Notes on MDM

Acquiring Targets, the Red Slit, the Guide Map

Acquiring a target on OSMOS was a bit of a learning curve.  The OSMOS 4x4k CCD can be used with two two different slits, a ‘centre’ slit and an ‘inner’ slit.  The inner slit is best used if you would like to concentrate on the redder end of the spectrum, and is thus dubbed the red slit.  The red slit is located just over 75% to the right edge of the CCD from the left side of the CCD.  When looking for targets, you first take an image without a slit/disperser in the light-beam.  The object will most likely be located very close to the centre of the CCD (as a result of focus and pointing maneuvers taken earlier in the night).  It is now your job to move the object into the portion of the CCD covered by the red slit.  This is done by:

1. Image the field and locate the object, while guiding using the guide camera

2. Put the red slit in the light beam and take another image; this results in a vertical bar on the CCD in the location of the CCD

3. Use the program oalign.py to calculate the separation between the centre of the object, and the centre of the slit:

oalign.py -l maskImage.fits fieldImage.fits *

this will calculate a number of steps (on the guide camera!!!) in the offset between object and slit.  In order to move the telescope to match the two up you must:

4. turn guiding off momentarily

5. enter into the guider GUI the number of steps to move the guider camera, enter (watch the stars on the guide camera jump out by the entered steps

6. move the telescope back  so the original guide star is back in the guide box, resume guiding

The object should now be in the slit.

NOTES: Important here is I was using the red slit.  The inner slit is quite far from the centre of the chip, and the guide camera can only move so far.  I found many times I was requiring the guide camera to make large movements that were TOO LARGE for its range of motion.  As a result, I would have to move the guide camera most of the way, and then begin guiding on a DIFFERENT star.  This would allow me to move the rest of the way.  Note also that there is a ‘red slit’ option on the guide camera GUI that forces you to use guide stars that are in the proper spot to account for such large changes.  I found that I could only switch to that option after making one small jump.

*this is considered a ‘back-up’ way of doing this.  There should be another way, that I was unable to get to work, that uses propsero scripts.

 

HgNe comp lamp

The Mercury-Neon (HgNe) needs only 5 sec of integration for a good comparison spectrum, however, the lamp needs to be on for at least 40 sec.  What happens is the Neon gas is first heated up, and that heated Neon gas is used to heat the Mercury gas.  This takes approximately 30 sec; it is safe to wait 40 sec in order to be sure that the Mercury gas has been heated up.  After the Mercury is heated up, the Neon gas is dialed down automatically leaving you with only a Mercury spectrum.

MDM Observatory: Day 5

On my last day at Kitt Peak, I decided to visit the 4m telescope.  This is the largest telescope on the mountain, standing about 18 stories tall, and actually reaches above the summit of the mountain.


In side the enclosure is a monster of a telescope, and they have a visitor viewing gallery that allows you to see it from the observatory floor.

Huge.  Just enormous.  and there are bigger telescopes in the world.  The largest optical telescope in the world is 10m (Keck I & II in Hawaii).  I can only imagine what they must be like to stand beside.

This was very impressive to stand beside.

The visitor area of the 4m also lets you walk a windowed area, showing you the view in all 360 degrees.  This is the view of the rest of Kitt Peak.  There are so many domes!

From the 4m lookout, this is a view of the MDM observatory.  The 2.4m is in the dome furthest to the left, the 1.3m is in the dome to the right of it.  The two foreground telescopes are both Radio ‘scopes (which operate day/night!).

The road down the mountain is amazing.

Heading home tomorrow!

MDM Observatory: Day 4

Plugging along merrily!

Every 12 hours I have to refill the instrument dewer with liquid Nitrogen.  This keeps the detector (CCD) VERY cold.  Nitrogen is liquid at -196 celsius, and the instrument usually stays about -120 celsius.  We want the detector cold so that there is no noise added to any images we take.

I’m getting into a good groove, and even checking out my spectra.  About 20 minutes of exposure will create that graph! cool.

MDM Observatory: Day 3

Today I went up to the Kitt Peak Visitors Centre to check out their outreach initiatives and giftshop/etc.  This is the visitor centre building.

That’s right, the visitor centre has its own observatory.  In fact, the visitor centre has at least 3 telescopes!  Impressive.  In the centre they had a number of small exhibits and information on the mountain/observatories/history/etc.  Very fun, I found a very large meteorite:


The centre was very good explaining the science behind telescopes, mirrors, and observing.  Here’s me at the focus of a small primarty!

I already posted this pic in twitter today, but it warrants another post here.  This telescope is so big, the instrument+detector are as tall as me!

While I don’t appreciate the clouds at night, they make for an amazing sunrise

MDM Observatory: Day 2

Today….today was interesting!

 

This afternoon I found out that I would be doing these observations on my own.  Originally, I was to be joined on the mountain by another collaborator of ours, who had used this telescope a number of times.  Given that I have VERY little experience working with large telescopes (just with the York 60cm really), this was going to be an opportunity for me to learn from an experienced observer.  Due to some unavoidable events, I am now to be on my own for the week (EEP!).  Needless to say, I was slightly apprehensive.  Could I really do these observations by myself?

Well, I dove in, and came out on top!  Lucky for me, my support network was strong.  My supervisor Pat Hall skyped with me as we both trouble shooted using the observatory.  Also, Rob Faison (using the 1.3 m) was open for questions when I had them.  Thanks to both of them, data was taken!

The MDM observatory has two telescopes: the 2.4m and the 1.3m.  I am using the 2.4 m telescope AKA the ‘Hiltner’ Telescope.  Here’s an image from outside:

The control room houses multiple computers, manuals, etc.  In my prep and data acquisition this was my desk:

6 computer screens.  All in full use, from left to right:

laptop: skype, star fields, notes, music (when taking data)

small black screen: CCD readout

twin screens: driving the telescope, controlling instrument, star fields, manuals, data crunching

raised black screen: displays the telescope telemetry (RA/DEC/HA, etc)

furthest right (facing away): guiding camera

 

all to point and use THIS:

The 2.4 meter Hiltner with OSMOS attached to the bottom (Black box) and the MDM4K CCD sensor (purple cylinder).  For scale, OSMOS and MDM4k measure roughly my height.  yowza, this things big.

Up all night working:

Got to see the sunrise in the east, silhouetting the observatories further up the mountain.