Optical Quality of 9.25 Edge HD

[cshahar]

Hi:

I am in the market to buy a 9.25 Edge HD. I will be using it exclusively to take h-alpha solar images (I have already ordered the ERF, etc.). One person responded to my want ad, and i asked him to send me pictures he had taken to judge the optical quality of this individual scope. He sent two pics, one with trailing stars and another of M81 that had no trailing. Is there any way some of you can judge the optical quality of the scope on the basis of this one image? I have included it in this post and wondered if you have any comments about it. How much variability is there between these scopes? I heard that the quality control is better for the Edge telescopes.

Thanks,

-Charles

[Ben the Ignorant]

These stars are tight and round, that's rather promising, but optical quality is judged in hi-res. It would take some planetary shots, or pictures of the intrafocal/extrafocal patterns.

[cshahar]

Thanks Ben. I appreciate the suggestions.

-Charles

[CraigT82]

To be honest I think the only way to check the optical quality of a particular scope is to go along and do a star test (excluding optical bench tests etc). That in itself raises challenges. A deep sky image like that can be affected by so many factors that are nothing to do with the quality of the scope. 

If you're serious about getting a 'good' one maybe you should reconsider buying used?

Craig

[cshahar]

thanks Craig. That is exactly the conclusion that i arrived at!

[ollypenrice]

Look at planetary images and the best in the world are taken with SCTs. Look at deep sky images and SCTs don't shine in anything like the same way. You need to look at images using the camera in question on the target in question in order to decide what will work for your projects.

Olly

[Uranium235]

The thing is, that image does not tell us (in regard to DSO work) what mount it was sat on. As its not just the telescope that needs to perform - but the mount as well. Guiding at that FL is a very tricky business indeed.

The mount in your sig *might* be ok for solar work where you are grabbing your images in a short burst (but it certainly wont thank you for touching/knocking it), however for DSO you will need something much more stable.