Perfect focus each time using a Bahtinov Mask

[AlexN]

Originally Posted by Dennis

Hi Alex

A 45 sec exposure, that surprises me - what was your optical system set up?

With the mask on either the C9.25 or Mewlon 180, with the TeleVue x4 PowerMate plugged in, I was focusing the DBK21AF04 using exposures of between ½ and 2 seconds on mag 1 stars?

Cheers

Dennis

Dennis,

optical system was Megrez 102 - UV/IR filter - QHY8, what I meant by that was, I used Nebulosity 2's focus routine with the mask to get the focus to where the mask said it was perfect, removed the mask, then took 5x45 second subs.. Its a little mini-project Im doing when the neighbors turn their flood lights on, or when the moon ruins clear nights... Photographing the named stars... Anyway, after focusing with the mask using the focus routine then removing the mask and taking the images, I found it was still a little soft..

[leon]

Maybe I will be blasted out of the water for this comment, but, so be it.

I can't really see why these mask things are such the rage all of a sudden, and not to sound like a smart arse, I have been doing diffraction spike focusing every since I have used the Tak.

With the Tak you can look through the angle finder attached to the Canon 5D, slowly move the focuser in and when the star light diffracts into different colours, you know your on the money. surly this applies to most scopes.

You can actually see it snap into focus, never misses.

I have never used any other form of focusing other than this method, but than that is just me, I suppose, and I'm half blind to boot.

Leon

[AlexN]

Leon, Unfortunately the QHY8 does not have a view finder...

[leon]

Ok Alex point taken, have to admit I didn't consider any other imaging devices other than DSLR's, sorry, my oversight, maybe I have been a little harsh in my comments.

Leon

[Dennis]

Originally Posted by leon

Maybe I will be blasted out of the water for this comment, but, so be it.
>Snip
Leon

Hi Leon

No one should be blasted out of the water for describing their experiences, techniques, approach or set up. There is always something to learn from each other and without the healthy exchange of information here on IIS, I’m sure we’d all be the poorer in our hobby.!

A scenario where the Bahtinov Mask really shines, for me, is in long focal length imaging. Trying to eyeball best focus at focal lengths of over 3000mm can be time consuming and often leaves me with a niggling doubt.

I find that the Bahtinov Mask helps me converge to best focus rapidly and confidently. But, there was life before the mask and I’m certain there is life without it too.

Cheers

Dennis

[Dennis]

Hi Alex

Ta for the clarification.

When I’m using the SBIG ST7, I converge to focus quickly with the Bahtinov Mask and then confirm best focus using the Focus routine in CCDSoft, the SBIG camera control software. This gives me the best of both worlds, vis-à-vis:

• Rapid convergence to a really good focus using my eyeball.
• Touching up final focus (if necessary) assisted by the software algorithm!

Cheers

Dennis

[Ian Robinson]

Unclear on what they do ?

[h0ughy (David)]

Originally Posted by Ian Robinson

Unclear on what they do ?

well either read the entire thread or go to the cloudy nights link on this

[wunder]

Originally Posted by leon

I can't really see why these mask things are such the rage all of a sudden, and not to sound like a smart arse, I have been doing diffraction spike focusing every since I have used the Tak.

The diffraction pattern on the masks is much brighter than some other methods of adding diffraction spikes. You can use much dimmer stars. Also, the way the center spike is framed in the outer spikes makes it very easy to get it just right.

[spearo (Frank)]

Folks,
let me tell you...I've just had a go with my home-made Bahtinov mask this weekend.
All I can say is:
WOW !!!!
images being processed right now i'll be posting soon.

