#21  
Old 19-08-2010, 07:21 PM
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GrampianStars (Rob)
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Quote:
Originally Posted by wasyoungonce View Post
Anyone used a WO type II with a 127ED or scope of similar FL (F7.5, 952mm)?
What about the Orion unit
https://www.bintelshop.com.au/Product.aspx?ID=8586
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  #22  
Old 19-08-2010, 07:24 PM
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mill (Martin)
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[QUOTE

I'll have to wait till I get my Lens back..and the clouds in Melbourne clear......yeah like that will happen![/QUOTE]


Yep it doesn't look good for the coming week too.
I am getting withdrawal symptoms
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  #23  
Old 19-08-2010, 07:54 PM
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wasyoungonce (Brendan)
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Originally Posted by GrampianStars View Post

To be honest I didn't even consider this one.

I have read that it works well and it certainly would appear to suit regarding the FL. Although, like the TV unit I believe it needs adaptors for 2" ..I don't see any available?

It's also kinda in the price bracket of the WO & TV units...competition is stiff!

On a plus side it's rated as a .85X reducer which is probably around the reduction I was after..the "goldilocks" reducer...not too much...not too little.
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  #24  
Old 12-10-2010, 06:43 PM
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wasyoungonce (Brendan)
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Well....after much procrastination and penny pinching I purchased the TV .8 reducer RFL-4087 and accessories.

Why this one?...well...I wish I had the ultimate answer in few words but suffice to say...mfgrs name; accessories; reviews; but not price. Although I must say with the $Aust as it currently is..this tipped the hat.

I'll post back when I can do some tests.


Thanks for all the help gents.
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  #25  
Old 12-10-2010, 07:36 PM
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mill (Martin)
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Quote:
Originally Posted by wasyoungonce View Post
Well....after much procrastination and penny pinching I purchased the TV .8 reducer RFL-4087 and accessories.

Why this one?...well...I wish I had the ultimate answer in few words but suffice to say...mfgrs name; accessories; reviews; but not price. Although I must say with the $Aust as it currently is..this tipped the hat.

I'll post back when I can do some tests.


Thanks for all the help gents.

Good luck with the test, raining now
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  #26  
Old 12-10-2010, 08:02 PM
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wasyoungonce (Brendan)
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Good luck with the test, raining now

Hi martin....Sigh! ..don't I know it . It's the way of it.
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  #27  
Old 25-02-2011, 10:27 AM
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Update on TV RFL-4087 reducer with 127ED

Alright an update, all is not going well with the reducer! I have my TV RFL-4087 reducer/Flattener and new ML focuser, so I can now reach in-focus enough to use the reducer.

I have spaced it to 56mm (T ring shoulder to focal plane..just scroll down a little) which is correct according to TV site . I even called them to confirm that this is the method for measuring this spacing.

TV said that by using this FL reducer and their T ring adaptors will naturally achieve the correct 56mm spacing for a DSLR.

So I did all that and...no go. The stars are not pinpoint at the edges, they are not gross but they are not pinpoint either.

I suspect I may have to shorten this spacing..which will be a real pain. I found I can create a 1mm shorter T ring spacing by disassembling the TV T ring and building a Frankenstein version from the parts of other T ring adaptors.

So I'll fiddle with spacing and report back...in the mean time..pulling my hair out at the thought that this reducer may be incompatible with the 127ED!

Last edited by wasyoungonce; 25-02-2011 at 01:18 PM.
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  #28  
Old 03-06-2011, 11:30 PM
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So Brendan, how did the "frankenstein" version work AFA the TV reducer vs 127mm OTA work out?

Cheers
Bill
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  #29  
Old 04-06-2011, 08:30 AM
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Well I still have some field curvature but I believe that is mostly due to focuser alignment as it is mainly in the lower 2 quadrants. The upper 2 are quite good at std spacing. I posted images of all this on the yahoo 127ED forum.

I have not had time lately to play with it.

