fredag 9. desember 2022

The Mars occultation on December the 8th

I got up at 5 in the morning to get ready. I had put out the telescope the previous evening so it would be acclimatized in the morning. I connected the camera to the PC and fired up FireCapture. I pointed the telescope to the Moon and focused as well as I could. I was ready, And I had half an hour to spare.

I had set up autoguiding which was working fine. I did take a full frame image of the Moon and Mars. Just as a start. I was ready.

There were some thin clouds in the view. But nothing that hindered the view.

As Mars was closing in, I changed the ROI to 400x300 pixels. And I planned to take a timelapse. I was ready a couple of minutes before Mars would disappear behind the Moon. And then things started going south. First, a thicker cloud moved past, causing autoguiding to fail due to the lower brightness, And Mars moved almost out of the view. I turned off autoguiding and moved the planet back into view. And increased the gain to compensate. I could now see the Moon's limb in the view already. My pulse increased as I now realized I had to speed things up. I set up a timelapse run. Continuous 100 frame videos of the scene. After the first video had been shot, a message popped up. "Do you want to overwrite the file?" Wait? WHAT? I pressed No. The message popped up again. The Moons limb was closing in. I went back to the main view to do things manually. But the record button was gone. It took precious few seconds before I realized that by NOT closing the autorun window, the record button would be gone. I closed it, and pressed "Record". Only to realize that Mars had slipped halfway out of view. I moved it back into view. My heartrate and blood pressure were now in the 200 range. I tried taking a number of files in a row just as I planned with Autorun, but the same message popped up. I realised the problem. File naming in FireCapture didn't allow several files to be written too close in time. So I had to wait a second or two between takes. I gave up the timelapse idea, and just settled for getting ANYTHING. And I did. After some processing, I did get a few decent shots of the occultation. And here they are. My heartrate and bloodpressure is now back to normal. I have learned some hard lessons about preparations. I thought I was prepared, and then this "feature" of FireCapture reared its ugly head, and my prep and planning failed. 

Tech details : 200mm Klevstov Cass at F/10. ASI178MC camera, gain 300, exposure 5mS. 100 frames per video. Stacked in AS!3 (100%), sharpened and RGB-aligned in Registax. Final touch-up in Irfanview.