I thought I'd done everything right last night and captured nothing useful. Here's how it went:
About an hour after dusk I did the following:
* I did an autofocus with the scope pointing at the celestial pole
* I checked the polar alignment with SharpCap and it was all OK from the session from a few nights ago
* I slewed to my target (M51)
* I engaged PHD2 and got it to calibrate and start tracking
* I grabbed my previous images of M51 from a couple of days ago and platesolved them, followed by using APT's Goto++ routine to get me within 12 pixels of the previous session
* I let the tracking settle down and it ended up at about 0.7 arc secs RMS
* I kicked off my 2 hour imaging sequence
So, what went wrong as all the above was silky smooth?
Bottom line:
* I started imaging before it was really dark enough, so the sky brightness was awful and therefore I spent an hour capturing poor SNR images. I was just too keen to start imaging before the sky was dark enough.
* I didn't notice the whispy clouds roll in; PHD2 was still achieving 0.7 to 0.8 arc secs guiding, but I was imaging through clouds, so even when it was dark enough later on I was ending up with blurry images.
* I've ended up throwing away all of last night's session as the images will actually make my end result worse.
Unfortunately tonight looks like I have a similar problem with clouds, but at least I'm not going to kick off that routine until I'm sure there is at least half a chance of getting some good stuff. I'll be going to bed before 1am tonight
On the plus side: all the technical bits are working fine and I'm pretty relaxed about getting an imaging session set up and going now
On the downside: I can still be a bit thick when it comes to timing and mother nature will always have her say.
About an hour after dusk I did the following:
* I did an autofocus with the scope pointing at the celestial pole
* I checked the polar alignment with SharpCap and it was all OK from the session from a few nights ago
* I slewed to my target (M51)
* I engaged PHD2 and got it to calibrate and start tracking
* I grabbed my previous images of M51 from a couple of days ago and platesolved them, followed by using APT's Goto++ routine to get me within 12 pixels of the previous session
* I let the tracking settle down and it ended up at about 0.7 arc secs RMS
* I kicked off my 2 hour imaging sequence
So, what went wrong as all the above was silky smooth?
Bottom line:
* I started imaging before it was really dark enough, so the sky brightness was awful and therefore I spent an hour capturing poor SNR images. I was just too keen to start imaging before the sky was dark enough.
* I didn't notice the whispy clouds roll in; PHD2 was still achieving 0.7 to 0.8 arc secs guiding, but I was imaging through clouds, so even when it was dark enough later on I was ending up with blurry images.
* I've ended up throwing away all of last night's session as the images will actually make my end result worse.
Unfortunately tonight looks like I have a similar problem with clouds, but at least I'm not going to kick off that routine until I'm sure there is at least half a chance of getting some good stuff. I'll be going to bed before 1am tonight
On the plus side: all the technical bits are working fine and I'm pretty relaxed about getting an imaging session set up and going now
On the downside: I can still be a bit thick when it comes to timing and mother nature will always have her say.
