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Some more photo questions.
- jhonan
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- dave_lillis
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19 years 5 months ago #6242
by dave_lillis
You need to center a bright star in the field of view first using an eyepiece,
then put on the camera as quickly as possible without moving the telescope.
If a star is out of focus, then you;ll see a disk of light where the star should be, if you turn the focus dial, you'll see it either getting bigger or smaller, there are 3 scenarios,
1, I've found that star images are extremely faint when looking through a SLR camera when attached to a telescope, try a bright star like aldebaren etc.
2, as you focus and the camera is moving away from the scope and the disk is getting smaller but then the focuser reaches the end of its travel but the disk is still present, then you'll need to get extension tubes to add extra distance to the camera, this is a common problem.
3, as you turn the focus dial and the disks are getting smaller but you do not reach focus before the camera reaches the start point of the focuser (fully up to the tube), if you can put on a barlow, this might help focsing, but usually there isnt much you can do about it.
I have a 4" F5 celestron refractor and when I put the camera on it the camera literally reaches focus when the focus tube is fully racked out.
Scopetronix.com do extension tubes.
good luck,
Dave L. on facebook , See my images in flickr
Chairman. Shannonside Astronomy Club (Limerick)
Carrying around my 20" obsession is going to kill me,
but what a way to go.
+ 12"LX200, MK67, Meade2045, 4"refractor
Replied by dave_lillis on topic Re: Canon D60 and focusing
But when I put the camera into the telescope with the t-ring and adapter it is almost impossible to focus the camera on anything through the telescope.
Focus the camera to infinity. Use the telescope focuser to focus with, otherwise things can get confusing!
But as michael said, we'd need more info on the type of setup you have.
You need to center a bright star in the field of view first using an eyepiece,
then put on the camera as quickly as possible without moving the telescope.
If a star is out of focus, then you;ll see a disk of light where the star should be, if you turn the focus dial, you'll see it either getting bigger or smaller, there are 3 scenarios,
1, I've found that star images are extremely faint when looking through a SLR camera when attached to a telescope, try a bright star like aldebaren etc.
2, as you focus and the camera is moving away from the scope and the disk is getting smaller but then the focuser reaches the end of its travel but the disk is still present, then you'll need to get extension tubes to add extra distance to the camera, this is a common problem.
3, as you turn the focus dial and the disks are getting smaller but you do not reach focus before the camera reaches the start point of the focuser (fully up to the tube), if you can put on a barlow, this might help focsing, but usually there isnt much you can do about it.
I have a 4" F5 celestron refractor and when I put the camera on it the camera literally reaches focus when the focus tube is fully racked out.
Scopetronix.com do extension tubes.
good luck,
Dave L. on facebook , See my images in flickr
Chairman. Shannonside Astronomy Club (Limerick)
Carrying around my 20" obsession is going to kill me,
but what a way to go.
+ 12"LX200, MK67, Meade2045, 4"refractor
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