Telescope Reviews: DSLR LiveView for telescope collimation

· Get a Cloudy Nights T-Shirt

· Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

You are not logged in. [Login]

Entrance · Main Index · Search · New user · Who's Online
FAQ · Calendar

Astrophotography and Sketching >> DSLR & Digital Camera Astro Imaging & Processing

Pages: 1

Moromete
sage

Reged: 02/15/12

Loc: Romania

DSLR LiveView for telescope collimation new

#5191880 - 04/26/12 03:06 PM

Has anyone tried to collimate a CAT on a DSLR's LiveView with a swivel screen instead of a laptop screen?

I'm thinking to collimate a C11 with Bob's knobs on the screen of a Canon T3i rotated towards me when I'm in front of the corrector plate.

Considering that Canon has exposure simulation on LiveView (unlike Nikon) is it possible to see clearly the diffraction rings of an defocused star on T3i swivel screen (by manipulating ISO and shutter speed)?

I don't want to drag any laptop with me.

Post Extras:

ewave
scholastic sledgehammer

Reged: 05/16/09

Loc: northwest NJ

Re: DSLR LiveView for telescope collimation new

[Re: Moromete]
#5191961 - 04/26/12 04:01 PM

This assumes all of your adapters and the cameras sensor's position is perfectly in line with your optical train. Me thinks not such a good idea, but might be ok if you only plan to image using the exact same configuration for you AP work. But overall, I wouldn't collimate that way.

Post Extras:

sullij1
Pooh-Bah

Reged: 11/08/08

Re: DSLR LiveView for telescope collimation new

[Re: ewave]
#5191971 - 04/26/12 04:05 PM

Quote:

This assumes all of your adapters and the cameras sensor's position is perfectly in line with your optical train. Me thinks not such a good idea, but might be ok if you only plan to image using the exact same configuration for you AP work. But overall, I wouldn't collimate that way.

Second this opinion.

Post Extras:

mpgxsvcd
Pooh-Bah

Reged: 12/21/11

Loc: Raleigh, North Carolina

Re: DSLR LiveView for telescope collimation new

[Re: ewave]
#5191992 - 04/26/12 04:14 PM

Quote:

This assumes all of your adapters and the cameras sensor's position is perfectly in line with your optical train. Me thinks not such a good idea, but might be ok if you only plan to image using the exact same configuration for you AP work. But overall, I wouldn't collimate that way.

Isn't that the point of doing this? If you collimate a different setup than what you will image with then in all likely hood you won't be collimated for imaging.

The point is to collimate, align, set your focus, and then image without adjusting anything. That way you know nothing has changed.

I don't ever use eyepieces anymore. I do everything I listed above using the swivel LCD on my Panasonic GH2. It's live view crop mode offers a no resolvable detail loss or light loss 8x or 10x magnification. That is perfect for setting focus and alignment that would be very difficult to get with an eyepiece.

It also shows me exactly what the image is going to look like up to 8 seconds of exposure. In addition I can crank the ISO up to 12,800 to simulate up to 5 stops more of exposure.

It works great for me.

Edited by mpgxsvcd (04/26/12 04:16 PM)

Post Extras:

Nils_Lars
Postmaster

Reged: 01/04/08

Loc: Santa Cruz Mountains , CA

Re: DSLR LiveView for telescope collimation new

[Re: mpgxsvcd]
#5192746 - 04/27/12 12:40 AM

Ya it does sound like a good idea but I guess youd have to leave all the adapters and stuff in place and only remove the camera to go between scopes.

Post Extras:

Samir Kharusi
Carpal Tunnel

Reged: 06/14/05

Loc: Oman

Re: DSLR LiveView for telescope collimation new

[Re: Moromete]
#5192855 - 04/27/12 03:02 AM

LiveView and collimation should be great! PROVIDED your arms are long enough (or the OTA is short enough) that you can twiddle the knobs and see the screen at the same time, impossible for me on a C14. I had to resort to a laptop. So just try it out in daylight and if you can reach everything then that ought to be the best method for collimating your scope. As for seeing diffraction rings, impossible on the larger scopes and less than perfectly still nights but there is a very quick and simple way around this. Read all about it here. Try it. Really works better than valiant eyeballing with the unaided eye.

Post Extras:

mpgxsvcd
Pooh-Bah

Reged: 12/21/11

Loc: Raleigh, North Carolina

Re: DSLR LiveView for telescope collimation new

[Re: Samir Kharusi]
#5193067 - 04/27/12 09:28 AM

Quote:

LiveView and collimation should be great! PROVIDED your arms are long enough (or the OTA is short enough) that you can twiddle the knobs and see the screen at the same time, impossible for me on a C14.

That is why we have cameras with screens that rotate and have lossless crop zoom functions.

Post Extras:

PatHolland
Carpal Tunnel

Reged: 10/11/09

Loc: Clever, Missouri

Re: DSLR LiveView for telescope collimation new

[Re: Samir Kharusi]
#5193098 - 04/27/12 09:54 AM

Thanks for the post and the info page Samir. I've always found collimating my 14" LX200 scope to be very, very difficult and always settled with a mediocre collimation after playing with it for 2 hours or so before imaging (or viewing). Getting the diffraction rings in a large scope is almost impossible in S.W. Missouri with average seeing.

Post Extras:

AlAzad
journeyman

Reged: 07/30/12

Loc: Urmia, Iran

Re: DSLR LiveView for telescope collimation [Re: PatHolland]
#5351576 - 08/04/12 12:03 PM

Can I use my DSLR for collimation? I always use a laser collimator for my newtonian. How can I use my DSLR? Is there any step by step guide?

Post Extras:

Alfredo Beltran
sage

Reged: 08/01/10

Loc: Bogota, Colombia, 4°48'02" N, ...

Re: DSLR LiveView for telescope collimation new

[Re: AlAzad]
#5352336 - 08/04/12 09:54 PM

For collimation I've used succesfully my Orion Starshoot Autoguider at 1sec exposures on the rear cell of my C6 SCT OUT OF FOCUS to make sure that I can see the shadow of the secondary mirror.

Then I activate in PHD the bulleye and center a bright star on top of it.

You can see the effect of the adjustments you make on the bolts immediatilly on the laptop screen. The telescope will be collimated when the shadow of the secondary is concentric with the white circle of the star.

Best regards

Alfredo

Post Extras: