North Group APOs

[adman]

Hi all,

does anyone who bought the 127ED APOs from North Group in China know whether they also do the 80mm triplet. The Made In China website says they do - but no other details like price etc.

I am guessing that it would be similar to the Meade Series 5000 Triplet APO (http://118.127.11.230/catalog/product_info.php?cPath=24&products_id=212).

Thanks
Adam

[AlexN]

Its very likely to be exactly like the Meade 5000 80mm triplet.. The North Group website used to list the 80mm triplet price and details, although I've not looked in quite a while.. I'd shoot them an Email and ask the question.. Would be interesting to find out what they are worth..

[adman]

I was reading an old thread today, and they talked about a contact with North Group called "Gilman" any ideas if he is still there?

[Octane]

Adam,

Yes, but, you mightn't get a reply quickly.

I was in touch with Gilman not so long ago. They're trying to sort out the issues with the ED127 not coming to focus with eyepieces.

Not sure how they'll sort that out, but, I did let him know that whilst it's not an issue for me (purely an imager at heart) that I did suffer from the same problem.

H

[adman]

You wouldn't happen to have his email address to hand would you??

Thanks
Adam

[adman]

Never mind, I just found his email address in an old post. I should look first and ask questions later...:P

Adam

[DavidU]

After sending several emails to Gilman wanting to order a 127 ED I still have received no email from him.

[adman]

hmm...that doesn't sound too hopeful. Humayun, how long ago did you get in touch with him? Was it by email?

Adam

[Octane]

Yeah, a couple of weeks back.

I asked him to get in touch with DavidU.

I think they're trying to sort out the focuser issues before taking any more orders.

H

[adman]

all the same, a little communication goes a long way...:shrug:

[gbeal]

Not Chinese New Year as well is it, that will likely make a difference.
Gary

[adman]

I did think about that. The actual day was yesterday. Year of the Tiger. I am hoping for it to be the Year of the 80mm Triplet APO ;)

I have sent Gilman an email asking for details, so we will se what happens.

[pmrid]

Sorry to butt in: I have the address handy so here it is:
gilman@northgroup.cn
Peter

[Octane]

He found the address already, Peter. I was hesitant in posting the address as he's not likely to reply to anyone as it is.

H

[Tandum]

If you look up Hong Kong Public Holidays you'll see they are off till the 16th at least.

[marki]

Would the Northgroup version be significantly cheaper then the meade version sold here? I paid about $800 from memory and it came with 2 inch diagonal and a ali hard case. It's a nice little refractor with good colour correction but the focuser is a bit iffy. Stuck a moonlite on mine and now it's a nice little imaging machine.

Mark

[Tandum]

This is from May last year, I dunno if the price has changed or if it's the scope in question :-

our ED80 with dual speed focuser, OTA,
with ring and dovetail rail,
with aluminium case package,
without diagonal,eyepiece,finder scope.
USD360

[marki]

So that makes it about $400 AU + shipping. Could get a reasonable saving from that.

Mark

[gb_astro]

Diverting the thread again.... but,

According to the Cloudy Nights tread on the the 127 "Promoted" focuser the problem is the focuser is just too long, even in the fully racked in position, for many eyepieces to come to focus when using a 2" diagonal.
Solution at the moment is to use a 1.25" diagonal or to order with the original "Standard" focuser or budget for a Moonlite or similar.

gb

[Octane]

Greg,

Thanks for that -- you had first hand experience with my baby. Bit annoying, wasn't it!

I've been in touch with Wayne at Starlight Instruments and am putting aside pennies for a you-beaut Feathertouch with automated focusing.

It seems a little sad that the focuser will end up costing about the same as the telescope itself. But, I guess I can always re-use the focuser if I change refractors in the future.

H

[gb_astro]

Still good value H.
Should be a joy to use.

Greg.

[AlexN]

A good focuser is one of those things that can last a hell of a long time... A FT can be adapted to work with many different scopes, the one I have on my TMB APO can be interchanged between that scope and the Intes Micro Mak Cass that I've got coming... All you need is the correct adapter to go between the focuser and the OTA you intend to use it on, and you can have one focuser for as many scopes as you own... The only downside is when your hellishly expensive focuser does not work how it should.. :(

[allan gould]

H.
I have a Moonlite focuser on my 127mm scope and its beautiful. I went for the dual speed with integrated lock mechanism. I thought the electric focuser would be too proud ie stick out too much- to use it in the case and with dual speed the focuser movements would be fine enough. Dealing with Moonlight was a real pleasure. Initially I ordered the wrong adapter plate as their site was a being updated for these focusers for the 127mm. Anyway he sent me a new adapter plate without waiting for the other to be returned at NO cost. It just screwed into place, was collimatable and worked a charm.
Just love it and I would seriously suggest that for ~$500 its a great purchase.
Allan

[Octane]

Allan,

I'm wondering if I cut into the foam in the case whether the housing for the motor would fit?

Moonlite was on my list as well but after having seen Frank (spearo's) and John (JohnG's) setups I was swayed to go the Feathertouch route.

In reality, there's probably really not all that much between the two, and, I'd be happy with either system.

H

[allan gould]

Humayan
From memory the moonlight electric focuser sticks out about 3 inches from the normal focuser position. Im not sure if cutting the foam in the case would do it
If I remember correctly, David Hough got a moonlight with electric focuser for his 127mm scope - if he reads this or you PM him he could enlighten you.
I think he posted some mods to his case to put two scopes? in it but dont hold me to that.
Allan

[h0ughy]

mine fits in the case with no modifications, all i do is loosen of the tube rings - rotate the tube and the focuser until the motor is on top and pointing towards you and it sits flat on top in the case when closed. its a tight fit but it works:thumbsup:

[Octane]

Thanks heaps, guys.

H

[Lothar]

Hello,
Is the North Group's 80mm APO in fact the same device as the Meade 5000 and the Explore Scientific 80 mm APO Triplets ?

I wonder how these triplets compare to the upcoming new Long Perng ED APO 80mm f/6.2 Fluorite doublets from Andrews.
Has anyone looked or imaged through one to see if they are any good?

The Gilman link does not seem to work, but this one does... http://njnorth.en.alibaba.com/productgrouplist-200018071/astronomical_telescope_and_accessor ies.html

Lothar

[wasyoungonce]

Got my 127 ED from North Group yesterday Arvo.

Ach mein Gott ..."it's big".

More info to follow soon.

[adman]

Nice! I'll take that one off your hands too when you're finished with it!

Adam

[wasyoungonce]

Ok so here is the guff.

The Cardboard box arrived with a sizeable hole in the side, but the inside transport box was unmarked. The inside transport case is well made, although, some of the expanded foam packing took a hammering in transit. It did it's job.

The Scope. It's a big long scope, dwarfs my WO70ED! Call me naive but somehow I thought it would be shorter. It's heavy as well, that is not too heavy to handle as the long tube gives lots of purchase. The scope is well finished and looks a million dollars even when not in use. Yet to try it on the heavens.

The Dew shield is removable (I was hoping for a sliding one like the Explore Scientific scopes) and heavy, too heavy for purpose. They should have a fibreglass Dew shield.

It has an Aluminium (industrial grade) screw on lens cap and you can only really access this with the Dew Shield off. It really needs a $2.50 plastic moulded lens cap to fit the Dew shield as well. I don't fancy removing/replacing the current one repeatedly as it's too close to the lens.

The Rings are OK, better than the std cheapo types but not by much. They have moulded square lands on the top & bottom of the rings with one threaded hole on each. I removed the top/bottom vixen rails & fitted it straight on to an 11" ADM dovetail. It all fits nicely but ATM I cannot comment on rigidity, time will tell. I wish the rings had a bigger lands & more wider spacing holes to securely bolt them down. This would make the rings acceptable.

The focuser. Appears up to the task and smooth enough. It has a adjustment on the top..I for the life of me do not know what it's for. I suspect it's focuser adjustment of some type. I'll leave this alone ATM. I don't know if I got the advanced focuser. I think I did.

Apparently the scope will not reach focus with a 2" diagonal. Which is due to the new "advanced focuser". I'm not concerned with this as I want it to take pretty pics. NG are working on a new focuser but ATM it's not available. My opinion on this is that most cheap scopes come with relatively poor focuser's. If you want better then there is the after-market segment like moonlight.

The Finder appears excellent. I ordered a correct image illuminated finder. A plain polished aluminium finish, nice graticule and good adjustment on it's illumination intensity. The finder holder is less than adequate. It doesn't hold the finder securely.

Diagonal. I ordered a 2" diagonal. This was a waste with the current focuser. It appears industrial grade and it's mirror surface appears excellent, but, that's all I got. No 1.25" adaptor and no threaded thumb screws. Meh! I should have ordered an 1.25" diagonal in any case as I believe I can reach focus with a 1.25", for eyepiece drift aligning.

Well that's about all. Cannot wait for 1st light. Melbourne skies have been dreadful lately so I expect this scope will extend the curse.

edit..
typos.

[wasyoungonce]

Cheeky devil...but if you never ask...you never know;)

[marki]

Collimation :thumbsup:

Mark

[wasyoungonce]

Thanks mark.

[wasyoungonce]

Ok update.

I don't have the advanced focuser, I didn't think I did. I can achieve focus with a 2" diagonal. I had a quick peek at the sky last night...balancing the scope on a table:lol:. From what I saw...great, absolutely no fringing crisp views, although that was only on 40X.

The focuser works great but there does appear some issues with the thumb screw (http://www.iceinspace.com.au/forum/showthread.php?t=47134&highlight=127ED) & keeping accessories square to the draw tube (http://www.iceinspace.com.au/forum/showthread.php?t=35042).

I have ordered some thumb screws from Scope stuff (http://www.scopestuff.com/ss_scr1.htm)and will add some extra around the draw tube collar. This should fix this issue.:prey:

I have measured the thumb screws and they appear to be M4 x .7 threads. Lets hope I measured them correctly as it's difficult to tell.

I also ordered some M5 x .8 thumb screws to add qty 3 to the finder. This may fix the finder but I suspect I'll have to buy a better finder holder (http://www.optcorp.com/ProductList.aspx?uid=105-166-170).

So far it's a good experience with some little warts. But for the price...:D

[Terry B]

Interesting the changes that have occurred with this scope. I have one of the early ones. My dew shield slides and the screw on cap fits into the dew shield. This makes it very easy to use. The scope came with 3 eye pieces that are OK. Otherwise it seems very similar.

[wasyoungonce]

Hi Terry. Is you cap a metal one that threads on or a plastic one?

[pmrid]

Mine hs the removable dew shield and I am happy with it because I removed it on day 1 and never replaced it. Instead, I use one of those wrap-around combined dew-shield heater collars that is light and kills 2 birds with the one prpverbial stone. I haven't weighed it but I'd guess that I have saved at least half a kilo or better this way.
Peter.

[wasyoungonce]

Actually that's a good idea.

I was wondering how & where to put a dew strap on the OTA as south of the lens is not the best place and on the dew shield is also 2nd best.

[Steffen]

Isn't that thumbscrew for locking the (rotatable) focuser?

I think collimation screws would be a set of three and be inside the focuser (accessible after you've taken off the rotatable part).

Of course, this is mere conjecture on my part, I have never see this scope in the flesh. But this is what/where I'd expect things to be.

Cheers
Steffen.

[Terry B]

It is an aluminium threaded cap.
I have made a dew strap from some nichrome wire sandwiched in some tape. This is wrapped around the back of the dew shield and this prevents any dew even when pointing straight up.
My scope is on a permanent pier so I never remove the shield or the strap. Works well for me.

[wasyoungonce]

Thanks terry.

[wasyoungonce]

Well, all of 20 mins outside with the ED127. Didn't even have time for an alignment before clouds spoiled the parade.

Anyway, scope appears great. Only tried TV 32, 25 & 15mm Plossl's which gave 30, 38 & 63X.

Stars nice & sharp no spurious colour's but this was all with low powers and not much cool down time. So it's difficult to tell but from the few star fields I saw the views were crisp & sharp indeed. Like the ED80 but more photons.

The finder is a mixed package. It exhibits what I think is off axis Astigmatism. The central area nice & crisp and the reticule crisp (yes I focused the main finder lens & eyepiece lens) but it appears to go out of focus off axis.

It's a bit hard to tell ATM with such a short effort.

So who brought in the clouds!:mad2:. Please take them with you when you go!;)

[pmrid]

I've been following this thread and wondering about the various points of difference that seem to have emerged between successive generations of these North Group 127 APOs. I've had mine a year or so now and think it's the duck's guts. Looking at the photos in this thread, I couldn't see the focuser clearly enough to say whether it is the 'old' or the 'enhanced' version. I specified the enhanced when I bought mine and am managing reasonably well with it - although has been mainly due to fitting a Hotech flattener to it. This was in part because of a small amount of coma in the extreme edges but also because I wanted to be able to take advantage of the much better system Hotech has of securing itself (and imaging gear hanging behind it) into the drawtube of the focuser using those compressed rubbed rings rather than those darned compression things that seem to me to throw things off-axis more often than not and only give a decent grip on heavy gear if you screw the locknut up really firmly. Why manufacturers don't put at least 2 securing screws onto these compression rings I don't know.
If it will help anyone I'd be happy to post a few photos of the focuser I have and you can compare with your own.
Peter.

[marki]

No it is a funny setup and I could never get it working on the 80mm meade version. I ended up putting a Moonlite (collimatable as you have described) on it and am very pleased with the result.

Mark

[wasyoungonce]

That would be great peter. I'm pretty sure I have the std older focuser everyone complains about! I'll breakout my camera as well.

If I can get it working to an acceptable level...great..if not...moonlite!

I'm Ok with that route as well;)

Except I'll have a bit of grovelling & saving to do.:eyepop:

Edit:

Pics added:

[pmrid]

Right. The pics didn't turn out all that well but they are clearly of a very different focuser. Mine is shown with a Hotech flattener in it and I include a few pics from last night so you can see the sorts of results the combination is giving.
cheers
Peter

[wasyoungonce]

Thanks Peter.

Yep we have different focuser's. I believe you have the advanced focuser (http://deepspaceplace.com/ed127.php).

I'm not disappointed with the focuser I have (although I have noted some problems so far) ...I don't have enough time with it to judge.

Edit:

I should have said I asked for an advanced focuser (in Emails) and the invoice stated "ED127 with advanced dual speed focuser for camera, OTA,with ring and dovetail rail,with aluminium case package,without diagonal, eyepiece, finder scope".

So I was expecting the Advanced focuser and appeared to have got the std focuser. Is this just a communication error or what?

[JohnH]

Here are the original and enhanced focusers side by side...the heavy duty unit has three machnied flats for the draw tube to ride on and the lock is not on the draw tube (so zero image shift). It is smoother and can carry a bigger load without flexure BUT it uses more backfocus than the original design so some eyepieces will not come to focus when a 2" diagonal is in use. No issues with CCDs or 1.25" diagonals however.

As a matter of interest I have both models available for sale if anyone is interested....with/without the 127 flange plate.

[Octane]

Brendan,

Get in touch with Gilman and let him know you've got the old focuser. He'll organise for a new one to be sent out.

H

[wasyoungonce]

Thanks H. In my communications with Gilman we spoke about the focuser and I was originally going to get the std focuser.

However in my last few emails to him (when we started talking costs) I asked for an Advanced focuser. I was quoted a price on the invoice that stated "Advanced focuser for cameras"...so I thought we were on the same wave length about this.

Appears not the case.

Anyway, it's not the end of the world, I've fired off a nice email about it to Gilman. I'm sure we can find a solution.

[wasyoungonce]

I love the world ...one door closes..another opens!

If I get no joy then I'll be eyeing your advanced unit;)

[sejanus]

I've been trying to buy one of these - well at least make contact as I ponder way too many scopes to buy. No luck - no reply on either the shopping website or his email address. Any secrets? :) Or is there anywhere local that is reselling them at an ok price? I found 1 certain shop that was selling it under the prostar brand but for $2900.

[Octane]

Gavin,

Flick me an email: octane2 AT optusnet DOT com DOT au

I'll forward your details on to Gilman. He seems to reply to me immediately.

H

[sejanus]

thanks mate, emailed.

[gb_astro]

Bintel has the Meade version for $2700.

gb.

[telemarker]

Aussie supplier here and a bit less at $1950

http://www.telescopes-astronomy.com.au/hioptic-pricelist-telescope-astronomy-refractor.htm

[sejanus]

thats getting closer. he's a good guy, I bought some bits off him for my old eq6 a couple of years ago.

[sejanus]

woohoo I got a reply from gilman. In his email he mentioned the tube was for observing only, and there was no mention of an advanced focuser or similar so I guess he pulled the plug on that stuff in the meantime.

So in general, if I just get the tube, then buy a 3rd party focuser I'll be ok photo wise right?

thanks

[wasyoungonce]

Or ask for an Advanced focuser price!

