The issue with central obstructions is that SGP gets confused on the size of the star when stars go to donuts. It’s not a limitation of HFR but a limitation of our star detection algorithm. If/When we get that fixed then scopes with central obstructions will focus just as well as refractors.
If you already own PinPoint you can try setting the focus method to FWHM which will use PinPoint and may deal with donut stars better. Again, not because it uses FWHM but because PinPoint may be better at figuring out what to do with donuts. I would really like to hear some feedback on using PinPoint as the metric provider with a centrally obstructed scope. I’ve been recommending it for a while but have heard no feedback from it (and I don’t own a scope with a CO to test with).
You might seek some suggestions from the Pixinsight authors. Juan Conejero seems easy to approach for help.
(Aside: I know he would love to have a few acquisition programs implementing the XISF image format instead of FIT. Apparently, it can do a lot more than FITs and it now the default image format for Pixinsight. The specs on this are open source. PI users such as myself would like to have it added sooner or latter. )
Right, but nobody has been able to define any clear advantages from the capture perspective. I understand the advantages from a processing perspective and since PI will always open FITS images and allow saving as XISF, I am not sure how us spending time on this would help anyone. I’m not saying that it wouldn’t just that I don’t understand how it would.
Agree 100%. I was just thinking out loud . There should be away to make the focus recognize obstructed stars as well as unobstructed.
If your are hitting the wall on the focus routine, Juan would be a good resource for ideas.
Just saying he would be likely be extra helpful if he heard you eventually might add XISF.
It is not high my wish list either.
By the way, it is easy make a refractor into a obstructed scope. Create a 40-50% obstruction with cardboard and some wire. Use masking tape to hang it on the dew shield in front of the lens ( not touching the lens of course). Now your driving a convertible. Sounds goofy but for testing this should be equivalent to a SC or astrograph
That would be great. TSX plate solve is probably the best image link software there is. It never fails. People who own paramounts already have this installed in their computers. I’m looking to use SGP for my automation but I just don’t have room to install more software in my observatory computer.
For information, SGP has the ability to set backlash in its focus algorithm. The current version of TSX does not. I prefer SGP, it may be a bit slower, since it is not selecting bright stars and using short exposures, but with its classic graphs I have more confidence in the final result.
I’m not sure what you mean tsx doesn’t have backlash compensation for focus? It’s built in to the driver not the software. It will be in the settings of what ever focuser you are using.
As I mentioned, if SGP integrates with TSX it will only be as a solver. We will NOT control a camera, telescope (well maybe a telescope), focuser, filter wheel, etc, through TSX.
However this is not something we’re even considering doing in the upcoming 12 months…
Tolga - backlash can be implemented in the driver or in the focusing software. TSX relies upon the driver having it.
Not all drivers/focus modules have backlash, however, even some well known ones do not. Usefully, SGP has it. It is also more useful that SGP has it, rather than the driver, since if you have one module that you share between different motors/scopes, you can set the backlash value individually in the equipment profile, to match the mechanicals.
For what it’s worth, I use SGP for focusing both my Takahashi FSQ 106ED, and my Edge 9.25 at f10 2350mm. On both scopes I get beautiful repeatable v curves and crisp focus. Temperature compensation ensures I can go hours without rechecking focus. Donuts have become a non - issue with the latest focusing routine. One of the greatest things about SGP’s focus routine is that I don’t have to leave the target. That is a huge convenience and time saver to me. I can’t imagine the improvement that some other focusing software would have to offer to make me be willing to leave the target every time I wanted to check focus. The only improvement that I would be happy to see would be the image download speed of SGP in general.
Hi Ken,
I find even with image history turned off the download speed of images is still pretty slow. I am using a full frame DSLR, so maybe there isn’t much can be done about it.