Getting the Mount back to a previous imaging coordinates

[cfpendock]

I also use AT for polar alignment.  And like Russellhq above, I also start with polarscope alignment.  This usually gets me to within 5' of correct.  AT then gives me the exact errors, and I try to get the mount within 2' - sometimes it is within 10" but this is rare.  I find that 2' polar accuracy can usually be coped with by guiding (depending on the position of the target).  I have no idea what would normally be considered as acceptable polar alignment accuracy - I suppose it depends on many different factors, but it would be interesting to know how close other people get.

I would say that total setup time, again using a similar procedure to Russellhq, is around one hour before I can leave the system to get on with it.

Chris

[IanL]

I do something similar, but it takes less than 30 minutes including carrying all the gear and setting it up:

1) Carry out all the gear from the house and set up, pull out extension cable from the garage. There are a few time saving tips here:

- I have pre-drilled some marks on the patio for the tripod legs, so I can literally drop it in them and have Polaris visible in the polar scope.  Just remember to paint them so you can find them in the dark.

- I keep the NEQ6 head on the tripod, and all the cabling, power supplies and USB hub are permanently attached to it.  All I have to do is plug the cables in to the cameras once the OTA is mounted, and run the USB/power cables from my imaging 'workstation' to get started.

- I have a large plastic 'Stanley' tool chest which I have modified to make the imaging 'workstation'.  All the power extensions are in the bottom, with a single plug to go in to the extension cable.  The laptop sits on a shelf set in to the tool chest and all the cables are made in to a couple of umbilicals using spiral cable wrap and cable ties.

Sounds a bit trivial, but this arrangement means I can set up and be sure all connections, etc. are working about as fast as I can carry the gear from the house.  10 minutes, perhaps 15 if I am feeling lazy or the kids are annoying me.  I reckon it would take 20 - 30 minutes if I had to plug in every connection and test one-by-one.

2) Eqmod polar align with polar scope.  This takes less than five minutes.  The wireless gamepad is a bit of a timesaver for the initial set-up process.  I don't bother with any further refinement most nights, as I find the alignment is good enough to get 1 - 2 arcsecond guiding at the kind of focal lengths I am using.  This step can be done as soon as it is dark enough to see Polaris, usually an hour or more before it is dark enough for imaging.

4) Use Astrotortilla to go to a bright star near target.  You do not need to do a three star alignment, as AT and EQMOD will sort it out for you as you work.  Just make sure you have (the default) 'Append on Sync' setting ticked in EQMOD, and tick all three of "Sync Scope", "Re-slew to Target", "Repeat until within" (1.0 arcmin) in AT.  With the right settings you can take a (10 second) exposure and have a successful plate solve in less than 30 seconds.  In my case the second exposure hardly ever moves the scope so I can be on target in under a minute.  Each time you slew and solve on a new target, you will get an other alignment point in EQMOD automatically so your gotos get more accurate throughout the night. 1 min.

The best AT tutorial is here:  http://lightvortexastronomy.blogspot.co.uk/2013/08/tutorial-imaging-setting-up-and-using.html
 

The biggest time saver in terms of parameters once you know AT is able to solve your images is to reduce the 'Search Radius' from 180 degrees to something smaller, maybe 5 or ten degrees at most.  If your first pre-alignment goto is off by more than this I'd suggest you have bigger problems to address, and searching a small radius for a match is much quicker than the defaults.

5) Focus using a Y-Mask, and the Bhatinov Grabber in APT (Canon Liveview obviously speeds up the process as you have realtime feedback). 1 min.  Again the slew to star and focus process can be done before it is fully dark, but I find I have to adjust the exposure time in AT to make sure I get enough stars for AT to solve.  Focus needs to be checked through the night anyway, but clearly the focus can shift more in the first couple of hours after dark so care is needed.

6) Goto target and calibrate PHD.  This takes 7-10 mins, mainly due to the PHD calibration phase.  Can take longer if the guiding parameters need fettling but usually not.

7) Take a 1-2 min exposure to check framing (I try to plan this ahead of time anyway to save having to re-focus the scope if the camera needs rotating).

8) Retire to the warm, fire up teamviewer and start the appropriate exposure plan.  Monitor guiding whilst watching TV with a beer.

If I start after it is dark, that is a total of 30 minutes from putting my coat on to taking it off again.  If I am able to start setting before it gets dark, I can actually be ready to image well before it is actually dark enough to do so.  What I really want to do is make a roll-off micro-observatory so that I can cut it down to just the focus and guiding calibration process, which should be perhaps 15 minutes at most.

[fredcs]

I also after the initial AT syncing (using 180 deg search)  change the setting, usually 10 deg. I have also edited the backend.cfg to load only the indexes I need by watching which indexes are used for solving and using the 'inparallel' setting in the backend.cfg and listing only the set of indexes needed. I than save the configuration in AT for the setup I'm using. 

[fredcs]

I use XP Pro on a core2duo at 2 ghtz and the total size of indexes I need is something like 1.2 gigs. So  I use the standard backend.cfg for the intial sync. After that I load the cfg for the setup Im using. Now my search is down to 10 deg and all 1.2 gigs of indexes is loaded into memory. Not churning the harddrive really speeds up the solve. I get 10 sec average. 20 max.

[russellhq]

...

4) Use Astrotortilla to go to a bright star near target.  You do not need to do a three star alignment, as AT and EQMOD will sort it out for you as you work.  Just make sure you have (the default) 'Append on Sync' setting ticked in EQMOD, and tick all three of "Sync Scope", "Re-slew to Target", "Repeat until within" (1.0 arcmin) in AT.  With the right settings you can take a (10 second) exposure and have a successful plate solve in less than 30 seconds.  In my case the second exposure hardly ever moves the scope so I can be on target in under a minute.  Each time you slew and solve on a new target, you will get an other alignment point in EQMOD automatically so your gotos get more accurate throughout the night. 1 min.

...

I find that AT will hang sometimes when I try to re-slew to a target straight away. I've no idea why but to avoid this I find that after the first solve, I slew to a new target and solve again. This stops AT hanging for me.