Gather data at a later date, how to align the frame the same

[Rudeviewer]

I was wondering.... now that I have shot a few DSO's, how do I go back with my scope to the exact same place to frame the shot for more data, but on another night.  Is something like this done via Backyard EOS or do I have to make tape marks on how to insert my camera for what targets I am going back to that way they align? 

[Kropster]

I could be wrong, but I think the stacking software will correct any rotation or image size differences, as long as the area photogrpahed is roughly the same each time.

[Rudeviewer]

It may make it easier now that I have a screw on camera adapter as opposed to the 1.25" that go into the eyepiece barrel.  It makes the camera be at the same angle always.  I can always load a few subs of what I am trying to recapture on the camera and use the live view to find a point of reference on the frame.

[Uplooker]

You can use a framing mask in APT, that lets you add some "dots" to a frame you have alread captured to identify a specific patern of starts. When you are next out you take a single shot and call up the focus mask. The mask is overlaid onto your new image. You can then see the misalignment of the markers and the actual stars in your new shot. Adjust the camera or the mount and repeat until you feel they are sufficiently aligned with each other.

Ian

[Rudeviewer]

Excellent!  I will definatly try that.  Ive wondered this for some time now but thought it may be a total stupid question, lol.

[ollypenrice]

Where possible I shoot either in landscape or portrait in alignment with RA and Dec. This means adding data from other instruments, other nights, or whatever is far easier. It also means you can give a NSEW orientation easily, which is more professional. ('North is up,' for example.) To align this way makes for repeatability and is easy because you just take a short (3 or 4 second) sub while slewing and see how the star trails lie. When they lie parallel with the chip you have it, and this will apply to any setup you're using.

Although I don't use it there are plate solving programmes like Astrotortilla which will put you back on target, though they won't rotate the camera without some serious spending on kit!

Olly

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/22435624_WLMPTM#!i=2266922474&k=Sc3kgzc

[Thalestris24]

Where possible I shoot either in landscape or portrait in alignment with RA and Dec. This means adding data from other instruments, other nights, or whatever is far easier. It also means you can give a NSEW orientation easily, which is more professional. ('North is up,' for example.) To align this way makes for repeatability and is easy because you just take a short (3 or 4 second) sub while slewing and see how the star trails lie. When they lie parallel with the chip you have it, and this will apply to any setup you're using.

Although I don't use it there are plate solving programmes like Astrotortilla which will put you back on target, though they won't rotate the camera without some serious spending on kit!

Olly

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/22435624_WLMPTM#!i=2266922474&k=Sc3kgzc

Hi Olly

Can you enlarge on your camera alignment procedure please. I'm not quite understanding exactly how you do it. I think I've got mine close to being aligned (haven't actually had a chance to check it properly - clouds ) but not sure how you get it exact.

Thanks

Louise

[lensman57]

I was wondering.... now that I have shot a few DSO's, how do I go back with my scope to the exact same place to frame the shot for more data, but on another night.  Is something like this done via Backyard EOS or do I have to make tape marks on how to insert my camera for what targets I am going back to that way they align? 

Hi Louise,

As Olly has said use the camera in either 0 degrees of rotation or 90 degrees by just making a small mark on the camera and the draw tube, I found this to be highly accurate. You can also use the frame mask of the APT or other capture software to mark the positon of 3 main stars in a frame and save it as a file so it can be referenced later. The satcking software will take care of small amount of rotation between the frames, in DSS you can stack one set of subs and then uncheck the lights , check the second set but right click the best sub of the first set and set it as a reference frame, all other sets of subs will be aligned to  this reference frame . 

Regards,

A.G

[Thalestris24]

Hi Louise,

 

As Olly has said use the camera in either 0 degrees of rotation or 90 degrees by just making a small mark on the camera and the draw tube, I found this to be highly accurate. You can also use the frame mask of the APT or other capture software to mark the positon of 3 main stars in a frame and save it as a file so it can be referenced later. The satcking software will take care of small amount of rotation between the frames, in DSS you can stack one set of subs and then uncheck the lights , check the second set but right click the best sub of the first set and set it as a reference frame, all other sets of subs will be aligned to  this reference frame . 

 

Regards,

 

A.G

Hi

Um I don't have any problems stacking or finding things - I just wasn't sure exactly how Olly aligned his camera in RA and DEC. He says to expose whilst slewing and I'm not sure exactly what he means. He's talking about exposing for a few seconds but I wouldn't get much of an image in that short a time...

Thanks

Louise

[russp]

Where possible I shoot either in landscape or portrait in alignment with RA and Dec. This means adding data from other instruments, other nights, or whatever is far easier. It also means you can give a NSEW orientation easily, which is more professional. ('North is up,' for example.) To align this way makes for repeatability and is easy because you just take a short (3 or 4 second) sub while slewing and see how the star trails lie. When they lie parallel with the chip you have it, and this will apply to any setup you're using.

Although I don't use it there are plate solving programmes like Astrotortilla which will put you back on target, though they won't rotate the camera without some serious spending on kit!

Olly

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/22435624_WLMPTM#!i=2266922474&k=Sc3kgzc

Sequence capture pro is brilliant - load up a previous shot, invoke plate solving and it will automatically move your scope to the exact same centre spot and then do another to check it's in the right place (you don't even need to align the scope first). I tend to attach my camera while the scope is in the parked position (pointing at celestal N more or less) in either landscape or portrait mode (which I think achieves the N up?) and then let the aligning software do the rest.

[russp]

Oh - I guess that only works with a refractor - doh!

[Thalestris24]

Oh - I guess that only works with a refractor - doh!

Ahh perhaps Olly was referring to only a refractor as well? I think it should be possible to align a camera on a newt too. I use Astrotortilla for plate solving and gotos. It will also goto a previous image.

Louise

[russp]

No I see what he's alluding to - bump up your ISO or binning and find a bright star. Open shutter while slewing say west only for 4 or 5 seconds.. if the star trails are horizontal then your camera is aligned N up - if not rotate and repeat until they are - will work with any setup. 

[lensman57]

Hi

Um I don't have any problems stacking or finding things - I just wasn't sure exactly how Olly aligned his camera in RA and DEC. He says to expose whilst slewing and I'm not sure exactly what he means. He's talking about exposing for a few seconds but I wouldn't get much of an image in that short a time...

Thanks

Louise

Unless you have an accurate camera rotator then you either align at 0 degrees or 90 degrees to a previously marked position. Astro tortilla or Capture pro are really modified GoTo systems and do not align cameras they will put an object in the center of the CCD and the rest is up to us I guess.

A.G

[Thalestris24]

No I see what he's alluding to - bump up your ISO or binning and find a bright star. Open shutter while slewing say west only for 4 or 5 seconds.. if the star trails are horizontal then your camera is aligned N up - if not rotate and repeat until they are - will work with any setup.

Ah ok. I think that makes sense. Presumably I'd have to slew in either RA or DEC just with eqmod? I normally just go to a target in Stellarium so the slewing bit didn't compute...

Cheers

Louise

[ChrisLX200]

Sequence Generator Pro (SGPro) will plate-solve and put the camera center in the right place, then if you have a motorised rotator (who does?) it will automatically rotate the camera to position - but here's the good part, it will also allow you to manually rotate the camera and guide you by, for eg., telling you how many degrees to turn the camera and in which direction. This is an iterative process but it will get you very close after a few tries.

For a phycsical alignment solution in the past I used a small (1/8" dia) dowel inset in the nosepiece which mated with a (1/8" reamed) hole drilled in the opposite part in the focuser adapter. This would also get pretty close repeatable alignment but SGPro's plate solving routine is better.

ChrisH