Super cheap Bahtinov mask cut for you. Choose from MDF or Acrylic

[ozstockman]

Hi guys,

I am offering these fantastic Bahtinov's focusing masks for sale. If you don't know much about these masks please read about them here (http://www.iceinspace.com.au/forum/showthread.php?t=35676).

They are cut to your size and requirements using precise computer controlled 50W laser.

I also promise that they will be affordable to anybody. At this point I can cut them from either 3mm MDF or from 2 or 3mm black colour acrylic panel(non transparent). See attached images.

A mask from MDF will be cheapest you have ever seen and acrylic one will be still cheaper than from anybody else.

Once your MDF mask is cut I give it good sanding in case you want to paint it.

They don't come with any mounting solution to keep the price as low as possible. However you can order the exact size as your tube internal diameter so the mask will sit tight. Otherwise you can use Velcro for mounting.

I have contacted Pavel Bahtinov and we have agreed that he will get a commission from me for each mask I will sell. I guess he deserves it as he has invented this fantastic masks.

Below are special prices for registered members of the following astro communities

www.iceinspace.com.au (http://www.iceinspace.com.au)
www.cloudynights.com (http://www.cloudynights.com)
and the following
yahoo groups
EQMOD
VC200L
Stark Labs Astronomy Software

Prices

MDF Mask prices are based on your scope aperture and it is $1.5 per each full inch for registered members of the websites listed above and $1.80 for everybody else.


Acrylic mask prices are also based on your scope aperture and it is $2.20(2mm) and 2.80(3mm) per full each inch for registered members of the websites listed above and $2.40(2mm) and $3(3mm) for everybody else.

Black acrylic is a bit reflective but it doesn't create any problems for focusing. If it does for you sanding will remove this problem completely. Moreover masks come with one side covered with protective paper that can be peeled off if you don't need it.

Generally 2-3mm acrylic can be broken by hand if you bend it hard or throw it many times on concrete flooring. However even when it's broken it usually doesn't fall apart and can be used over and over again.

2mm acrylic mask will be more than ok and strong enough for scopes from 3"-6" and sometimes even for lager ones up to 8". I cut one for my Vixen 8" VC200L and it's still quite strong. However if you need stronger one I would recommend a mask made from 3mm acrylic.



Discounts

If you need more than two masks I can give you a discount and I will combine shipping to keep shipping cost as low as possible

Shipping

Shipping cost to any address in Australia via regular post will vary from $1.10 to $5.60 and depends only on your mask size and its weight. Registered, express and insurance are optional.


Payment

I accept both PayPal or bank deposit to my account in ANZ

How to order

If you want to order a Bahtinov mask please PM me the following details
- your scope clear aperture.
- your scope focal length
- outer diameter that you need.

If your scope has a secondary mirror at the front I would recommend to leave a solid centre on your mask. It doesn't affect focusing while it makes a mask much stronger. If you want to have it you will need to measure your scope secondary mirror holder diameter and let me know the result along with all other details. The solid centre diameter shouldn't be exactly the same as the holder one. You can even make it less 3-5mm. You can check the last picture to see an example how it's done on my VC200L OTA and what the mask looks like with and without the centre.

If you are not a registered member send me an email to ozstockman at gmail dot com


* 11" is a maximum I can cut in one piece as it's close to the maximum working area of my laser machine wich is 12"x24". External diameter of your 11" mask should not exceed 11.8".
However if you happy with a mask made from more than one piece that can be connected and glued together there is no limit.

I also can cut any other complex shapes. Please PM me.

Added:
-Price is based on an aperture of a scope not on an actual size of your mask which is always be wider. So don't try to pay me more than it costs :-)
- For scopes that have an aperture which isn't a represented by a whole number in inches it's rounded up to the closest one. I.e. a price for ED80 which is 3.15" will be 4x$2.20=$8.80 for 2mm acrylic and 4x1.50=$6 for MDF. I guess it's fair as the actual mask size is much over 3.15" and even over 4" considering that there is some border added to the mask based on your requirements. This only affects price calculation for your mask. Don't forget to mention the actual aperture of your scope and focal length as it's all required for generating correct cut pattern for your scope.

I have sold out all previous stock of 3mm black acrylic and new stock of 3mm black acrylic panels comes with plastic protection which is transparent. I still have old 2mm thick black acrylic panels which have non-transparent protection as shown on the pictures.

