CCD and DSLR Bahtinov masks

[chunky]

Hi all,

I have tested a laser-cut version of the Bahtinov masks both visually and photographically with a 10" Astrograph and a 4" semi APO. Incredible. Super easy either by hand, or by motor-driven focusser. As mentioned on the threads, it is also very 'directional' allowing you easily to always approach from the same 'side' for focussers with backlash. I haven't tried yet (soon!) but I think they will be exceptional on SCT / RC's.

Couldn't improve on the focus (40D live view) going straight to the moon and focussing there. Great either with planet, bright star, or less (depending on your F,no and light pollution filters). The best thing for manual focus that you look at the spike positions, so you don't need the OTA to settle between adjustments - your eyes just follow the spikes.

The model pictured below worked for both F9 and F5 just as effectively.

I am offering them in 3mm black acrylic, or 3 / 4.5 mm MDF for $5 less (that you can spray matte black), so you can choose rigidity or nice-looking (acrylic is more brittle). I need you to measure the size of your OTA and give the INNER diameter, and the resulting mask will be around 0.3mm smaller than this - to mount with blu-tack or just mount inside the dew-shield / cover as required.

Happy for pickup ex Sydney, and prices are:

$40 + post 3-4" OTA (up to 110mm diameter)
$50 + post 5-7" OTA (up to 180mm diameter)
$60 + post 8-10" OTA (up to 300mm diameter)
$80 + post 12-14" OTA (up to 450mm diameter)
Larger sizes on request

Multiples: 15% off for 2 or more, 25% off for 5 or more, so please gather multiples if you wish - better for me, better for post, better for everyone.

NOTE:
I am going away Saturday week for 4weeks, so you will need to get an order away quickly to give me time to custom make them.

To look at my acrylic ones:

http://www.pbase.com/clinton_wood/image/103196197 (http://www.pbase.com/clinton_wood/image/103196197)

Regards
Clinton

[TrevorW]

Hope you are donating some profits to the designer

Cheers

[bojan]

I have the same hopes....

[gmbfilter]

Ive ordered one

[chunky]

Thanks to everyone who has ordered masks. The Mr Bahtinov retirement fund will be absolutely flush with cash after all the first batch of royalties are sent. :)

My experience over the weekend: On large masks - over 150mm - the 3mm acrylic is not the correct material - I managed to break mine - when I deliberately dropped it - mind you it still worked great - with the spikes unaffected by the missing bit around the edges.

The smaller ones seem to be fine, but as I have already told a couple who ordered the bigger ones: I have substituted a 1.6mm ABS plastic that is more 'drop-proof' for the same price as the acrylic.

Anyway, I have probably time for one more batch before I am away, so let me know. Up to 305mm masks are $10 freight in Australia, send me a PM and I will let you know the details for bank transfer.

Happy Masking
Clinton

[AlexN]

can not wait!!!

Its good to hear about the ABS plastic being drop proof... I'm the worlds biggest butterfingers.. If something can be dropped, I have or will drop it eventually. :D

Alex.

[allan gould]

Hope not the QHY8:eyepop:

[Star Catcher]

Just a note to let you know I tried out the mask tonight on my C11. It works very well and is superior and faster than trying to eyeball it or using software feedback. I have used hartman masks in the past but this mask gives a much clearer indication when you have reached focus.

I expect the mask will become my primary focussing tool whenever I do manual focussing.

Thanks.

Ted


Ted

[chunky]

Hi Ted,

Great to hear it! I had yet to try an SCT, so it seems that all classes - reflective, refractive and now catadioptic work well with the masks.

Thanks for the feedback
Clinton

[Hagar]

Mine arrived today and looks really good. Can't wait to give it a try but it looks like the Astro gods are watching and have brought in the clouds.
Nice Job at a nice price and it fits perfectly. ABS plastic is the way to go.
Thanks Clinton

[AlexN]

mine arrived today also... both fit brilliantly, I'll be testing them out over this weekend :)

Cheers Clinton.

Alex.

[leon]

Yes Doug, you are dead right, I totally changed my set up today, although the Tak is there I added a 5D with my 135mm F/2.0L and put the other 5D on the Tak, I can see those clouds moving in, :scared: so really , you did it before, me so it is your fault. :lol: :lol:

Leon :thumbsup:

[5ash]

looks great but dont you have to design each one for a specific telescope using the aperture and focal length as parameters,?
regards philip

[chunky]

Hi there,

I am back in the country again, so if you are interested in masks, then just let me know.

So far everyone who has one has been happy with them, so let me know what sort of scope you have, and I can fill you in on what the results have been for that sort of scope.

