Plate solving a Meade DSI 2 pro image

[GeneN]

Hi,
My image starts out flipped vertically and rotated by -90 degrees.
I know the exact center of image (M15 or M57) and plate scale.
I added FIT's headers for position, ASTAP does not see them or I am using the wrong ones so I double clicked on the position and type in the Messier number.
No matter how I try I always get a fail for solve.

I used IRIS to 2X the image, flip vertical and rotate by -90 and feed the result to ASTAP, still no luck, always fail.

Thoughts?

Thank you for your time!

Gene

[han.k]

Hello Gene,

If the position is correct, then the problem is either a wrong scale or it is just a poor or stretched image. Orientation doesn't matter.

Try the auto option in stack menu tab alignment. Select auto and hit solve again. See attached.

If that still doesn't work, give me a link to the image so I can see the image. Upload it for example to nova.astrometry.net and share the link.

Clear skies, Han

[GeneN]

Hi Han,
Ok, I did upload to
http://nova.astrometry.net/user_images/4248555

Thanks for the link!
It did find a solution as M15

Please be advised, I live in very light polluted skies and the image train does show heavy vignetting also.

Thank you!
Gene

[han.k]

Hello Gene,

Unfortunately the resolution of this Meade DSI2 camera is only 752 x 582 pixels . Normally I recommend 1280x900 pixels minimum. If it is a good image you could down to something 700x700 pixels but this DSI2 is producing 8 bits images which looks like video screenshot. The sensitivity is also not so good. With 60 seconds exposure you would expect more stars.
Also the stars are a little oval which doesn't help either.

I have tried in the past, but this camera doesn't work well with ASTAP. Only Astrometry.net will solve these images reliable.

So i have no working solution for this camera. ASTAP will work with almost any other camera but not this one.

Clear skies, Han

[GeneN]

Hi Han,
Thank you again!
Do you think any relevant manipulation would allow a solve?
Say double image size using pixel replication
Subtracting out DATAMIN from all pixel values ?

The relevant headers show
SIMPLE = T / file does conform to FITS standard
BITPIX = 16 / number of bits per data pixel
NAXIS = 2 / number of data axes
NAXIS1 = 748 / length of data axis 1
NAXIS2 = 577 / length of data axis 2
EXTEND = T / FITS dataset may contain extensions
BZERO = 32768 / offset data range to that of unsigned short
BSCALE = 1 / default scaling factor
DATAMIN = 16035 / Minimum value
DATAMAX = 35030 / Maximum value
XPIXSZ = 8.6 / [um] Pixel Size X, binned
YPIXSZ = 8.3 / [um] Pixel Size Y, binned
XBINNING= 1 / Binning factor X
YBINNING= 1 / Binning factor Y
FRAMEX = 0 / Frame start x
FRAMEY = 0 / Frame start y
FRAMEHGT= 577 / Frame height
FRAMEWDH= 748 / Frame width
FOCUSPOS= 5755 / Focuser position in steps
END

[han.k]

Hello Gene,

Doubling will not help. The solver require some accuracy in the star distances. This is not given by a 752 x 582 resolution and doubling will not make a difference.

I have tried in the past with the DSI2 and for some good quality images it can solve but mostly it will fail.

With my ASI1600 camera it can solve images of 0.1 seconds exposure and use typical 5 second to be sure. Your image is already 60 seconds exposed and should contain more stars

I tried also PlateSolve2, but that program can't solve your solve either.

The only reliable solution is to use a local or online astrometry.net solver. That will work with CCDCiel.

Clear skies, Han

[GeneN]

Thank you Han!
Best to you and yours this holiday season!

Gene