[Dennis]

That is a very decent gesture Mike and I applaud you for your personal integrity and business ethics in acknowledging the “inventor” in this manner.:thumbsup:

Cheers

Dennis

[TheDecepticon]

I'll take one for my 200mm Bintel reflector. I'll pm you tomorrow with the tube size and the secondary hole size. MDF would last longer possibly, but the acrylic would be more water/moisture proof. Is a direct bank deposit ok? Thanks.:D

[Octane]

Mike,

Fantastic! I'll put an order in for 3 masks soon.

Regards,
Humayun

[ozstockman]

Thanks Dennis. I guess it jus a way it should be. I know that some guys from USA offered comission as well but I have no idea whether Pavel has accepted it or not.

For me it wasn't hard to convince him because we speak the same language :-)

[ozstockman]

yes, direct bank deposit is even better as there is no fees for me.

Just a small note on providing complete details for ordering. When you order please send me the following details

your scope aperture
your scope focal length
outer diameter of your mask.

Some of the guys who has already PMed me are mentioning model numbers like ED66. Yes, being in that area I can guess that 66 stands for aperture but it's better if you confirm it along with a focal length.

Regarding outer diameter of your mask, it is really up to you and I guess only depends on how you want to mount this mask. If you want to keep it inside your tube by just placing it in there it should be as close to your tube inner diameter as possible.

If you want to mount your mask using Velcro I guess it should the outer diameter of your tube.

If you don't know yet there is a online generator for Bahtinov's masks at http://astrojargon.net/MaskGenerator.aspx

If you feel comfortable you can generate your own mask yourself and just email me svg file(s). In this case I need to know only your scope aperture for correct quote. I will cut then exactly what's in the file you send to me. No need to convert svg to anything. It's a perfect file format for cutting using Corel Draw.

Please be patient once you sent me a PM with your order or questions. I will reply to everybody as fast as I can.

[ozstockman]

Regarding the colour of acrylic

I have found a supplier today for black acrylic panels and these guys are close to me. However they are asking for them at least 8 times more than I can get a peach one for.
If I started cutting masks from black acrylic the price per inch would jump to $3. Do you think black colour masks are worth extra 80c?

[troypiggo]

I would have thought 80c more is a pretty minuscule premium in the astro gear world. :)

I'm curious about these and their 3mm thickness. I assume the acrylic is shiny and/or buffed, but don't know about the cut surface finish. Any issues with reflections from light at an angle off the 3mm cut surfaces?

[ozstockman]

It's 80c per inch so for a 10" scope there will be $8 difference in price.

Yes, it's a bit reflective and not 100% non transparent. However it doesn't affect focusing. I have tried to focus on a pole with a very bright bulb 5 kms away from me and there is no difference between a MDF mask and an acrylic one. Both masks work very well.

In terms of transparency, I could get light through with a 8 bright LED torch. But it was placed 70mm from the back of a panel. Once it's moved away further I couldn't see light from the torch at all.

I think I can get 2mm black acylic panels for just a bit more than I am getting peach pannels. In this case it won't affect pricing at all.

Do you think 2mm black would be better?

[ozstockman]

I have just modifed my original post by removing a peach colour mask and adding black ones. Also there are new pictures attached showing a black mask.

Everybody who has already ordered and paid for peach colour acrylic masks can get them as I reserved what's left for these orders. If you ordered and paid but haven't recieved a message from me that your mask are ready you can switch from 3mm peach to 2mm black as they are both sold for the same price.

cheers,

Mike

[g__day]

Can you also do Carey masks? If you're going to offer advanced masks, maybe the Carey mask is a step up from a Bhatinov mask?

[ozstockman]

Hi Mattew,

No problems. I can do them as well if there is any interest n these masks.
However there may be some issues with 3mm thickness of material I'm using. According to http://www.btinternet.com/~gfcarey/careymask.htm 3mm isn't good and it's recommended to use 1.9mm

Also there is a question about copyright. is this design legal to produce? I am not so good at this stuff. At least with Bahtinov's mask I had an idea and I could contact Pavel to arrange all these things.

Anyway I can try 3mm thickness with Carey's mask design and compare it with the same made from something thinner. If 3mm thickness works and somebody wants it I can just cut it. In this case I won't offer a mask itself to avoid any legal issues. I will offer cutting service for any cut pattern that customers want.

Also if anyone has ideas on new mask design but it's required to be tested I can do it. We can find some cheap material like A3 heavyweight paper to keep the cost down and I will cut as many combination of new design as needed for lower fees.

I can cut foam, MDF, pine(tried up to 15mm and it works) and acrylic if it can be cut from panels no bigger than 24"x12". I can even create some complex shapes from thicker foam, wood or acrylic if stacking thinner parts together isn't a problem.

