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New Focusing Aid

George

By George
in Imaging - Discussion

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George

George

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Billy if you don't mind please :mrgreen:

SW ED80

OD 115mm
FL 600mm
F/7.5

SW 250

OD 285mm
FL 1200mm
F/4.7

Also you say using a different gas will discolour the stainless, shouldent matter because it would be prudent to paint matt black anyway to minimise reflections.

Again I would go for the cheaper option (not cos i'm tight but because I'm absolutely skint) :laughing2: :laughing2:

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Psychobilly

Psychobilly

Posted
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Here are the laser cut prototype for my CPC800 and my Skywatcher Equinoxe 66...

Cut in mild steel rather than stainless so taht I can try then unfinished and painted black...

If I ever get a clear night :clouds2:

8275_normal.jpeg

(click to enlarge)

Billy....

I'll just have a bite to eat than i'll do the two masks templates that I have promised...

Here's some test images that Reggie took using a plastic mask made from one of the earlier templates.

8276_normal.jpeg

(click to enlarge)

Thanks Reggie - I'm still waiting for clear skies :)

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Psychobilly

Psychobilly

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Here's a Third Order Mask For Tal 2M as requested...

8277_normal.jpeg

(click to enlarge)

For Reflectors can people include a rough OD of the Central obstruction... I am adding cros hairs at the center of the mask and people can then adjust to suit.

For manual cutting I am generating third order masks as there are less and wider slots so teasier to cut...

Billy...

On to your's next George :clouds2:

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Psychobilly

Psychobilly

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You need a sheetmetal company that has a CNC laser or water jet cutter... and need the drawings in a form that they can work with. I do all the drawings in Autocad but only post "jpegs" for people to hand cut.

Depending on the results people get I was planning of pricing up having them made as I have a local company that has all the equipment needed. ( they made my prorotypes for me today one for the CPC800 and one for the Skywatcher equinox 66)

Billy...

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Psychobilly

Psychobilly

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The Skywatcher 250 mask has now been split into 2 halves so that i can print on A4 the pdf's are here...

http://www.btinternet.com/~psmithuk/Focus_Masks/Skywatcher250/PS_SW250_LHS.pdf

http://www.btinternet.com/~psmithuk/Focus_Masks/Skywatcher250/PS_SW250_RHS.pdf

If these work i'll upload all the other masks splitting as necessary over the next few (rainy) nights

Billy...

Here are the others that fit A4...

http://www.btinternet.com/~psmithuk/Focus_Masks/Tal_2M/PS_TAL2M_Fullsize.pdf

http://www.btinternet.com/~psmithuk/Focus_Masks/Skwatcher_Equinoxe_66/PS_SWE66_Fullsize.pdf

http://www.btinternet.com/~psmithuk/Focus_Masks/Skywatcher_ED80/PS_SWED80_Fullsize.pdf

Thats all for tonight folks...!!!

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daneel

daneel

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Converted the bitmap into an SVG file readable by inkscape, so you can stretch the image to fit your scope. Had to rename it filter.jpg, so all you need to do is rename it back to filter.svg and install something like inkscape that speaks vector graphics.

No good at cutting things out or making things - perhaps my wife could knit me a Hartmann filter? Is this shape too complex to cut out of pizza boxes?

How did you mount the discs on your camera and scope Billy? Can't make that out from the pictures.

post-13879-133877346208.jpg

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Jeff RV

Jeff RV

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Much cheaper version, http://home.comcast.net/~dandkmccrady/Articles/FocusMask/FocusMask.htm

:) Think about it!! I really can't see the results of this being any different to be honest.

Correct me if i'm wrong, but isn't this a bit of an expensive gimmick?

Jeff.

They needn't be that expensive...

I do all the "cad" work myself minimising the programming time....

An 8 foot x 4 foot sheet of 0.8mm stainless is round £50 and you can get a load out of that...especialy if you nest different sized masks onthe sheet.

If you laser cut using compressed air rather than nitrogen it helps keep the cost down but with some

"staining" of the metal around the cut..

If you can get away with unfinished stainless then thats obviously cheaper...

It will be interesting to see how they work the "videos" show how they masks allow you to get critical focus very easily. I have tried rough cut masks and they are ok.. the precisely cut stainless ones I have had made in the past are much better as you get very good merger of the sub "images" at focus.

I am extremely fortunate in that I get my "prototypes" cut for free...I always offer to pay for materials and machine time but usually a contribution to the Coffee fund is all thats required...

Billy...

1000mm F5 comming next as soon as someone posts the OD of the OTA :p

A sheet of stainless is not that expensive then 8) , 12" for an LX90 may be!! :)

I've only got a hacksaw :clouds2:

Jeff.

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Jerry3672

Jerry3672

Posted
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Pricing is horrendous, it's not even his idea, if it were the original guy (Pavel) who was selling them at that price I'd be tempted because he's a small man with a great idea trying to scratch a living, but I'll be damned if I'm lining someone elses over stuffed pockets on this one. I believe all of the data is open source according to spike-a's legal team, If I make my own I'll definitely make a donation to pavel directly if at all possible.

Hi all,

I

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Jerry3672

Jerry3672

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Hi all,

I am the one on cloudy nights that made the first Pavel Bahtinov style focus mask. I am also the one on the Russian forum that is hosted by Pavel. I have offered Pavel my math formula that is much easier for the do it yourself guy that Pavel likes to help.

Part of the money collected for the mask will go to Pavel just as I stated on cloudy nights on day one when several people asked for me to make them masks. He deserves the credit as the designer and a royalty fee.

The TM for Spike-a is for the trade name of a Bahtinov style mask. Please read the Russian posts from Pavel. you will see he have many different variations.

It looks like a few others are going to make Bahtinov masks for a fee. I hope they do as www.spike-a.com has done by crediting Pavel Bahtinov as the designer and sending a proper royalty

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Reggie

Reggie

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Hi Jerry, As soon as I've done some conclusive testing and it proves to be as good as is claimed I'll make a donation, no worries there. Not sure exactly when that will be though, I need to setup all of my hardware and the software to compare with the mask and get some decent clear nights to do it all in, lets hope its this side of christmas, eh? :clouds2:

Please pass on to Pavel my sincerest thanks for giving out the information on the 'Bahtinov Mask'. It's not every day you see what could be a truly useful item that isn't going to cost the earth to own.

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Psychobilly

Psychobilly

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Hi Jerry,

No problems with crediting and "paying" just wanted a couple of different people to try out the templates I have been generating on different scopes to make sure I had captured any critical aspects of the design.

It's just that I have acess to the CAD and contacts that have the necessary equipment laser cutting machinery to produce accurately cut masks in variety of materials - its not cost effective to produce one-offs so would have to get a sheetful done in one hit - the sheet could have any combinations of various designs nested to get maximum usage out of the material.

Potentially the largest cost is machine/programming time as the machine runs 2 shifts per day at my contacts firm. I do the CAD and sheet layouts to reduce the time that the machine operator has to spend "programming" the machine- It's a case of importing the Acad Drawings and processing throught the CAM software to check for any errors and set the overall cutting order etc.

Billy...

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