Venus - first night out with the laptop

[furrysocks2]

Just before tea time, I bolted a wooden platform to the top of my photographic tripod and used an IKEA "DRÖNA" storage box as a light/dew shield and the laptop sits in that rather snugly - may need to add holes for USB, CPU fan exhaust, etc.

I got the ST102 on an EQ3 out on the lawn after doing kiddy bedtimes, with the laptop next to it. Not too long later I went out and Venus was low, and pretty much directly behind neighbours chimney exhaust for some of the session. Cloud kept drifting in an out, but I was doing my best to focus it on the laptop screen, running a PS3 Eye webcam with L filter through a 2x barlow. The full stack then includes a 1.25" visual back, a small 1.25" filter holder (side slot with velcro closure), T adaptor to a 2" nosepiece. With no finder, I took to removing the camera, sighting Venus through the barlow. Captures were done at 640x480@75fps , yielding ~3000 frames letting Venus drift from corner to corner.

I took a single video with a red filter before the clouds came across - to be fair, it had been in and out of view for a good few minutes, and I think the video started to overexpose as it cleared even more than expected towards the end of the capture. PIPP and AS!2, 10%, 1.5x drizzle, convoluted:

 

I turned to Orion and tried the PS3 Eye with a 0.5x focal reducer at 0.1fps but couldn't get anything to focus on - worth trying again.

Clouds cleared Venus, so back to get LRGB captures. Filter holder was rotated at an awkward angle meaning I was catching filters in the dark - next time, I'll have it oriented upwards.

I ran PIPP in batch mode on them all, and stacked each of them in AS!2 - 3%, 1.5x drizzle, no sharpening. Loaded them each as layers in Gimp, converted each to grayscale and back to RGB, crudely "colourised" each layer and manually set the opacity %ages to stack them, without any further manual alignment. I have not used the L layer, and I think the filters are visual not CCD, or camera was adjusting white balance, but barely any difference in the G and B channel appearances and the R was orangey. I guess I should at least turn off auto white balance and capture in mono next time. I flattened the image, still unsharpened, then ran through Registax and fat fingered some wavelets. Back into Gimp, feathered a mask around my half-Venus and adjusted the midpoint to bring just the half-disk levels up - there was a lot of haze nearby that I didn't want to stretch. I know my processing needs education and practice...

It is what it is - or rather it is whatever I've processed it into. First images of Venus, though.

 

I played around a bit with a couple of more sensitive cameras and a 0.5x reducer, and packed up. I have no idea at what point the frost settled on the primary lens but it was pretty bad when I eventually noticed it at the end.

All in all, some valuable experience to build on - I need to work on a few things.

 

[furrysocks2]

I know that playing with bad data really isn't going to get me anywhere and I'd much rather have been imaging with a different camera on a different scope but the aim of the night was purely a crack at using the laptop and filters...

But here's a quick final image I just made - rather than Registax wavelets and masked stretch as I did before, I used Gimp's unsharpmask on the stacked RGB - just default settings - I think I did it three times - just enough to make it look nice to me, once fewer would probably have been ok but once more was too much.

I know I'm probably overprocessing and totally unskilled at that, but this is possibly the one out of the three that I'll keep as my "first Venus".

[Pete Presland]

Congratulations on your first venus image. A very nice start!

[furrysocks2]

14 minutes ago, bunnygod1 said:

Congratulations on your first venus image. A very nice start!

Thanks.

More megapixels in the post, and a bit of work to do on the dob stability and control, then I can try again.

[Pete Presland]

I grab every opportunity that I can, even if I think the conditions are not ideal. I might skip the odd session in a long run of clear nights, on the rare occasions we get that.