Lunar Mosaic (Frustration) 23rd May

[AndyUK]

I decided to spend a night trying out a full lunar mosaic with my C100ED, Toucam 840k and a 2x barlow. It probably wasn't exactly the most ideal night to try this exercise (with so much being "flat" and the seeing being pretty poor) but it was simply something I wanted to try...

I ended up taking a total of 72 bitmap stills (the full bitmap image is over 36Mb, although viewing at 100% really shows up my focusing and also that I should have used stacking to get around the poor seeing). However, when I came to put it together, I found that I'd missed 5 areas (4 frames) which was REALLY frustrating!

I haven't put this through photoshop yet (which I'm hoping will sharpen it up a bit more) but I did go out the following night and took the remaining 4 frames to see if I might be able to "patch" it (although the seeing was even worse), but I then discovered that the moon "wobbles" (I should have realised this as I read it in S&N recently). It appears to have tilted about 12 degrees - Although I can try a bit of trial and error, I wondered if anyone knew the absolute daily "wobble" so that I can try and rotate them and hopefully merge them in...?

Although it probably isn't worth it, I hate to leave projects unfinished(s) and trying to locate the areas on the moon to take "missing" frames the following night was certainly a bit of a challenge... if nothing else it also taught me to be even more careful next time!

[brianb]

Take a low resolution frame set first, use scaled bits of that to patch any minor holes in the high resolution set & hope that no-one notices. (Since I've been using this method I haven't actually missed any holes, so Sod's Law probably applies too!)

[AndyUK]

Thanks Brian - I'll try that next time. Hopefully Sod's law will apply for me also...

I did manage to "patch" the holes with the images I took the following night (using rotation of 12 degrees left), although I had to build the mosaic up from scratch again. Here's the final bmp cut (although I still need to do a bit of work in photoshop - It's now 77 frames):

Hopefully the seeing will be better c. 17-19 June, although I think I might do a better job with an ED Barlow - The one I have is a standard Skywatcher and I have a feeling that it's perhaps letting the 100ED down. I've also now got myself a Bahtinov mask so I should be able to get my focus pinned down better as well...

[jgs001]

That's better Andy, load the AVI or bmp into iMerge (drag and drop) at capture time, and build up a quick and easy mosaic as you go, that way you can easily see if you've missed any bits.

[AndyUK]

Cheers John - I must admit, I'd never thought of putting it together at the time of taking them, but having gone through the frustration / disappointment at the time, that makes a lot of sense... Thanks!

[jgs001]

You're welcome, I found it out by accident... but it works... it's only a rough and ready of the avi to make sure there are no gaps, so accuracy isn't quite so important.