camera focusing problem

[lordthanatos]

please help

here link to my problem

http://forum.skyatnightmagazine.com/tm.asp?m=14720

thanks

[Jamie]

Hi Lordthanatos i would try and focus on the moon first before you try for stars. (walk before you can run and all that)

BTW pop a post in the welcome page let us know a little about yourself.

[moondog]

lordthanatos

I have a 350D and use it for prime focus on my refractor.

Presumably you remove the Canon lens and replace with a Canon T mount adaptor to 1.25 ins nosepiece that you put in the focuser instead of the eyepiece?

Have you tried the setup during the day focusing on a distant electricity pylon? It's a lot easier in the daytime !

Is there any point when what you are focusing on begins to look a bit better? Is it when the focusser is being racked in or out?

If it's starting to improve when the focusser is being racked in and then the focusser stops - you have a problem - not enough inward focus. I don't think you can do anything about this. If the opposite is the case and the focus improves has you rack the focusser out you could get a spacer ring to go in front of the T mount adaptor to give you extra focus. I think that reflectors do not have as much focuser movement as refractors and that this can cause problems with a DSLR.

I'm sure that someone who uses a reflector for imaging will be along to help you.

Hope you get sorted soon

MD

[lordthanatos]

yeah its when im racking in when it improves,is there really nothing i can do???

[FLO]

To solve this problem (being unable to rack the focuser in far enough), you could consider fitting a barlow first, changing your focuser for a lower profile type or moving the mirror a little further up the tube.

If you are just starting out, I suggest you skip imaging altogether for a while and simply use the scope for regular eye-to-eyepiece observing. I have seen several healthy astronomy hobbies 'crash and burn on the runway' from an early involvement with imaging.

[lordthanatos]

what you mean by moving the secondary mirror further up the tube?????

been doing eye 2 eye for sometime now

[FLO]

It is not an ideal solution but if you move the primary mirror cell up the tube, say a centimeter, then the point of focus (the tip of the light cone) is pushed a centimeter further out of the focus-tube.

Try the barlow first

[lordthanatos]

hi, tried the barlow, only improved things abit,but i was wanting to do more widefield shots rather than zoomed in, looks like i picked the wrong scope eh !!

[FLO]

... looks like i picked the wrong scope eh !!

Not necessarily,

For visual, I cannot think of a better reflector for the same money.

For imaging, yes, there are other scope/mounts that are better suited.

[moondog]

For widefield imaging a lot of people use a small refractor, say 66 to 80mm F5 to F7 with a 2 ins focuser.

A decent one would take great widefield images with the 350D. Look on the Widefield section ( and Deepsky) and see what other SGL members have used.

It's unfortunate that you can't get the reflector to work - enjoy just using it visually.

MD

[Kaptain Klevtsov]

With the Skywatcher Newt that I have you need to unscrew the tube from the 1 1/4" eyepiece adapter. That then has a T mount thread on it. Screw the T mount onto that, fix it to the camera and fix it into the focuser.

http://stargazerslounge.co.uk/index.php?topic=4276.0

BTDT

Captain Chaos

[Ant]

Is your focuser a 1.25" or a 2"?

On my 8" F5 the focus point for the 300D (at prime focus) is about 2mm from maximum IN focus. If I remove the lens part of the barlow and screw that into the 2" adapter then the FOV is smaller but the focus point moves out.

There is a product called a coma corrector - I *think* it was moonfish that I was talkignt to, but they told me that the (positive) side effect of the coma corrector is that it moves the focus point out slightly. Not much but it might help.

Ant

[GordonCopestake]

Baader MPCC is the thingy you want

[FLO]

Baader MPCC is the thingy you want

Found this: http://tinyurl.com/gblrc

[GordonCopestake]

Thats the thingy me bobby me

[daz]

Does Aunty Flo have a price on those??

[FLO]

Does Aunty Flo have a price on those??

After SGL discount : £89.95 8)

(Google 'Baader Coma Corrector' for some great reviews!)