Gina's Esprit 80ED Pro Unboxing and First Impressions

[JohnC64]

It's the reflections!!!

Olly

I now have an image in my mind of  a '60s doo-wop band playing in the corner of Gina's Obsy

[Gina]

I can only think that the light cone is different to what you have had before and is hitting/reflecting off  something in the telescope/sensor lightpath.

Yes.  Reducing the aperture at the front of the lens cell to 60mm certainly stops the effect - I guess the next thing would be to try a 70mm aperture or whatever and see just how much it needs stopping down to cure the problem.  I wonder if I have anything with a 70mm or 75mm hole in it.  I don't think I could cut an accurate enough hole by hand.  When my lathe comes it may be a different matter

Edited November 16, 2013 by Gina

[ollypenrice]

You just need a strip of wood with a pinhole in one end, cut to the length of circle you need. Just pin this to a piece of card via the pinhole and use the outer end as a guide for a Stanley Knife or whatever.

Olly

Elegant refinement;

You don't need two lengths of wood for the inner and outer radius.

You don't????   

No! You just need two pinholes!!

Bu-bum.

Edited November 16, 2013 by ollypenrice

[swag72]

Are you planning on having to use a mask all of the time then Gina or is this just diagnostic to then return it for fixing?

[Gina]

Are you planning on having to use a mask all of the time then Gina or is this just diagnostic to then return it for fixing?

This is diagnostic at present.  I'm still hoping there will be something I can do to fix it but it isn't looking very hopeful.  In the worst event I may have to get a replacement.  I would like to stay with this model of scope as it would seem to fit my requirements nicely.  No way could I afford a Tak this winter.

[Gina]

You just need a strip of wood with a pinhole in one end, cut to the length of circle you need. Just pin this to a piece of card via the pinhole and use the outer end as a guide for a Stanley Knife or whatever.

Olly

Elegant refinement;

You don't need two lengths of wood for the inner and outer radius.

You don't????   

No! You just need two pinholes!!

Bu-bum.

I have a tool somewhere that I used to cut large round holes in plastic boxes.  It's basically a craft knife on a scale with a pin point for the centre.  I'll see if I can find it

[Gina]

It will be interesting to see just how much aperture reduction is needed to cure the problem.  I'll make a series of aperture masks to try next clear night.  I'm also just wondering if the flattener might just cure it but I guess that's just grabbing at straws

Edited November 16, 2013 by Gina

[Alien 13]

This is diagnostic at present.  I'm still hoping there will be something I can do to fix it but it isn't looking very hopeful.  In the worst event I may have to get a replacement.  I would like to stay with this model of scope as it would seem to fit my requirements nicely.  No way could I afford a Tak this winter.

I am sure your findings will be very helpful to a lot of people it would have been so easy to say opps its broken get a replacement but understanding whats going on is relevant to any refractor, i take my hat off to you for your efforts.

[FLO]

Can I just say, Gina is experimenting because she wants to. Not because she needs to

We have a replacement Esprit-80 put aside for her, should she decide to accept it. She also has the option of a full refund. 

Gina, we don't mind you dismantling the telescope and experimenting so-long as you don't remove or adjust the lens cell. Please

HTH, 

Steve 

[ollypenrice]

I think that a very small stopping down will do it. That's my hunch anyway. I don't think the flattener will help.

Olly

[Gina]

Can I just say, Gina is experimenting because she wants to. Not because she needs to

We have a replacement Esprit-80 put aside for her, should she decide to accept it. She also has the option of a full refund. 

Gina, we don't mind you dismantling the telescope and experimenting so-long as you don't remove or adjust the lens cell. Please

HTH, 

Steve 

That is quite correct - I like to find answers if I can.  If this is something relatively simple that I can fix myself I'd be very happy.  However, ATM it doesn't appear to be and I'm doing some serious thinking.

Thank you for putting an Esprit aside for me Steve - I much appreciate you superlative service

I won't remove or adjust the lens cell Steve - this is a very critical thing needing specilised equipment, that I appreciate.

Cheers

Edited November 16, 2013 by Gina

[swag72]

If you are using an aperture mask and the problem sorts out, would this not be a design issue that would apply to all of the scopes? Surely whatever is causing it would be the same in all of the scopes?

[Gina]

I think that a very small stopping down will do it. That's my hunch anyway. I don't think the flattener will help.

Olly

I think you are probably right on both counts.  If the problem exists in the optical path ahead of the FW as it appears I can't see how a flattener could change it. 

The FW, filters and camera have all been used with camera lenses of shorter FL and therefore steeper light cone as well as with other telescopes, so I can't see those being the problem.  The lenses mostly have 8 bladed irises and produce 8 points when stopped down but round stars at full aperture.  So the conclusion must be that the problem is in the telescope.