[Sharnbrook]

Hi Mike,

The Bahtinov mask for my C 9.25 arrived today. It was well packed, the turnaround was very quick, it is well made, and the cost was very reasonable. All in all, a first class job, and thank you.

Highly Recommended.

Now I have to try it out.

[GeorgeC]

Try cutting the Carey mask from 1.5mm ABS plastic.

Feel free to make as many masks as you like. Patenting the design would have cost me at least £20000, and I doubt if anyone will make enough of them to get that back.

[ozstockman]

Hi George,

It's just a problem to find 1.5mm plastic here in Melbourne. I have found frosted one for a reasonable price and tried to paint it black but it doesn't work at all.

But anyway if I find something to cut your mask design from and people are interested in it you can still get commission from me. Doesn't matter for me if you haven't patented it :-)


cheers,

Mike

[citivolus]

Question for you Mike: What is the thickness of the cut area from the laser, assuming 3mm acrylic? My aperture is large enough that I need to do a design in two interlocking pieces, so I need to know what tolerance to build in to compensate for lost material in areas where there may be a complex join.

Also, I am assuming that the cut will be asymmetric, with the area further from the laser losing slightly more material. I can work around this by having the second piece mirrored, so that it is assembled by flipping the piece over so that the edges meet up.

Regards,
Eric

[mithrandir]

Hi Mike,

My masks for the C8 and ST80 arrived Tuesday. All neatly packed and safe.
I like the idea of having the design specs engraved on them.
Another happy customer.

My way of attaching? I put a couple of holes in the outer ring separated 90 degrees and 3mm outside the tube/dew mask diameter. 6g/25mm s/s screws and 6mm star plugs give me a non-scratch weather proof finish.

Regards
Andrew

[TheDecepticon]

Another happy customer here as well. Focused in about 2 minutes including a few test shots to verify. Best 14 astro bucks I've ever spent.
Thanks heaps!!:D:D:D

[Tandum]

Thanks Mike, that little WO70ED mask works a treat.

[ozstockman]

Thanks guys for your feedback.


I have found a supplier of cheap thin(0.9mm) plastic and I think I can offer it as an alternative to cheap MDF masks. It should be the same price as MDF. It is a cutting board sold in ALDI. They come in a pack of 4(red,yellow, green and blue) and I will be able to cut masks from them as long as ALDI sells them.

They are flexible and won't break even if you bent them. However they are slightly transparent. I will check how they work this week.

Since they are thin I can also cut Carey masks from them.



Sorry guys these boards don't work for my laser at all. They are catching fire and starting to melt when cut with the laser. I will keep looking for something thin that will work for carey masks.

[firstlight]

Thanks Mike, my mask arrived at the QLD Astrofest before the weekend. Good quality, well packed and priced. Hope you are able to turn a quid for the work you are doing.

Cheers
Tony

[Rigel003]

My 2mm acrylic mask arrived safely the other day. Super quick service and a nice product at a great price. It even has the scope details etched into the surface. Thanks so much, Mike.

[ozstockman]

Sorry guys these plastic boards from ALDI don't work for my laser at all. They are catching fire and starting to melt when cut with the laser. I will keep looking for something thin that will work for carey masks.

[ozstockman]

Brendan, your PM inbox seems to be 100% full and I haven't been able to reply to you.

[citivolus]

You can get rubberised cutting boards from Spotlight and the like. I hand cut a focusing mask from one a few years back. I wonder how they would go with a laser?

They are made of a few layers of rubber or similar material laminated together.

Regards,
Eric

[bmitchell82]

all cleared up now :) send away

[Allan_L]

Hi Mike,
I have a Celestron SCT (CPC1100).

I have tried a previous one of these, but there is this big plastic cover (over the central obstruction) in the centre of the lens that makes it difficult to place the mask flat.

Do you think it may be possible to cut out a central hole to let it lay flat against the lens.
Or do you think it would be better to oversize the mask to sit on the outer tube rim.
The mask would be about an inch from the lens in that case.

I am unsure how this would effect true focus.

Any ideas?

[GeorgeC]

After a lot of experimentation I have failed to find a thin plastic sheet that can be cut by a laser. They all buckle under the heat.

My best results are with paper card such as used for mounting photographs. I have had excellent results with 1.4mm card (my original prototype!) and recently 1.0mm card.

To keep them flat I made a 3mm perspex support, as can be seen in this photo.
http://www.btinternet.com/~gfcarey/september2009/cardmask.jpg

By the way, Jim Kendrick of Kendrick Astro Instruments recently did an assessment of the Carey mask. With a short 530mm scope he found that it could achieve an accuracy comparable to and in some cases slightly better than a Bahtinov. His recommendation is that the Bahtinov is more suitable than the Carey with short focal length scopes (I agree).
He also commented that the Carey probably would appeal more to DSLR users.

