Frustrating attempts at astrophotography again. I battled with my equipment and battled with intermittent high level cloud. Scope again was working a treat. Perhaps slew speed problems really are related to temperature? I think the low during last night's session was about 16C. Still needed the dew heater anyway.
Because I had nice views the previous night, I thought I'd have a go at imaging Saturn with the Nikon DSLR. No focal reducer, just diagonal and DSLR attached at the back-end via doubled x2 Barlows (so x4). I just had enormous problems getting Saturn to appear on the live view screen on the DSLR. I played with the focus back-and-forward, removed the whole setup and checked I hadn't left the plastic cover inside the first Barlow (as I have been known to do). Shone torch down the scope from the big end and that at least showed there were no major optical obstructions, the screen on the camera went very bright.
Finally figured out the solution. My plan was to take a short video of Saturn. To capture astro video on the DSLR I normally set the camera settings to manual video, so that I can override the shutter speed and take video at 1/60s when shooting at 25 FPS. But when trying to find Saturn in live view mode the camera is then set on 1/60s. Turned manual video mode off, set shutter speed to 5s and then Saturn appeared in the live screen. So, lesson to be learnt, when trying to get the planet to show in the screen on the back of the camera, forget the video settings to start with, set the shutter speed really slow 5s-10s and get the planet nicely centered in the camera screen. Once that is done, now start changing the camera settings to take live video.
Anyway, by that time I'd had enough mucking about with Saturn, so I just took a quick 2-minute video and moved on.
Had a go at imaging M29. I slewed to Deneb and tried to get the focus as good as I could by taking 5s exposures and adjusting the scope focus each time. I then slewed to M29.
But I had real problems getting the nice little cluster in the center of the DSLR image. This is not the first time I have had this problem, but I am new to DSO prime-focus photography. I was taking exposures but the cluster was half-off the FOV. I tried centering again and again in the finder, but I wasn't improving anything. Just getting half-decent images of half the cluster.
Cloud was increasing, so packed in for the night.
I have ordered a Vixen Flip Mirror Diagonal. We'll see if this helps me to get stuff in the center of the camera field of view.
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