CCD and DSLR Bahtinov masks

[chunky (Clinton Wood)]

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

Regards
Clinton

[TrevorW]

Hope you are donating some profits to the designer

Cheers

[bojan]

Originally Posted by TrevorW

Hope you are donating some profits to the designer

Cheers

I have the same hopes....

[gmbfilter (Geoff)]

Ive ordered one

[chunky (Clinton Wood)]

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.

Alex.

[allan gould]

Originally Posted by 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.

Alex.

Hope not the QHY8

[Star Catcher (Ted Dobosz)]

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 (Clinton Wood)]

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 (Doug)]

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, so really , you did it before, me so it is your fault.

Leon

[5ash (Philip)]

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 (Clinton Wood)]

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 (Mike)]

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 (Matthew)]

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 (Clinton Wood)]

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 (Clinton Wood)]

Hi Ric and Alex,

Thanks for the feedback. It is appreciated.

Glad they are doing the job.

Regards
Clinton