Jump to content

SkySurveyBanner.jpg.21855908fce40597655603b6c9af720d.jpg

Does this sound like a collimation issue


IDM

Recommended Posts

I have been trying to image the planets using Stella Lyra classical Cassegrain and can get reasonable focus but never good. I know about frame rates and roi and can get up to 200fps. When I look at the computer screen with Jupiter the moons never look tight or star like and Jupiter has a bright haze from about 3 o’clock to 6 o’clock position.

the camera is a Zwo asi224mc.

I mostly use refractors so collimation is new to me.

any thoughts?

thanks

Ian

Link to comment
Share on other sites

I wouldn't recommend trying to judge the status of your collimation using a planetary camera and your laptop image.  When I take images of Jupiter it often looks just as bad as you say on screen but the scope is well collimated.  Check it before your imaging session in the usual fashion with a short focal length eyepiece and a defocussed view of a bright star or one of Jupiter's Moons.

  • Like 1
Link to comment
Share on other sites

I found that with the collimation evenly slightly out on my C8 SCT, so that I tolerated the appearance of double stars for ages, the planetary imaging significantly improved when I tweaked the collimation (using an eyepiece and Polaris).

The raw planetary images on a laptop always look rubbish.

Edited by Cosmic Geoff
Link to comment
Share on other sites

Sharpcap seems to rely on measuring star size across the sensor (I may have misunderstood) so I don't think its as good as the APT method. So i have downloaded APT and will give that a go. I will also try the defocus donut method just to see what I can see.

Thanks,

Ian 

Link to comment
Share on other sites

Just centering the donut doesn't necessarily ensure optimal optical collimation. I'd add successively evaluating for on-axis coma closer and closer to focus. The Tri-Bahtinov is a great way to establish that the mirrors are parallel, even if they're not necessarily coaxial.

Then again my brain is polluted with all sorts of Richey-Chretien crud, so what do I know.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.