How do you get photos of your collimation.

[Mr Spock]

My collimation is spot on. I've tried to photography it with little success. I couldn't get my camera in the right place; same with the iPhone.

This is the best effort with my iPhone. I haven't got it central (don't know how) so it looks as though the secondary is off centre when it isn't! Aaaagh!

Image quality is terrible too 

[Ricochet]

Though a collimation cap perhaps? The smaller hole should help with centring. You could also use a Cheshire but you would need an app with manual focus else you'll just get a photo of the cross hairs. 

[Spile]

On 30/09/2022 at 19:01, Mr Spock said:

My collimation is spot on. I've tried to photography it with little success. I couldn't get my camera in the right place; same with the iPhone.

This is the best effort with my iPhone. I haven't got it central (don't know how) so it looks as though the secondary is off centre when it isn't! Aaaagh!

 

Image quality is terrible too 

I see offset, tilt and rotation errors with your secondary...

Edited October 2, 2022 by Spile

[Mr Spock]

Um, no you don't. What you see is an image taken from the wrong place! 

[kev100]

I've been having all sorts of problems with collimation ever since my scope blew over whilst at Astrocamp the other week, but I think it's getting there. Pic taken through a collimation cap...

Kev 

 

 

[ollypenrice]

How are you attaching the camera? Getting it centered and square is critical. You'd normally use a T-ring which fits into your camera as a lens does, then use a nosepiece, 2 inch or 1.25 inch, between that and the telescope. There are also adapters to hold mobiles but I've no idea how precisely they place the camera. My guess would be 'not very.'

Olly

[Spile]

4 hours ago, Mr Spock said:

Um, no you don't. What you see is an image taken from the wrong place! 

I’d assumed you had taken the image through a peep hole? 

[kev100]

1 hour ago, ollypenrice said:

How are you attaching the camera? Getting it centered and square is critical. You'd normally use a T-ring which fits into your camera as a lens does, then use a nosepiece, 2 inch or 1.25 inch, between that and the telescope. There are also adapters to hold mobiles but I've no idea how precisely they place the camera. My guess would be 'not very.'

Olly

I just used my phone up against the collimation cap for the pic. Will try a t-piece and DSLR tomorrow.

[ollypenrice]

10 hours ago, kev100 said:

I just used my phone up against the collimation cap for the pic. Will try a t-piece and DSLR tomorrow.

Actually I misunderstood the OP's question. I thought he wanted a photographic confirmation of good collimation but what he wants is an image of the optical train, I believe.

Olly

[Spile]

This is my interpretation of your image. I see some tilt rotation error.

 

[kev100]

5 hours ago, Spile said:

This is my interpretation of your image. I see some tilt rotation error.

 

Thanks for that, still a little way to go 🙂

[Spile]

8 hours ago, kev100 said:

Thanks for that, still a little way to go 🙂

Only a smidge by the looks of it.

[kev100]

It was miles out after being blown over ... With bent secondary vanes and a damaged focuser. I'm happy it's not far away now.

[Shibby]

I have recently used an OCAL. I think that centering the sensor is critical and difficult with any normal "webcam". Each individual OCAL comes with its own offset figures to compensate for the imperfect placement of the sensor during manufacture. This just offsets the circles in the software though, so I guess doesn't affect the image itself.

[Shibby]

Images taken are here: 

 

[tooth_dr]

50 minutes ago, Shibby said:

I have recently used an OCAL. I think that centering the sensor is critical and difficult with any normal "webcam". Each individual OCAL comes with its own offset figures to compensate for the imperfect placement of the sensor during manufacture. This just offsets the circles in the software though, so I guess doesn't affect the image itself.

Having recently bought an OCAL, I think it's a very accurate tool and takes any guess work out of the collimation process.

[Mr Spock]

OCAL sounds great, except you need a laptop to go with it...

[tooth_dr]

19 minutes ago, Mr Spock said:

OCAL sounds great, except you need a laptop to go with it...

I thought initially you were looking help to collimate, but reading back it says you have the collimation spot on.  What is the purpose of the photo?

[Mr Spock]

29 minutes ago, tooth_dr said:

What is the purpose of the photo?

I thought if I could photograph what a collimated Newt looked like I could help people who wanted to collimate theirs.

No good deed goes unpunished as they say. All it's done is bring me grief so I've abandoned the idea.