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2013_09_1718

Weather:

Very clear and dry air mass overhead.  Sadly it’s also nearly full moon.  Low tonight in low 50s, low humidity but some dew likely by later.  No wind, seeing not great, maybe 2.4 arcsec?

Rig #1:  Nova Del 2013

The first night trying this object – it’s quite bright.  Just to get my feet wet I set up to obtain spectra in the region of several iron lines: Fe II 5169, 5198, 5235, also some others redder than that – not sure what they are.  Basically using the same setup as I’d been using for the WR campaign, which finished last week.  So 1200 line/mm grating, 35 micron slit, centered at about 5200 Angstroms.  Tomorrow night, if it’s clear I’ll shift to the 2400 line grating and 23 micron slit.  There’s plenty of light.

I did not take any standard star spectra for tonight’s data.  Need to get re-familiarized with the tools in ISIS and using the MILES catalog.  Note I was able to run about 2hr 20min past the meridian for this object.  Last image taken around midnight.  Took a series of -20C darks and biases.

Rig #2:  ASAS-SN 13ck

The object is much fainter than the last time I imaged it.  That plus the near proximity of an almost full moon is making it difficult to get decent S/N – running 240-second images and it looks like a S/N of around 35 – 40, at least at the beginning of the night.

I had some trouble getting the telescope to focus properly.  This is a problem that appears when the temperatures begin to fall.  It’s especially noticable when the mirror is riding “horizontally” on the central baffle.  There is less force from gravity to secure the mirror on the focusing mechanism.  Two things to try:

1) run the focus through it’s entire length a few times to distribute the grease

2) make a labeled dial to “calibrate” the focus.  That way I can, say, rack the focus clockwise (allowing mirror to settle towards the back of the telescope) and then rotate counterclockwise to force it back into a “weight-loaded” position, and know exactly where the position of the focus knob should be rotated to.  Basically just a graduated dial for the outer ring and a pointer on the focus knob itself.

Anyway, after finally getting the telescope focused the S/N improved (not surprisingly) to around 45 – 50.

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