APOD: M2-9: Wings of a Butterfly Nebula (2013 Sep 15)

[neufer]

What is the period of revolution for the stars in the center of the disk?

Approximately 90 years from eyeballing:
http://asterisk.apod.com/viewtopic.php? ... 39#p208813

[Rick]

caramba, I am speechless. The big pooobahs at APOD hit one out of the park. Time for an ice cold one to stop the vibrations

Second one out of the park, then. Word for word identical, just re-processed picture. (well, not "just", but you see what I mean)

[Chris Peterson]

In the image description in Judy Schmidt's 'Geckzilla' website it mentions STIS/MIRVIS data. I have found that STIS is the Space Telescope Imaging Spectrograph on the Hubble Space Telescope but, despite lots of searching, I have not been able to find what MIRVIS stands for. It is not even defined in the Hubble Legacy Archive glossary section! I guess the IRVIS part may be InfraRed VISual.

The STIS instrument has a fancy sort of "filter wheel" called the mode selection device. It consists of a large number of gratings optimized for specific modes, as well as a prism and a simple mirror. The particular mode selecting element used for an image is identified in the FITS header as the optical element. MIRVIS means the mirror was used- that is, a direct image was made, not a spectroscopic image using one of the gratings.

[geckzilla]

caramba, I am speechless. The big pooobahs at APOD hit one out of the park. Time for an ice cold one to stop the vibrations

Second one out of the park, then. Word for word identical, just re-processed picture. (well, not "just", but you see what I mean)

The 2002 APOD actually an image which uses data from 1997. That's 5 years prior to this APOD's data. It's the same object but by no means identical. There are striking differences. Sept. 15th's APOD is also twice as detailed in resolution.

The STIS instrument has a fancy sort of "filter wheel" called the mode selection device. It consists of a large number of gratings optimized for specific modes, as well as a prism and a simple mirror. The particular mode selecting element used for an image is identified in the FITS header as the optical element. MIRVIS means the mirror was used- that is, a direct image was made, not a spectroscopic image using one of the gratings.

Thanks for that explanation, Chris. I thought it might be something like that. I have been wondering if it's filtered light or not. I get the impression that it's either unfiltered or minimally filtered. I was trying to explain it to some of the commenters over at the reddit post for the image.

[DavidLeodis]

Thanks to neufer, geckzilla (Judy Schmidt) and Chris for their help in my query about the acronym MIRVIS.

[Beyond]

MIRVIS = mirrored visual.

[geckzilla]

I also just received a response from STSci about MIRVIS.

Hi,

MIRVIS is a filter combination for the STIS - Mirror plus Visible.
There are two different settings. One gives 3050 - 5550 and
the other 5550 - 10,000 Angstroms.

Hope this helps!

[DavidLeodis]

Thanks to Beyond and again to geckzilla (Judy Schmidt) for their help in finding what MIRVIS stands for. The help of all who have replied to my query is much appreciated. I hope I did not put any of you through too much time and effort.

[Beyond]

All i did was shorten Chris' explanation. So you didn't put me through any time or effort at all.

[Rick]

caramba, I am speechless. The big pooobahs at APOD hit one out of the park. Time for an ice cold one to stop the vibrations

Second one out of the park, then. Word for word identical, just re-processed picture. (well, not "just", but you see what I mean)

The 2002 APOD actually an image which uses data from 1997. That's 5 years prior to this APOD's data. It's the same object but by no means identical. There are striking differences. Sept. 15th's APOD is also twice as detailed in resolution.

I meant identical wording. And it's the same Hubble picture, with more processing. Great work on the picture, a bit lazy on the text.

[geckzilla]

I meant identical wording. And it's the same Hubble picture, with more processing. Great work on the picture, a bit lazy on the text.

It's not the same Hubble picture with more processing. It's an entirely different picture with different processing of the same object.