[Visionoz]

I believe that price of $2900 includes the Moonlite focuser instead of standard factory one

HTH
Cheers
Bill

[JohnH]

North Group may have stopped making/shipping those parts due to the need to re-design to address the backfocus issue. If you want the advanced focuser the quote I had was this ...

2" Dual Speed Crayford Focuser for ED APO152, 127, 102, 80,USD145,
postage is about USD25,
paypal charge is USD10,
total is USD180,

If you cannot get the part from North Group and do not want to go all the way up to a Moonlite or Feathertouch then I will let it go for AU$100 plus postage.

John

[gb_astro]

I see he has the 102 and 80 triplets as well.

gb.

[wasyoungonce]

PM sent

[wasyoungonce]

Well finally the clouds cleared for around 3 hrs!

Here are some rough pics, all not focused correctly to boot.

The 1st is a clip from Ptolemy Cluster. I definitely didn't get the focus right. I just focused on live view...didn't zoom in for focus. Anyway it shows quite a bit of purple flaring. I suspect this is just focusing though as the below results were better.

The 2nd is a clip from M20. I refocused using live view zoom then slewed to M20. I should have tried re-focus at the target! There is substantially less flare but the stars are un-focused! Sigh!

The last is just 4 x 180s exposures of M20 (ISO400)...then in came the clouds. DSS stacking didn't like the un-focused stars and has left some artefact's on the image of them.. somewhat.

There is some field curvature...all in the same direction. Maybe some focuser droop or camera not square?

So ATM I need to do some more pretty pics to really test this out before judging. I like the light gathering of the 5" though!

Edit:

Forgot to say...it was awfully cold and the M20 unfocused stars do look a bit like dew. It's a possibility.

[JethroB76]

You caused a bit of a "to do" on CN :lol:

[wasyoungonce]

I don't know why..it descended into anarchy real quick for no real reason.

Meh...people have a right to know where their scopes are made. For years everyone knew where their scopes came from now days it's not so clear.

The China manufacturers & their inter-relationships is very interesting and exists for some reason that escapes me ATM. Suffice to say they are producing ever increasing level of good products.

[sejanus]

whats the link on CN?

[wasyoungonce]

Probably best to leave that discussion on CN (http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/3859659/page/1/view/collapsed/sb/5/o/all/fpart/1) and not import it here.

[sejanus]

Well I've given up on our mate Gilman. He either doesn't reply full stop, or takes 5+ days to and then ignores half your message. I'm not sure if it's a english comprehension problem or not but it's out for me.

A bit of a shame as a few pics david sent me looked great, anyway bugger it I'm going to punish the credit card and get a Tak or televue. Most likely a Tak.

I'm glad you guys had better luck though.

[adman]

Yeah - its best to take that sort of anger out on something plastic :lol:

[wasyoungonce]

Ok...continuing my post previously about some chromatic aberration I am getting with my scope.

I appear to be getting some violet "hue" with my 127ED. This hue is always on bright stars and elongates away in an elliptical manner from bright stars. Always in the same direction!

I'm suspecting there is a misalignment in my optical path causing this. I can understand a "hue" concentric with a bright star but not always trailing away in one direction!

These pictures tell the story.

So all you NG refractor guys what do you think or recommend I should try.:shrug:

[Tandum]

Have you checked the collimation (http://www.spacealberta.com/equipment/refractor/collimate.htm)?

[Octane]

Bren,

Are you using a Bahtinov Mask to reach focus? Are you focusing on a blue star? I had this problem on blue stars. I found if I focused on a yellow star, focus was still acceptable, but, it almost completely got rid of the halos.

H

[wasyoungonce]

Hmm good point.

I did try inside & outside defocused star test (the 1st time I used it...around 15th Jul) and the rings were concentric...from what I can remember. I didn't see any off axis hue doing this and at the time thought all was honky. I haven't used it since due to Melbourne weather.

Maybe I should try an inside/outside focus test again & this time take pics.

I should have also rotated the OTA in relation to the camera & tried some more pics to see if the off axis hue moved in relation.

[wasyoungonce]

Hi H,

The stars are from M8 lagoon nebula. I actually focused on Antares, nice red bright star nearby:lol:. I didn't use a mask, just live view (magnified 10X)

[Moon]

I found you need to be just **slightly** out of focus to mininise the blue halos. It's easy with Liveview. Have a look at the youtube video half way down this page.
http://deepspaceplace.com/ed127.php
James

[Octane]

Yep, I'm with James. I think I've mentioned this before.

Focusing on a yellow star is great, but, if focusing on a blue star, a very minor slight teensy weensy minute small tiny nudge out of focus will all but remove the pesky halos.

You're doing the right thing with Live View at x10.

H

[wasyoungonce]

Sorry guys.

My internet bombed out in the middle of all this last night.

I was replying & ..then ...nada!

[wasyoungonce]

Ok, thanks James & H.:thumbsup:

Looks like a good night tonight for more fun, frustration & frivolity.

I'll do some star defocused tests with a bright star & webcam.

I'll try some happy snaps after focusing on a yellow star.

If I see the halo in pics again I'll rotate the scope OTA in relation to the camera to see if they change direction.

[wasyoungonce]

Alrighty...I'm outside ATM and I focused & backed it off a touch!...What a change ...all good.

I did star tests...all good.

I'll post some happy snaps later. Thanks to all indeed!:thumbsup:

[Octane]

Bren,

Happy to hear that. Happy imaging. :)

H

[DavidU]

That's great news Wasyoung. Look forward to some piccies.

[wasyoungonce]

Dad left his page up..Silly him. He loves his daughter Emma most and he is still outside looking at the sky! What a nerd, but a cutie at the same time. PS i hate maddie.

[MrB]

Haha, how funny is that! :lol:
Hello Emma ;)
I wonder if dad's gonna find it as funny as I do?

[wasyoungonce]

Dads back....1 x daughter for sale...going cheap!:rofl:

[Octane]

Hahaha, that was gold!

