A couple of evenings ago I tried platesolving. I simply pressed platesolve and sync and it solved and then I went to Andromeda and unbelievably (to me) there is was on the screen.
Last night I tried platesolving for 2 hours and never managed it. Nothing was any different from the previous night.
I find that it takes 10-20 seconds from EQMOD to respond to an instruction - eg move in a certain direction, unpark, switch tracking on, I assume this shouldn't be the case? What could the problem be there.
Beginner problems
Re: Beginner problems
Many things could be wrong. Frustrating but the best way to learn. Here are a couple of possibilities that I have encountered in the past..
1) Platesolving requires that the camera detects enough stars. So it might be the image was less bright, the focus not right or need to check whether the histogram looks similar to the first night.
2) It could also be that on the second occasion the telescope was just pointing too far away from where it was meant to be. Platesolving works but not if you are 15 degrees or so off target in the first place. This can be a question of polar alignment not being right --- or the wrong time or physical location in whatever planetarium programme you are using to guide the scope (I had this problem recently when I noticed that my Ioptron mount software wasn't syncing with the time one the PC and had suddenly placed me in China!).
Also -- when getting the scope correctly synced with the planetarium program (Stellarium in my case) it pays to go gradually. So --following polar alignment and initial set up - you should start with the scope position as being indicated as true North (assuming you are Northern hemisphere) aligned with the pole. Then I tend to use a star quite near the pole as first alignment point for plate solving - for example a star in Cepheus. Often this is several degrees out. But once that first nearby point is correctly synced using plate solve the second and third points etc become progressively more accurate.
hope this helps
Tim
1) Platesolving requires that the camera detects enough stars. So it might be the image was less bright, the focus not right or need to check whether the histogram looks similar to the first night.
2) It could also be that on the second occasion the telescope was just pointing too far away from where it was meant to be. Platesolving works but not if you are 15 degrees or so off target in the first place. This can be a question of polar alignment not being right --- or the wrong time or physical location in whatever planetarium programme you are using to guide the scope (I had this problem recently when I noticed that my Ioptron mount software wasn't syncing with the time one the PC and had suddenly placed me in China!).
Also -- when getting the scope correctly synced with the planetarium program (Stellarium in my case) it pays to go gradually. So --following polar alignment and initial set up - you should start with the scope position as being indicated as true North (assuming you are Northern hemisphere) aligned with the pole. Then I tend to use a star quite near the pole as first alignment point for plate solving - for example a star in Cepheus. Often this is several degrees out. But once that first nearby point is correctly synced using plate solve the second and third points etc become progressively more accurate.
hope this helps
Tim
Last edited by timh on Thu Sep 30, 2021 12:38 pm, edited 1 time in total.
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Re: Beginner problems
Hi,
the most common problem with plate solving is the star count found by the plate solver being either too low ( < 20, not enough data for it to work on) or too high (> 200, too many stars - possibly detecting hot pixels as stars). Watch the progress notifications (or the SharpCap log) to see how many stars the plate solver finds. If there are too few then either increase exposure and/or gain (if you cannot see stars on screen) or reduce the 'sigma' setting in the SharpCap options. If too many then take the opposite actions. Note that you should not use display stretch when deciding if you can see enough stars on screen.
On the delays with EQMOD - no, that shouldn't happen. How is your mount connected? Is it wireless by any chance? I could imagine that being slow if the connection is bad, but I have not seen anything like this with a wired connection.
cheers,
Robin
the most common problem with plate solving is the star count found by the plate solver being either too low ( < 20, not enough data for it to work on) or too high (> 200, too many stars - possibly detecting hot pixels as stars). Watch the progress notifications (or the SharpCap log) to see how many stars the plate solver finds. If there are too few then either increase exposure and/or gain (if you cannot see stars on screen) or reduce the 'sigma' setting in the SharpCap options. If too many then take the opposite actions. Note that you should not use display stretch when deciding if you can see enough stars on screen.
On the delays with EQMOD - no, that shouldn't happen. How is your mount connected? Is it wireless by any chance? I could imagine that being slow if the connection is bad, but I have not seen anything like this with a wired connection.
cheers,
Robin
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woldsweather
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Re: Beginner problems
Sharpcap was detecting anywhere between 1/2 and 900 as I varied settings. I have no idea what the sigma setting is so will have to look that up. I don't really understand what stretching is other than getting more pout of what data you have.
I focused with a Bahtinov mask on Jupiter at the start though the rays on the mask were blurry despite being evenly spaced and stars didn't look sharp on screen. Later I focused more.
The mount is connected via a Lynx Astra EQMOD cable. Whether I move the mount by the directional arrows or switch tracking on it takes anything up to 20 or more seconds to respond and sometimes doesn't respond at all. I would really like to get to the bottom of this problem.
Tim
When you say the scope was pointing too far away from where it is meant to be I don't follow that. After polar alignment with Polemaster I assumked the next thing was to plate solve and then if worked then to sent the scope to where you want it with Stellariume. Is that not how it works?
When you say you use a star quite near the pole how do you mean use it? How do you find your alignment star when you aligned aligned?
I would be grateful for your comments - thanks.
I focused with a Bahtinov mask on Jupiter at the start though the rays on the mask were blurry despite being evenly spaced and stars didn't look sharp on screen. Later I focused more.
The mount is connected via a Lynx Astra EQMOD cable. Whether I move the mount by the directional arrows or switch tracking on it takes anything up to 20 or more seconds to respond and sometimes doesn't respond at all. I would really like to get to the bottom of this problem.
Tim
When you say the scope was pointing too far away from where it is meant to be I don't follow that. After polar alignment with Polemaster I assumked the next thing was to plate solve and then if worked then to sent the scope to where you want it with Stellariume. Is that not how it works?
When you say you use a star quite near the pole how do you mean use it? How do you find your alignment star when you aligned aligned?
I would be grateful for your comments - thanks.
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woldsweather
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Re: Beginner problems
Last line should say How do you find your alignment star when you are not aligned?