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Old 23-07-2020, 01:16 AM
Tasaurora (Si)
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Astrophotograph with Dobson scope?

It looks like I’m inadvertently heading to the “dark” side of Astro photography as it’s going to help me get much better vision of what’s out there. (Re - get kids more interested than just looking at another star).

So - I’ve read a fair bit about EQ mounts and specific scopes for the job and wedges for AZ mounts etc and I have none of that lol.

Is anyone simply using a goto skywatcher 10” with a camera ? Why is such a scope deemed unsuitable given the tracking capabilities? The kids are handy on a laptop - hoping this fact will involve them more...
The eyepiece will accept 2” eye pieces - to get started, is it worth just getting an adapter for eye piece / camera? I have an old Fuji finepix that has multiple settings - but - it doesn’t have detachable lens, can I simply measure the external of the fixed lens and specify that for the interface ?

I’m such a noob at using the scope - I’m already in the deep pool and this is like someone throwing rocks at me now, so apologise for stupid questions.

Last edited by Tasaurora; 24-07-2020 at 05:37 PM.
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Old 25-07-2020, 10:31 AM
sunslayr (David)
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Easiest way is to get something like this smartphone adapter for your eyepiece. If you enjoy it then you could always think about getting a dedicated astro camera or slr and do prime focus astrophotography without an eyepiece. The reason people don't use an alt-az mount like a dobsonian is because objects rotate over time. But for short exposures it's fine, so have fun.
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Old 25-07-2020, 10:57 AM
Startrek (Martin)
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Thatís a fine visual scope you have there which can get into some entry level Astrophotography. Ive had the Skywatcher 12Ē Goto dob for 2 years now for visual only and itís fantastic
Although you are limited to short exposures ( up to 20 or 30 sec) due to tracking and field rotation, you can still have a lot of fun imaging the planets , moon and various DSO objects like star clusters etc...
Something like an old Canon 450D or 600D and a T ring and adapter will get you started
Maybe down the track if you want to get more serious about AP a popular EQ mount like a Skywatcher HEQ5 is a good choice as it can handle an AP payload of up to 9kg.I started with a 6Ē f6 newt on my HEQ5 and still use it, or alternatively an 80mm or 100mm refractor
Good luck and enjoy this amazing hobby !!
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Old 25-07-2020, 12:02 PM
raymo
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To answer your question regarding your scope's suitability for AP; there are
three distinct reasons.
Firstly, GOTO tracking is intended solely to keep your
target in view for extended periods of time, and is nowhere near accurate enough to keep stars stationary for exposures of more than a very short time, seconds rather than minutes.
Secondly, as stated by Martin, a phenomenon known as field rotation rears
its ugly head after 15-30 seconds, and distorts your stars. This is a feature
of alt/az mounts.
Thirdly, alt/az mounts have to track the target by moving in discrete tiny
up/down [alt] and sideways [az] steps using two motors, whereas an
EQ mount mimics the Earth's rotation, and a motor running continuously in the opposite direction to the Earth's rotation keeps the target stationary, with only occasional little corrections by the second motor needed to correct for any inaccuracy in the mount's polar alignment, and imperfections in the motor drive system.
raymo
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Old 13-08-2020, 01:33 PM
Tasaurora (Si)
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Thanks for info - buying phone mount to get started.
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Old 13-08-2020, 05:56 PM
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Tulloch (Andrew)
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Don’t forget about the planets - using a tracking alt/az mount is perfectly fine for imaging the planets using a (Canon) DSLR or dedicated planetary camera.

Andrew
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