Planned multi night imaging question

[Jkulin]

Hi All,

I've never done imaging of the same object over multiple nights and wondered how some of you manage to get your equipment pointing in the same place night after night?

I use Astro tortilla and Astro Photography tools, when I have had a software crash and had to reboot and realign everything, I have used the "goto image" in AT and that has put me reasonably back in the same place as previously but not perfectly.

For the first time in a very long while we have three consecutive nights appearing clear, I would like to put my eggs in one basket and concentrate on one possibly two targets over this period.

Although I have a permanent pier, I do take my mount, OTA etc. off the pier after each session, I leave the CCD and FW still attached to the OTA until I decide which OTA I am using on the next session.

I know that I can use the Star Alignment in PI to put everything back together and that I would need to do a small dynamic crop, I would just like to minimise the loss as much as possible.

Am I fussing over nothing or is there a better way to do this?

Many Thanks for your thoughts.

[Davey-T]

You need to gen up on plate solving, not sure but I think Astro Tortilla supports it.

Dave

[Jkulin]

Thanks Davey, so is it something that I have not already tried in AT, as I mentioned I have already used the "GoTo image" Function in AT?

[RayD]

As Dave says you need to plate solve.  I use SG Pro, open up and image, solve it and then use the coordinates as my target (or just open the saved session which will already have the coordinates set).  Once I slew to the coordinates I then use the "centre on object" function and it puts me within 20 pixels total, but usually much less than this, and with my Mesu usually between 0-5 pixels.

If you don't have these functions in AT then once in the general vicinity you may need to blink between images to align perfectly.

[Davey-T]

There you go

Dave

https://sourceforge.net/p/astrotortilla/home/Home/

[Jkulin]

Thanks Lads, probably didn't explain very well, I grab the last image taken using AT's GoTo option and then use AT to plate solve and centre, it's accurate but obviously won't align perfectly due to the time of the image etc.

I don't think there is a away in APT to save the last session, I'll have a dig around and see if there is as that would be a very helpful option.

So from what you are both saying, I am doing things correctly anyway.

[RayD]

8 minutes ago, Jkulin said:

Thanks Lads, probably didn't explain very well, I grab the last image taken using AT's GoTo option and then use AT to plate solve and centre, it's accurate but obviously won't align perfectly due to the time of the image etc.

I don't think there is a away in APT to save the last session, I'll have a dig around and see if there is as that would be a very helpful option.

So from what you are both saying, I am doing things correctly anyway.

Yes John you are doing it right.  Plate solving is the only really accurate way.  It may be that there are settings which can be altered to adjust the accuracy threshold.  In SGP you can set the acceptable deviation, which I set quite low, so this may be there in AT?  Worth a look.

[Jkulin]

Thanks Ray,

APT doesn't support within the program AT, but funnily enough AT does interface with APT, thus why the plate solving works. APT offers pointcraft and platsolve 2 as it's internal plate solving options, neither of which I have got to grips with yet, but having a look within APT you can centre the FOV at the RA and Dec settings and get it to aim, I've attached a couple of screen grabs.

[RayD]

6 minutes ago, Jkulin said:

APT doesn't support within the program AT, but funnily enough AT does interface with APT, thus why the plate solving works. APT offers pointcraft and platsolve 2 as it's internal plate solving options, neither of which I have got to grips with yet, but having a look within APT you can centre the FOV at the RA and Dec settings and get it to aim, I've attached a couple of screen grabs.

Yes that looks like the settings there John.  It looks like you can solve, sync and store the results, and then centre on it.  You'll see the error is set to 50 which is fairly high.  I have mine set to 20 and to 3 attempts, and I always get there, even when using my AVX.

Long term it may even be worth having a look at Platesove2. It's one of the ones recommended by Main Sequence (SGP authors) and seems to have very good reports.

[Jkulin]

Thanks Ray, I'll have a look and have a mess, hopefully can sort.

