Author Topic: Focus!  (Read 5120 times)

G1ZmO

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Focus!
« on: February 26, 2013, 11:40:58 AM »
Ok I tried to follow the instructions that came with the bahtinov mask but can't quite see what's wrong

According to the instructions I should
  • take a test shot with the mask on
  • zoom in and compare the image to the example spikes
  • adjust the focus and take another shot until I get one that looks like the example

Problem is that it looks nothing like the example!

http://flic.kr/p/dXTbVn

http://flic.kr/p/dXYRJC

Is this what it should look like?
Any ideas?

Ta

Paul
Paul

perthskies

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Re: Focus!
« Reply #1 on: February 26, 2013, 12:05:31 PM »
« Last Edit: February 26, 2013, 12:09:25 PM by perthskies »
Sold my Dob, got Star Adventurer and other stuff

gary1968

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Re: Focus!
« Reply #2 on: February 26, 2013, 12:37:11 PM »
Your image aint what I would expect mate...... are you sure it is collimated correctly? I still think it needs done with a cheshire to ensure the mirror is central..... I dont think a laser can do that.
 
Gaz
Skywatcher star discovery 150p
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G1ZmO

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Re: Focus!
« Reply #3 on: February 26, 2013, 06:28:25 PM »
It might be collimation mate, I seem to need to re-do it every time I move the scope now and it seems to be off by miles each time.
Paul

Teslar

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Re: Focus!
« Reply #4 on: February 26, 2013, 06:33:51 PM »
Images don't open for me at least just a 404 error. What scope are you using and does the mask match the F rating of your scope ?
Mounts: HEQ5, NEQ6
Scopes: Teleskop Service  10" CF , Skymax Mak 180Pro, ED80
Visual: Baader Hyperion 5,10,17,31 & Zoom
Camera: QHY8L, QHY IMGOH, QHY5L-II

G1ZmO

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Re: Focus!
« Reply #5 on: February 26, 2013, 09:00:11 PM »
Yes, the mask was spec'd for the F5 305mmFL scope. See: http://scottishastronomers.com/forum/index.php?topic=954.0

The pics are set to allow everyone to see them.

Try the un-shortened url: http://www.flickr.com/photos/53431651@N03/8508675943/
« Last Edit: February 26, 2013, 09:02:13 PM by G1ZmO »
Paul

blinky

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Re: Focus!
« Reply #6 on: February 26, 2013, 09:43:42 PM »
I get the same as you Paul, it's fine, increase the exposure a little and it should look more like the samples.  Also dont worry about the star shape when the mask is on, it will elongate them slightly and make it look like it is not collimated.

G1ZmO

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Re: Focus!
« Reply #7 on: February 26, 2013, 09:59:45 PM »
Would I be correct in thinking that, with an untracked dob, the ability to shoot through the DSLR is really limited to the moon (or sun) and that if I want to do any planetary stuff I'd probably need to use a webcam and stack AVI frames?
Paul

blinky

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Re: Focus!
« Reply #8 on: February 26, 2013, 10:04:35 PM »
Yep, field rotation would very quickly cause star trails :(

turbolord

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Re: Focus!
« Reply #9 on: February 26, 2013, 10:26:20 PM »
Modern Canon Dslrs have very good 50fps video functions

G1ZmO

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Re: Focus!
« Reply #10 on: February 26, 2013, 10:28:04 PM »
nah, I have a 350d with no video function :(
Paul

gary1968

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Re: Focus!
« Reply #11 on: February 26, 2013, 10:30:07 PM »
Does Backyard EOS not work with the 350d?

Sent from my HUAWEI U8815 using Tapatalk 2

Skywatcher star discovery 150p
Canon 1000d
Philips spc900 webcam
Loads of other bits n bobs

Everything will be OK in the end, if its not OK its not the end........

G1ZmO

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Re: Focus!
« Reply #12 on: February 26, 2013, 10:43:04 PM »
Hmm that does appear to be compatible with my camera Gaz. I may have to try this but will have to buy myself another laptop for windows. Now this presents 2 dilemmas; where would I purchase such a beastie and, could I bear to actually use an MS product outside of work! lol
Paul

Teslar

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Re: Focus!
« Reply #13 on: February 27, 2013, 07:02:23 AM »
Looks like a focus issue to me. I always focus to the best I can visually before I put the bahtinov on. Then it's just a case if fine tuning.
Mounts: HEQ5, NEQ6
Scopes: Teleskop Service  10" CF , Skymax Mak 180Pro, ED80
Visual: Baader Hyperion 5,10,17,31 & Zoom
Camera: QHY8L, QHY IMGOH, QHY5L-II

boabsta

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Re: Focus!
« Reply #14 on: February 27, 2013, 08:26:08 AM »
Backyard Eos only works for the 350d if you have xp. Its not supported in vista 7 or 8. Found that out the hard way.
 
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Funk it, close enough ;D