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Looks like it's lunar tonight then...

JamesF

By JamesF
in The Astro Lounge

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JamesF

JamesF

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Clear sky forecast all night, but there's a slight haze in the sky which means moonlight has already killed most of the sky. I can see a small darker patch between Lyra and Hercules, but that's about it. Looks like I shall be sticking to lunar observing tonight...

On the bright (hah!) side, I have done a full collimation of the 10" dob -- focuser, secondary and primary, using a webcam and Mir de Collimation to get the secondary properly centered and aligned, and then re-aligned the Telrad and RACI finder. I had replaced the focuser because my previous Skywatcher one wasn't running true and needs some work to sort it out properly. The new one does run beautifully true, but needs another spacer before my 27mm Pan will reach focus. I have the spacer, but no stainless bolts long enough so I have ordered some and with luck that should all be sorted over the weekend.

James

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Luke

Luke

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Well done getting that job out of the way, beats my installing a new camera driver that took me a week or two. :grin: I'm tempted to image the moon tonight if it clears soon, seeing as the sun could not be lured out of hiding earlier.

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JamesF

JamesF

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What do you exactly do and how long does it take? You make it sound like a big job. is it?

It's not major, just a bit time-consuming I guess.

I started by removing the spider and secondary and marking a point on the inside of the OTA directly opposite the focuser. I then put a laser collimator in the focuser and adjusted the focuser so the laser pointed at the mark and continued to do so as the focuser moved in and out.

Once that was done I replaced the spider and secondary, put a webcam (with a lens in) into the focuser and used SharpCap with the reticle provided by Mire de Collimation to centre the secondary under the focuser and make sure it presented as a circle and once that was done, that the centre spot on the primary appeared in the centre of the circle.

I finished off by using the laser collimator to collimate the primary.

The secondary was much further "up" the OTA than it should have been. There's now a gap of about 7mm between the back of the secondary holder and the spider. I might invest in some stainless allen bolts to replace the collimation grub screws and perhaps the main secondary retaining screw too, but the main thing to sort out now is getting enough backfocus to allow my Panoptic to come to focus.

James

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Iancovici

Iancovici

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It's not major, just a bit time-consuming I guess.

I started by removing the spider and secondary and marking a point on the inside of the OTA directly opposite the focuser. I then put a laser collimator in the focuser and adjusted the focuser so the laser pointed at the mark and continued to do so as the focuser moved in and out.

Once that was done I replaced the spider and secondary, put a webcam (with a lens in) into the focuser and used SharpCap with the reticle provided by Mire de Collimation to centre the secondary under the focuser and make sure it presented as a circle and once that was done, that the centre spot on the primary appeared in the centre of the circle.

I finished off by using the laser collimator to collimate the primary.

The secondary was much further "up" the OTA than it should have been. There's now a gap of about 7mm between the back of the secondary holder and the spider. I might invest in some stainless allen bolts to replace the collimation grub screws and perhaps the main secondary retaining screw too, but the main thing to sort out now is getting enough backfocus to allow my Panoptic to come to focus.

James

Sounds very complicated but also interesting!

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Tinker1947

Tinker1947

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It's not major, just a bit time-consuming I guess.

I started by removing the spider and secondary and marking a point on the inside of the OTA directly opposite the focuser. I then put a laser collimator in the focuser and adjusted the focuser so the laser pointed at the mark and continued to do so as the focuser moved in and out.

Once that was done I replaced the spider and secondary, put a webcam (with a lens in) into the focuser and used SharpCap with the reticle provided by Mire de Collimation to centre the secondary under the focuser and make sure it presented as a circle and once that was done, that the centre spot on the primary appeared in the centre of the circle.

I finished off by using the laser collimator to collimate the primary.

The secondary was much further "up" the OTA than it should have been. There's now a gap of about 7mm between the back of the secondary holder and the spider. I might invest in some stainless allen bolts to replace the collimation grub screws and perhaps the main secondary retaining screw too, but the main thing to sort out now is getting enough backfocus to allow my Panoptic to come to focus.

James

Something like this......http://www.a2a4.com/acatalog/KNURLED_THUMB_SCREWS_HIGH_A_2-1.html

DSC_9468.jpg

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Tinker1947

Tinker1947

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They certainly look like they'd do the job, though from the website it's not at all clear to me what length they are.

James

My invoice shows M3 X 16mm, i hope its the right invoice, but if there to long they can be made shorter,,,stretching them if there to short just won't work...:)

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JamesF

JamesF

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My invoice shows M3 X 16mm, i hope its the right invoice, but if there to long they can be made shorter,,,stretching them if there to short just won't work... :)

Ahh. Do we think that where they've put, for example, "M3 x 16M ..." on this page: http://www.a2a4.com/acatalog/M3_KNURLED_THUMB_SCREWS_H_T_464-1.html that they actually mean M3 x 16mm?

James

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cantab

cantab

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Clear sky forecast all night, but there's a slight haze in the sky which means moonlight has already killed most of the sky. I can see a small darker patch between Lyra and Hercules, but that's about it. Looks like I shall be sticking to lunar observing tonight...

I never got the memo and went looking for DSOs :huh: Well, mainly to test out my mum's new monocular. Rubbish conditions here in Birmingham; clouds and gaps, clouds in what look like gaps to the naked eye, the moon and the city between them drowning out half the sky :sad: And if Vega at one point looking like a double star is anything to go by, yeah, bad seeing to boot.
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