If any of you have tried a Carey mask I would be most grateful for feedback.

[Dennis]

I’m not sure of how the C9.25 corrector cell and secondary holder compare to those of the C11, but here are a couple of photos showing my C9.25 Bahtinov Mask.

I glued a thin strip of closed cell foam around the circumference of the mask so it keeps the mask proud of the secondary holder, with the foam strip sitting nicely in the corrector cell. The side walls of the corrector cell prevent the mask from flopping about.

Cheers

Dennis

[Allan_L]

Thanks Dennis,
That looks great.
Can you please tell me what is closed cell foam and where would I get it.
Also how did you attach it? I presume it needs to be very exact to get a good fit?
Thanks again for the heads up Dennis.
Great job :thanx:

[Dennis]

The normal (open cell) foam used in chairs, cushions, etc is the spongy stuff that absorbs water and is quite soft, limp and squashable – not suited to our needs.

Closed cell foam is the stuff used in camping mats (between your sleeping bag and the tent floor) or in those inter-locking square mats sold in camping stores for tent or caravan entrances. It is generally more rigid, quite tough and does not absorb water as it has been chemically blown.

I had an old camping mat so I just cut a thin strip approximately 10mm wide and then used a contact adhesive to glue it to my stainless steel mask (from H0ughy) which had been spray painted with a matt black paint.

You spread a layer of glue on the edge of the foam strip and a layer of glue on the circumference of the mask. Wait approx 10-15 mins (read the instructions) and the glue dries to become slightly tacky and then you carefully mate the foam strip with the mask, curving it as you work your way around. The main downside with contact adhesive, apart from the fumes it gives off, is that once the two surfaces have been pressed into contact, that’s it – you cannot unpeel the foam strip and mask to re-seat the strip, so you need to get it right 1st time.

Cheers

Dennis

[ozstockman]

I am afraid they won't work too. I might be able to cut them without burning but they are thick and very expensive. May be their price isn't an issue as I have seen some of them cheap in the Reject shops but they are still thick(>3mm I guess) It may be worth doing Carey masks from 2mm acrylic in this case.

[ozstockman]

Hi George,

I thought about the same solution but not with acrylic support. It would waste a lot of acrylic and it's quite expensive. MDF will be much cheaper. The only problem is that the whole mask will suck in water from air and it will bend eventually and loose its shape.

[GeorgeC]

Yes, MDF is cheaper, but I bought a big supply of perspex!
The absorbtion of moisture is a problem. My 1.0mm mask starts to bow a little after taking it out into the night air. I keep it indoors during the day and it flattens out perfectly. I then take it out and focus while it is still straight. The bowing does not actually do much to the diffraction spikes because the slots remain parallel.
I might devise a support that does not require gluing the card into it.
If the card is free to expand and contract then it may stay flat.

If only someone would produce black perspex 1.5mm thick!

[ozstockman]

I don't think it would affect focus if you put it one inch from the lens but it might be harder to mount as the mask will be one inch away from the scope and will hang on the trim only.

I can cut out the centre from the mask so it would fit on the plastic cover but it would probably reduce your scope aperture. There should be a solid ring at least 5-6mm thick around the hole. And this would be taken from your scope aperture unless plastic cover diameter is less than the central obstruction diameter.

We can do also what Dennis suggested and I will leave the solid centre on your mask but there might be another problem. Your mask aperture is already very close to the maximum I can cut. If you add too much for you mask OD to mount it on the trim it will exceed 290mm OD I can cut.


Regards,

Mike

[ozstockman]

I just wanted to reply that at this point I cannot do Carey mask. Unless you are happy to get one made from 250gsm paper and it isn't bigger than 200m in diameter :-)

[bmitchell82]

:) so your basically saying for my telescope Carey isn't a option. thats cool, ill just go the Bat mask and use Bat grabber to see how close i am

[GeorgeC]

I am a long way away in the UK, but if you want a Carey mask to try out I can make one for you. Probably out of mounting card.

[bmitchell82]

card wouldn't be a option, too light and flimsy plus with Dew, that would be the end of its life! looking for something a little more durable! I can cut out a cary mask to see how it goes anyhow, ive got some nice thin plastic so ill give it a go

[gsb]

Hi Mike I sent you a PM a few days ago ordering 2 masks, on checking for replies it shows my message was not sent???. 1 mask was for a Celestron 9.25 seconfd was for a meade 80mm APO. If you did not recieve this PM let me know and I will resend the details.

