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new mount vs modified camera


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Hi all

I am currently using an unmodified canon EOS 100D Skywatcher eq2 mount with the RA economy drive for astrophotography in my backyard. I'm just borrowing the camera from a family member so I cannot modify it. my lenses are 18-55mm, 50mm and a 55-250mm.

my question is whether it would be be best to get a better tracking mount or a new camera which I could modify. 

I'm looking at either a star adventurer or a star adventurer mini because they seem to be the best value cheap astrophotography mounts. they both have a polar scope (which my current mount does not have) and the mini is cheaper but probably can't track as well at longer focal lengths. i notice that a lot of the images from my eq2 mount are ruined by vibrations and they are limited to 30-60s (even at 50mm), would these mounts fix this?

The camera would increase my sensitivity to H alpha, i'm not sure whether that would make a bigger difference than a different tracking mount.

Any help would be appreciated

Thanks

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H alpha signal is almost always faint, meaning it needs long exposures to capture. If you can't track you can't do long exposures... so I think that answers your question and confirms the golden rule of mount first.

Olly

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Hi

There are several things that can help stabilise a tripod, assuming it is level.

Use the tripod on stable ground, decking wobbles for example.

Don't extend the tripod legs fully.

You could put something a little heavy on the tripod accessory tray, or hang a weight from the centre of the tripod.

Fill the tripod legs with sand.

Use a remote trigger for the camera shutter.

 

Edited by happy-kat
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7 hours ago, happy-kat said:

Hi

There are several things that can help stabilise a tripod, assuming it is level.

Use the tripod on stable ground, decking wobbles for example.

Don't extend the tripod legs fully.

You could put something a little heavy on the tripod accessory tray, or hang a weight from the centre of the tripod.

Fill the tripod legs with sand.

Use a remote trigger for the camera shutter.

 

Thanks, i'll try some of these and see if they help

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On 25/10/2020 at 21:39, Astro NGC said:

 i notice that a lot of the images from my eq2 mount are ruined by vibrations and they are limited to 30-60s (even at 50mm)

Sounds like something isn't quite right with the setup. I started imaging with an EQ2 with economy motor and 650mm fl scope. Exposures of 30 sec were typical without star trailing with 60 sec on occasions. You mention exposures ruined by vibrations, so something must be causing vibrations. Is the camera shutter triggered remotely? Is the scope balanced (slightly east heavy in RA can help)? An out of balance scope could cause judder. My EQ2 mount settles within a few seconds of being touched, though it is the Meade tubular leg version rather than the SkyWatcher type. What about polar alignment - is this reasonably good? Poor polar alignment can show as star trails.

The economy motor speed can be a bit tricky to get correct as the motor can run slightly fast initially. If the speed is not correct star trailing will result.

Issues with motor speed or polar alignment will show as star trailing. Mount vibrations may show as an image that looks slightly out of focus. If the RA worm gear adjustment is too tight it can result in RA judder and star trailing.

An unguided Star Adventurer is unlikely to be an improvement over your EQ2. Upgrading the EQ2 motor to one with accurate RA speed could be useful as it would save the fiddle of RA speed setting:

https://www.firstlightoptics.com/sky-watcher-mount-accessories/skywatcher-ra-motor-drive-for-eq2.html

 

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12 hours ago, bobro said:

Sounds like something isn't quite right with the setup. I started imaging with an EQ2 with economy motor and 650mm fl scope. Exposures of 30 sec were typical without star trailing with 60 sec on occasions. You mention exposures ruined by vibrations, so something must be causing vibrations. Is the camera shutter triggered remotely? Is the scope balanced (slightly east heavy in RA can help)? An out of balance scope could cause judder. My EQ2 mount settles within a few seconds of being touched, though it is the Meade tubular leg version rather than the SkyWatcher type. What about polar alignment - is this reasonably good? Poor polar alignment can show as star trails.

The economy motor speed can be a bit tricky to get correct as the motor can run slightly fast initially. If the speed is not correct star trailing will result.

Issues with motor speed or polar alignment will show as star trailing. Mount vibrations may show as an image that looks slightly out of focus. If the RA worm gear adjustment is too tight it can result in RA judder and star trailing.

An unguided Star Adventurer is unlikely to be an improvement over your EQ2. Upgrading the EQ2 motor to one with accurate RA speed could be useful as it would save the fiddle of RA speed setting:

https://www.firstlightoptics.com/sky-watcher-mount-accessories/skywatcher-ra-motor-drive-for-eq2.html

 

I think the polar alignment should be ok, even though there isn't a polar scope. i also think the motor speed is good as i spent a while to get it correct with a telephoto lens

my setup isn't balanced as the counterweight is too heavy for just a camera and lens, this could be the problem but i'm not sure what i can do about that

Thanks

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21 hours ago, bobro said:

Sometimes a weight can be improvised (the can is full of sand). Note - this image shows a DIY guided EQ2.

Sand.jpg

can you adjust the weight's distance for different payloads?

if not would it be better to purchase a lighter counterweight for the adjustability (the star adventurer counterweight appears to have a similar diameter) so i can use different lenses?

also, you mentioned having a 650mm scope, is this the 130p (not the DS version) because I have that and it cannot focus to infinity with a canon 100d, is there a solution to this problem without using a barlow lens?

thanks

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The beer can was for a bit of fun, but sticky tape does the job of adjusting height.  🙂

Yes, a 130P reflector scope (various manufacturers) can be modified to come to focus with a DSLR. One way is to take a hacksaw to the tube, cutting something like 35mm from it at the main mirror end. 

Scope_shortening (1).JPG

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Hi

My €0.02...

Dismantle, clean, lubricate and adjust the mount. Then nail the polar alignment in readiness for your new modified camera;)

Cheers

Edited by alacant
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On 30/10/2020 at 13:01, alacant said:

Hi

My €0.02...

Dismantle, clean, lubricate and adjust the mount. Then nail the polar alignment in readiness for your new modified camera;)

Cheers

yeah, that's probably something i should try

thanks

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