Nikon D3000 +skywatcher 1145 help

[MGB]

Hi There

i Have a Nikon D3000 and bought the t2 and adaptor with a barlow and put it onto my skywatcher 1145 synscan telescope i had it on iso 1600 for between 20 secs up to a couple of minutes and all i got where black pictures but one of them had i think a star but it could of been dust.its manuel mode but on trying to get the f/ just reads f/00 and thats on the telescope im new to this any idea what im doing wrong has anybody got a similiar set up willing to give me some ideas.the wife is buying me a tamron 70-300 lense for christmas would this be ok to use for astrophotography as well comments appreciated thanks david

[baggywrinkle]

I wouls suggest a daytime set up and practice. Attach the camera and point the scope at a distant object and see what you get. What were you focusing on for your night shots. Does the 'scopes focusing mechanism give you enough focusing travel?

The F0 would be normal in manual mode as the telescope is not an electronic lens, it cannot tell what the F number is and you cannot control it.

If the mount is an AZ Goto the several minutes exposure would not be possible, 20 secs is about the max with a driven AZ mount.

The Tamron lens sounds OK but for widefield work you need something like a lower focal length lens. This can then be mounted on a standard tripod.

[reddoss]

Hi MGB,

            I am just wondering if you can get enough back focus with your set up. I do not know much about  the  1145 synscan telescope, other that it has an AltZ mount which are not suitable for long exposure astro-imaging. For that you need a German Equatorial Mount (GEM). Here is a link to a website which will give you a good idea on how bto make a start  http://www.astropix.com/HTML/I_ASTROP/TOC_AP.HTM

Also if you have a local astronomy club or society there are likely to be members  who will be able to help and advise you about  astro-imaging.

[bogdog]

trying to get the f/ just reads f/00

thats because you have no lens attached...normal

did you focus on stars using an eyepice then switch over to camera?(hoping that focus would remain)....it wont

you have to focus just with camera attached,then try using liveview screen and zoom in on the star,you will have 30 secs i think before

liveview closes on you but keep trying until you reach focus...but do it on the brightest star you can find

then try a 10 sec exposure at 3200 iso..yeah its noisy but will give you a brighter result to check on

you can then delete that pic and reduce iso knowing that you are in focus

hope this helps

[MGB]

Thanks for all your help apreciated thanks>