Emma rocks! :)

H

[MrB]

I'm still laughing.... hahaha

[Coops]

Hello

For those who didn't get replies to Gilman, I've been emailing him for the last couple of days with success.

I initially went through the Alibaba link getting a reply couple of days later.

[wasyoungonce]

Now my daughter is back at the "home"...I can post & leave web pages up!

Here are some quick pics. Outside focus/inside focus x 2 (diffraction rings). I used Antares for this.

M8 (enlarged crop) focus backed off, 60s sub.
M8 enlarged crop 300s sub.

M8 crop enlarged focus backed off (only a very very slight hue)...and the same with focus done at 10X liveview (notice the hue).


edit:
One thing...the outside focus diffraction rings had a blue hue on the upper right quadrant and violet on the lower left! pretty much same inside focus diffraction rings.

Focusing was accomplished by 10X live view then backing off & taking 60s subs to see the result. This is not ideal and easy to get frustrated. Anyone know if a Bahtinov mask can be designed for yellow wavelengths diffraction focus pattern? Indeed what wavelength are the masks made for?

I did some Avi's of focusing in/out but have not reviewed them yet.

Once again thanks to all members for helping me with this!:hi: and putting up with my wayward daughter!

[DavidU]

The mask will focus the full spectrum of the star. If a slight Longitudinal aberration has the violate end more out of focus than the yellow/green (quite typical) I would use the mask with a yellow filter then a blue to see the difference in focus.

[DavidU]

Also I would say your collimation is slightly out or a tilt in the camera plane.
Trow up a diffraction pattern like #2 and shift the scope around so the image goes around the camera chip and see when the offset violet becomes more uniform.

[wasyoungonce]

Thanks David. yep will try that. But...clouds are back!

Is it worth getting or using an artificial star for this?

[DavidU]

Yes you bet. I have built a white on and a blue one. The trick is to have it 300+ feet away from the scope of it will be impossible to throw a diffraction pattern. During the day (direct sun) a 10mm ball bearing on a stick works a treat !

[wasyoungonce]

1st processed pic with 127ED and re-focus technique, M8.

Not posted in Deep space threads ...it's kinda an over done traget...anyway it turned out ok.

I think it's missing some fine detail and I'm guessing as I get better at focusing this will be better. I also need to track down why one side of my outside focus diffraction rings look violet & the other blue! As David said, more than likely due to camera nose piece not square or such like.

So, here's proof. The scope does work!;)

edit:
oh.. DSS stacked 15 x 5 min subs & darks from my dark library (no flats). DSS reported FWHM of around 5.1 to 6.1...that's a little high!....anyway...Curves, levels, some selective colour adjustments, and one smart sharpen in CS3.

[wasyoungonce]

Just a quick question.

After looking at the inside/outside diffraction patterns...they are compressed top right.

I also noticed a pic I took of NGC6744 showed coma in dim stars, same direction as compressed diffraction pattern.

So I need to collimate. I know I can use an artificial star (if I could get the distance between myself and the artificial star) but what about a Cheshire eyepiece or laser collimator or such like.

What's best, cheapest & easiest? I imagine a Cheshire?:shrug:

[DavidU]

A refractor Cheshire.

[wasyoungonce]

Thanks David.:thumbsup:

forgot to ask..is a laser collimator any better (probably is for a newt) or is it hype not needed especially for a refractor.

[DavidU]

A laser is good for collimating the focuser. Just remove the lens cell and replace it with a round piece of white paper with the exact centre marked, so if the focuser is spot on the laser will be dead centre .Make sure the laser itself is collimated (turn it around when in the focuser).

[DavidU]

http://www.spacealberta.com/equipment/refractor/collimate.htm

[JohnH]

I understand that great care must be taken when removing the lens cell as the obejctives components can move if this is not done right.

In case you have not found it here are the 127 ED's instructions:

http://explorescientific.com/telescopes/127mm_ed_apo.html

(slightly different model - with reversable dew shield but think the reast is the same). BTW can anyone confirm the correct way to remove the dew shild from the NG model - I assume the coloured ring unscrews? Seems very tight on mine...

[GrahamL]

A little harsh Emma don't you think .. maybe next time a change in password and a few choices photos from the past are in order:thumbsup::rofl:

[Octane]

I vote Emma's post, post of the year.

H

[DavidU]

Here Here !:lol:

[wasyoungonce]

Now you see why I go & spend my nights outside in the cold!

Pity me!:lol:

[wasyoungonce]

Thanks for that David.

[DavidU]

What suburb are you in Wasyoung?

[wasyoungonce]

Lilydale....between the cemetery and the lawn cemetery & the poo farm (water treatment)....:lol:

Ahhh I can feel (& smell) the tranquillity:lol2:

[DavidU]

Ah nice, much darker in Lilydale.

[Brundah1]

Brendan,

See your getting your teeth into the ED127, good on you.

I'll behind you very soon, soaking up the good advice too. Its great to have the friendly advice of those who ventured into the unknown with these great value scopes.

Just finalising all the bits n pieces, but not hopefull about the WX next month. BTW tonight is quite good here, even though BOM said it would be raining clouds and showers!

Cheers,

David

[wasyoungonce]

Hi David.

I wanted to share all experiences I am having with it..good or bad. It's a great light gathering bucket.

[Logieberra]

Hey guys

Out of interest, what do you pay to get one of these on shore? With diagonal and advanced whiz bang focuser?

Happy for PM's if the details are super secret.

Cheers.

[wasyoungonce]

Ok and bit of an update for everyone.

After tests I have come to the conclusion (obviously with the assistance of others..a big thanks to them) that there is an issue with the Optics on my 127ED.

It has a prominent blue/violet flare on stars (across the field) when at perfect focus. Yes I can re-focus most of this out but it is at the expense of defocusing stars.

