is this a focusing issue?

[ndastgir]

Hi everybody,

I need a bit of experts' advise on this picture I took last night. I don't seem to get those pin sharp stars... I focus on Jupiter using the live view on DSLR, connected to a laptop, zoomed 10x. is this a focusing issue? or am I doing something else wrong?

I am using a modded 450D with CLS Clip filter, Guiding with 9x50 finder & Lifecam Studio & PHD guiding.

this is a single 10min shot @ ISO 800.

mount is EQ3-2 goto on pier

Any feedback is highly appreciated.

Naeim

[Astrosurf]

Hi Naeim, I can't see your image at work as it's being blocked. I wouldn't focus on Jupiter as it's not a point source like stars are. I find planets swim about due to atmospheric turbulence so I can't focus on them easily. I use a Bahtinov Mask on stars to focus. Is the image actually of Jupiter?

[lensman57]

Hi everybody,

I need a bit of experts' advise on this picture I took last night. I don't seem to get those pin sharp stars... I focus on Jupiter using the live view on DSLR, connected to a laptop, zoomed 10x. is this a focusing issue? or am I doing something else wrong?

I am using a modded 450D with CLS Clip filter, Guiding with 9x50 finder & Lifecam Studio & PHD guiding.

this is a single 10min shot @ ISO 800.

mount is EQ3-2 goto on pier

Any feedback is highly appreciated.

Naeim

Hi,

Focus on a bright star first, not a planet. You are probably saturating the pixels of your camera chip with a single long exposure, this could lead to star bloat. Best to take 30 or 40 at 3 minutes or a bit longer or shorter and then stack the data using DSS or something else and see what you'd get. You'd then need to post processand bring out details in the DSOs by masking the stars. There are some tutorials on the net you search for them but it is an involved process. Producing pinpoint stars with budget equipment is not an easy task I regret to say. The capture looks fine to me BTW.

Regards,

A.G

[RogerTheDodger]

Slightly out of focus hence the doughnut stars. try using a bahtinov mask to achieve focus on a bright star, or if you are using the DSLR in your sig have a play with FWHM focussing with either BYEOS or APT if you are connected to a laptop - you may need to do a bit of reading up to ensure your DSLR can do this with those programs.