was found to be stiff and a bit crude.
Its f7.5 so you'd probably want a flattener
Its not awful, but the larger apeture is negated by less-than sterling optics and finish.
I had a very quick look recently, but wasn't overly excited - the (visual)resolution was no better than my 8 year old 102 doublet.
But it does have a whole inch more light gathering.

I've also recently had a look through an FLT110 and a FLT98. I can't imagine anyone being displeased with either. No noticable CA or SA.
Maybe a little 'warm', but it could have been the dust in the air.

Both the 98 & 110 are for sale at Andrews for about the same as you'd pay to import one.

You could have worse dilemmas! :)
Happy hunting,
PJH
Just my .$02

[Omaroo]

FLT-110 on the forums here for $2,350

http://www.iceinspace.com.au/forum/showthread.php?t=51179

[Tandum]

I was in a similar situation earlier in the year. I got all the info on the 127ED APO, which would be closer to $1200 delivered. I waited as there was no rush and picked up a tak fs-102 with reducer locally for a price I could deal with and haven't looked back. You never know what's around the corner.

[blueskies123_89]

Oh thats so tempting!


Regarding a tak, one of the reasons I didn't include it in the list, besides the price, is that I heard about the ... well... price of all the adapters. Have you found that troublesome?


Ok, hearing you guys' opinions has turned me off the 127ED a fair bit. I want this scope to last a fairly long time, so I guess I should go for the others.

With the WO scopes, do people find that you must have a field flattener to go with them?

George

[AlexN]

WO makes a dedicated field flattener for the FLT110 and FLT132. Its rather expensive, but it will provide a beautiful flat field of view over most of the common CCD sensors..

[Octane]

I don't get this comment.

What, do you intend on leaving it in the elements, 24/7/365? Do that to any telescope, and, it won't last long.

I'm quite happy with the images my ED127 is producing. It's the best telescope I've ever owned. Pinpoint stars across the field, with slight curvature in the bottom right of mine. A flattener will fix it. No vignetting on the 40D. On the full frame 5D Mark II, there is considerable vignetting. Having said that, it's something that critical flats could likely resolve.

Regards,
Humayun

[blueskies123_89]

I'm sorry Humayun, I did not mean any offense. Regarding that comment, all I meant was I don't want to change scopes for a while. I have since gone back and looked at your images, and they are sharp to the edge. For example, is that image of the Pleiades close to full frame?

Also, I have read some comments about the focuser supplied with this scope, have you had any trouble in that aspect - or is the Explore scientific version different to the NG version?


Yes I just searched the the past S&T, and there's a review showing the comparison b/w with and without the flattener.

George

[Tandum]

The camera rotator for the tak was pretty expensive, around AU$250 I think, but I rarely use it :(

I believe the new photographic focuser on the 127ED is acceptable. pmrid has just received one.

[allan gould]

Again there is bashing of scopes and opinions that people have only read about. Actual experience of scopes would be invaluable here. Like Hum I have a 127mm ED scope that is flat to the edges. No flattener needed. No colour on bright stars. I'm not offering opinions on other scopes except for wo. Have a wo triplet ed that has colour etc and not a flat field. Don't bag the 127mm if you havnt used one. The focuser on mine wasn't as bad as some, but a moonlight focused transformed it.
Just make sure you get the hand figured Japanese glass in the 127mm AND not the chinese machine figured glass, remember you do get what you pay for.

[pmrid]

When I bought my Ed127 I specified that I wanted the new 'improved' focuser for imaging work. And so it is. It is a mix of good and not-so-good. The good is that it is smooth, positive and has a decent focus lock that does what it should. The bad is that it uses a compression ring and I have a dislike of those things.
Optically, I can't fault it at all. I'm delighted by the image quality.
Peter

[blueskies123_89]

Hmm, so do you specifically ask for the Japanese glass from NorthGroup?



Oh good, that gives me more confidence.

Also, having never owned a refactor since my first department scope (except for my ED80 guide scope) - Do any of you ever collimate a refractor? Part of the reason for me wanting one is that I would travel with it a lot, and whilst I'll take very good care of it, I don't want to collimate everytime I get to a new spot as with a newtonian.

George

[Kal]

Where did you find out this information?

All the ED glass for the 127 scopes is japanese made from Hoya, being FCD1 (FPL-51 equivalent).

All of the refractor lenses for these scopes will be machine made in china.

Unless there is some other 127 scope that I am not aware of?

[Hagar]

A point to remeber when budgeting for your new scope. You will most probably require a field flattener or reducer/flattener for your imaging with any or all of the refractors mentioned.
I believe there to be a nice Tak FSQ106 for sale in the classified section but this would probably stretch the budget a bit further but no flattener is required with this astrograph. It is basically purpose built for wide field imaging. There is also a WO 132 for sale complete with flattener. Must be shipped from NZ but Gary is quite up to date on this proceedure by now. It is a good price and knowing Gary it will be in excelent condition.
Good luck with your purchase.