[alexbb]

I do this manually. I take a short frame, throw it in Registar. Adjust, another shot, check and repeat if needed. Usually I get there in 1-5 minutes. I don't mind since I start preparing quite a while before starting shooting.

It might be possible to use Registar in evaluation mode without saving and see if this suits you.

[Jkulin]

Thanks Alex, always worth having a look, have you a link to Rigistar?

@RayD I have had a mess with Platesolve 2 this afternoon and can get it to solve from an image, so fingers crossed it will work with APT.

[RayD]

1 minute ago, Jkulin said:

Thanks Alex, always worth having a look, have you a link to Rigistar?

@RayD I have had a mess with Platesolve 2 this afternoon and can get it to solve from an image, so fingers crossed it will work with APT.

Great news John.  No reason why it shouldn't work and it will certainly make life easier, and once running you can have a play with the deviation settings etc. to get it centering as accurately as you want, or is possible with your mount.

Good luck.

[carastro]

Sounds like you already have it cracked.  I often do multiple imaging nights on the same target, I just try to get it manually in the same position, and normally end up having to take a slight crop at the end.

Carole 

[Jkulin]

Thanks Carole and Ray, unfortunately I had to learn quicker than expected :-(

Was remotely watching the guiding and then viewed the images and noticed that the images were upside down...yeah the dreaded automatic Meridian Flip, spoke to my mate and he said, no problem make a mask in APT and then line it all up and jobs a good'un! Was it hell...I needed to rotate the CCD to get it to line up, so did a plate solve from the last good sub and recommenced, I'd already done 12 images prior to the flip but didn't get any flats, they were only to preserve the core of the galaxy I was imaging and were L 180sec x 6 and Ha 180 sec x 6, should I worry that I had no flats for them or flip the flats after the Meridian flip and use them?

So what was to be an nice Twelve O'Clock finish is now going to be a 03:00, will take a gamble and leave the stuff out over night with a bag over the mount and the OTA, have done nearly 4 hours now and only another 2 hours to go until tomorrow night!

[alexbb]

Here you have the registar link: https://aurigaimaging.com/

And you don't need to rotate your camera after a meridian flip. The stacking software will rotate the images 180 degrees.

[RayD]

6 hours ago, Jkulin said:

Thanks Carole and Ray, unfortunately I had to learn quicker than expected :-(

Was remotely watching the guiding and then viewed the images and noticed that the images were upside down...yeah the dreaded automatic Meridian Flip, spoke to my mate and he said, no problem make a mask in APT and then line it all up and jobs a good'un! Was it hell...I needed to rotate the CCD to get it to line up, so did a plate solve from the last good sub and recommenced, I'd already done 12 images prior to the flip but didn't get any flats, they were only to preserve the core of the galaxy I was imaging and were L 180sec x 6 and Ha 180 sec x 6, should I worry that I had no flats for them or flip the flats after the Meridian flip and use them?

So what was to be an nice Twelve O'Clock finish is now going to be a 03:00, will take a gamble and leave the stuff out over night with a bag over the mount and the OTA, have done nearly 4 hours now and only another 2 hours to go until tomorrow night!

John the flip should make no difference.  If you are plate solving it should work this out and get you to exactly the same place but upside down.  When you process your images they will get flipped automatically during this process.

I've not touched my CCD position for months and I always image past the flip.

[Yoddha]

Hi John,

PointCraft was build with a thought for multi-night imaging Just load an image from the previous night, solve it, then use "<< Solved"  and GoTo++ or regular GoTo. Also you can use Store to save the position in the Object Browser and skip solving the image every night  

[Jkulin]

Thanks Alex for the link, I'll have a good look at that.

Thanks Ray & Ivo, I was getting a little tired last night so probably wasn't thinking straight, I need to re-examine the images after the flip and maybe it was OK to just continue after an automatic flip, the problem is that we get so few clear nights that I panic a little to cram as much data in so that I can process at a later date.

