1.3MP webcam on an 8.5" dob

[furrysocks2]

I took my first image of the moon a couple of nights ago, through my 3" reflector.

Tonight, I pulled my DIY dob outside the door for a quick look at the moon. I carried it a bit further up the path and knocked on the neighbour's door - she loves to have a look through it when I've got it out. It's 8.5" f/7.6 and the mirror's in an awful state.

After enjoying visual for a while, I took a few photos on my wife's iphone through a few different EPs - all overexposed I think - she's taken her phone to the pub. I was holding her up from leaving!

Left at home to look after the kids, I rushed to pull the PC and monitor outside and put the webcam on it. Clouds stayed away for a good hour. I found the best focus while taking a few 10 second videos. I decided I'd take 50 frame videos and as the moon was moving through the FOV so rapidly, I'd set it to take 5 videos with no wait in between. That way, I could set up with an object near or off the left hand edge, and I'd get a few videos of it passing through.

I've got 16 sets to go through and pick out which ones I'm going to spend time processing, but couldn't resist a quicky to start.

Here it is.

(edit: oversharpened)

[Charic]

That's amazing.

I have a web cam,  an Xbox Live Vision, which  I know will work on my Windows 7 PC,  but I`m hoping to see if it works on a recently installed Linux Ubuntu OS on an old Acer laptop.
I have also inherited another PC identical to my own spec!  installed  a second hand  1TB HDD on which I`m hoping to install Windows 10,  so I have three options, but it would be easier  using the laptop.

[furrysocks2]

1 hour ago, Charic said:

That's amazing.

I have a web cam,  an Xbox Live Vision, which  I know will work on my Windows 7 PC,  but I`m hoping to see if it works on a recently installed Linux Ubuntu OS on an old Acer laptop.
I have also inherited another PC identical to my own spec!  installed  a second hand  1TB HDD on which I`m hoping to install Windows 10,  so I have three options, but it would be easier  using the laptop.

Cheers. I have the same cam somewhere. Looking forward to seeing what you get.

I'm currently using SharpCap and Registax in a Windows 7 VM running over Ubuntu - couldn't get full res capture in Linux for anything. I do wish I had a laptop.

 

I've got a few more images roughly processed...

 

[furrysocks2]

AVIs have come out at 30 frames and some of those frames looked identical. So I'm not too disappointed with these, given I'm only stacking 20 or so frames each time and drifting across FOV by about 4%.

I'm just imagining what I might get with a tracking mount, no wind and longer captures (and inevitably, more megapixels).

[furrysocks2]

I was trying to work what I observed last night, firstly trying to determine the FOV.

I took a pixel measurement of one of my images and of the background and came up with a scale factor to overlay my image, confirmed by reducing opacity. I managed to fit in just over four and a half of them across the diameter of the moon. If the moon's about 0.55 degrees just now, then given pixel measurements I should have an X axis FOV of 0.125 degrees - right enough about four and a half. Does that make sense to anyone? Does it make sense that my webcam's giving me approx 0.125 x 0.94 degrees in an 8.5" f/7.6 scope? If I assume that my webcam has a 1/3" sensor, and pixel size of roughly 3um x 3um, then an online FOV calculator gave a similar enough FOV, so I think I'm right enough - roughly 0.4"/pixel. Therefore, if I know the sensor size of a DSLR I might soonish buy (ha!), then I could calculate roughly what proportions of the moon I'd get with/without barlow/focal-reducers, etc... I think. Need to go read up a bit.

 

I also found it useful to produce the following image, as I still don't know my way around the moon's features at all.

I've a few more to add once I process them and I can label them, etc.

[furrysocks2]

I've been trying to improve on the processing of Mare Humorum, spurred on by michaelmorris's shot in this thread. Really useful to see what detail it was I was missing - what my smudges should resolve into.

My biggest problem, other than stability due to wind, was that my dob doesn't track - the videos are short.

In an attempt to process more frames, I used PIPP to join four out of the five videos from a set, selected lunar close up and put the AFB box over the area I wanted. The output video showed this area with an ever increasing black border to the top right as the FOV drifted over the course of the captures. But this, at least, had a relatively stable area in the bottom left.

I used Autostakkert for the first time, loosely following a youtube tutorial. And got this...

 

A slightly unfair comparison below as left and right represent different capture sets but to be fair, there won't be a lot in it - left is a single video from one set run through registax, right is four videos from a different set ran through PIPP and then Autostakkert.

 

I could spend time doing a like for like, but my time is probably better spent making my dob track the sky. I'm just happy with the fact that I'm able to go back and improve on my first image at all.

[laudropb]

A lot of hard worked, but rewarded with some nice shots.

[furrysocks2]

50 minutes ago, laudropb said:

A lot of hard worked, but rewarded with some nice shots.

Thanks. Too much hard work, though.

I'm off to start on the azimuth drive.

[furrysocks2]

No drive yet.

Odd session just now - was packing up and stepped out the door and moon was out so from inside the workshop, pointing the scope out the door, I got some USB extension cables, ran a monitor downstairs and set up.

Windows refused to capture from the webcam so I had to use Linux, limited to 640x480 for some reason and no exposure contol. Had to set it to auto, let it drift and auto adjust to the level I thought I wanted it then untick so it'd stay at that exposure - I let it go too dark. Also, sensor is filthy - the workshop is not a clean room - so much dust showing in single frames.

Drift across the field of view was at the same rate as last time, but I took 20-odd second videos and selected an area in PIPP which would be present more or less throughout the video, so they're all crop of 640x480.

Then AS2 with drizzle 1.5, but I couldn't upload TIFs here and I think Gimp converted them to 8 bit and they were pretty dark to begin with. So at least I've got two more images with a few more frames this time (perhaps 100 each), but they're pretty shonky.

 

Don't they look awful?! Second one looks fake, and stylised at that - 15 shades of gray or something!

Here's how not to do it. Ha!

[michael.h.f.wilkinson]

Very nice webcam results!

[furrysocks2]

54 minutes ago, michael.h.f.wilkinson said:

Very nice webcam results!

Thank you.

[moonomaly]

Can't believe that's a webcam! I like the over-sharpening, it makes them look like pencil drawings.