Bahtinov mask and barlow lens

[adamsp123]

Peter i think we have decided your Y mask is the wrong way round?

LOL

Back to front, topsy turvy, slots should be solid and solid should be slots, use the Russian cyrillic alphabet?

[glowjet]

i was going to buy one.

but having read this thread i might be able to save £20.how do i make one and what with? they look very time consuming and fragile

pete

I should hold on a bit, Peter is going to experiment with the Y type, making one of the Y ones will be a whole lot easier.

John.

[emagine]

Just wondering...would it be possible to use a Bahtinov mask with binoculars as well? I made two cut out using the generator fro astrojargon. I used 1100mm as my focal length (for 22x zoom), and aperture as 50mm, I wonder if it was right or not. Cut out two masks for each of the objective...and they don't do anything at all apart from obscuring my view. Can't see any diffraction spikes whatsoever. Just wondering if I'm doing anyting wrong.

[adamsp123]

Just wondering...would it be possible to use a Bahtinov mask with binoculars as well? I made two cut out using the generator fro astrojargon. I used 1100mm as my focal length (for 22x zoom), and aperture as 50mm, I wonder if it was right or not. Cut out two masks for each of the objective...and they don't do anything at all apart from obscuring my view. Can't see any diffraction spikes whatsoever. Just wondering if I'm doing anyting wrong.

Are you imaging through the binos? The reason for using a mask as I see it is that when trying to focus a camera the image is pretty dim and hard to judge when in correct focus, you pick a bright star and using the mask you get dead on focus then you go to the object you wish to image remembering to remove the mask first.

Using ones eyes in place of the camera it is easy to focus without any form of aid.

[Uranium235]

I tried mine last night, it worked a treat with the EP. But when I tried it with the cam at prime focus I couldnt see any spikes through the viewfinder. Would it be ok to focus on Mars first, and then slew to my target? As at the moment, Mars is one of the brightest things in the sky from my location.

I could just take some short subs with the mask on to judge the focus, but it would be a pain to have to go back and forth to the laptop to check the pattern.

[glowjet]

Just wondering...would it be possible to use a Bahtinov mask with binoculars as well? I made two cut out using the generator fro astrojargon. I used 1100mm as my focal length (for 22x zoom), and aperture as 50mm, I wonder if it was right or not. Cut out two masks for each of the objective...and they don't do anything at all apart from obscuring my view. Can't see any diffraction spikes whatsoever. Just wondering if I'm doing anyting wrong.

With the FL of 1100, your bars should be in the region of : 1.25mm to 3.6mm wide, ( Bahtinovs formula ) with only a 50mm objective try a simple Y pattern with 2mm wide bars, I have a pair of 10x50`s and I measured the focal length to be 190mm ( light path from objective to eye piece ) this works out at around 1mm wide for the bars, not sure about the effect of covering both objectives though, have not had a Chance to try it yet.

John.

[emagine]

@Adam. No, I'm not imaging using my binoculars. Since the mask works alright with a DSLR, I was wondering if it was possible for me to use them with binoculars as well. I observed a little bit from the backgarden last night, but had to come back in when the neighbours starting getting strange ideas. Will try again tonight and find out if I see any spikes this time.

[emagine]

Tried again just now. While observing Mars, all I could see through the mask were four cones of light were their tips joined together. Adjusted the focus till they disappeared altogether. Why on earth can I not get anything done right!?

[emagine]

Btw..it was in perfect focus when the cones disappeared, but thats not how the mask is supposed to work.

[adamsp123]

Tried again just now. While observing Mars, all I could see through the mask were four cones of light were their tips joined together. Adjusted the focus till they disappeared altogether. Why on earth can I not get anything done right!?

Could be that Mars has a distinct diameter where as stars are a point light source, use a bright star to try it next time.

[Psychobilly]

Extended souces dont really work that well but can make interesting images... try it soemtime.. A nice crescent phase of venus works well...

I doint know if anyoen was waiting for this "Peter" to try any variation of the mask if you are it will be a whiule as the scopes in the obs are in bits after a debacle with a new piece of kit... and a the moment I am so wound up it as it was all working quite well before it may well be a while before it all gets put back together

Peter...

[adamsp123]

I doint know if anyoen was waiting for this "Peter" to try any variation of the mask if you are it will be a whiule as the scopes in the obs are in bits after a debacle with a new piece of kit... and a the moment I am so wound up it as it was all working quite well before it may well be a while before it all gets put back together

Peter...

Very sorry to hear that Peter, hope it gets sorted out, keep cool, I had major problems a while ago nearly ended up doing a "Basil Fawlty" at one stage, went indoors and had a brew to calm down or else some very expensive kit would have bit the dust.

[glowjet]

Thats a darn shame Peter, sorry to hear of your troubles, hope you soon have them rectified,

John.

[Psychobilly]

Its to avoid a Basil Fawlty that I am keeping the doors firmly locked for a while...

This particular item would have been in smithereens by now if I didnt want to ultimately get it working or recover its cost...

Peter...