How to place back a secondary mirror?

[SECSIO]

Hi everyone!

First of all, my scope is a SkyWatcher Black Diamond 254/1000 (3.9f), this information may be helpful.

Last night I tried to collimate my scope in the darkness, I usually use a torch, but that time I forgot to bring it, I got confident and despite of collimating the scope I ended unscrewing the main screw of the secondary mirror by scewing too much the collimating screws... Yeah, a complete disaster. I was able to turn the whole secondary mirror with my hands, but I did not have a proper screwdriver to place it again in its correct position. Once I got the correct tools, I could place the secondary mirror in front of the focuser and I screwed it to fix it. I do not know what is the correct way to check if I placed the secondary mirror in the center of the focuser, I attach a picture from the inside of my focuser, I think it is placed correctly but as I said I did not perform any kind of measurment, I just used my eyes looking through the center of the focuser.

 

[alacant]

Hi

Where is the focuser? The secondary isn't offering a circular appearance and may need to go further toward the primary.

Looks like a good staring point though and may well be fine if you're just observing, but for anything else, probably better to adjust it.

The easiest way is a to use a Cheshire sight tube. One with cross hairs, even better. 

HTH

 

[SECSIO]

45 minutes ago, alacant said:

Hi

Where is the focuser? The secondary isn't offering a circular appearance and may need to go further toward the primary.

Looks like a good staring point though and may well be fine if you're just observing, but for anything else, probably better to adjust it.

The easiest way is a to use a Cheshire sight tube. One with cross hairs, even better. 

HTH

 

My scope is a reflector, so the focused in in the top of the tube. Its relief to know that the second mirror at least looks well faced to the focuser. 

Edited August 9, 2020 by SECSIO

[alacant]

15 minutes ago, SECSIO said:

focused in in the top of the tube

Sorry. I meant in the photo you sent. At which point on the circumference would it be found?

Cheers.

[SECSIO]

33 minutes ago, alacant said:

Sorry. I meant in the photo you sent. At which point on the circumference would it be found?

Cheers.

Sorry, I was in a hurry, now I understand what you meant. The focuser is in the top of the picture, here you are other picture from a better angle.

On the other hand, I have a GSO laser collimator which I recently collimated, but in this case I think a passive collimation is better to place back my secondary mirror. 

 

 

 

 

Edited August 9, 2020 by SECSIO

[alacant]

It needs adjusting.

Try this then this.

Cheers.

 

[SECSIO]

18 minutes ago, alacant said:

It needs adjusting.

Try this then this.

Cheers.

 

Thank you! ^^