Imaging considerations

[Andypeck101]

Good morning all,

I've been a lapsed astronomer for a while and recently got back into things,  I've refreshed my equipment going for a Celestron Nexstar Evo 6. Great scope and worth the added tracking makes following targets much easier (certainly compared to my old dob).

I'm wondering now what I need to bring my planetary imaging A game.  

I used to have an old webcam but that seems to have gone walkabout, so thinking about  ZWO 120 or 224 colour camera. But I'd there any thing I need to consider around extension tubes atmospheric disturbance filters or are they more of a nice to have. 

I'm also thinking about another diagonal, or would you image directly from the back of the scope?

What about auto focusers and how do they work, presumably I need to hook this up to a laptop and use the feed from the camera to make adjustments?

Is there anything else for consideration?

Apologies for the barrage of questions. 

Andy

 

[vlaiv]

ASI224

ADC (atmospheric dispersion corrector).

x1.5 barlow element (any x2 barlow element will do if placed at correct distance to sensor. Closer you place it - smaller magnification factor, further away - larger magnification factor. Cheap option Baader classic Q x2.25, expensive / best option Baader VIP)

Electronic focuser as option (I don't use it - but many people prefer to use electronic focuser). You don't need auto focuser - one controller by computer, you just need way to focus without disturbing OTA and introducing vibrations. I just deal with vibrations - touch up focus, wait second / two - judge focus from live image, repeat if needed ...

USB3.0 capable laptop with SSD and enough disk space (you'll need around 50 or so GB free - more you have, longer videos and more interesting project you'll be able to do - like animations of shadow / moon transits on Jupiter and so on).

Don't use diagonal mirror for imaging - use simple extension. SCTs are designed to work at certain primary / secondary distance. If you change that distance too much (and you do when focusing) - you introduce spherical aberration. It is best to use it as you would for visual - with supplied diagonal. It was probably optimized for such usage.

This means that if you have it with 1.25" diagonal - it's best to insure that camera sensor is about 80mm away from rear port of telescope (100mm if you use barlow as barlow moves out focal plane).

 

[Andypeck101]

@vlaiv thank you for such a comprehensive reply,  it's very much appreciated and gives me a good starting point to work from.