The mask is simply wonderful. I got focus either at F/11 or with the 6.3 reducer on the C14 without any problem (i do use the live view function of the Canon 20Da which really magnifies the image)

I got great focus in seconds and it was so easy, every time i'd line up on a star to synchronize and refine the next goto to a target, I'd put the mask on and check the focus.

make one for yourselves, you wont regret it.

frank

[RB (Andrew)]

Originally Posted by spearo

The mask is simply wonderful. I got focus either at F/11 or with the 6.3 reducer on the C14 without any problem (i do use the live view function of the Canon 20Da which really magnifies the image).

frank

Thanks for posting Frank, I want to make one for my 20Da too.

[h0ughy (David)]

Originally Posted by RB

Thanks for posting Frank, I want to make one for my 20Da too.

Which One RB? LOL

I found that foam core board is not the best - bad idea for the ed80 and the 127ED - yet to do it for the c8 and the 10". laser cut is the answer

[RB (Andrew)]

Originally Posted by h0ughy

Which One RB? LOL

[ozstockman (Mike)]

Originally Posted by jerry3672

Hi all, I'm new to your forum and would like to explain what is going on with www.spike-a.com

The focus mask was offered because of the interest people had at cloudy nights to have me make them masks. So John helped me by placing the spike-a web site up so people that could not make a mask had somewhere to purchase one. We have attempted to get Pavel to allow the use of his name on the mask. So far we have no response from e-mails. I went to an lawyer to find out what the correct royalty should be and how to send Pavel the credit he deserves. If anyone here speaks Russian, I sure could use the help communicating.

Jerry

Hi Jerry,

If you want to contact Pavel I am sure that you can find his current email on http://www.astronomy.ru/forum/index....=profile;u=408

I have never met him but I don't think there is more than one Pavel Bahtinov(Павел Бахтинов), who lives in Samara in Russia and is keen on astrophotography. Moreover the page above has a link to astrophoto.chat.ru as a personal webpage.

I reckon that Pavel can speak English or at least can write and read in English but if you have problems or need any help communicating with him let me know. I speak Russian and can help with it.

cheers,

Mike

[wunder]

Hi Mike- thanks for your offer!

We were able contact Pavel and are getting the details worked out. Thanks for your offer on translation- we may take you up on that, as Pavel doesn't speak any English.

[wunder]

By the way- our original problem contacting him was his Spam filter software intercepted all of our emails!

[h0ughy (David)]

Well i posted some infor last night - then deleted it this morning. for those first 5 templates it was going to cost 140.80, i am getting a new quote for a further 3 templates for Mr Simmons. these will be made from 1.2mm 304 grade stainless steel. I make a fundamental stuffup in the design - now corrected (thanks Dennis).

[Dennis]

Originally Posted by h0ughy

Well i posted some infor last night - then deleted it this morning. for those first 5 templates it was going to cost 140.80, i am getting a new quote for a further 3 templates for Mr Simmons. these will be made from 1.2mm 304 grade stainless steel. I make a fundamental stuffup in the design - now corrected (thanks Dennis).

Hi Dave

Thanks for generating the drawings for the C9.25, M180 and Vx102 – I appreciate your work!

It’s a real pity that you couldn’t get the Gold Leaf Crinkle finish, with a contrasting Platinum Inlay and Diamond Encrusted Edges! Oh well, stainless steel will have to do!

Cheers

Dennis

[h0ughy (David)]

Originally Posted by Dennis

Hi Dave

Thanks for generating the drawings for the C9.25, M180 and Vx102 – I appreciate your work!

It’s a real pity that you couldn’t get the Gold Leaf Crinkle finish, with a contrasting Platinum Inlay and Diamond Encrusted Edges! Oh well, stainless steel will have to do!

Cheers

Dennis

you know between my first submission and speaking with you they cut out the entire first lot this morning......after i told them to hold.....

their mistake (for cutting) my mistake for not ordering the gold leaf and diamond encrusted coatings the platinum inlay was tacky

[Dennis]

Originally Posted by h0ughy

.... my mistake for not ordering the gold leaf and diamond encrusted coatings the platinum inlay was tacky

Just make sure that only the non-diffracting edges are decorated with the Diamond Encrusting!

Cheers

Dennis