Lunar X

A challenge was set on AC, that given the Satellite images were showing clear of cloud here, that I see if I couldn't capture the Lunar X (Also known as the Purbach X). I grabbed all my gear, as this was the first time I'd actually had an opportunity to see this odd surface detail as it's only visible as an X for about 1 hour a month, and to date it's always been cloudy.

I went out to check, and yep, very clear and crisp, and I saw a fast moving satellite shoot across the sky, heading west to east. It wasn't bright enough, and appeared to have been too fast for the ISS, besides there are no visible passes predicted. Checking HA, it appears to have been Lacrosse 3.

I went in and grabbed the gear. Levelled, aligned on the moon, dropped in the 5mm Hyperion, and the Lunar X leapt off the surface. I couldn't believe how easy it was to spot, I'd been expecting to spend a while hunting for it. I'd been planning a session with the SPC900, but didn't really have time, so just put the 450d at prime and had a play.

At 600mm, no sign of the X



However, adding in the 2xTC, and the X becomes clear or at least findable



I then figured, what the hell, I needed to get closer to make this work, so I put Tal 2x barlow inline, after struggling with focus, I popped the diagonal back in, although I'm never too keen on doing this, something about the precarious perch of the SLR on top of the diagonal, but the X shows up really rather well.



I then threw caution to the wind, and decided to just go for it, replacing the Tal x2 with the Antares x5 barlow. This was a bit tricky to focus and I didn't quite nail it, the tiniest motions, from breathing near the focus knobs for instance, are amplified to a silly degree, but in spite of that it worked, the X is clear even if the focus isn't spot on.



Given that these are all single frame exposures, and there has been no stacking, I'm really rather pleased with the results. I think to improve the last one, I'd need to replace the Celestron rack and pinion, single speed with a double speed Crayford and a motor focuser. This may happen in time.

I had wanted to get back out there later this evening and have a go at M42. However, it's damn cold, my back hurts, and Orion was too high and south by the time I could have got out, what with some high level clouds appearing to be moving in, I decided to give it a miss and have a beer instead.