Astro-Imaging Help Requested

[MattDay2u]

Hi Everyone,
I've got a CPC1000 HD Deluxe and bought a T-Ring & T-Adaptor to connect my DSLR. I can't even seem to get the moon in focus, so I'm thinking that a micro-focuser is required. The Celestron HD Pro Wedge looks to be another good item, particularly if I want to get planetary shots; however, I'd appreciate some guidance from anyone who has actually gone through this. I find myself a little more cost-conscious than normal at the moment. Are Celestron's astroimaging cameras better, worse, or no different from a mounted DSLR. I've noticed some of these cameras mount on the front lens of the scope. To make it simpler for replies, I'm looking for answers to the following questions: 
> Is something like the Starlight Instruments Feather-Touch MicroFocuser worth the cost, and will it last as long as the scope?
> Does the Celestron HD Pro Wedge improve astroimaging by reducing jitter introduced by the computer tracking. 
> How does the computerised tracking of the CPC know whether or not there is a wedge-mount between the scope and tripod to adjust for tracking? 
> Are marketed astroimaging cameras such as the Celestron Skyris 236C fundamentally better than DSLR's? (I have a Canon 5D Mark IV, which is relatively high-end with loads of features about which I'm not even aware yet)
> Finally, I'd appreciate any suggestions or recommendations. 

Thanks very much in advance!!

[symmetal]

Hello MattDay2u and welcome to the forum.

Air turbulence in the Earth's atmosphere (called the 'seeing') causes problems for getting single sharp images of the Moon and planets, as the image 'swims' around with different areas going in and out of focus. The normal method is to do 'lucky imaging' where you take a video of the subject and use software to select and stack the best frames (the 'lucky' frames) where the seeing is momentarily good.

If you switch your camera into live-view you can see the image 'swimming' about which makes focusing difficult. The best way to focus is to view a bright star using a bahtinov mask on the front of the telescope, then swing back to the moon without touching the focus again. You can take a number of manual frames using an intervalometer so you don't have to touch the camera and make the image shake. Hopefully you'll get some sharp images.

It's better to switch the camera into video mode and take a 30s video. If the camera has a 'crop sensor' video mode where it uses the centre 1920 x 1080 pixels of the sensor rather than interpolate the whole frame down to the video resolution, you'll get a sharper image. You really want to shoot the video in uncompressed 'raw' mode but the Canon can't do that and you'll have to use the 'mov' format which will give compression artifacts when stacking. It should still give you a much better image than single shot though.

The astro-imaging cameras like the Skyris let you shoot video in raw uncompressed mode and also let you use a cropped area of the frame to enable a higher video frame rate, very useful when imaging planets as they only occupy a small portion of the sensor. The most common cameras to use at the moment are those from ZWO. They are favourably priced compared to others and give very good results. They are USB3 so can shoot at frame rates up to 200 frames per second so can possibly 'beat' the 'seeing' distortion .

There shouldn't be any need to get the FeatherTouch focuser at the moment, as using a bahtinov mask in liveview on a bright star, your existing focuser should be OK.

Using a wedge putting it in Equatorial mode the image will be more stable as it will only be driving in RA rather than stepping in DEC and RA when it's in Alt/Az mode, but that isn't necessary for planets and the moon as the exposures will be very short. Equatorial mode is only really needed for long exposure imaging of DSOs. There should be an option in the Setup options of your scope controller to tell it whether it's in Alt/Az mode or EQ (wedge) mode.

There are several free programs to do the image selection and stacking, Autostakkert is a good stacking program and PIPP is a useful pre-processing program as it will convert your MOV files to RAW, to use in Autostakkert.

I hope that's enough to get you started. 

Alan