- This topic has 5 replies, 3 voices, and was last updated 1 year, 2 months ago by
.
-
Posts
-
I loaded the 1800 grating into the Lhires.
Calib image, what are those short vertical lines near bottom of image?
Flat image, what is that bright streak across the image?
Unlikely to be 2 faulty lamps.
I have never seen either before!
Any thoughts.
JackHave you looked inside the spectrograph? Given both frames are giving weird results, it makes me wonder if something has been knocked out of alignment.
Another clue could be that bright line in the flat, and the odd short offset calibration lines, both appear at the same vertical offset. That could indicate something seriously out of alignment or light leaking in from outside.
Andy
Check for a scratch in the mirror slit coating
If it is that, you should see it in the guider image
Cheers
RobinAndy and Robin,
I have 2 slits and slot supports and changed from the 35 to the 23 micron slit.It appears the latter is faulty.
Question, Would the wide slits be useful?
https://www.shelyak.com/produit/se0122-fentes-19-50-75-100/?lang=en
Thanks for your inputs,
JackIt is probably still useable, with a dab of black paint over the scratch or just avoid putting the spectrum in that region.
Slits wider than the normal seeing are good for extended objects (eg comets nebulae etc) allowing more signal to be collected and for absolute flux measurements ensuring all the flux is collected (both with a reduction in resolution of course)
Cheers
Robin
- You must be logged in to reply to this topic.