Edited November 16, 2013 by Gina

[Gina]

If you are using an aperture mask and the problem sorts out, would this not be a design issue that would apply to all of the scopes? Surely whatever is causing it would be the same in all of the scopes?

Well it can't be a design issue of any importance or, as you say, it would apply to all Esprit 80EDs.  So I have to come to the conclusion that the problem lies in this particular sample and is a QC issue.  As Steve says, FLO are testing all Esprit 80EDs they are supplying before dispatch, so they are applying further QC at no extra cost.

[Gina]

Findings from my testing and observations :-

1. There are no reflecting surfaces within the light path.
2. There are no intrusions into the light path.
3. The filter wheel and adapters with 460EX camera have been used with other scopes and also with lenses and apart from irises in the lenses when stopped down, there's no problem.
4. When the scope is stopped down from 80mm to 60mm with an aperture mask in front of the lens assembly the problem disappears.

The conclusion from 1. 2. and 3. is that the problem lies with the telescope.  No. 4 indicates that this is probably caused by some problem with the lens system.  Without actually dismantling the lens unit there is no way of telling what.

I could mess about with aperture masks and find out how much aperture reduction is required to cure the problem.  But what help would that information really be?  I guess if it were to turn out that a 79mm aperture mask cures it, that would be very little change in focal ratio and would render this particular telescope useable.  But would even a slight stopping down at that position upset the optical design?  I think it could well do. 

The bottom line is "Am I happy to go on messing about, spending time and effort on a long shot?"  No I am not.

The conclusion then after weighing up all the probabilities is that I will ask FLO for a replacement telescope.  I am satisfied - quite happy in fact - that this model of scope will provide what I want and therefore a replacement is my choice.

I would like to thank Steve for his patience in this matter

Edited November 16, 2013 by Gina

[ollypenrice]

Good decision. Still thinking aloud, what about defective edge blackening of the lenses? Like you I like to get to the bottom of these things.

Olly

[Gina]

Good decision. Still thinking aloud, what about defective edge blackening of the lenses? Like you I like to get to the bottom of these things.

Olly

I couldn't see anything.  I would have liked to have pinned down the exact cause but it wasn't possible.

[Gina]

Later on last night the skies cleared so I decided to have a go at M42 unguided.  Being low in the sky, and without finished PA, longer subs produced star trailing so I limited it to one minute subs.  In the end the cloud came back and I only managed about 10 subs each of Ha, OIII and SII.

Here's the result then of 11 x 1m Ha, 10 x 1m OIII, 10 x 1m SII all unbinned.  Stacked in DSS, stretched in Ps, aligned with Registar and the rest in Ps.  SII -> Red,  Ha -> Green, OIII -> Blue.  Histograms balanced and Selective Colour applied to give the Hubble palette.  Noel's Actions were used profusely to reduce the stars, enhance the DSO, sharpen and reduce noise.  Selective Colour used to kill the magental in the stars as far as possible.  The image was cropped to just the centre part with just under 1200 pixels wide for uploading here - there was no resizing so it's pixel for pixel.  Saved as PNG for optimum results.  Considering the defective telescope, short exposures only  - no long ones to catch the fainter stuff etc. I don't think this is too bad.  Bright moon too.

EDIT... Well it looked a lot better in Ps

Edited November 16, 2013 by Gina

[FLO]

The conclusion then after weighing up all the probabilities is that I will ask FLO for a replacement telescope.  I am satisfied - quite happy in fact - that this model of scope will provide what I want and therefore a replacement is my choice.

No problem

I'll phone to make arrangements when we re-open Monday.

Good decision. Still thinking aloud, what about defective edge blackening of the lenses? Like you I like to get to the bottom of these things.

Olly

That's my hunch too Olly. The other Esprit-80 are producing nice round star shapes so I am guessing Gina's has an obstruction or reflection somewhere in the light path. I have reserved an Esprit-80 for my own use but I'll probably use Gina's instead. Hopefully we'll solve the mystery

Steve

[Gina]

Thank you Steve - I look forward to hearing from you

I shall be very interested in your findings

Cheers

[dmahon]

What happened to Gina's scope - was it a one off problem?

[FLO]

We hope so  

Gina has kindly offered to test an adapter we are preparing for market that will (should) ensure her camera is placed precisely at the correct distance. I am driving to Gina's tomorrow or Wednesday with another Esprit-80 (for comparison) and the adapter. 

HTH, 

Steve 

[Gina]

Thank you Steve   And for your phone call yesterday

[Tinker1947]

Well i hope there's tea and jaffa cakes to refresh you when you arrive...

[Epicyclus Dave]

Special pick up's require frothy latte & Fox's choc cookies