Graeme Brown

[dpastern]

Mike - thanks for your help via PMs. I've sent you another PM just now with an order for 2 and some questions!

Cheers,

Dave

[ozstockman]

Hi Graeme,

can you please resend it. I cannot see anything from you in my pm inbox.

cheers,

Mike

[dpastern]

Mike - received my goodies today - very nice! Thank you!

Dave

[DavidTrap]

Received mine today - hope they work as well as they look!!

Thanks
David T

[Ghost_Returns]

Whooeee PM sent ;)

[ozstockman]

Hi guys,

I have added more details and a picture regarding all masks except the ones for refractors.

See my first post located at the top.

cheers,

Mike

[AstroFlyer]

PM sent :)

[keppar]

PM sent

[AstroFlyer]

Another happy customer...:D
My mask arrived yesterday.:thumbsup:
Thanks a lot Mike.

Arek

[freespace]

Got mine today. Cut to perfection.

Mike does fantastic work, very happy with my mask!

Cheers,
Steve

[GeorgeC]

In an earlier post there were comments that a Carey mask from 3mm acrylic was not so good and needed a thinner material. I have now done some experiments with my 10" reflector and 3mm acrylic and it is perfectly OK. Previous trials were with a 6" scope.
I suspect that some of my disappointing results were due to poor tracking. Have a look here http://www.btinternet.com/~gfcarey/careymaskten.htm
for some examples.

[ozstockman]

Thanks George for letting us know about results with 3mm thick Carey mask.

I will try to cut one for myself and test it shortly.

[Benno85]

Mine arrived today for the ED80 - black acrylic. Another happy customer :D

[PeterM]

Hi Mike,
I sent you 2 pms a few weeks ago re ordering a 12inch mask for my LX200R with an Optec F7 reducer. Did you get these?

Thanks
Peter

[ozstockman]

Hi Peter,

No, I didn't receive any pm from you. Please emil me to ozstockman at gmal dot com.

Cheers,

Mike

[Phoenix]

PM sent

Thanks Mike.

[OzRob]

I got mine and it looks very smart!!!

[Phoenix]

Yet another happy customer - three masks arrived today. Wasn't expecting them until well after Christmas as we all deserve a break this time of year. Nice surprise. Perfect workmanship, with f/ratio engraved on each one.

Well done Mike - very much appreciated. Have a great Christmas.

Cheers
Steve

[ozstockman]

Hi guys,

Thanks for your feedback.

Everybody who has ordered and paid recently should receive their masks this year. All orders have been already posted.

I am going on holidays till 2nd of January and might not be able to reply to your PMs. I will do it once I am back.

Merry Christmas and Happy New Year!

Cheers,

Mike

[ozstockman]

I am still cutting masks out if anybody is interested.

[mithrandir]

Mike, would you be interested in cutting masks for Al's fishing line Bahtinov?

http://www.iceinspace.com.au/forum/showpost.php?p=560110&postcount=292

A bit more light would make focusing easier.

[ozstockman]

Hi Andrew,

If Al doesn't mind I can cut them out for you guys. However you'll have to do fishing line yourselves.

cheers,

Mike

[wasyoungonce]

Qty 3 Masks ordered & delivered, from Mike to me in 4.5 working days!

Now that's service...and the masks...they are excellent.

Thanks Mike.:clap:

[ozstockman]

Thanks Brendan for your feedback.

If my inbox here on IIS seems to be full and you cannot pm me email me to ozstockman at gmail.com

I am trying to empty it regularly but sometimes it's filled up with messages much faster than I expect.

[ozstockman]

up

[Jaybee]

Hi Mike
I'm an engraver based in the Barossa Valley SA. I have a 600mmx600mm Laser and cut all sorts. I don't know if this helps but Laser & Sign Technology www.lasetech.com.au (http://www.lasetech.com.au) sell Engraving stock manufactured by IPI in the US. They have a 1.6mm ABS with a high acrylic content that is designed to be engraved and cut by lasers. The downside is that it is matt black on the back, but the front surface has a colour overlaid. You could always use the coloured side as the back though, if all you are doing is cutting. It WILL buckle when cut, so to get past this, I use double sided tissue tape to hold it flat to the table. Once its cut, it will stay flat.

Hope this helps
John

[ozstockman]

Thanks John. I will check with them for ABS plastic. I hope it won't be expensive. Both times I was trying to buy spare parts for my Universal laser from them they gave me almost 2 times more quote of what it really costs in US.