Regards
Clinton

[ozstockman]

Hi Clinton,

will a 8-10" mask work with Vixen VC200Ls?

cheers,

Mike

[Ric]

Hi Clinton, I must say my mask is working a treat with the LX200R and leaves my Hartmann mask way behind when it comes to fine focussing.

Many thanks.

[AlexN]

^^ Another happy customer :) ^^

Scary thing is. im starting to love my focusing mask more than I love my telescopes :)

[g__day]

If anyone wants to get a feel for what it can do - simply copy a mask - expand it in Photoshop or whatever to the size you want it - print it on A4 - take it to work or Officeworks and transfer it onto a transparency.

The cost to get a working model and play with it is under $3 - if you like it and can see its value - order one. I cut my one from cardboard with a model knife before I thought of the photocopy to transparency route -and it has worked a treat for the last few months.

If you want to have a permanent version you can take out to the field - buy one knowing how effectively it will work!

[chunky]

Hi Mike,

Sorry - I didn't see this in the public replies:

I have sold a couple of masks for VC200L's. The first one (Doug in Mt Beauty) was great, the second one showed up an optics problem in the scope, but the mask was fine. Those two were both slightly different diameters, so rather than me make one that doesn't nicely fit, make sure you give me the exact diameter. From memory, one was 224 and one was 226 in diameter. Freight above 210mm wide is $15.

Regards
Clinton

[chunky]

Hi Ric and Alex,

Thanks for the feedback. It is appreciated.

Glad they are doing the job.

Regards
Clinton

[chunky]

Hi All,

Just a change for those who are interested: I have a new 'colour' for the masks. Most have been silver / black or black / gold in colour, but if you wish, you can purchase a fluoro pink / white mask as an alternative. The interesting thing is that it is easier to spot on a dark night in your accessory box. Still is very light and bends easily - not like the acrylic that breaks if dropped.

Use the mask with the pink side down.

Order info: measure the size of your OTA dewshield and give the INNER diameter, and the resulting mask will be around 0.7mm smaller than this - to mount with blu-tack or just use gravity inside the dew-shield / cover as required - that is what I do. Specify an inner diameter for SCT/RC / modified Newts if you wish to have it fit over the secondary.

Happy for pickup ex Sydney, and prices are:

$40 + $10 freight etc 3-4" OTA (up to 110mm diameter)
$50 + $10 freight 5-6" OTA (up to 180mm diameter)
$60 + $15 freight 8-10" OTA (up to 300mm diameter)
$80 + $20 freight 12-14" OTA (up to 450mm diameter)
Larger sizes on request

$25 freight internationally

Multiples: 15% off for 2 or more, 25% off for 5 or more, so please gather multiples if you wish - better for me, better for post, better for everyone.


Regards
Clinton

[leon]

Could I please ask this question, dose this mask have to be positioned on the objective lens, or can it sit half way down the dew shield, or on the end for that matter.

I ask this as my Tak 106 dew shield, although the same diameter all the way down it dose have a small ridge half way down the shield, so if one had to place this mask on the objective it would not be possible unless the mask was made considerably smaller.



Many Thanks.

Leon

[AlexN]

I use the one on my C11 about 1" from the corrector, The one for my Megrez 102 about 4.5~5" from the objective on the end of the extended dew shield... Both seem 100% spot on..

Heres a pic, Focused through the camera view finder (no angle adapter, so 0x magnification) with the mask 4 or 5 inches from the objective.

[keppar]

How do I go about ordering one?

[AlexN]

Send Chunky a PM!

[leon]

Nice Alex very nice and thanks for the info.

Leon

[chunky]

Hi there Leon,
Sorry I didn't check the messages here yesterday.

But it is a really interesting point. I had only experience with pretty much on-the-objective , but I would have thought that no matter where the mask is, it would still generate parallel light patterns that would be focussed at the film plane regardless.

For my Newtonian, the primary mirror doesn't know where the mask is, and doesn't care, as long as it is sitting relatively square to the incoming light.

It would vary if the mask was INSIDE the objective, probably, but for instance you could incorporate the mask into the end cap of the scope, so that it would not have the possibility of touching the objective on a refractor.

I think I have two TAK refractors with the masks, and they have reported that they work well.

Regards
Clinton

[leon]

Many thanks for your reply, I reckon if it goes down the dew shield and rest on the ridge I was talking about in the last post it might just do the trick.
That would place it about 50 mm from the objective.
I will PM you if I intend to purchase.

Leon :thumbsup:

[chunky]

Hi everyone,

I have added a few options that people might be interested in: For Hyperstar / large SCT users, I can halve the mask so that you can use the mask without removing the camera. Call it HALF-MASK. Price is the same

Secondly, for users who have trouble getting the masks out with the tight fit, I can do a custom radius tab - a reverse arc that allows you to slip a fingernail under the edge to remove the mask more easily - you could get a fingerprint on the objective if you . Just call it a REMOVAL-TAB, and let me know your clear aperture as well (just let me know the actual scope - that makes it easy), so the tab doesn't intrude on the function of the mask.