I have performed star alignments, Cheshire alignments, focuser alignments and lost of tests with CCDInspector.

Gilman previously sent me an article on Lens alignment and I have fiddle with this (a little) with no change. This does not appears to be a main lens alignment issue as the star test is quite good. What is causing this?...who knows?...in my limited opinion it looks as if the centre lens may be causing this aberration.

I have more pics and a video of focus on my Picasa page (http://picasaweb.google.com/brokenback09/127EDCollimationAndFocusTests#) if anyone is interested.

Anyway I've sent an email to Gilman asking for replacement scope (send mine back) or lens cell exchange.

So ATM it's all in the lap of the Northgroup. Lets see what eventuates.:shrug:

edit:

I think I'll take my frustration out on the cat...oh..we don't have a cat...maybe Emma then!;)

[marki]

Could you post the article? Could be very helpful for a little problem I am having.

Cheers

Mark

[wasyoungonce]

It was only an article about the AR5/AR6 scopes...Uploaded.

It is in fact different to the 127ED lens cell. The Explore scientific owners guide is better (http://explorescientific.com/manuals/explore_scientific_product_manuals. html).

[mill]

Lilydale and dark??? :rofl::rofl::rofl:
Come in my backyard and then we talk dark :P
I hope Gilman will get back to you soon Brendan :thumbsup:
PS: did you get my email?

[DavidU]

Wasyoung, here is a typical longitudinal map of RBG (a triplet APO)) trace that shows the blue is a little out of focus while the red & green are.

[casstony]

There was a write up on the myastroshop website about these refractors but the link isn't currently working. Apparently they specified a different centre element in the Prostar version which markedly reduced chromatic aberration compared to the scopes coming direct from Northgroup.(flame shield on :) )
They had photo's on the site showing images through both versions of the scope, with no obvious blue halo through the Prostar.

If you send the scope back, perhaps you could ask if you can get the upgraded center element?

[Octane]

Don't take it out on Emma -- she rocks! : )

Sorry to hear about the issues you're having. And, my apologies for my lack of assistance. I've no knowledge on optics other than how to take an image. : (

H

[wasyoungonce]

yes I did..and sorry ..I have been busy with wayward family and telescopes.

And...yes Lilydale is dark...if you close your eyes..and imagine!;)

Hopefully it will get resolved to everyone's expectations, thanks.

[wasyoungonce]

I got an interferometer report with my scope..FWIW. I don't/didn't expect APO quality but IMHO it's behaving like an Achromat.

I'm manly concerned that the flare is across the field & not concentric with the stars..but biased badly to the upper right side of stars.

[wasyoungonce]

Hi H...no problems. I kinda know myself something was not right but it wasn't gelling as the star test shows a nice diffraction pattern.

As I've said if the hue was concentric I would have a better chance of focusing any aberration out but it's biased to one side.

When I re-focus the flare out the stars are becoming defocused so I'm caught between the flare & de-focus.

edit:

Emma's Ok...ATM..If I'd try to take it out on her...she'd kill me!..Well not really but I would want to face that.

[wasyoungonce]

Hi Tony...Hmm ... I had read this and was thinking this...wishfully thinking that is. If I venture back to CN on this topic I'd need more than a flame suit.

It's something I can bring up with Gilman..maybe:D.

It's just a bit of bad luck but someone had to have issues.

[marki]

Thanks mate :thumbsup:

Mark

[casstony]

They can take themselves a bit too seriously over there - it's like you're in a court of law sometimes.

[DavidU]

Wasyoung, here is a good read..........
http://deepspaceplace.com/ed127.php

[wasyoungonce]

Thanks David.

James is a moderator/owner of the ED127 Yahoo forum (http://tech.groups.yahoo.com/group/ed127/). I watched his video of focus and he gets Chromatic Aberration but it's concentric with the stars. (edit: I did a similar focus video (http://picasaweb.google.com/brokenback09/127EDCollimationAndFocusTests#55004 17840922485314) and it shows that my optics produces a rather large flare off axis compared to his).

I have got a reply from another David on this forum (David Dells..yahoo ED127 forum that is) who had a similar issue but the flare was not as bad as mine. He has adjusted his to an acceptable level of concentricity.

I asked him if this adjustment had an effect on his star diffraction pattern before or after. ...aka what was his diffraction pattern before & after wrt the aberration. Still awaiting a reply.

[DavidU]

Wasyoung, I had a really close look at your images and It looks to me like it is slightly out of collimation and has a pinch in the optics.
Do you have (or can make) an artificial star? What collimation tools do you have?

[Moon]

Agree - it does look like that doesn't it. I hope you get it sorted out soon.
James

[wasyoungonce]

Hi David the 1st diffraction pattern, 06 Jul, (http://picasaweb.google.com/brokenback09/127EDCollimationAndFocusTests#55005 90247528213122) was the original untouched factory adjustments. This was in reasonable seeing conditions.

The next diffraction pattern, 26 Jul (http://picasaweb.google.com/brokenback09/127EDCollimationAndFocusTests#55005 90247528213122), was after a minor adjustment, was in much more poor seeing conditions.

Some images, like the 06 Jul look as if the pattern is NQR..in this case pinched (on top) but I compared this with other images I did on the same night and in this case the "pinch" in the pattern is gone...It was just a seeing aberration when the pic was taken.

There is a slight concentric error in the 06 Jul image pattern, slightly up & to the right.

Here is another star image from the 26 Jul.

I reckon the pattern, while not perfect is "good enough" ...well at least not to cause this flare.

I have a pair of eyes:eyepop:, star tests when the clouds go away :cloudy:and a Cheshire:astron:.

