Migration to SGP, keeping MaxImDL for processing?

Sequence Generator
1

Hi there, new here.

Judging from CN-threads, a lot of users has already come over from MaxImDL to SGP, and seems awfully happy. I also understand that most users of SGP have chosen Pixinsight for processing.

Want to try SGP now.
But not Pixinsight, at least not yet. I’ll stick to the easy calibration and stacking for a while. I don’t have time to swap everything at once.
Has anyone chosen this track? Good/bad experiences?

And it would be a good exercise to check that any new capture software I invest my time in, will not streamline my imaging files for just one processing software. Never liked that MaxIm had imaging and processing in the same program, but should not be a problem with the aging/strange UI for doing just processing.

I became a bit worried when I saw how poorly MaxIm imported RAW files that I had from a mobile session.
The first thing to check was matching write/read of essential FITS header keyword/value pairs:
http://mainsequencesoftware.com/Content/SGPHelp/SequenceGeneratorPro.html?DataStoredintheFITSHeader.html
https://diffractionlimited.com/help/maximdl/FITS_File_Header_Definitions.htm

I assume both parties honor standard/common dictionaries; http://heasarc.gsfc.nasa.gov/docs/fcg/standard_dict.html and http://heasarc.gsfc.nasa.gov/docs/fcg/common_dict.html.

But already from my first glance at the use of “extended” keywords, this seems to fail completely:
MaxIm uses CCD-TEMP and SET-TEMP. While SGP writes TEMPERAT, for the same as CCD-TEMP.

Anyone with an incredibly smooth (script based etc) FITS conversion utility?
Is it correct that SGP does not write SET-TEMP? (some keyword I didn’t guess?)

I really would like to take the SGP-path, but I’m drawn towards a principle of having certain critical interfaces clearly defined and working at more than a single point of connection with the outside world.

Please assure me :slight_smile:
Thanks.

2

Olav,

Here’s a copy of a recent FITS header created by SGP, you can judge for yourself whether or not it meets your needs.

var P = new FITSHeader;
P.keywords = [ // name, value, comment
[“SIMPLE”, “T”, “file does conform to FITS standard”],
[“BITPIX”, “16”, “number of bits per data pixel”],
[“NAXIS”, “2”, “number of data axes”],
[“NAXIS1”, “3352”, “length of data axis 1”],
[“NAXIS2”, “2532”, “length of data axis 2”],
[“BZERO”, “32768”, “offset and data range to that of unsigned short”],
[“BSCALE”, “1”, “default scaling factor”],
[“CRPIX1”, “1676”, “reference spectrum pixel coordinate for axis 1”],
[“CRPIX2”, “1266”, “reference spectrum pixel coordinate for axis 2”],
[“CTYPE1”, “‘RA—DEF’”, “standard system and projection”], // row 10
[“CTYPE2”, “‘DEC–DEF’”, “standard system and projection”],
[“OBJECT”, “'B33 '”, “Object name”],
[“DATE-LOC”, “‘2017-01-07T21:15:48’”, “Local observation date”],
[“DATE-OBS”, “‘2017-01-08T03:15:48’”, “UTC observation date”],
[“IMAGETYP”, “'LIGHT '”, “Type of frame”],
[“CREATOR”, “‘Sequence Generator Pro v2.6.0.5’”, “Capture software”],
[“INSTRUME”, “‘SBIG ST-8300 CCD Camera’”, “Instrument name”],
[“FOCUSER”, “‘Moonlite DRO Focuser Driver’”, “Focuser name”],
[“FOCPOS”, “1450”, “Absolute focuser position”],
[“FOCTEMP”, “0.922666666666667”, “Focuser temperature”], // row 20
[“FWHEEL”, “‘SBIG Filter Wheel’”, “Filter Wheel name”],
[“FILTER”, “'Ha '”, “Filter name”],
[“EXPOSURE”, “900”, “Exposure time in seconds”],
[“CCD-TEMP”, “-24.9367560713856”, “Camera cooler temperature”],
[“SET-TEMP”, “-24.9367560713856”, “Camera cooler temperature”],
[“XBINNING”, “1”, “Camera X Bin”],
[“CCDXBIN”, “1”, “Camera X Bin”],
[“YBINNING”, “1”, “Camera Y Bin”],
[“CCDYBIN”, “1”, “Camera Y Bin”],
[“XPIXSZ”, “5.4”, “Pixel Width in microns (with binning)”], // row 30
[“YPIXSZ”, “5.4”, “Pixel Height in microns (with binning)”],
[“TELESCOP”, “‘Gemini Telescope .NET’”, “Telescope name”],
[“RA”, “85.1241247505203”, “Object Right Ascension in degrees”],
[“DEC”, “-2.31473398854742”, “Object Declination in degrees”],
[“CRVAL1”, “85.1241247505203”, “RA at image center in degrees”],
[“CRVAL2”, “-2.31473398854742”, “DEC at image center in degrees”],
[“OBJCTRA”, “‘05 40 29.790’”, “Object Right Ascension in hms”],
[“OBJCTDEC”, “’-02 18 53.042’”, “Object Declination in degrees”],
[“AIRMASS”, “1.30740857095957”, “Average airmass”],
[“OBJCTALT”, “50.99108”, “Altitude of the object”], // row 40
[“CENTALT”, “50.99108”, “Altitude of the object”],
[“FOCALLEN”, “1624”, “The focal length of the telescope in mm”],
[“FLIPPED”, “T”, “Is image flipped”],
[“ANGLE”, “92.25”, “Image angle”],
[“SCALE”, “0.69502”, “Image scale (arcsec / pixel)”],
[“PIXSCALE”, “0.69502”, “Image scale (arcsec / pixel)”],
[“POSANGLE”, “92.25”, “Camera rotator postion angle (degrees)”]
];

