Connecting to OAG?

[tooth_dr]

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p2722_Lacerta-Off-Axis-Guider-for-Canon-EOS-cameras---11mm-length.html

i bought this ^^^

 

What do I need to connect a C mount camera to it?

 

Thanks!

[Ibbo!]

You will need a "T" to "C" adaptor

https://www.firstlightoptics.com/adapters/flo-low-profile-female-t-thread-to-male-c-thread-adapter.html

[tooth_dr]

I wonder if that will add too much, 8mm seems a fair bit 

[LightBucket]

8 hours ago, tooth_dr said:

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p2722_Lacerta-Off-Axis-Guider-for-Canon-EOS-cameras---11mm-length.html

i bought this ^^^

 

What do I need to connect a C mount camera to it?

 

Thanks!

Looks like you need a T2 female to C mount..

Maybe like this

https://www.365astronomy.com/C-Mount-Adapter-from-C-Mount-male-to-T2-female-thread.html

 

[alacant]

9 hours ago, tooth_dr said:

What do I need to connect a C mount camera

Hi everyone. The OP has an OAG with a canon male bayonet on one side and an m48 on the other.

AFAICT there is no easy way to adapt eos to C. 

Probably not what you want to hear but my answer would be either stick with your Canon camera or get a refund and go for this instead.

Good luck anyway as I'm sure that after this post there will be myriad of simple solutions!

 

[RayD]

10 hours ago, tooth_dr said:

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p2722_Lacerta-Off-Axis-Guider-for-Canon-EOS-cameras---11mm-length.html

i bought this ^^^

 

What do I need to connect a C mount camera to it?

 

Thanks!

It largely depends what guiding camera you are going to use on it, so what back focus distance it has.

On my Atik OAG I had issues getting things close enough so used this which gave me most flexibility, but of course this will only work on a 1 1/4 barrel type camera such as Lodestar of GP CAM etc. or with one such as ZWO with the nosecone fitted.

The one linked by @Ibbo! is the one I would recommend, but if you think 8mm is too much then you may need to look at alternatives like I had to.

[tooth_dr]

Seem to running into a few issues!

 

Firstly my chip is set quite far in with the camera I’m planning on using.  13.5mm to the glass over the chip so maybe 15mm to sensor. Where do you measure from to work out distance from prism in the OAG?

 

Secondly there is an M42 ring on my MPCC that doesn’t come off and it blocks the prism when screwed on via M48. I’m going to have to cut this off.

 

If I could work out the distance I guess I would know better!

 

[tooth_dr]

1 hour ago, alacant said:

Hi everyone. The OP has an OAG with a canon male bayonet on one side and an m48 on the other.

AFAICT there is no easy way to adapt eos to C. 

Probably not what you want to hear but my answer would be either stick with your Canon camera or get a refund and go for this instead.

Good luck anyway as I'm sure that after this post there will be myriad of simple solutions!

 

I’m not trying adapt EOS to C, I’m trying to connect T2 mount to C for the guide cam!

[vlaiv]

By the looks of it guide cam sensor should be somewhere between 35 and 45mm away from prism body.

If sensor is at most 20mm inside guide camera housing (it will probably be less than that), and T2-C (CS) adapter is 8mm that would give you less than 30mm so I suspect it will be ok.

Once mounted put camera closest to the prism, focus your main camera sensor and then work in small increments by pulling guide cam away until you hit focus.

From what I see on Baader MPCC T2 thread should be removable (if it is mark III if it is one of earlier versions, I'm not sure).

If you have trouble unscrewing it, like it is stuck and you can't work it loose, I have simple method for dealing with such problems. Just find another T2 accessory, I usually take T2 extension ring, and screw it onto T2 thread of part you wont to work loose - screw it in tight, and then unscrew both together. Having something screwed in on the other end alters the shape very slightly and reliefs pressure that is holding tight preventing you from unscrewing original thread.

