Keeping Diffraction Spikes Aligned

[Clarkey]

This is probably a bit of a daft question, but with scopes with secondary mirror holders how do you keep them aligned if imaging on multiple nights? With my other scope (ED80) this is not a problem. As long as the image is close to being aligned, once stacked and cropped it becomes a clear image. With the RC, unless I do not move the camera at all between imaging sessions, it is virtually impossible to align the diffraction spikes. Using a X on the screen can get pretty close, but if having to frame a subject at an odd angle this will not work either. I know a camera rotator would work but this is a bit out of my budget for now.

Has anyone got a neat way round this problem?

[tooth_dr]

3 minutes ago, Clarkey said:

This is probably a bit of a daft question, but with scopes with secondary mirror holders how do you keep them aligned if imaging on multiple nights? With my other scope (ED80) this is not a problem. As long as the image is close to being aligned, once stacked and cropped it becomes a clear image. With the RC, unless I do not move the camera at all between imaging sessions, it is virtually impossible to align the diffraction spikes. Using a X on the screen can get pretty close, but if having to frame a subject at an odd angle this will not work either. I know a camera rotator would work but this is a bit out of my budget for now.

Has anyone got a neat way round this problem?

Rotating the camera wont change the spikes position relative to the sky, so you shouldnt find moving the camera causes any problems.  But it's critical that you dont rotate the OTA within the rings, as this WILL move the spikes relative to the sky.

[Clarkey]

Oh yes. D'oh! There was me trying to work out what I could image in one night or multiple nights without touching anything......

I'll quietly go to a dark corner and hang my head in shame. 🤪

At least I have a RC so rotating the tube is not a problem!!

[tooth_dr]

1 minute ago, Clarkey said:

Oh yes. D'oh! There was me trying to work out what I could image in one night or multiple nights without touching anything......

I'll quietly go to a dark corner and hang my head in shame. 🤪

At least I have a RC so rotating the tube is not a problem!!

as an owner of two reflectors, I've learned the hard way 😂

[Clarkey]

Am I allowed to offset this bit of stupidity by saying that so far I have:

a) not left my lens cap on

b) not left my bahtinov mask on

However, there is a first time for everything. (I have done 6 hours of blue data instead of luminance, but I don't think it counts).🤣

[Hughsie]

Aye to leaving the Bahtinov mask on.

Also a first for me was sitting inside watching the guiding on PHD2 suddenly become erratic and then finding the cat was rubbing around the tripod legs! 🐈

[tooth_dr]

I spent 15 minutes fiddling with the gain and settings in PHD2, wondering why the guidestar was really faint - then I realised it was cloudy!