We are pleased to be able to announce the availability of a new medium resolution optical survey created by Axel Mellinger. This three color all-sky survey provides beautiful large-scale true-color images of the sky. For regions less than 30 degrees, the resolution is about 0.01 degrees. For larger regions the data is sampled from 0.1 degree pixels. For more information on these data check out the survey web site.
This survey provides an excellent complement to medium and low resolution surveys in other wavelengths, e.g., IRAS/IRIS and RASS and the new Fermi gamma-ray surveys that we plan on introducing in the next few weeks.
All-Sky Aitoff Projection of Mellinger data
Many thanks to Dr. Mellinger for allowing us to include these data in SkyView.
The image above was created using the following arguments.
survey=mell-r,mell-g,mell-b
quicklook=jpeg
rgb=true
projection=Ait
size=360,180
pixels=1000,500
sampler=Clip
The Mellinger survey is only available through the SkyView web site and cannot be retrieved using a local copy of the Jar file. The survey sets some defaults differently from other surveys. The default scaling is linear and the min and max values are set to 0 and 255 to preserve a consistent scaling regardless of the region you happen to pick out. We also set the ClipIntensive keyword when the Clipping sampler to preserve the scaling.
That is an unbelievable picture. It is amazing what NASA does because being a citizen on the outside, you only hear about things like the Space Shuttle. I am actually proud to be a tax payer at this moment.
Keep up the good work here on this SkyView project, I’ll be coming back to see new pictures. I’ve bookmarked this site.
Wow!
Man all this space discovery technology just gets better and better.. I hope tp see more great images.
THat is an amazing image, I’ve had a look at the otyher Mellinger images and there a lot of equally superb shots there as well.
That photo is excellent. I can see many different uses for photos of this quality including some interesting wallpaper prints.
skyview from nasa, i think this unbelievable picture was made with super camera and etc,
Wonderful image. I just love outer space and was lucky enough to visit NASA in 2005. [link to commercial site deleted] Thanks!
What an ABSOLUTELY INCREDIBLE IMAGE. Thank you NASA for you continued efforts. Images like this are enough to keep my 7 year old son completely intrigued with Space!
Hello, is the SkyView RAID system working right now?? although I’ve seen no update on the blog regarding this, aside from the previous update posted.
Thanks in advance, also looking forward to more medium resolution samples
SkyView’s hardware was not directly affected by the recent problems. Some related systems had issues, including the server which holds the database used by our blog.
Regards,
Tom
wow, digital all sky mosaic images are amazing.
woow thats all i say 😀
Many thanks to Alex and your team for providing this very nice survey.
I suggest to have two things in Skyview improved. The data in the FITS files is type floating, “BITPIX = -32”. however the data is in range 0 to 255 as defined in “COMMENT Units: Byte-scaled intensity” It would be more efficient to make 8 bit FITS files “BITPIX = 8” An other major problem with Skyview FITS files is that the data range is not given. ESO and MAST provide this in the header data as:
DATAMAX = 19596 /Maximum data value
DATAMIN = 1168 /Minimum data value
This additional FITS header data would be most useful in processing Skyview images in my planeterium program HNSKY. The Mellinger survey will be available in the program from today.
Thanks for the comments…
While the input data may have byte values, resampling can cause the computed pixels to be non-integers, so even with
survey that start with integers, floating point outputs0 are possible. You are correct that with the default nearest neighbor sampling the user will only get integer values, but SkyView does all it’s computations in double precision. We could think about an option where the user could scaling to integers.
Your idea that we put the actual range of the data in the FITS file makes a lot of sense. We already provide that in the web page output, so we’re already computing it. We’ll put that in the next revision thanks.
You may wish to check with Alex Mellinger regarding use of his survey in your program. His data is not in the public domain.
Tom
Tom,
Don’t worry, I will not use the copyright protected data of the Mellinger survey directly but proving an interface to Skyview.
The advantage of 8 bit or 16 bit FITS will be the smaller file size and therefore increased download speed.
I have noticed that the field size of the downloaded FITS files is limited to about 142 degrees. Not a problem, just an observation. This is the web command line:
http://skyview.gsfc.nasa.gov/cgi-bin/pskcall?return=fits&sampler=Lanczos&Survey=MELL-R&VCOORD=0,0&PIXELX=1000&PIXELY=1000&SFACTR=300
Thanks again,
Han
Also my excuse for the wrong spelling of dr. Mellinger firstname Axel.
Han
Dear Han,
The limit to the size of the region you retrieve is a characteristic of the size of projection used. The default Tangent projection will show a maximum of one hemisphere of the sky, and only reaches that as the image size approaches infinity. Other projections can be used to see more of the sky in a single image. When you specify the size of the image in degrees (with SFACTR above), you are specifying the size in the projected coordinates, not on the sphere. For small maps where distortions are minimal these will be the same, but as you try to get very large images substantial distortions are inevitable. Other projections,
Car, Zea, Ait may be more appropriate for very large images.
With regard to use of the Mellinger data: I am not a lawyer, but I’m dubious that the license we have from Dr Mellinger permits the kind of use you envisage. The Copyright notice indicates:
Copyright: Axel Mellinger. Permission is granted for use in research and personal, non-commercial use. Please contact Axel Mellinger for permission for other use.
This copyright still applies even if you get the data through us.
Regards,
Tom McGlynn