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Gina

Mountings and Controls For Widefield Imaging Rig

309 posts in this topic

Focuser is working pretty well :)  About 2000 ticks of the Astroberry Focuser to go from end to end of the focus gear sextant.  Since the Astroberry Focuser is set up for 10,000 ticks range, I'll edit this and recompile to limit it to 2000 ticks - I don't want to risk running off the end of the gear teeth.

Rotation control is also working fine.

(The damage to the pink rotation ring was due to removing the extension ring which was found to be unnecessary and got in the way.  It doesn't affect operation.)

135mm lens focus gear 02.png

Edited by Gina

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The widefield imaging rig is now ready for attaching to the NEQ6 mount and pointing out of the east facing window for further testing.  First test will probably be manually focussing on the far trees about a mile away in daylight.  Then whenever we get some clear night sky I can test the auto-focus.  If those tests prove satisfactory it will be time to move it out onto the EQ8 mount in the observatory and maybe do some real image capturing.  Looking forward to that :D

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Been checking the focussing indoors at about 4-5m which needed the lens focus rotating a lot more than would be needed for astro or even between tree and infinity.  Just a matter of loosening the clip that holds the gear to the focus sleeve and setting the focus roughly by hand.  Then with the remote focuser set to half way align the pinion with the half-way position on the gear sextant and tighten the clip.  From there the focus can be finely adjusted remotely.

100 ticks of the Astroberry Focuser produces a noticeable defocussing of the image so I think something like ±50 ticks around the true focus should give a good V curve.  Anyway, I'll find out in due course.  I could easily change the gear ratio by 2:1 either way if wanted.

Focus 700.pngFocus 800.png

Edited by Gina

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Visibility is very poor today.  Have rig pointing out of the window and have hand focused on far trees but too limited by the visibility to fine focus with any accuracy.

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Visibility has improved though still misty.  Here is the view looking roughly south through the living room window with rig sat on top of bench PSU on table.  Full size and zoomed in.  Very dull weather, exposure of 0.01s with gain of 300 through Ha filter.

View S Full size 01.pngView S Zoomed In 01.png

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Increased exposure to 0.3s and reduced gain to 0, manually changed focus remotely in 10 tick steps to get best focus I could while watching the zoomed in KStars FITS Viewer.  The tower in the image is around 5 miles distant.

View S Full size 02.pngView S Zoomed In 02.png

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Here is the full resolution image as saved by KStars in FITS format converted into PNG in PixInsight for upload, no post processing.  Focus started out at 1000 ticks after focussing by turning the 135mm lens focus sleeve by hand and tightening the gear clip.  I then went in 100s of ticks followed by 10s of ticks in the Astroberry Focuser driver in INDI Control Panel -- KStars.  Ended up at a setting of 770 ticks.

Light_1440.png

Edited by Gina

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I'm happy with the focuser though the "proof of the pudding" has to be stars.  The rotator control works fine but it tends to move off the set angle.  The stepper motor is unpowered except when actually moving the barrel - it might be better if it were powered to hold position.  Seems I've gone a little bit too far in making the drum/barrel/cage easy to turn.  I guess I could add a bit of extra friction.

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Been checking the rotator and found the reason the cage doesn't stay put towards the 180° point - it was the USB cable feeding the camera and due to where it was attached to the end bracket the stiffness of the cable was pushing the cage away.  I've now cured it by fastening it to the end bracket in a different place.

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