But from what I have found the star diffraction test is by far the best..when I can get one done!


edit:
I asked a about an artificial star for testing (like a Hubble Optics star) previously as I wanted to fiddle without relying on the weather nor a moving star..is it worth it? maybe yes in this case? Will an artificial star show chromatic aberrations or are they limited in their wavelength output? This I ponder some.

Here are some other star diffraction patterns 06 Jul (actually the 1st image is dated the 26 Jul). The Seeing varied quite a bit \which gave varied diffraction patterns. I noticed previously the pattern also shows some chromatic aberration on the diffraction images.

[wasyoungonce]

Reply from Gilman already.

Asking to return the lens cell for adjustment or replacement under their TNT account.

Apparently they are on a summer holiday break so if they are slow in reply...you can appreciate that it's not always due to the obvious.

Wow..cannot get better nor quicker service than that!:eyepop:

Do they know how to do business or what!:thumbsup:

[JethroB76]

great news

[DavidU]

Great news ! Saves me from going to your place to fiddle with the bl00dy thing:lol:

[wasyoungonce]

Ha..guess you don't like a fine Chardonnay to cross your palate after a hard day/night doing diffraction patterns.:rofl:

[DavidU]

Mmmm, a nice crisp wooded Chardonnay !
Brendan, I have searched a stack of optical tests and you may be interested in the star test of a WO FTL 110 (about 1/4 down the page). Very similar aberrations to yours .
http://translate.googleusercontent.com/translate_c?hl=en&ie=UTF-8&sl=de&tl=en&u=http://www.astro-foren.de/showthread.php%3Fp%3D39697&prev=_t&rurl=translate.google.com&usg=ALkJrhjHRm1Z77rb9BDnkG2mFqTplNq akQ#post39697

[wasyoungonce]

Hi David.

Thanks for the linky...I've been looking at Wolfgang's site a bit. He did a test of the early 127ED's. I don't think his appraisal was too endearing. However this test was done quite awhile ago ..I think the early Meade 127ED and I've seen worse performers from this test reports.

Probably the main thing is browsing his site and looking at the tests...my optics are performing no better than some achromatic's ATM.

Anyway..its done & dusted...already on the big steel bird on its was to China.

I can only say that gilman's response has been 1st class. He said they will repair/replace..then I asked if they have "upgraded optics"..he replied and said no..they are replacing in any case.

I've had a good look at the lens cell. It has 2 pairs of grub screws (120degrees apart) that act radially on individual lenses. They position the rear 2 lenses radially. There are a set of front grub screws and they appear to act radially as well ..there does not appear any lens cell tilt. probably not needed of you can adjust each lens individually.

So ...its now a waiting game.

Oh ..aaand I was thinking...nice crisp cardboard chardonnay!:lol:

[DavidU]

Ah yes ! Chateau' de Cardboard ! I have a nice vintage of this.....March!:lol:

[adman]

Cardboardonnay - also known as shuddernnay!

[wasyoungonce]

Found an optic interferometer test of the ES 127ED, here (http://translate.googleusercontent.com/translate_c?hl=en&sl=it&u=http://astro.uni-tuebingen.de/%7Egrzy/APO.html&prev=/search%3Fq%3D127ED%2Bstar%2Btest%26 start%3D10%26hl%3Den%26sa%3DN&rurl=translate.google.com.au&usg=ALkJrhghZvIoG3Z6yFJbJZ4FBji_Z5f 88w). (Top of page) Haven't had time to read it all or who did the test ATM. It's Wolfgang Grzybowski's site not Wolfgang Rohrs site..

Edit:
Annnd at the very bottom of the page he appears to be shimming radially exactly the same lens cell as the 127ED. Obviously he found an issue with radial adjustments and shimmed to correct...I wonder?

[DavidU]

that's a very good report indeed. It's German.

[wasyoungonce]

It does look ok...better than the earlier Meade 127ED report he did (un-known date) half way down this (http://translate.googleusercontent.com/translate_c?hl=en&sl=it&u=http://astro.uni-tuebingen.de/%7Egrzy/9.html&prev=/search%3Fq%3D127ED%2Bstar%2Btest%26 start%3D10%26hl%3Den%26sa%3DN&rurl=translate.google.com.au&usg=ALkJrhh7G_PGQTHMjbKBO4AJISBaxmD sgg) page.

He appears to work for Tuebingen Uni (http://astro.uni-tuebingen.de/). Looks as if he has tested lots of scopes from RCOS to the ED80.

Interesting..but "I no nothing..." of German!

Would love to find out why he shimmed the optics of the127ED? Lord his pages are hard to navigate!

[wasyoungonce]

Ok for anyone who's interested in the 127ED.

This gent Wolfgang Grzybowski's tested a 127ED scope under the generic name "OMEGON" (http://babelfish.yahoo.com/translate_url?doit=done&tt=url&intl=1&fr=bf-home&trurl=http%3A%2F%2Fastro.uni-tuebingen.de%2F%7Egrzy%2FAPO.html&lp=de_en&btnTrUrl=Translate) (at the bottom of the page). He had big troubles with it with: coma; astigmatism; and what appeared as a flare (blue/violet) (I'm reading into that but his pics show this was happening).

To give you an idea of how bad it was..the Strehl was .17!:( and the rest of the figures were poor as well.

He inserted new spacers, re-shimmed & adjusted the lenses and ended up with Strehl of .93. Much better.

This looks pretty much as what I was getting in my scope. I was also getting funny shaped stars across the field with coma and flaring.

It appears he liked it after he did the adjustments.

I hope mine (lens cell) comes back as good as this?:D

edit:

It appears..l (http://www.astroshop.de/blog/?tag=omegon)ens spacers (http://au.babelfish.yahoo.com/translate_url?doit=done&tt=url&intl=1&fr=bf-home&trurl=http%3A%2F%2Fwww.astroshop.de %2Fblog%2F%3Ftag%3Domegon&lp=de_en&btnTrUrl=Translate)are available (or suggested) in Europe as a retro fit for these lenses. He also appears to have some commercial interest in this OMEGOM brand as they listed his Optics adjustments "guaranteed performance" from the astroshop.de selling these scopes. Thus he must test and adjust each scope.

