SharpCap Forums

I'm relatively inexperienced with Sharcap. Just spent a night with a C11 + 6.3 plus focal reducer and an Svbony 705C (IMX 585) doing some EAA. It was the first time with this combo. Seeing was not always perfect but generally ok. Shapsolve kept coming back with 'fail'. It has alway worked with a 120/f7 refractor and the same camera in similar viewing conditions so I assume I'm overlooking a setting / trying something beyond the abilities of this camera and telescope combo.

All advice gratefully accepted.

Pat Neville

Hi Pat and welcome

What happens a lot (happend to me too ), is that in the SharpCap Settings under the Plate Solve tab, a focal length is defined.
So maybe in your case too? If so, set it Do Not Use and try it again. I use that setting too with my 2000mm scope and it's just as fast.

Menno

Thanks Menno555.

I eventually got around to ticking the <Do Not Use> box but it made no difference.

Have nothing but positive to say about Sharpcap so maybe the sky conditions were quirky last night. It's semi-tropical here and humidity sometimes gets sucked in on high from the coast. Stars seemed bloated/soft last night as well for no good reason. Back spacing was as per recommended.

H.

Hi,

that setup with the C11+Reducer+IMX585 has a focal length of about 1750mm and a field of view of 0.36x0.21 degrees. SharpSolve is designed to go down to 0.25 by 0.25 (needs the larger catalog below 0.5x0.5 - use the download button in the settings to get it). The extra width may not be enough to save you from the lack of height of the image.

Once you start getting close to that low field of view limit, it does get less reliable and it becomes more critical to get plenty of stars that are well enough exposed to be detected.

Try longer exposures and potentially use binning to reduce noise to help the star detection work - that might get you running. Note that at that scale there are some areas that have very low star counts that might simple not work at all because there is so little to see.


cheers,

Robin

Many thanks for taking the time Robin.

I will try as you advise as soon as the weather permits. The limiting factors in my set up were probably complicated the other night by the onset of a new episode of La Calima; and stars were indeed scarce in some of the areas I was scanning.

For the next 3-4 days even the nearest star won't be visible during daytime on account of this insufferable Calima.

Nothing to be done.

Pat

Hi Pat,

I hope the weather clears soon - I had to look up the Calima online as I hadn't heard of it before, and it doesn't sound nice

When you do get a chance to test, if you still encounter problems, save a few typical images to file and then you can try running them through the online plate solving tool at nova.astrometry.net to see if they work there (that one uses the same plate solving engine as Astrotortilla). You could also share them with me so I can see if anything can be done to help make them solve.

cheers,

Robin

Thanks again Robin. I'll do as you advise the next time I roll out the C11.

The Calima has been grim, but I can see sunlight again this morning

Hooray!

Pat

Hi Robin,
A question about the solver. Is there a flag somewhere that I can set so that when I record a series of images via the capture menu, each one will automatically solved and also saved as solved .fits file?
Thank you very much for your feedback and best regards,
Roger

Hello Roger,

A flag somewhere ? ... No

But, if you start to use the script ... then it should be possible to write something that performs what you propose.
One of the problem will be to have some functions for read/write a FITS image.

Robin ... is it possible to use some SharpCap internal functions for that ?
I know that it exists several .net or C# libraries for the FITS. But an internal function would be easier.

Regards,
Jean-Francois

Hi,

unfortunately there isn't a way to add plate solving information to each frame as it is captured that is built into SharpCap. As Jean-Francois says, it would likely be possible using scripting, but even that feels a bit clumsy.

To answer the scripting question, if you have received a frame from SharpCap via the scripting events then you can call .SaveTo(...) on it - it will allow a save to PNG, TIFF or FITS, depending on the filename passed in. You would need to pass AllowOverwriteDisposition.DoNotAllow as the second parameter (or one of the other enum members). You can load frames using the following script code
Note that this function will return python 'None' on failure to find a file, so be sure to check.

cheers,

Robin