Although I have been messing and learning about using the 383 as my first CCD/FW combo, last night was my first real "go for it as you have ironed out all the bugs" session, turned out not bad, had to sort out the flats this morning as they were far too bright compared against my Nikon D800 flats, I think I have sorted them now, blimey doesn't it take a lot longer with LRGB and Ha.

I just need to grab some Ha tonight and then hopefully can process it all on a cloudy night.

[tooth_dr]

I’m struggling a bit with APT and plate solving. Spend an hour last night trying to get it to work and then it started raining.

I have used it on many other nights working ok, but it’s never working perfectly first time.

Sometimes it says it’s solved but it hasn’t moved. Other times it moves to below the horizon. And sometimes it’s says cannot move telescope. There is clearly some issue with software communications but it’s really really annoying. 

[Yoddha]

Tooth_dr, I suppose that you are using the Sync button when you solve images, right?

I have no experience with EQMod Are there settings that could block the GoTo alignment or GoTo commands?

[tooth_dr]

11 minutes ago, Yoddha said:

Tooth_dr, I suppose that you are using the Sync button when you solve images, right?

I have no experience with EQMod Are there settings that could block the GoTo alignment or GoTo commands?

I'm not using EQMOD, just have my hand controller plugged.  APT tells me to sync, I usually agree if it's in the right place!!

[Yoddha]

So you are using kind of ASCOM driver? Any settings there that can influence the Sync/GoTo?

[Jkulin]

Hi tooth_dr, I am far from being capable to advise, but if I can help then will do.

By APT are you referring to Astro Photography Tools or Astro Tortilla?

If it is Astro Tortilla then, you need to connect your scope from the drop down list which on mine only gives me one option and that is the Ascom interface, you will then be able to select Solve and Sync in the check boxes.

If you are referring to Astro Photography Tools, then you will still need to connect your scope so that it can control in in order to sync. The next part using Plate solve 2 and All Sky Plate Solver, I am still playing with, so would hate to give bad advice, but from my experience you will need to interface your scope with the program, I use Ascom, however I may have a look at SGP and see if there are any benefits to the change..

[tooth_dr]

1 hour ago, Jkulin said:

Hi tooth_dr, I am far from being capable to advise, but if I can help then will do.

By APT are you referring to Astro Photography Tools or Astro Tortilla?

If it is Astro Tortilla then, you need to connect your scope from the drop down list which on mine only gives me one option and that is the Ascom interface, you will then be able to select Solve and Sync in the check boxes.

If you are referring to Astro Photography Tools, then you will still need to connect your scope so that it can control in in order to sync. The next part using Plate solve 2 and All Sky Plate Solver, I am still playing with, so would hate to give bad advice, but from my experience you will need to interface your scope with the program, I use Ascom, however I may have a look at SGP and see if there are any benefits to the change..

 

Thanks John, I guess I should have been more clear   APT - astrophotography tool, paid version.  I have the Skywatcher Ascom drivers downloaded.  I have had it working on several nights, it's just that on some nights it refuses to work properly.  I end up turning the EQ6 off and on, and trying different orders of connecting them together, and then it just works.  I've tried setting the date/time in the hand controller, not setting the date/time, putting it in PC direct more (APT crashes) and other combintations.  Then it'll just work.  I think that the hand controller must be interefering with it.

 

Generally I auto solve, it takes a photo, then it solves it and puts up coordinates - these appear right.  Next I pick a target from the goto menu, and it ends up either 1) slewing to some other part of the sky and solving it as the right place but it's wrong (I pick an obvious one like M45) 2) slewing for 1 second at slow speed then platesolving as the right place even through it's not right 3) not slewing at all, and saying cannot execute something.  I think this is the second maybe third night now it's played up, and I've spent over an hour platesolving, only for it then rain, and I got no imaging done!