Mike

[Jaybee]

Mike,
I have always found them to be very comparable, price wise. Spare parts are a thorn in our sides though! I have a Gravograph Laser and spare parts are horrendously expensive. I too, buy most of mine from an Engraving supply firm in the US. Consumables are a different matter and are priced fairly well. A 1200mm x 600mm sheet is around $70.00. They (IPI) have just released a new product called Laser Tuff, this is even better than the normal stuff, and doesn't warp as much and is the same price as the old product. You will most likely need an account to purchase from them. If this is a problem, let me know and I can supply you. I can even send you a small piece to sample if you want too, before you buy a full sheet. if your interested, pm me.

[chunky]

Hi there

They aren't expensive for parts, either. It is just that US sell directly from manufacturer stock at tiny margins, because they buy at very different prices to what the dealers have to buy for.
If you have tried to run a business (not a hobby) in Australia, you know that you can't sell parts at tiny mark up, not when you have to warehouse, stock etc., for 20 different models They might have a few hundred thousand dollars tied up in parts easily.
Also, people buy machines from other suppliers who now are not interested in dealing in lasers (like EMSS), and then want back up from the main supplier . . . ., who you don't want to spend $40 more on for a part - you just can't afford a 'spares' department if you can't afford the overheads because the parts are too cheap in the first place.

Gravograph might be a little different - they are factory owned in Oz.

c

[kenthoi]

Thank you ozstockman (Mike) for the beautiful cut Bahtinov mask. Service is extremely quick. Unbeatable price. A very satisfy customer indeed.

[that_guy]

Do you make one for Canon DSLR lenses?? these might come in handy.

[seeker372011]

mike
many thanks for the mask

I should have done this ages ago instead of mucking around trying to make my own out all sorts of materials and trying to cut the pattern out with a stanley knife
narayan

[ozstockman]

Hi Tony,

if you tell me all details(focal length, aperture and mask diameter) I will cut it out for you. I cut out two for guys from IIS but both times I was told all specs. One of those wasn't Bahtinov design though.

Cheers,

Mike

[joecool]

Finally got to try mine out. One for 5" Celestron XLT SCT and one for LX200 10". Used Bahtinov Grabber to remove any guesswork. Even on dim stars where you cannot see any lines extending out it tells you exactly where focus is. This makes it soooo easy!
Thank you Mike.

Mark.

[apaulo]

Thanks MIke for the mask it arrived safe an sound.

I can,t strongly recommend enough the service and quality of the bahtinov mask Mike made for me.

A pleasure doing business with you.

Regards Focused Pictures apaulo!.

[davewaldo]

Another very happy customer here! Thanks Mike!

Fast production and shipping! A+++ :D

[erick]

PM coming, thanks Mike

[ozstockman]

willow, please change settings for PMs. I cannot sent you my reply. It says that you don't want to be contacted :-) You can also email me directly ot ozstockman at gmail dot com

[firstlight]

Thanks Mike,

My mask arrived at the Queensland Astrofest on Friday morning and I was able to put it to use that night. Once again a quality product and prompt service. I will be in contact regarding a mask for Anne-Louise's 10 - 22 mm Canon lens.

Cheers
Tony

[erick]

Superb service! Great result! Thanks Mike

[erick]

I have added two little knobs, top and bottom, to add in placing and removing the mask from inside each OTA. First use last night - neat!!

[roddz]

Hi Mike could I please order 3 Masks.
The first 2 in 2mm Acrylic, both for 100mm refractors.

1: 100mm 800mm FL 118mm diameter
2: 100mm 500mm FL 116mm diameter

the 3rd in 3mm acrylic for a Vixen VC200L

3: 200mm 1800mm Fl 218mm diameter, aprox 75mm central obstruction.
Thanks Rodd
roddz@spin.net.au

[vk2emq]

Mike,

I'd be interested in getting some Bahtinov masks, however on doing some research in forums here and elsewhere about possibilities for automated focussing I came across references to the Carey variant of the Bahtinov Mask -

http://www.iceinspace.com.au/forum/showthread.php?t=45396

http://en.wikipedia.org/wiki/Carey_mask

This appears to offer superior indication of "perfect" focussing compared to the Bahtinov mask on which it is based, however is much more difficult to fabricate, requiring much thinner substrate base material for the mask.

Could you please advise if it would be cost effective for you to fabricate a Carey Mask ?

best regards,

John vk2emq

[ozstockman]

Hi John,

I would be happy to make Carey masks especially if there is any interest in them. However as we discussed it with George on the 2nd page of this topic material used for them should be 1-1.5mm thick. So far I couldn't find anything not expensive and thinner than 1.5mm. I will check with my current acrylic supplier if they have any plastic that is 1-1.5mm thin.