Thirdly, for those who want finer focus control, I can do a special mask at a lower degree. I already use a slightly finer angle than recommended by Mr Bahtinov, but I want some feedback on this going forward, so if any new orders want to try one then just call it the HI-RES mask, and for the next 4 orders I will supply a standard mask of the same size as well.

Existing mask users: If you want to try a HI-RES one as well, let me know and we will work something out.

Thanks for all the encouraging feedback, by the way, and for the samples of work that you have sent.

I just picked up a new 50D (which will stay unmodded), and with live focus and the new hi-res 920,000 pixel screen at 10x magnification the diffraction spikes are just unbelievably clear. I can highly recommend the 50D, except that I have seen evidence of the 'dark-river' problem that I fortunately did not see on my 2 20D and 2 40D bodies.

Regards
Clinton

[TrevorW]

This may sound dumb but I assume the masks have to sit exactly level with the objective to get the proper reading as the diffraction spikes can still appear even if the mask is slightly askew.
:shrug:

[chunky]

Hi Trevor,

I haven't really tested it, but it would be easy to do so. I suspect that it would not be sensitive to that sort of distortion, however, if you tilted it so that the effective angle of the two angled patterns were different, then it might be harder to accurately bisect the two angles with the major spike in the middle.

Would the angles actually change?

I will try it out and let you know.

Regards
Clinton

[Omaroo]

Hey there Clinton. Just a quick note to say thanks for the mask you sent me for the Tak. It works a treat.

Now - can you do a small one that fits snugly into a 50mm camera lens filter ring - either with the filter glass in or not? I'd like to be able to use it for my widefield setup.

[danielsun]

Hi Clinton,
I am keen on ordering two masks one each for a 10" and 8" newts.
I will measure my inside diameters and PM you shortly.


Cheers Daniel.;)

[chunky]

Hi Chris,

Glad to be able to help, and glad that they do the job. It seems like the faster scopes in particular really go well, since the focus point is so tight on those FS series scopes. You must have quite a 'tak club' down there, with a couple more of the tak club receiving theirs last week. Thanks for the demos!

I will send you a PM

Clinton

[chunky]

Hi all,

Chris (omaroo) requested a 'filter-ring' mask, and I have experimented with different materials to come up with something.

I found a very hard wearing 'rip-stop' laminate (uv treated so they won't degrade), that I think will last a long time. It is also self adhesive at any time, so you could stick it to the filter glass and you would have a screw in mask, as well as being able to be just placed on the filter.

I am really happy with them - the corners are unbelievably sharp because they are thin.

Price is $40 including freight up to 82mm filter ring size. ring if you need larger, and you can use the material for standard masks if you wish as well.

[Omaroo]

Sounds great Clinton - I can't wait to try it out! I have a dedicated daylight filter ready to go now, and this will make using camera lenses so much easier. As filters just screw into each other, it'll be super easy just to screw the mask on, set focus with a couple of quick three second shots and then remove it.

I have rubber bands on my lenses so that the focus ring doesn't move easily. I think that if loosely screwed on just a quarter turn to hold it there, the removal process won't move my focus at all. I'll eventually make up a robo-focus stepper-driven system any way.

Thanks again! :thumbsup:

[Omaroo]

The 50mm filter mask review:

http://www.iceinspace.com.au/forum/showthread.php?p=391451#post391451

[danielsun]

Received the masks, thanks Clinton your a legend :thumbsup:
Can't wait to try them out.
It was a stunningly clear night last night first time in ages but I was out at a Christmas party till very late, Thought that'd be right.

I will let you know how they go.


Cheers Daniel.

[Ross G]

Hi Clinton,
I received the 2 masks for the Vixens.
Excellent workmanship and very fast service.
Hopefully we will try them out next weekend.

Thank you

Ross

[monoxide]

recieved mine today, thanks mate :thumbsup:
looks great, and fits perfectly.
cant wait to give it a go

[chunky]

Hi there,

Thanks for the kind comments guys. Great that we can all be 'focussing' better!

Regards
Clinton

[chunky]

I just wanted to offer 50% from any masks ordered in the next couple of months to give to the Red Cross Relief that Mike put up as an announcement on the weekend.

I also want to offer my sympathies to all of those who have suffered loss of loved ones and property.

Nothing else to say, really.:( How devastating.

