Secondary placement in collimation

[sorrimen]

Hi all,

First off, hope this is the correct place for this sort of post. Anyway, I’ve only ever collimated my 8” dob using a collimation cap and as a result my secondary isn’t quite right under the focuser. I was just wondering if anyone knows what sort of effect this will have view-wise? Seeing as everything else is collimated as perfect as I can get it, does this actually have any real effect? I’ve added some images below. As you can see it’s not wildly out of place but enough that after a second look it’s clearly closer to the top in the picture than the bottom. Thanks!

Ross

[Sunshine]

To me, that secondary looks pretty well centred, more importantly are you happy with the views? issue is that once you begin adjusting the secondary (unless you're glaringly off) it is really easy to make a mess of the whole thing. If it were me I would not split hairs especially when it comes to the secondary as its position can be easily messed up, adjusting for one angle usually affects others and it becomes a pandoras box situation. Just my opinion but I would gauge using a star test and whether or not things look sharp through the eyepiece on a night of decent seeing.

Edited July 7, 2022 by Sunshine

[sorrimen]

3 hours ago, Sunshine said:

To me, that secondary looks pretty well centred, more importantly are you happy with the views? issue is that once you begin adjusting the secondary (unless you're glaringly off) it is really easy to make a mess of the whole thing. If it were me I would not split hairs especially when it comes to the secondary as its position can be easily messed up, adjusting for one angle usually affects others and it becomes a pandoras box situation. Just my opinion but I would gauge using a star test and whether or not things look sharp through the eyepiece on a night of decent seeing.

Thanks for your response. I guess you’re right actually, I’ve gone against all that I’ve read and am chasing absolutely perfect collimation, rather than what I’m happy with. I’m loving the views so can’t really complain!

[Spile]

There is no such thing as absolute. Tolerance is the key word. With a Cheshire eyepiece and sight tube combination tool you will be able to judge your alignment.

Based on your images, it looks fine.

Edited July 8, 2022 by Spile