Note to self

[CedricTheBrave]

When you read a post advising best practise take heed and apply!

I read a few weeks ago that you should tie a piece of string to your bahnitov mask to prevent it from falling when you slew!

I now have to order a new one

If only I listened and applied!! Doh!

[poogle]

Build your own mask from thick paper, it's free and will survive a fall to the ground

http://astrojargon.net/maskgen.aspx

/Patrik

[CedricTheBrave]

Ah cool thanks

Taking note

[StuartJPP]

Build your own mask from thick paper, it's free and will survive a fall to the ground

http://astrojargon.net/maskgen.aspx

/Patrik

I made one myself from medium card, but it wasn't stiff enough (cutting really stiff card precisely is quite a challenge). So I tried to stiffen it up by applying PVA, anyway to cut a long story short it isn't as flat as it used to be, kind of wavy...even after sandwiching it between two phone books (remember them?). Oh and I ended up with a sore finger (from all the pressure from cutting) as well as a blunt craft knife...if I had to do it again, I'd probably buy one...you have been warned

[CedricTheBrave]

I am understanding that anything astro related is never easy

[IanL]

I used foam-core board to make a Y mask.  They're a lot easier to make than a Bhatinov since you just have to cut three 'pie slices' to leave the Y pattern.  You need a sharp craft knife and steel ruler to make sure you get a nice clean cut through the board (three cuts, first to slice to top layer of card, second to cut through the foam and third to cut through the bottom layer of card works best).  Glue on a couple of tabs of foam-core to sit inside or outside your dew shield.

I just used some matt black automotive spray paint to colour it.  The first one worked like a charm, but when I went to make a second one with slightly cleaner edges, the paint dissolved the foam-core around the edges and I ended up with a warped mess.  I think the key is to apply several thin coats and let them dry, and maybe tape up the edges to stop the paint soaking in too much.

The Y pattern works fine with bhatinov grabber (built in to APT); it only just shows up on maximum zoom in live view, but the software has no problem picking up the spikes and showing how close I am to focus.

[JamesF]

I read a few weeks ago that you should tie a piece of string to your bahnitov mask to prevent it from falling when you slew!

I'd not heard of this idea, but it's blindingly sensible.  I shall add a loop to mine.

James

[CedricTheBrave]

mine smashed into about 40 pieces

[JamesF]

Blimey.  That's not good news

I've just remembered I have  wrist strap from an old compact camera lying about somewhere.  I shall drill a hole in the mask and loop that through it.  Should look a little neater than a piece of string.

James

[CedricTheBrave]

it'll be dark James

[JamesF]

it'll be dark James

I know.  String just offends my sensibilities for some reason

James