As for PixInsight, it is an excellent program for both pre- and post- processing but has a steep learning curve. There are numerous tutorials, both written and video, on the Internet to help you get started and Warren Keller’s new book, Inside PixInsight, is excellent.

I have been using SGP for several years and wouldn’t go back to other programs I’ve used for any reason. Just the Framing and Mosiac Wizard is worth its weight in gold :>).

Regards,

BobT

3

Thanks Bob, that helped a lot!
Good to see that both CCD-TEMP and SET-TEMP joined the team!

Will not dwell with every FITS keyword (haha), but this temperature thing was important.
I guess your sample in not really from the universe where the the actual camera temperature coincided with the setpoint at a 15-decimal precision (both “-24.9367560713856”), more like SGP is writing the camera temperature to both fields.
Not the worst thing that could happen, but even from my relatively short experience in this hobby I have had several cases where SET-POINT definitely has helped sorting things out.
Also, good to see from the (beta) 2.6.0.6 Changes, that developers have “Rounded camera temperature to a whole number for insertion into file names”. Guess I will choose the beta after all, even though SGP newbies are warned against it.

The MaxIm FITS page with extension “definitions” that I linked to referred to the “SBIG proposal for FITS keyword extensions”, along with a dead link. Nothing to be found by web search. (Makes you wonder if this was someones idea at the pub, that someone forgot to tell anybody about.)
Anyway, if there’s no collaboration between software vendors leading to a standardized set of FITS extensions, each vendor’s public page on FITS keywords and use, to adhere to, will have to do.
Could really wish to have such pages constantly updated with current keywords in use, and a history of when they were added, deprecated and removed (the latter two, hopefully not too much). Just like the IAU FITS Working Group do.
I’m not saying I have a lot to choose from in this case, but I will continue to let this property weigh a lot when comparing astronomy software. (know this sounds very anti-pragmatic)

Now slightly off-topic, but depending on the current state of Pixinsight, my questions may not have surfaced at all:
Any thoughts about how fast and convenient pre-processing in Pixinsight is compared to MaxIm, once you know the programs reasonably well?

Just one final question, an easy one.
Is there an image file/folder structure coming out of SGP, described somewhere?
Looked around, but can of course try and see. Probably not a problem with MaxIm anyway.

Thanks :slight_smile:

4

Olav,

I haven’t really noticed the time it takes to preprocess in PixInsight so I went back and preprocessed a target. There were 30 bias, 20 darks, 20 flats, and 15 lights in the group. Since SGP lets you set up file names, mine are arranged so that I can copy entire folders into the PI BatchPreprocessing script and PI will sort them out. Now, my computer is a six core Xeon processor (which runs with 12 virtual cores) so it is fairly fast. PI will use all available cores on your computer. The entire preprocessing time for the above was 2 minutes 28.8 seconds through calibration. Stacking took 20.91 seconds and integration took 19.76 seconds.

Check the SGP Help files on how to arrange your directory structure, it is extremely flexible.

Your mileage my vary.

Regards,

BobT

5

@olav

We are pretty lenient with FITS headers if there is a legitimate reason to add or modify one. In the past:

  • We have added headers that were in the FITS standard and were missing (I think we added AIRMASS last… it only takes a few minutes… usually).
  • We have added extended headers to be more compliant with other software.

If you need something, just drop a note on the forum explaining the situation.

This is largely user defined and can be different for different sets of gear. It is flexible enough to handle almost anything you would want for file system organization.

http://www.mainsequencesoftware.com/Content/SGPHelp/TargetDataFileNaming.html

6

Thanks again Bob,
I see, due to the precision in your measurements, this is just a matter of starting automated operations, no sifting through frames or other manual manual actions (pondering).
Well in that case it is great, the MaxIm (nearly) all-in-one action would not mean much of a difference.

7

Good.

Thanks, I failed to see that one.
Works just like I hoped :slight_smile:

8

The precision was not mine, PI reports the time it takes to run a process.

Good luck on making your software decisions,

BobT