I am about to get more powerful laser with 3 times bigger working area than I have now. It means that I will be able to cut out bigger masks(up to 20") and will be able to do it faster. So may be I can try some plastic I didn't have a success before. It didn't work as my laser cut it very slow and it melted. Now if more powerful machine will cut it faster it might work.

Regards,

Mike

P.S. Since to my equipment update my current 50W laser must be sold. It won't be cheap as these types of equipment are very expensive. However considering its price when its new mine will be a few times cheaper. If anybody is interested in it please pm me.

[mithrandir]

Can you do cuts at an angle like this sectional view? It would get the thinner edge, but require two passes. Or does the mask require both corners to be at 90 deg?

[ozstockman]

Sorry for the delay Andrew.
No, my laser cannot do angle cuts. It cuts at 90 deg only.

I have got some thin plastic from my supplier. It's about 1.5mm thick. However I haven't tried it yet and it's clear. I asked them for something suitable for picture frames and that all they sell that is thinner than 2mm. They don't have it in any other colour but may be it's possible to spray paint it in black.

[Marty]

Hi,

I have a CPC1100 and Hyperstar setup want to get a Carey Mask made.

My research indicates that there are a few ways of using a Mask with Hyperstar..... Mounted on the end of dew shield, a split hollow center mask, or take the camera off and fit a hollow centre mask over the Hyperstar.

I imagine that mounting on the end of the Dew shield would be the fastest when needing to refocus due to Temp changes, but is it as accurate?

If using the Dew shield mount, the end of the Dew shield is ~400mm from the OTA and ~200mm from the camera.

So would I use a central obstruction in this case? and what size obstruction? same diameter as the camera (EOS 550D) or less considering it will be 200mm away?

I am also a bit concerned about the weight of 3mm MDF/Acrylic mask and that the dew shield might just flop off the end of the scope. It's a Kendrick Zap Cap made from ~1mm black ABS plastic with a Velcro seam and rubber non slip heater strip, so not able to handle much weight without slipping.

I noticed from reading this thread that you are constantly on the hunt for new materials; so what is the lightest material you currently have that may do the job? is MDF/Acrylic still the only options? or have you found some thinner ABS plastic now?

George Carey - "In an earlier post there were comments that a Carey mask from 3mm acrylic was not so good and needed a thinner material. I have now done some experiments with my 10" reflector and 3mm acrylic and it is perfectly OK. Previous trials were with a 6" scope.
I suspect that some of my disappointing results were due to poor tracking. Have a look here http://www.btinternet.com/~gfcarey/careymaskten.htm
for some examples."

Ozstockman (Mike)- "Thanks George for letting us know about results with 3mm thick Carey mask.
I will try to cut one for myself and test it shortly."

Just wondering, did you get a chance to test yet?

Regards,

Marty

[GeorgeC]

I am using a Carey mask made from 3mm acrylic on a 10" scope with no problems. I was having difficulty before, but I now think that that was due to a rather poor mount. I have an ASA DDM60 now which remains rock steady during a 20 second exposure. The diffraction spikes are good and sharp. If your mount moves around at all the spikes get smeared and are less distinct.
For my 6 inch scope I still use a paper card Carey mask which is quite thin (<1.5mm). It gets a little warped if I leave it in the observatory for a while but still works well. Here is an example:

http://geoastro.comeze.com/masks/6mask.jpg

[Marty]

Hi George,

Good to hear 3mm is ok now :)

Do you have any ideas about mask center obstruction sizes and how they might be relevant when mounted out on the front of a dew shield with a Hyperstar inside?
Or would I be better getting a 2 part split mask made and popping it straight on the OTA?

[GeorgeC]

A central obstruction should be no problem. Obviously if the obstruction is very large you will get dimmer spikes. A mask that is in two pieces (I assume you mean that when you say 'split mask') will not be a good idea. The angles involved in a Carey mask are such that any error in getting the two halves fitted together will destroy the accuracy. You judge focus by comparing the very narrow separation in left/right spikes and a fraction of a degree error would make this impossible. This would also apply to the Bahtinov mask.
If the two halves were cut precisely and fitted together without any gaps then it could work. Perhaps..:question:

[Carl]

Hi Mark
Noticed your thred re making Banhotov masks.
Are you still doing them? I live in North East Victoria. need mask for 80ed
and C8 scopes

Cheers Carl

[Carl]

Hi Mike
The thread seems a bit old. Are you still making them. I need 2

Cheers
Carl

[ozstockman]

Hi Carl,

I have just replied to your email. I can still make 5-10 masks for small scopes of 2mm thick black acrylic but I run out of 3mm for big scopes. Since these days there is much less offers for masks coming from ISS I have been thinking to stop selling masks after I run out of all 2mm thick acrylic that I have now in stock.
Only if there is at least 8-10 people who want 3mm thick acrylic masks for big scopes it will be worth for me to update my stock for 3mm thick black acrylic panels.

