Initial alignment/Star Atlas/Plate Solve

Image processing, astrometry, photometry, etc.
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umasscrew39
Posts: 35
Joined: 20 Feb 2019, 17:47

Initial alignment/Star Atlas/Plate Solve

Post by umasscrew39 » 23 Feb 2019, 13:14

My initial alignment is off and my scope is way too up high to use the finder scope. I was hoping to use the Star Atlas tool to help me align or plate solve. I noticed that the Star Atlas does not open - I get an error saying: GSC not found. Do I need to down load this atlas from another source? What is the best way with AA7 to get the initial alignment done? I redid my PA last night.

Dunmunro
Posts: 52
Joined: 10 Jan 2019, 01:11

Re: Initial alignment/Star Atlas/Plate Solve

Post by Dunmunro » 23 Feb 2019, 17:39

umasscrew39 wrote:
23 Feb 2019, 13:14
My initial alignment is off and my scope is way too up high to use the finder scope. I was hoping to use the Star Atlas tool to help me align or plate solve. I noticed that the Star Atlas does not open - I get an error saying: GSC not found. Do I need to down load this atlas from another source? What is the best way with AA7 to get the initial alignment done? I redid my PA last night.
You are now about to be initiated into the mysteries of plate solving... :o

? icon->index->plate solving.

[EDIT: Plate Solving uses an internal database independent of the star atlas so it will function without the star atlas]

Fabio should be able to send you a link to download the GSC (I can't recall where I got mine (I also downloaded the USNOA2 star catalog from the USNO)) but if you already have it you would go to:

File->preferences->star atlas tab->use the dialog box to set star atlas to the correct directory. You should go through the preferences tabs carefully and enter your info as appropriate in the different tabs.

IIRC, you took some sample images.

load one of these images and plate solve it:

load the image. It's helpful to zoom out a bit.
On the left hand side of the main AA7 window there are a series of icons including one called "find coordinates". click on this icon.

You may have to experiment with some of the settings including the "image flipped" box. Once you get a successful plate solve the RA/Dec will display at the bottom of the AA7 main window as you move the cursor over the image.

Top of the AA7 main window-View-> statistics will give the plate scale and image centre; make sure that this info is correct as false solves can occur when the Horizontal field parameters are too loosely set. Once known you can enter the correct info into the "find coordinates:" window and reduce the percentage to ~1-2% and then click "save parameters". You can also experiment with increasing the number of stars to 6 or more, again to reduce the probability of a false solve.

Now we are ready to use plate solve assisted GOTOs.



Telescope control window->Goto tab-> enter target name or coordinates -> click Goto button-> telescope slews to where it thinks the target is.
EDIT: Now take an image with the imaging camera (IIRC ~30 seconds is typically sufficient).
Telescope control window->Center tab->Goto (plate Solve) tab->[ this will display the target coordinates] click the Center button to plate solve the current image and find the actual current location and an option to goto the target location.

cheers
Last edited by Dunmunro on 23 Feb 2019, 21:01, edited 2 times in total.

Iver
Posts: 4
Joined: 08 Jan 2019, 04:32

Re: Initial alignment/Star Atlas/Plate Solve

Post by Iver » 23 Feb 2019, 17:45

Hi, in files/preferences/star atlas you need to set the path for catalog 1 to the gscdata file that came with AA.
Iver

umasscrew39
Posts: 35
Joined: 20 Feb 2019, 17:47

Re: Initial alignment/Star Atlas/Plate Solve

Post by umasscrew39 » 23 Feb 2019, 22:37

oh boy, will give it a go

will plate solve work on not-so-well-focused images? One of my problems is trying to learn too many things at once, resulting in not learning them at all. Moonlite focuser new and filter wheel with OAG new (but not using guiding yet) and of course, anything in AA7 new.

I also downloaded the GSC catalogue from the link Fabio provided when I purchased AA7. I extracted the data in a new folder on my desktop and entered that path in the preferences under Star Atlas for catalogue. I got an error message that the path was not found. Thus, my other challenge. I am a Mac guy and I despise Windows :(

Dunmunro
Posts: 52
Joined: 10 Jan 2019, 01:11

Re: Initial alignment/Star Atlas/Plate Solve

Post by Dunmunro » 23 Feb 2019, 22:57

umasscrew39 wrote:
23 Feb 2019, 22:37
oh boy, will give it a go

will plate solve work on not-so-well-focused images? One of my problems is trying to learn too many things at once, resulting in not learning them at all. Moonlite focuser new and filter wheel with OAG new (but not using guiding yet) and of course, anything in AA7 new.

I also downloaded the GSC catalogue from the link Fabio provided when I purchased AA7. I extracted the data in a new folder on my desktop and entered that path in the preferences under Star Atlas for catalogue. I got an error message that the path was not found. Thus, my other challenge. I am a Mac guy and I despise Windows :(
I know, a new a OS can be a pain. I have the same problem - I want to do it all at once, but I find that I have to make a paper list and then work through it methodically.

Defocused images might be a challenge...depends on how bad they are.

A quick and dirty way to get reasonable focus is to place a cardboard mask over the front of the OTA:

http://www.sfu.ca/~dmunro/DSLRTestPage.html
(see bottom third of the page)
and use the SCT mirror focus to get a reasonably focused image and then switch to using your Moonlite Crayford.

I would extract the data into a subfolder of your Astroart7 folder:

Ex: C:/Astroart7/GSC

I prefer to install AA7 into the root of C: drive (as per above) so that the folder and file locations are easy to find. However, the best way to enter the path into the star atlas preferences is to use the [...] button which is directly under the proper motion year setting on the preferences window.

umasscrew39
Posts: 35
Joined: 20 Feb 2019, 17:47

Re: Initial alignment/Star Atlas/Plate Solve

Post by umasscrew39 » 24 Feb 2019, 00:03

Got the GSC issue resolved.- thanks

I think I can get a decent focus initially. I still do not understand how the moonlite does auto-focus and how that relates (if at all) to the auto-focus feature in AA7.

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