Settings to reject frames with clouds

[dasman]

What settings do I use to have sharpcap reject frames with clouds? I think it has to do with the FWHM and/or the Brightness filters? So my questions would be What initial settings would I chose in each of those to get started? And how do those filters work? I have read the documentation but I am still confused.

Last night I fell asleep while imaging and my stack was ruined by clouds. I also am curious if these filters will help when an individual frame gets shaken when yhe train goes by? I live 200 feet from train tracks!

Thanks in advance for any help or advise.

Dave

[admin]

Hi Dave,

both the filter on FWHM and on brightness should help.

Thin cloud will typically put halos around brigher stars, increasing FWHM, although the overall signal may not be so clear as it could also dim the image, causing the stars that are used for the measurement to change. The dimming of the stars will likely be picked up by the brightness filter though. Thicker cloud will obviously wipe out the stars completely, which should be picked up by both filters (and anyway the frame would be ignored because of no stars for alignment).

If you have saved raw frames from a previous session that had cloud at times then you could run those through the 'Folder Monitor Camera' and replay them into live stacking to see what happens to the FWHM and brightness measurements as the clouds come in to confirm.

As to trains, yes, the FWHM filter should pick up that sort of vibration in the same way that it would pick up poor tracking causing the star to move or bad seeing conditions. Finding the right threshold is a case of trial and error though.

chers,

Robin

[dasman]

Robin thank you! Sorry it took so long to reply. One last question. If the train goes by and the frame is rejected, is that frame only rejected from live stacking, or from raw frames as well?

Thanks again!

[admin]

Hi,

that depends on your setting for saving raw frames, you can select to save only the stacked frames (in which case it won't be saved), or to save all, in which case it will be saved.

cheers,

Robin

[kaymann]

Hi,

that depends on your setting for saving raw frames, you can select to save only the stacked frames (in which case it won't be saved), or to save all, in which case it will be saved.

cheers,

Robin

Is this new to 4.1? Where can I find this setting? Awesome to have that capability!!

[admin]

Hi,

no, it has actually been there a long time. See the screenshot in the docs here : https://docs.sharpcap.co.uk/4.0/#Left%20Panel

You need to change the 'Raw Frames' option to one of the four available options.

cheers,

Robin

[kaymann]

Hi,

no, it has actually been there a long time. See the screenshot in the docs here : https://docs.sharpcap.co.uk/4.0/#Left%20Panel

You need to change the 'Raw Frames' option to one of the four available options.

cheers,

Robin

I just read the 4.0 manual like a book and still I missed that - the options are fantastic Ugh that I missed that one! Cannot wait for the 4.1 manual we have been clouded over it seems like all summer so reading is my alternative to EAA/AP/FATS (Fun At The Scope)

[admin]

Making slow but steady progress with the 4.1 manual. Currently on about page 95 of 322, but I am expecting it to get substantially longer as I work through and add the new functionality.

I am also taking the opportunity to rework some parts - adding more information, particularly when questions have been asked about something several times in the forums, I am trying to get the information into the documentation.

cheers,

Robin