But I get the feeling no flattener/reducer really works 100% with the 127ED triplet. Unless of course they (the OEM) release one.

I need to collimate my focuser and re-do the test. So I need a LASER to align it. Did anyone say...cash flow issue!
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  #30  
Old 04-06-2011, 01:20 PM
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AAah! good to hear that it's actually workable!

The MoonLite you have can be collimated - I see!
Are you saying you need a normal laser collimator like those used in newts collimation? IF yes, PM me your address and I'll send you mine and you return that to me after you're finished with it - it's supposed to be collimated already etc and I've used it a few times on my 12" dob but it hasn't been used for anything else now for the last 8 months!!

HTH
Cheers
Bill

Quote:
Originally Posted by wasyoungonce View Post
Well I still have some field curvature but I believe that is mostly due to focuser alignment as it is mainly in the lower 2 quadrants. The upper 2 are quite good at std spacing. I posted images of all this on the yahoo 127ED forum.

I have not had time lately to play with it.

But I get the feeling no flattener/reducer really works 100% with the 127ED triplet. Unless of course they (the OEM) release one.

I need to collimate my focuser and re-do the test. So I need a LASER to align it. Did anyone say...cash flow issue!
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  #31  
Old 04-06-2011, 01:24 PM
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wasyoungonce (Brendan)
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Hi Bill that's a kind offer.

PM sent.

Brendan
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  #32  
Old 14-06-2011, 12:09 PM
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Heads up on progress.

Just used Bills LASER collimator and centre spot of refractor with lens off. Thanks a million Bill.

LASER spot was 10mm left and 5 mm high (view from front of OTA), so yep focuser alignment was out.

All fixed now (adjusted the CFL focuser) so we shall soon have some results on the reducer again. I did note that applying around 2kg force to the draw-tube caused the LASER spot to move around .5~1mm. This is way more than my camera mass force but I didn't expect this.
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  #33  
Old 29-06-2011, 12:21 PM
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Ok the final word on the Televue RFL-4087 .8X reducer flattener on the 127ED.

It fails.

I aligned my ML focuser to the OTA using a LASER (thanks very for the loan from a fellow IIS member Visionoz) and the results, while improved are probably only acceptable in star elongation to around 70% out from the centre.

This image is a corner crop but it gives you an idea of the best I can wring from the reducer flattener. F6 imaging looks great with this scope (with the reducer fitted) you get a whole lot more sky real estate but the damn star elongation is a real off put. I'll still use it but crop out the offensive areas...which kinda negates the reason for a reducer.

Thus I do not recommend the Televue RFL-4087 .8X reducer for this scope. Looks like we have to wait for the OEM to get their act together. Sigh....(That was an expensive mistake) ...if ever at this rate.

regards

Brendan
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  #34  
Old 30-06-2011, 08:16 AM
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Brendan

Are you sure your issue is not with finding the "ultimate" correct spacing for this reducer/flattener?

Cheers
Bill
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  #35  
Old 30-06-2011, 09:04 AM
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wasyoungonce (Brendan)
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Hi Bill.

I previously looked up the TV site and found the correct spacing which is 56+/-2mm. I even called TV USA on the phone to confirm this.

I also have the TV spacer kit TLS-2245 which has various spaces from 1mm, 2mm to 25mm and have tried combinations of these, photographically, unsuccessfully. I went so far as to make a hybrid T ring that was 1.5mm shorter focal path length and this didn't work as well.

I found the optimum spacing with the least star elongation was at the published spec distance. However, my stars are not pinpoint at this and are worse at any other spacing distance. At this optimum spacing they are not grossly elongated at the edges, in fact they are probably better than the native focal length edge stars.

I purchased this unit as others had reported that the other major FL reducers like WO etc did not work with the triplet. The Astrotech type II and Hotech field flatteners apparently work very well but I was after a reducer flattener.

I got to say...at F6 the image FOV is ..to coin a phrase "most excellent" and enticing.

I'll still use the reducer but crop out the offensive areas which kind of negates the usefulness of the reducer.
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