plate solve and sqm 17

Anything that doesn't fit into any of the other forums
zoltrix
Posts: 32
Joined: Fri Nov 12, 2021 9:48 pm

plate solve and sqm 17

#1

Post by zoltrix »

hello

from by balcony light pollution is quite poor
I measure sqm 17-17.5
can plate solve work in such enviromental conditions ?
newtonian 130/650
User avatar
admin
Site Admin
Posts: 13179
Joined: Sat Feb 11, 2017 3:52 pm
Location: Vale of the White Horse, UK
Contact:

Re: plate solve and sqm 17

#2

Post by admin »

Hi,

quite likely - normally seeing (by eye, no stretch) 20 or more stars would be sufficient, although you may need to make adjustments to the plate solving settings to get the stars detected properly.

Saving an image and then uploading it to nova.astrometry.com is also a good test - the online plate solving engine there is similar to the one used by Astrotortilla/ASPS/AnSvr.

cheers,

Robin
zoltrix
Posts: 32
Joined: Fri Nov 12, 2021 9:48 pm

Re: plate solve and sqm 17

#3

Post by zoltrix »

Thanks Robin

does the type of scope make any significant difference as far as plate solve and live stacking are concerned ?
I mean , in both cases you need a minimum number od stars
a small refractor encompasses a larger zone of the sky but up to a limited magnitude
the direct opposite for a large aperture and long focal length scope
which one would you suggest ?

cheer

Alberto
User avatar
admin
Site Admin
Posts: 13179
Joined: Sat Feb 11, 2017 3:52 pm
Location: Vale of the White Horse, UK
Contact:

Re: plate solve and sqm 17

#4

Post by admin »

Hi,

generally the shorter the focal length, the better it works - you need less plate solving data installed to solve reliably for a 1 degree FOV than you do for a 0.1 degree FOV (and the process is *much* faster as there are less fields to test). Additionally, with a small FOV you can sometimes hit areas of sky that are lacking even reasonably bright stars, causing problems.

cheers,

Robin
zoltrix
Posts: 32
Joined: Fri Nov 12, 2021 9:48 pm

Re: plate solve and sqm 17

#5

Post by zoltrix »

Hello

finally I was able to try plate solving for the first time but it failed
I was concerned about light pollution (sqm 17-17.5)
I got the message "too many stars" :o
What shall I do ?

thanks in advance
bye

Alberto

PS

scope: newton 130/650
camera : zwo asi 178 mm (mono)
software : asps
zoltrix
Posts: 32
Joined: Fri Nov 12, 2021 9:48 pm

Re: plate solve and sqm 17

#6

Post by zoltrix »

hello

further to my previous post about plate solving failure
Some doubts

# I select the first star for alignment from the synscan menu of my AZ Gti mount
should the "Scope controls" pannel show the relevant RA and DEC ?
if so, it does not
apart from that , the scope control seems to work fine

# 2 I use "All Sky Plate Solving" which accepts tif and jpeg file formats only
It seem that Sharpcap export png files
may it be the reason for failure ?

# 3 Besides using the "Find my location" Button I tried also the "Plate solve" and "Plate solve and resync " functions from the menu
the former works, the latter does not

Thanks in advance for your support

bye

Alberto
User avatar
oopfan
Posts: 1321
Joined: Sat Jul 08, 2017 2:37 pm
Location: New York
Contact:

Re: plate solve and sqm 17

#7

Post by oopfan »

Hi Alberto,

I don't think I'll be much help, but maybe I'll say something that rings a bell.

With regards to plate solving, which region of the sky are you trying? I ask because I've always had problems with Cygnus. It's just not SharpCap alone. I tried another platform, and I have the same problems with Cygnus. Curiously, when I upload the image to nova.astrometry.net, it solves it! Now, I must admit that I am using an old version of SharpCap: 3.1. So it's got to be three years old. The other platform I mentioned is equally as old. I've made sure that the solver's index files are loaded and appropriate for the telescope's focal length. nova.astrometry.net sees a lot of usage, so I would imagine that the authors are continually improving the code and/or index files.

Brian
User avatar
admin
Site Admin
Posts: 13179
Joined: Sat Feb 11, 2017 3:52 pm
Location: Vale of the White Horse, UK
Contact:

Re: plate solve and sqm 17

#8

Post by admin »

Hi,

the astrometry.net engine that runs the actual plate solving back end for ASPS, AnSvr and Astrotortilla is quite happy accepting PNG files, even if the user interface of those applications may not accept them - no worries there.

If you are getting messages about too many stars then consider turning up the 'sigma' setting in the SharpCap plate solving settings - that will make the star detection for plate solving less sensitive. If you happened to save any images when you were trying to plate solve you could test those using the 'Test Camera 1' without waiting for another clear sky opportunity.

If you use the 'locate me/GPS' button then SharpCap will search instruct the plate solving engine to search within 15 degrees of the current mount co-ordinates. If you use 'plate solve only' the SharpCap will request a search of the whole sky (slower, although it will use the co-ordinates of the mount if the mount is connected as the starting point).

The best way to dig further into this would be for you to share the SharpCap log from the run where you have the plate solving problems - the log may be quite large, but it contains all the details of the plate solving operation and is usually a good start. If you have a saved image file then even better!

thanks,

Robin
zoltrix
Posts: 32
Joined: Fri Nov 12, 2021 9:48 pm

Re: plate solve and sqm 17

#9

Post by zoltrix »

oopfan wrote: Sun Nov 21, 2021 2:00 pm Hi Alberto,

With regards to plate solving, which region of the sky are you trying? I ask because I've always had problems with Cygnus.
hi Brian

it was the western region with Cygnus but I did not select stars of this costellation

bye

Alberto
zoltrix
Posts: 32
Joined: Fri Nov 12, 2021 9:48 pm

Re: plate solve and sqm 17

#10

Post by zoltrix »

hello

I found the attached files in the SharpCap capture folder
I tried also with sigma = 75 instead of the default value 50

bye

Alberto

PS

in the Scope controls pannel should I read the coords of the selected star ?
Attachments
M31_00001resized.png
M31_00001resized.png (201.04 KiB) Viewed 672 times
M31_00001.CameraSettings.txt
(741 Bytes) Downloaded 43 times
Post Reply