[JohnH]

Arghh! Brendan,

I just caught up with this thread - and I feel awful - the advanced focuser made things worse - I am so sorry - quite happy to swap it all back and give you a refund mate.

On another note great that you have gone into this so deeply and good that gilman is responding too.

Re-spacing a triplet lens is not for the faint hearted that is for sure...but I am intested to see how your scope goes after a factory calibration (or replacement), as I read it getting the three lenses just right is a black art - rotating each element independantly and re-testing each time to get a best result - eeek.

John.

[wasyoungonce]

Hi John.

No it's not the focuser. Your offer is thoroughly decent...but the original focuser had off axis issues as well.

I managed to centre/tilt adjust the advanced focuser somewhat to get nice flat field analysis and centred optics..happy with that. Yet the scope still showed coma (actually astigmatism) and chromatic flare.

This German site shows that indeed these issues are due to the lens spacing and adjustments. He appears quite thorough and not superfluous on his words but it does appear he tests scopes for astroshop.de (and vegaoptics.de)... so be careful of commercial relationships and their tests! That said..I'd be happy with an expert backing the scopes I am buying and they appear to be guaranteeing results.

It's indeed a learning curve but I wouldn't have it any other way! The only way to learn is to make mistakes! It makes interesting reading for those who have the scopes.

I'm sending Gilman some info from this site. I don't know Gilman's position in Hioptic/Northgroup..aka is he a technician? So, I don't know if this will be well received nor passed on.:shrug:

[wasyoungonce]

Update: New lens cell being sent out to me.

Gilman said that my lens tested ok on the optical bench but stated something along the lines that... "yes we know you have trouble with it". It's difficult to tell in translation..and they might not want to say to me "you're an idiot" or "yes there is an issue"?

So, I cannot state what they are thinking wrt to my cell but in short they are sending out a new cell.:thanx: Gilman has been very helpful. I cannot fault their assistance or customer care.:thumbsup:

I have trolled CN and it appears "only one" other user had a similar issue to me. I got to say, out of hundreds ~ thousands of these being sold around the world (under different names)...that's pretty damn good.:2thumbs:

I'll post back when its up and running ...and the damn clouds clear.

[Sylvain]

Hey everyone,

I was just wondering if any of you know whether Gilman and North Group are able to supply the 102 apo refractor?
Their alibaba page mentions only the 80mm and 127mm, but I would rather get the 102 as it's less bulky than the 127 but offers more aperture than the 80.

Any feedback would be appreciated!
Cheers ;)

[wasyoungonce]

Received new lens cell from Northgroup yesterday. A big thanks to Gilman on this. They bent over backwards in helping me.:thumbsup:

Managed just a little peek at the sky last night before clouds rolled in. The air was quite turbulent so tests are taken as a grain of salt. However it looks very encouraging. Acid test..Venus. Small amount of fringing...60% less than previous. This (fringe) is expected given Venus is so bright at the moment.

Moon shots came up quite good and some focusing tests good as well. Here is a small de-focused test on Beta Centauri..which is a very blue star. The main thing is that fringing is pretty much concentric with the star.

I tried to snap the ptolemy cluster but clouds beat me and I didn't get focus accurately..so maybe next time. There is still some fringing but as I said it's concentric with the stars which is encouraging.

[DavidU]

Looking good !

[Octane]

Fabulous news, Brendan.

Can't fault Gilman for service.

He emailed me and was asking what to do with your case. I asked if a replacement lens cell had been sent out and at the time he said he would send one shortly.

H

[wasyoungonce]

Gilman has been just great. It certainly shows their thirst for consumer confidence in their products. As I said there is only one other case of someone else who wasn't that happy with their lens performance (their scope was replaced..an ES product). Of all their scopes sold around the world...that pretty good.

The main difference I saw with this lens is that that any chromatic aberration was concentric with the stars. I wanted to take some snaps of the Ptolemy cluster as it has a high grouping of quite blue stars.

Venus is an acid test for any refractor and I'd expect some fringe on this. I noticed the moon pics showed less fringe.

Hopefully the clouds will clear and I can post more results soon.

[DavidU]

It is great of Gilman. It's unusual as I had the money for a 127 but gave up trying to get hold of him.

[JethroB76]

:lol: He asked for your advice in dealing with another customer?

Great result btw

[Octane]

Jeff,

Yeah, it's happened a couple of times now.

I've forwarded a lot of people his way, and, so he somehow respects my opinion -- despite me knowing absolutely zilch about optics. It's gold. He's offered to send me out accessories and what not for my help. So sweet, lol.

H

[wavelandscott]

Not to detract from the good service and outcome in this instance but do be careful with your generalization and assumptions...not that I know otherwise either but the insertion of "to my knowledge" might be a good addition to your statement.

I'm glad it is all working out and that you are happy (as it seems are others).

[JethroB76]

:lol: That's awesome- you scope guru!! :prey2:

[wasyoungonce]

Hi H...Thanks.....I kinda guessed that they were at a bit of a loss what to do about this all. Thanks for the input.....Gilman thinks highly of you...the class favourite :P.

The lens cell is probably most expensive part so replacement is not done frivolously.

I guess they are also not really set up for repair/replacement...so it was new to them as well.

Anyway..when the clouds clear...more play!

[wasyoungonce]

Point taken...although it's well known that the unhappy make the most noise...internet noise that is;)

[netwolf]

I have found Gilman will eventuall respond, sometimes it just takes some time. Unfortunately havent got around to saving enough penies to buy anything yet.