Re: ASTAP Plate Solve Failing During APPM

Dale Ghent

A typical cause for the "Star database limit was reached!" error in ASTAP is that the inappropriate star database is being used in ASTAP, usually when the FOV is small, such as when high focal lengths are being used. An EDF 155 would be close to where it'd say you should have the H18 database in use in ASTAP, rather than the H17 one. The number in the database name refers to the star magnitude included in it. The only drawback to using the H18 is that it consumes twice the disk space as H17 does.

So, you can uninstall H17 (it's essentially a subset of H18) and install H18. You can then run ASTAP, hit the button with the sigma character on it, go to the Alignment tab, then ensure that the "Star database used" setting is set to either H18 or (preferably) Auto. If Auto isn't there, you have an older ASTAP installation and it would be good to update it.

On Jul 15, 2022, at 16:38, <> wrote:

Hi Ray – another chapped suggest 1000 stars and 5 deg of radius search – I will try as soon as possible.

Thanks for the suggestion,


Ps – if it works, I will let you know so that maybe you can add to your notes for the future.

From: <> On Behalf Of Ray Gralak
Sent: July 15, 2022 8:58 AM
Subject: Re: [ap-gto] ASTAP Plate Solve Failing During APPM

Hi Chris,

The error message in APPM’s popup window indicates the reason:

“Star database limit was reached!”

That’s an error from ASTAP. I believe that means ASTAP reached some internal limit on the number of stars it can process given the area of sky. So, maybe try setting “Max number of Stars” to something other than “0” which will use the default you have setup when manually running ASTAP.


From: [] On Behalf Of
Sent: Thursday, July 14, 2022 7:45 PM
Subject: [ap-gto] ASTAP Plate Solve Failing During APPM

Hi – for anyone who may have run into this using ASTAP, I’m hoping that there may be some suggestions as to what I’m doing wrong.

For clarity, in SharpCap, I have no issue plate solving with ASTAP.

Here is the set-up (scope = EDFS155):


And I get this (more or less exposure time doesn’t seem to make a difference).

Any help would be appreciated.



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