Eastern Vail with POSS2 red & blue data

[gorann]

Here is an RGB image from the monochrome glass plate images (taken through a red and a blue filter) from the Palomar Observatory Sky Survey II (1990ties) downloaded from the Mikulski Archives site. They used the Oschin 48-inch (1.2-m) Schmidt camera on the Mt Palomar Obsy. Here I used both red and blue data and made a synthetic green (a 50:50 mix of red and blue) to make a RGB image. Much of the work in this case went into aligning stars since the red and blue did not match up perfectly over the whole image, so I had to divide it up into 6 squares where I aligned the colour channels. All done in PS.

I think there is some very nice details in the data and tight stars, but I get the feeling that the dynamic range of these glass plates is not as high as in our modern 16bit digital images, so it is not possible to bring out as much dust as we are getting used to.

Comments and suggestions most welcome.

[Knight of Clear Skies]

Interesting stuff, good to see some old data liberated and presented in a manner that wouldn't have been possible when these plates were taken in the 80s. I had a quick look at MAST but found it a little confusing, do you have any tips for downloading data from it please?

[gorann]

11 minutes ago, Knight of Clear Skies said:

Interesting stuff, good to see some old data liberated and presented in a manner that wouldn't have been possible when these plates were taken in the 80s. I had a quick look at MAST but found it a little confusing, do you have any tips for downloading data from it please?

Thanks!

Here is the link to  the page where you either put in the name or catalogue number of the object or its co-ordinates. The I chose 60 x 60 arc minutes image size. If you download as gif you will see it after a few seconds (so start with that to see what you get). The you can download as fits (best quality) which will end up in your downloads folder and you have to add .fits to the file. Use the POSS2 (red and blue or IR) since they are much better than POSS1 (those are from the 1950ties). Not sure what the other databases are (HST Phase 2 seems to be the same as POSS2)

http://archive.stsci.edu/cgi-bin/dss_form

[Knight of Clear Skies]

Thanks, will have a play with this later if I can find the time. Had some fun browsing some of the brighter emission nebulae in the red channel.

[gorann]

1 hour ago, Knight of Clear Skies said:

Thanks, will have a play with this later if I can find the time. Had some fun to browsing some of the brighter emission nebulae in the red channel.

Have fun Knight of Clear Skies!

Looking more at the image I got the feeling it could be improved by some star-size-reduction, so here is a less "snowy" version. The sky is clear right now (maybe you fought off the cloud dragon?), for once, so I am off to the obsy to try to get some data of my own!