webcam

[steviep]

Hello

I have a nexstar 127slt. Webcam and adaptor. Is it better to go straight through without the rught angle viewfinder or not. Hope this makes sense

Steve

[JamesF]

I prefer not to use the diagonal because it just introduces another source of potential problems.

You will find the that focus position changes massively though.

James

[steviep]

Thanks for the reply, does that mean that the 1.1/2 adaptor needs to be longer? Also is it appropriate to use a Barlow or does that make things worse.

Steve

[JamesF]

It doesn't need to be longer because a Mak focuses by moving the focal plane rather than by moving the eyepiece or camera to meet the fixed focal plane as happens with a refractor or newt.

In fact, a side effect of the way Maks (and SCTs) work is that by moving the camera further away from the OTA the image becomes bigger when it is in focus.

For planetary imaging a barlow will be useful though you may want to start without one to get the hang of things.  For lunar or solar imaging you probably don't want a barlow unless you're trying to get images of specific features (in fact with this OTA the image of the lunar or solar disc will just about fill a crop-sensor DSLR frame perfectly).

I'd start with the camera only and find focus on a distant object (television aerial, tree, telegraph pole etc.) during the day to get the hang of things.  Perhaps use the eyepiece without the diagonal too to find out how much difference there is in the position of the focuser between the two (or "turns of the focuser knob, in what direction").

You may find this is all quite tricky at first, particularly where planetary imaging is concerned.  The camera sensor is a very small thing to get the image to land on, and even when you do if the image is too far out of focus you may not even be able to see it's there at all.  Practice really helps.

James

[steviep]

James

thanks for the advice, appreciated

Steve