Clinton

Thanks for those who have bought - around $200 extra to the fire effort - thanks

Prices are still the same
Happy for pickup ex Sydney, and prices are:

$40 + post 3-4" OTA (up to 110mm diameter)
$50 + post 5-7" OTA (up to 180mm diameter)
$60 + post 8-10" OTA (up to 300mm diameter)
$80 + post 12-14" OTA (up to 450mm diameter)
Larger sizes on request

[asterisk]

Hi Clinton

I would like to order a couple of your masks. Any chance of clearing some space in your PM inbox so that I can do this? :):)

Cheers

[peter brown]

Hi,
Could you please give me an update on the mask I ordered for my SkyWatcher 100ED last week?
Thanks,
Peter B
Payment has been transferred last week

[chunky]

Hi Peter and Geoff,

The mail box is cleared, Peter, sent you a PM last week, and Geoff - let me know how you go with the mask.

Thanks
Clinton

[pmrid]

Hi Clinton, afraid your mailbox reports as being full again. I wanted to thank you for sending the masks BUT to note that one of them seems to have been meant for someone else. I ordered 1 at 225mm and 1 at 144mm. I got the 225 but instead of 144, I have a very attractive mask of 95mm dia. When you can, please send me your suggestions for a replacement/swap.
Peter

[Tamtarn]

Hi Clinton

Had not had a chance to try out our mask since purchasing it from you last year, due to our set up being dismantled and the in progress building of a ror observatory.

Our last two posted images were focused using the mask and we are very happy with the results. The mask works well on the C9.25 and has made focusing quick and easy.

Thanks

David

[Allan_L]

Hi,
I would like to order some masks too, if possible, please.
PM sent.
Regards
Allan

[Alchemy]

i wondered if you got my message, just in case the mail box is clogged again.

clive

[chunky]

Hi Clive and all,

Just was away for over a week - and semi off-line. Back on line now!

Regards
Clinton

[erick]

And still in the manufacture and delivery business, Clinton?

If so, I'll PM when I work out sizes.

Thanks
Eric

[chunky]

Hi Eric,

Just PM me when you are ready. Working around interstate trips, but it will be fine.

Regards
Clinton

[erick]

OK, that's great. I'm going to try the trick of copying a mask template on transparency sheets so I can roughly check the technique out on different scopes and the wide-field camera lens.

[chunky]

Hi everyone,

Carey masks are now on the menu. Same prices as per the existing full and partial Bahtinov masks, for either DSLR lenses, or scopes:

According to my feedback, it may be better for the shorter DSLR lenses where it is harder to get the magnification of the image, or for non live-view DSLR's.

Also: For those who prefer to have the masks sitting like a dust cap - outside the dew shield, rather than close to the glass - I can do a wider version that you can mount on a dew shield that has been turned into a 'donut'. I just need the inner diameter of the OTA as well to build it correctly.

Happy for pickup ex Sydney, and prices are:

$40 + post 3-4" OTA (up to 110mm diameter)
$50 + post 5-7" OTA (up to 180mm diameter)
$60 + post 8-10" OTA (up to 300mm diameter)
$80 + post 12-14" OTA (up to 450mm diameter)

Larger sizes on request

Happy focussing
Clinton

[Omaroo]

Hi Clinton - I've tried to PM you with no success. Can you pls post your email address?

Could I trouble you to make a Carey mask for me, for my new newtonian, that has an internal tube diameter of 202mm and a 50mm central obstruction? If you forward your details to me I'll deposit straight into your account as before. Was it $60 plus postage within Sydney?


Thanks mate
Chris

[GeorgeC]

I am delighted to see that there is some interest in my 'Carey Mask'.
One thing to take note of: The Carey mask needs to be cut from a fairly thin sheet. I tried 3mm acrylic and it wasn't so good. My best results are with thicknesses below 2mm. The one I use regularly with great success is cut from 1.5mm photographic mounting card.

If you have used a Carey mask please let me have some feedback.

[chunky]

Hi there all,

Still have masks available, and with no restrictions on the maximum size mask.
Carey masks on an ultra-thin material are available, as are DSLR lens masks, split masks for SCT's with Hyperstar.

Masks are specialty materials specifically for lasers and are designed for long life, very low weight and no brittleness, and the masks themselves are designed and custom cut for you especially.

Yep, MDF works, and acrylic work for a while . . . . but these are very high quality, exterior-grade materials - hence the higher price.

If you wish for 5mm dowell holes, so they can be mounted on the outside, these can be done at no extra charge.
Regards
Clinton

[danielsun]

Hi there clinton, The masks you made for my 8" and 10" work beautifully.:thumbsup:
If possible I would like to get a couple more made up, one for an ED80 and also one for my canon lens.
Will PM you shortly with the sizes.

Cheers Daniel.