Simple Bahtinov mask construction

[Bizibilder]

I thought I'd post some pics of my new Bahtinov mask. It is made from a Tesco black "folding clipboard" and four bits of foam plastic.

The plastic clipboard is about 1.3mm thick and is JUST big enough to cut a mask for my 200P at 9.25" OD.

The foam blocks are carefully undercut so that when in place they grip the end of the telescope tube (rather well I must admit!). They are attached with Dunlop Thixofix contact adhesive - hot melt glue gun would also work but both superglue and pva failed a test piece that I made.

The mask was made by taping (double sided) a printout of the correct design to the plastic. Cutting out with a SHARP stanley knife and then trimming any loose bits with a scalpel.

[dlp]

Crikey, if I'm ever in the operating theatre I will ask for you - brilliant! How long did that take you?

David

[Bizibilder]

About two hours - there are a LOT of slots to cut!

[Astrokev]

Must have the patience of a saint! Excellent job.

[yesyes]

That looks professional. Well done!

And I do like the foam-clip idea. Must find out if I can add these to my £5 AstroBoot mask...

[Bizibilder]

I forgot to say - Total cost was £1.60 for the clipboard (and I still have the clipboard as I only used the fold-over cover to make the mask!!)

[Bizibilder]

It works!! Deneb focussed in less than 30seconds, just a quick look through "live view" and then two 5sec exposures to get perfect focus as the "live view" one was just a tiny bit "out".

[Herakles]

Nicely done.

Clear Skies

Pete

[Makron]

Nice job! Thank you!

[adamsp123]

A very nice piece of construction, I must admit when I did mine, on thick paper, I reduced the number of slots by tweaking the input data on the template website I used.

[Bizibilder]

Just an aside - The four foam blocks that I used to hold the mask to the scope actually work very well! It is easy to slip the mask on and off the end of the scope and there can be no damage to the scope/paintwork at all. As a bonus I keep the mask on top of all the bits in my foam-filled "flight case" - it just squashes flat.

[doorhand]

Excellent thread!! Thanks for posting this Bizibilder. As a skint newbie, i do enjoy reading these diy projects.

[carpman]

i just finished mine just same tech (blue peter style) know where near as good as Bizibilders (Top half is rough as hell but second half came out well) but for first attempt im pleased will post pics tomorrow

[Gina]

Do these make a big difference? Is it really worth all the effort? Do they work with every sort of scope? I too am a "Blue Perter" sort of person

[nightfisher]

bizi, that is a superb bit of work, i used my bahtinov for the first time last night, works really well, but i cheated and bought mine!

did you ever see my tal servo focuser, its on this section

[Catanonia]

Do these make a big difference? Is it really worth all the effort? Do they work with every sort of scope? I too am a "Blue Perter" sort of person

Yes, you will not get a better method of focusing over than computer aided.

I buy mine from ebay, the guy that supplies FLO at about £18 a shot. Well worth it and he will make any that you want. He recently did mine for my SuperNewt at F2.8 and I tell you, the slots are very very small.

Morris Engraving is the chap on ebay or go to FLO for standard scope types.

[Damo636]

Another excellent piece of work Bizi, thanks for sharing.

[Bizibilder]

Yes Gina they work on any scope. I'm too mean to fork out on commercial ones! I have made masks for the 200P, both 120 refractors (same mask!) and the 80mm refractor and the 180 Mak! All for less than £2.50. That was for the two Tesco clipboards - the foam was "free".

A couple of hints - use a new blade in a stanley knife to cut them out and a steel ruler to get the edges straight - and MIND YOUR FINGERS!! For glue I find that "contact adhesive" is the one to use - even if it is a bit smelly.

[nightfisher]

does the 180 mak work well with the mask, im looking at getting one for mine

[Bizibilder]

Yes - they all work. Very intuative and easy to use.

[Gra]

Excellent tread Bizibilder, will have to give this a go over the xmas period.

[Bizibilder]

I have a confession to make! The masks for the ED80 and 120 are slightly different in that the slits are cut in a thinner piece of plastic (from a Tesco's black plastic file) and this, in turn, is stuck to a thicker annulus cut from the plastic clipboard - I did this as is it difficult to cut the narrow slits in the thicker plastic.

The job is much easier with this method - you can use a lighter weight scalpel and a single stroke of the blade will cut the plastic cleanly. I've appended a pic of the mask for the ED80 made by this method.

An extra hint - don't skimp on the double sided tape when sticking the template down or the whole thing will move and you get wobbly slits!

[Herbig]

I use prit stick to fix the template, it's easy to remove it when you've finished, you can wash your finished mask to get rid of any residue.

[Bizibilder]

Exellent idea! (As long as you glue ALL of the template down so it can't move.)

[Psychobilly]

The designs can also be printed onto transparency and they will still work...

Useful as a test before spending a few hours with a knife on shorter fl designs...

Peter...