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platesolving catalogs

Datalord
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Datalord

Datalord

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I'm trying desperately to figure out the best catalog for use with my setup. I have GSC working, but at 2400mm FL it is very unforgiving. I use PinPoint together with the ASA sequence software, but I'll figure out how to make something work if it isn't supported.

What I need is someone with more experience to tell me the difference between the different catalogs and what would be a good catalog for my scope. I need something that can find a target even if I'm a few degrees off. GSC only allows for rougly 30" off target, which is very narrow.

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vlaiv

vlaiv

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Recently I did some research and needed a catalog and I was recommended this one - and I believe it is indeed very good one.

Problem with catalogs and plate solving software - there is no "standard" format, so each plate solving software can use one or just a few catalogs that it was designed for - you can't just tell it to use any catalog.

Maybe you can see what sort of format plate solving software uses and prepare / transform catalog in that particular format and then use it (in principle this would work, but not sure if such info is accessible).

Anyway, here are catalog files if anyone finds a use for them:

https://archive.stsci.edu/prepds/atlas-refcat2/

Here is a brief from the page:

Quote

ATLAS-REFCAT2 is an all-sky reference catalog containing nearly one billion stars down to apparent magnitude m ~19. The catalog includes PanSTARRS DR1, ATLAS Pathfinder, ATLAS re-flattened APASS, SkyMapper DR1, APASS DR9, Tycho-2, and the Yale Bright Star Catalog. Gaia DR2 serves as the source of the astrometric solution for ATLAS-REFCAT2, with typical systematic errors of < 5 mmag RMS, although this can be as much as 20 mmag near the Galactic plane.

and you can use Readme file to see the structure of the catalog:

image.png.f790549ddf80912b5df70d0ffa7ad0d8.png

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Datalord

Datalord

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23 minutes ago, vlaiv said:

Problem with catalogs and plate solving software

I'm slowly reading myself into this corner. Essentially, if I want to use the advanced features of the mount, I must use the software it comes with. In this software, you set the catalog, which is then sent to PinPoint, regardless of what is possible to set up in PinPoint. 🤬

image.png.aeb5abf8a2bf90b72ef6ed11f6c5610a.png

Seriously, for all the mechanical wonder that goes into these things, you should think they could hire some developers who understand how to make things at least reasonably user friendly.

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Datalord

Datalord

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5 minutes ago, andrew s said:

40x40 8s not too extreme. How long are you exposing for and at what arc secs per pixel?

Regards Andrew 

No, it's not too bad, but while you are fumbling around with PA and sky solving and everything else, it quite quickly means you are pointing 40" wrong and suddenly solving fails completely. I'm imaging at 0.52 at bin1, but for solve pictures I do 5s bin2 at 1.05.

I guess I should be clear: Solving is easy when the scope points the right place. less than a second. But I need to have it solve for when it is misplaced by some reasonably wide margin.

Edited by Datalord
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vlaiv

vlaiv

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Any way to sync the mount from custom coordinates?

Maybe you can take an image and use some other plate solving solution (astrometry.net or platesolve2 or similar) and then sync manually - to get the mount to know where it is pointing approximately and then use quick plate solve that it offers?

Does it come with ASCOM driver? I think ascom driver can by synced from software quite easily. I use SGP and Platesolve2 and it works - it's not fast but it solved every time for me (in about 10-15s).

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Datalord

Datalord

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1 hour ago, vlaiv said:

Any way to sync the mount from custom coordinates?

Yep, all of that is working. 

Maybe I need to explain that the software works by making an autopoint file with points all over the sky. Then it takes a photo of each, platesolves each to get an error file of the entire sky, then uploads to the mount. If this platesolving doesn't work, it's pretty much game over.

Second case is for the unguided function. you give it a target and a set of exposures. Then it runs the trajectory of the target, takes images and plateosolves to see the errors. This is then used to make sure the encoders compensate for misaligned PA and flex. Again, this is 100% depending on platesolving working.

And the absolute idiocy of it all is that I can always just upload an image to astrometry.net and get it solved within a minute, but these 🤬 pieces of software can't figure out to extend the search a bit further.

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JamesF

JamesF

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49 minutes ago, Datalord said:

I tried figuring out how to get USNOA2, but either I'm stupid or the links don't work? http://tdc-www.harvard.edu/software/catalogs/ua2.html

Looks like many of the download links for USNOA2 are broken or something is wrong with the system configuration that is stopping them working at the moment.  How about this one?

http://www.newcastleobservatory.ca/node/255

James

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JamesF

JamesF

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2 minutes ago, Datalord said:

Worked, thanks!

I better wait downloading it until tomorrow. Not a nice citizen to take all the bandwidth during shooting time...

Probably still daylight for them.

James

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JamesF

JamesF

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Ah, right, yes.  Mind you, Spain is strange like that.  We were on holiday a little east of Malaga last summer.  There was no supply of drinking water, but the internet connection was way quicker than at home.

James

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JamesF

JamesF

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Not sure you'd really want to connect to the original USNO source for these files.  Here's what it says when you do manage to connect:

Quote

Connecting to ftp.nofs.navy.mil...                                              

 You are accessing a U.S. Government (USG) Information System (IS) that is
 provided for USG-authorized use only. By using this IS (which includes any
 device attached to this IS), you consent to the following conditions:

-The USG routinely intercepts and monitors communications on this IS for
 purposes including, but not limited to, penetration testing, COMSEC monitoring,
 network operations and defense, personnel misconduct (PM), law enforcement (LE),
 and counterintelligence (CI) investigations.
 
-At any time, the USG may inspect and seize data stored on this IS.
 
-Communications using, or data stored on, this IS are not private, are subject
 to routine monitoring, interception, and search, and may be disclosed or used
 for any USG-authorized purpose.

-This IS includes security measures (e.g., authentication and access controls)
 to protect USG interests --not for your personal benefit or privacy.

-Notwithstanding the above, using this IS does not constitute consent to PM, LE
 or CI investigative searching or monitoring of the content of privileged
 communications, or work product, related to personal representation or services
 by attorneys, psychotherapists, or clergy, and their assistants.
 Such communications and work product are private and confidential.
 See User Agreement for details.

James

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