Quote:
Originally Posted by Eden
This is spot on -- it gives you access to pretty much the entire FoV and when you can't find a guide star straight away, you just adjust the X/Y stage. How much adjustment is required depends on where you are pointing, e.g. the availability of red dwarf class stars and the size of your guiding sensor. Peter uses a Starlight Xpress Ultrastar on his rig, which has the more generous sensor size. Some folks use their "old" imaging camera for guiding, eliminating the need to adjust the stage at all!
Give me a holler if you want to try the ONAG out at some stage, I'd be more than glad to send it up to you.  |
Thanks Brett, appreciate that mate
I've decided at this point to take a pass on the ONAG as I don't think it'll make a enough of a difference to me to justify the expense, especially with the exchange rate the way it is at the moment.
Quote:
Originally Posted by rally
Lee,
If you are remote imaging then you will be using the tools that allow you to plan and manage your remote imaging session
So you are selecting your guide star in the planning stages rather than trying to find one by trial and error on the night.
For example - if you are using TheSky with an OAG/guide camera - you either download (if its a standard known arrangement like SBIG cameras) or create from scratch your own camera Field of View Indicator (FOVI) use the create tool
This is a little scaled diagram of the geometry of your main camera and guide camera that has the correct relative positions, sizes and correct image scale for your system - OTA, Flattener, camera etc
Once enabled in TheSky, the good thing about this is that providing you are using ASCOM compliant hardware, the rotator is calibrated to astronomic North, It not only shows you what you are pointing at and what stars the guide camera can see by the overlay on TheSky's planetarium view, it also allows rotation information to be sent from TheSky to your planning software and in real time from the rotator back to the TheSky.
You use the GSC catalog to select a suitable star based on your experience with system - eg magnitude and exposure time and now your imaging session is able to be planned on the desktop beforehand.
There is plenty of info on this availble on the SB site that can guide you through the process.
The difference is you will know before you start - exactly which star you intend to guide on before you do the image session and you will have already calculated the centre of field position and the camera angle of rotation for both composure and for the selection of a suitable guide star - now everything is known and planned
This assumes of course that your mount is polar aligned and calibrated and doesnt suffer from any significant backlash.
A friend of mine was doing this on his EQ6 - so its quite possible.
But if you are remote imaging I am not sure how you would be doing it on an EQ6 - you ideally want a mount that is capable of remote imaging - has a home position and accurate homing process or absolute encoders.
Rally
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Thanks for the detailed post :-)
My main point was: If you could remotely rotate the OAG and imaging camera independently of each other, you'd be a lot more likely to be able to keep your composition exactly as you'd like, and find a good guide star. I wasn't talking about finding one through trial and error necessarily, and this is true regardless of prior planning or trial and error.
I consider myself to operate in a "semi-remote" fashion because I'm as lazy as anybody you'll ever meet. My gear sits up in the paddock about 300m away from the house, and I'm trying to reduce the amount of time I spend walking back and forth. I seriously spend most of the nights that I image walking back and forth... recently I motorised a focuser which resolved most of that, but there's still some things that could be improved, like being able to keep guiding after doing a flip.
Ideally I'll get it to a point where I can go up once at the start to open things up and turn everything on, and once at the end to pack everything up.