If anybody wants 3mm thick MDF masks instead of one cut out of 3mm thick black acrylic I can do them anytime. I cut out a lot of stuff of 3mm -18mm thick MDF everyday and I always have MDF in stock

Cheers,

Mike

[Logieberra]

Hey guys

How important is it for the mask to be perfectly centred (in relation to the primary mirror / lens)? I've fitted my 10" mask to the newtonian, and when I look through the focuser - the centre lines of the mask do not line up perfectly with my secondary vanes - indicating she's off perhaps 5mm.

What's the science behind it? Will this be fine, and make no difference? Or should I re-drill?

Cheers.

[GeorgeC]

I did some experiments with the Mask simulator. It showed that there was no noticeable effect of have the mask off centre.
Have a look at http://geoastro.comeze.com/careymask.htm down the page a bit. This was for a Carey mask but I am sure the Bahtinov would produce the same result.
George

[Tandum]

I had a 10" mask hanging from the top of an 8" scope using tape last week-end and it worked fine. ie: 2" of the mask was hanging off the bottom of the 8" scope.

Mike has just sent me a new mask for the 8" scope and it fits like a glove. Thanks mate.

[Logieberra]

That's a relief! Good Info. Thanks guys.

[ozstockman]

3mm black acrylic is back in stock. Moreover from now I can do solid masks with OD up to 59cm in diameter.

[stephenb]

Hi Mike, I've sent you a PM sent re: a DSLR mask

[stephenb]

Has anyone mounted on to a DSLR lens? Any thoughts on the best method? My idea was to buy a cheap screw-on filter, perhaps take out the glass itself and mount the Bahtinov mask in place of the glass.

(Sorry if this is out of the terms of reference with the classifieds, but there seems to be a lot of justified discussion on this product).

Regards,
Stephen

[Domino]

pm sent

Cheers, Maurice

[ozstockman]

up.

If you need a mask I am still making them. At least until all 2mm and 3mm thick black acrylic is sold out.

[Jfinis]

Hi Mike,
Received the 10" mask today now have to wait for the weather so I can try
Thanks for the quick turnaround

Regards
Jim :)

[Poita]

what measurements do you need? I'd like one for the 4" refractor and the 10" SCT.

[alistairsam]

Hi Peter,

I'd like to order a 3mm acrylic mask for my 8" F4. will PM details.

Thanks
Alistair

[Merlin66]

PM sent

[John0z]

Mike,

I would like a few masks for my scopes. I had better start focusing properly - now that I have time to try some more photos after the lunar eclipse on the weekend. I will send you a PM.

-John

[alistairsam]

Hi Mike,

are you making these masks? I haven't received a reply to my PM and post.

Thanks

[ozstockman]

I have just replied to your PM John.

[ozstockman]

Yes I am.

I have just checked my PM inbox and I cannot see any messages from you. Please send it again or email me to ozstockman at gmail dot com

[alistairsam]

Hi Mike,

I'll resend the details.
Thanks

[John0z]

Mike,

My masks arrived just now. Thanks a lot. I can't wait to try them out.

-John

[alistairsam]

PM Sent

[traveller]

PMed you mike. Cheers.

[h0ughy]

just sent you a pm Mike for an inquiry for two masks - one for a meade 14" and one for a celestron C11

[Liz]

Hi Mike

Can I order 2 please. One for my 10" Dob, and for my 127mm Mak (Skywatcher).

Cheers
Liz :)

( your inbox is full - a popular man!!)

[ozstockman]

Hi Liz,

Please send me a PM one more time. I have just cleaned my inbox.

Cheers,

Mike

[ozstockman]

Hi guys,

there is no 3mm thick black acrylic left in stock so I won't be able to do masks for 8" and bigger scopes in 3mm black acrylic. However I can still do them in 3mm thick MDF if you do not mind MDF masks. For scopes smaller than 8" I still have 2mm thick black acrylic. Not a lot of it but it should be enough for 8-12 masks.

After 2mm thick acrylic is sold out I will be able to do masks in 3mm thick MDF only.

So if you need one please order it asap.