Hi,

I use Envisage to take my pictures with mu Meade DSI.
One of the advantages of this software is that in "Normal operation" mode it atomatically evaluates frame quality and stacks the best frames in a composite image.
I have a cheap scope with a cheap mount, so it has some tracking problems, and I have no guiding.
That makes that some frames have quite bad driftted stars (most are quite good), and I noted that sometimes Envisage gives higher quality evaluation % value to bad frames than it does to good ones (with no star drift), so it stacks a lot of bad frames and discads a lot of good frames.

My theory is that this happens when there is some very bad frame between the "evaluation frames" making Envisage to evaluate frame quality comparing against a bad "evaluation image" resulting in those weird quality % values.

Am I correct?
If so, how can I avoid this problem without saving all frames and handpicking the best ones?

Best regards,

Germán

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Germán Bresciano
Montevideo, Uruguay
http://picasaweb.google.com/German.Bresciano
Hokenn 150 750 PEQ3-2 w/dual axis drive
Meade RB-60 (60mm x 700mm)
Meade DSI-C, Vesta Pro SC1.5, SPC900NC SC1
Bushnell binoculars 10x50mm

Hi German  -  I understand your problem and this is one reason that I prefer to save all images and "handpick" the images before stacking off line. I believe that the quality evaluation of Envisage for deep space work has some limitations as noted in previous threads on this site. I usually sit in front my astronomy PC while each image is being taken. When I see one that is not good I delete it straight away from the Meade images directory. This technique should work for you unless you are taking very short (eg less than 15 second) images. When I put the images into ImagesPlus for grading I usually find that all the images are then of "A" quality with only sometimes a few "B" grade.  Overall I find that the final composite image is usually better than that achieved "automatically" by Envisage. Nevertheless, the "automatic" mode is fine for just scoping an object which I sometimes do before undertaking "serious" imaging. Cheers Peter

 

 

 

 

 

Hi, German

As Peter correctly points out, your best bet is to "save all" & sort them after the fact. Using the Image Processing tab in Envisage is one easy way to page through them...or AIP4WIN has a decent sorting feature if you have the software. I use ImageTOOLSca.

I think the "reason" is that Envisage was originally developed for the LPI. The frame quality parameter works quite well with the LPI, or with the DSI when doing planetary or lunar imaging. it just doesn't work very well for DSO's.

Chuck

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Chuck Reese
CDIP Certified: Nebula, Galaxy, Solar System, Stars & Clusters Imager
CDIP Mentor: Nebulae & Solar System Categories
For information on the Certified DSI Imager Program, see:
http://autostarsuite.net/forums/1427/ShowForum.aspx

I am trying a processing software that evaluates image quality through FWHM, star Roundness and other criteria.
This is very helpfull to sort and select frames based on those parameters, making easier to select good frames for stacking.
It would be great if eEvisage had user selected quality criteria like those, so one use the best criteria for frame sorting or selection for the particular object and observing situation.

I want to suggest that to Envisage developers but I don't know where to do that.

Germán

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Germán Bresciano
Montevideo, Uruguay
http://picasaweb.google.com/German.Bresciano
Hokenn 150 750 PEQ3-2 w/dual axis drive
Meade RB-60 (60mm x 700mm)
Meade DSI-C, Vesta Pro SC1.5, SPC900NC SC1
Bushnell binoculars 10x50mm

I can pass this on for you (but, I would not hold my breath while I wait for a new release :-)

Chuck

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Chuck Reese
CDIP Certified: Nebula, Galaxy, Solar System, Stars & Clusters Imager
CDIP Mentor: Nebulae & Solar System Categories
For information on the Certified DSI Imager Program, see:
http://autostarsuite.net/forums/1427/ShowForum.aspx