Quote:
Originally Posted by beren
Don't know if it's happened to you yet {but it will  } getting clouded out after setting up, drift aligning,balancing, target and guide star acquisition and focusing without the images has to be the most frustrating thing I have ever experienced  |
haha I can imagine, Stuart.. I'm not looking forward to it at all. I keep forgetting the basics too, like re-balancing after I put the cameras on, and then wonder why I get trailing after 60s unguided exposures.
Frustrations like that can happen with planetary imaging too, but it takes far less time to setup and start capturing..
Quote:
Originally Posted by jase
Hands free? Don't think you're close yet Mike... 
Welcome to the world of DSO imaging. To do it right takes dedication and patients. There is no such thing as simplicity in this game. Now that you’ve tried it, you can appreciate the effort involved. Seriously though, the more money you throw into hardware/software, the easier you can make it, but in return typically technical complexity increases.
Take computerised focusing as an example. While some may disagree, computerised focusing is the only way to accurately focus a telescope for DSO imaging purposes. Computerisation will guarantee that you’ll hit the critical focus zone every time (and usually under 90 seconds). However to achieve this you need a stepper motor mounted to a focuser that can be computer controlled. Then, the software to control the stepper motor. Software like FocusMax is free. It’s not too difficult to set up, but I’ve had quite a few headaches building a good focus v-curve model – thus the complexity.
Another example is telescope pointing. I couldn’t tell you the last time I looked through a telescope to see where it’s pointing and if it’s framed the object correctly. I use software to handle this. The software (ACP/Pinpoint) takes a picture to match stars in the field, then plate-solves these stars against a well known accurate catalogue. If the original image indicates the pointing is out by sub arc second accuracy, the telescope is instructed to move to the exact position (and in the process builds a pointing model for future corrections). Again, more complexity in software configuration.
This is just the tip of the iceberg in automated image acquisition. When all software/hardware components work harmoniously together, the imaging sessions are very productive. However, if one component fails, precious time is wasted as they’re typically dependant on each other. I’ve shared your frustration before. I suggest making small steps as you advance. You’ve probably already realised that acquiring the data is mundane work (when things are working well), it’s the image processing where things get tricky (and even more frustration).
Remind me why I decided to enter into DSO astrophotography again... |
Great post Jase, definitely highlights the potential problems in automated imaging, but also the rewards if it's all done right.
I have no intention of going to those extremes though - I just don't have the money, the equipment or the location to go to those lengths. If I had a permanent setup in an observatory, i'd definitely start down that road - at least with computer controlled mount, focus, etc.
But for now, I think i've almost got everything I need to take acceptable images from my backyard. I just need my skill to advance
And more time in the night!
I'll never produce
great images, but i'm happy with the progress i've made and can now do better DSO images than I thought I could.
Quote:
Originally Posted by [1ponders]
How have you got your guidescope mounted Mike? You should be able to adjust it enough to get a guidestar and with the DMK and an exposure of half a second of so you should have guidestars popping out your whazoo.
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My guidescope is in some rings that have the 3 adjustment screws like a finderscope - so it can be pointed somewhat away from the imaging scope, but not
too far.
Just while imaging NGC253 the other night, while composing the shot I noticed that the DMK sometimes had some bright stars, and sometimes didn't (as I panned around). In the end I had a FOV where I was able to use a 0.5s exposure which was bright enough, but I can imagine times where there isn't a bright star nearby?
Would a (cheap) focal reducer on the guidescope be an option? The faster focal ratio would then allow brighter images with the same exposure time.. perhaps picking up stars that were too faint before? Maybe the focal length would be too short then?
I'll take some pictures of my DSO imaging setup next time I'm out.