Check if you can move prism up and down in OAG. You should be able to do this. It alters Prism position relative to sensor. You don't want it too close to sensor because then it will cast shadow on sensor (flats deal with this, but stars in that part of the image can develop horizontal spikes because diffraction of edge of prism). This way you can have prism be in light path and not hidden behind adapters / spacers (like you say it is now behind T2 part). It also alters focus position a bit, so first position prism the way you want it and then do the focusing.

HTH

[Davey-T]

You need to get roughly the same distance from the imaging camera sensor and guide camera sensor, so the 55mm DSLR distance needs to be matched by the guide camera.

Dave

[tooth_dr]

2 minutes ago, Davey-T said:

You need to get roughly the same distance from the imaging camera sensor and guide camera sensor, so the 55mm DSLR distance needs to be matched by the guide camera.

Dave

Thanks Dave, just a bit trickier to measure at 90 degrees?

[tooth_dr]

5 minutes ago, vlaiv said:

By the looks of it guide cam sensor should be somewhere between 35 and 45mm away from prism body.

If sensor is at most 20mm inside guide camera housing (it will probably be less than that), and T2-C (CS) adapter is 8mm that would give you less than 30mm so I suspect it will be ok.

Once mounted put camera closest to the prism, focus your main camera sensor and then work in small increments by pulling guide cam away until you hit focus.

From what I see on Baader MPCC T2 thread should be removable (if it is mark III if it is one of earlier versions, I'm not sure).

If you have trouble unscrewing it, like it is stuck and you can't work it loose, I have simple method for dealing with such problems. Just find another T2 accessory, I usually take T2 extension ring, and screw it onto T2 thread of part you wont to work loose - screw it in tight, and then unscrew both together. Having something screwed in on the other end alters the shape very slightly and reliefs pressure that is holding tight preventing you from unscrewing original thread.

Check if you can move prism up and down in OAG. You should be able to do this. It alters Prism position relative to sensor. You don't want it too close to sensor because then it will cast shadow on sensor (flats deal with this, but stars in that part of the image can develop horizontal spikes because diffraction of edge of prism). This way you can have prism be in light path and not hidden behind adapters / spacers (like you say it is now behind T2 part). It also alters focus position a bit, so first position prism the way you want it and then do the focusing.

HTH

Thanks for that! I think my MPCC is one piece, I bought it in 2010. 

[vlaiv]

3 minutes ago, Davey-T said:

You need to get roughly the same distance from the imaging camera sensor and guide camera sensor, so the 55mm DSLR distance needs to be matched by the guide camera.

Dave

Not quite 55mm, EOS flange distance is 44mm, here OAG is playing part of T2 adapter (that is usually 11mm) so prism to sensor distance is going to be more like less than 55mm, then there is field curvature - you can have a few mm less because prism is quite a bit off the axis. So depending on OAG construction, I would say it certainly won't be more than 45mm.

[Davey-T]

Get the DSLR focused then raise / lower the guide camera to hopefully focus it if there's enough up / down adjustment.

Dave

[tooth_dr]

28 minutes ago, Davey-T said:

Get the DSLR focused then raise / lower the guide camera to hopefully focus it if there's enough up / down adjustment.

Dave

I just can’t really do this until I buy an adapter either 4 or 8mm!

[Davey-T]

21 minutes ago, tooth_dr said:

I just can’t really do this until I buy an adapter either 4 or 8mm!

Adapters, the bane of the astro' imagers life, I've got dozens of the darn things 

Dave

[tooth_dr]

3 minutes ago, Davey-T said:

Adapters, the bane of the astro' imagers life, I've got dozens of the darn things 

Dave

I’m looking at possible options here just to try it out, elastic bands and other items 

[tooth_dr]

Problem 2 solved, hacksaw, file and some black marker:

 

 

[alacant]

On 24/03/2018 at 12:13, tooth_dr said:

I’m not trying adapt EOS to C,

What a relief!

[alacant]

On 24/03/2018 at 12:43, vlaiv said:

Check if you can move prism up and down in OAG. You should be able to do this.

Just in case anyone is trying, you can't; it's fixed. Unfortunately it's made so as to work for full frame Canon as well as aps-c so not optimal for the latter:(

HTH.