Glad it's not just me that's having trouble opening the .tar files.
Yep, tried 7zip and no cigar.
Quote:
Originally Posted by sheeny
I keep getting an "invalid archive directory" error., which may be the result of:
The archive file does not exist or is in use by another program.
The specified folder does not exist.
The file is not an archive.
The archive has been damaged or corrupted.
There were disk errors or insufficient memory while reading the archive.
The archive contains invalid or illegal filenames.
Yes, get them too.
The image below is a mask I made this morning for the SA. It places a solid screen close, has a small ridge, but not touching the glass grating. It is stoped by the retaining ring.
My question, to save me some time, is "Where (from center) should I drill the hole? My main spec. set-up is a meade 4" f9 with a ST7e.
It all looks very promising to me!
I did some experiments last night on a convenient street light and was able to get some further distance between the SA and the DSI3 chip. It is now in the order of 105 - 110mm.
The set up is: DSI3 - SA spacer - 0.6focal reducer - ext tube - SA.
Not sure of the ang/px yet, but it should be about 6-7, as the zero order and then spectra covered 75 - 80% of the long axis.
That'll do for the moment, if only the stupid clouds would go away...
My question, to save me some time, is "Where (from center) should I drill the hole? My main spec. set-up is a meade 4" f9 with a ST7e.
Here's my calcs, Jeff. I don't have enough info to give you a dimension but I think I can give you enough to work it out.
Your ST7e is 756 x 510 pixels at 9µm, corrrect? That makes the CCD 6.804mm wide, so the edge is 3.4mm from centreline. You want to drill the hole in from this just enough to compensate for the f/9 focal ratio of your scope and allow a bit either in position or hole size to get the zero order image just off the edge.
So:
x = 3.4mm - 3.4y/F
where
x = the distance from the centreline to the projection of the edge of your ccd on the mask;
y = distance from the ccd to the mask;
F = focal length of your scope = 900mm.
I would suggest maybe x is OK for the position of the hole if you allow a little extra in the size of the hole.
The minimum diameter of the hole is d = y/9 + 9µm (allowance for raleighs criteria) + a gnat's whisker to get the zero order image off the edge and for userfriendliness while trying to align your star.
Al.
Last edited by sheeny; 10-03-2009 at 02:55 PM.
Reason: Correction!
Jeff,
Looking very good!!
Just remember to position the diaphragm in line with the dispersion!!
I'm looking forward to the results.....
BTW still having problems with the .TAR ( I get the same error message with WinZip 12)
Any other ideas?????
It does look good, doesn't it?
The only other thing I can think of with the .TAR files, Ken is that maybe they are legal filenames/directory names for Unix inside the .TAR file, but they aren't legal for windows. I don't know if that's possible, I'm out of touch with unix/linux these days...
Maybe if someone has a Linux system they can try and let us know?
Below;
1) Spec, full width frame, during slew. -no stars in spectra
2) Full raw frame minus dark, no stars in spectra
3) VSpec results.
The mask is on the wrong side so I had to mirror the frame. Easily fixed by rotating the mask by 180deg.
Focus is much much more difficult.
Only 1x7sec exp for each
As for .tar, maybe somebody with linux could open them and resave as .zip. Big job I imagine.
Now that looks good!!!!!!
I think the potential is there to give a cleaner spectra, with no loss of resolution, what do you think??
Believe me getting a star image in a 3mm hole is NOTHING compared with the fun and games of finding and hold one on a 20 micron slit!!!!!!
Re the TAR; I downloaded a trial version of Alphazip which reads TAR files etc and found ALL the files I downloaded from the HST site were corrupt in one way or another...I'll give it a miss...
I tried downloading some of the tar files in linux but they are empty files.
I could get successful files from here http://archive.stsci.edu/
Just enter eta carina and optical/ IR and download the data sets. They open in linux easily. Haven't tried windows yet.
Last edited by Terry B; 11-03-2009 at 12:04 AM.
Reason: typo
BTW
I think we are now breaking records for the most read, and longest Thread on IIS.... say's something about the general interest in the Subject!!!!!!
Gents,
confirmed that my setup with now work at 7 ang/px without too much drama.. I tried it in the 120mm + the 80mm refractor and was iniitially surprised that I got the same result for each scope. The brain fade cleared and it was another moment!
Ang/px is irrelevant to the scope, it's 100% to do with the SA - CCD distance.
My main spec. set-up is a meade 4" f9 with a ST7e.
.
Don't do it Jeff! Not yet!
