PartnerObserving Log for 2007 Mar 16/17

Observers: Rick Pogge, Peter Garnavich
Support: John Hill on-site, Olga Kuhn on-call
TO: Aaron Ceranski

Afternoon weather is beautiful, last night's clouds were gone after sunrise, temperature on the summit is in the low 60s. More like June than March.

All times below are UTC 2007 March 17

0051 - Doing dark-enclosure calibrations: 25bias and dark900. Done at 0122

0135 - Clouds threatening from the south, coming in from Mexico. Night will likely not be photometric.

0148 - start of twilight sky flats, 6h/+27.
  • Uspec first 3x scaling, first 50K, prob. non-linear, 2nd under 45K to 20K; then Uspec180 5x scaling, 13K, 8x - 12K-5K
  • V 10x scaling, 13K-
  • g180 12x scaling, 8K-

0223 - setting up Primary. Then running fine focus tests to verify some offsets (still too light to observe). John thinks there is something wrong with the parameters from a couple nights ago.
  • B - 0231 - running Bfinefoc - top: offset=0.072 fwhm=2.49 bot: offset=0.065 fwhm=2.79
  • g - 0239 - running Gfinefoc - top: offset=0.044 fwhm=2.34 bot: offset=0.036 fwhm=2.42
  • r - 0243 - (Rfastextra took a couple extra iterations, got a bad fit), running Rfinefoc @ 0251 - top: offset=0.033 fwhm=2.12 bot: offset=0.031 fwhm=2.80

Instantaneous (5s) seeing is 0.45-0.56". Yow!

0255 - going to GRB070311 for 5x200s r shot (RA=05:50/Dec=+03:22.5). predict r=24-25mag, Tweaking primary with Rfastextra. Started observations at 0302, running the 5x200s OB twice (this after we didn't see the target in the first 200s shot)
  • Image 1: 030322 - 0.58" seeing, very round and sharp. GRB not visible, but we can ID the field w/o problems. pounding away...
  • Image 2: 030720 - 0.57" and very round
  • Image 3: 031127 - 0.58" and very sharp
  • Image 4: 031530 - 0.58" and very sharp
  • Image 5: 031938 - 0.59" and not as sharp before.
  • Image 6: 032438 - (start of OB run 2) - 0.63", not as round as before. - focus center moving onto chip 4 from chip 2
  • Image 7: 032836 - 0.66" and not as round.
  • Image 8: 033237 - 0.68" satellite streak on image, missing the event...
  • Image 9: 033634 - 0.70", slipping out...(we've changed a bunch in elevation...)
  • Image 10: 034043 - John moved mirror by -3um focus between images to see if it improves seeing on this one - 0.66" and rounder at field center.

Lesson, when this far over, update primary setting more frequently. We probably should have done this between OBs.

0345 - heading towards Weaklens/A611gr - will tweak primary and check seeing at g before proceeding since this has a strict seeing criterion. g5s snap 035738 has 0.51" seeing. We're going...A611-1.ob:
  • Image 1: g 300s - 040054 - did not get to Repository disk until 0411 - 0.62" and very round - hard to find faint stars in a galaxy cluster...
  • Image 2: g 300s - 040638 - seeing still 0.62 and very sharp
  • Image 3: g 300s - 041224 - picked a galaxy for guiding, but seeing is 0.61" and very sharp
  • Image 4: g 300s - 041808 - picked a star this time..., 0.59" seeing - lens arcs are very clear in this cluster
  • Image 5: r 300s - 042345 - looks like it is guiding on a compact galaxy - 0.56" seeing and very sharp.

These are spectacular images... but some scattered light on Chip 3 from a nearby bright star?

Note added later I looked at this set of images -- the ghost is apparent in r only - not in g or Uspec. There is a bright K star, HD65392 (B=8.105, V=6.508) at 07:59:51.37, +36 04 55.5, so only 9.5" and 4.5" N and 16.73 arcmin and 16.83 arcmin W of the field center for the 2nd & 3rd pointing. Doesn't show up so strongly in the 1st pointing although the star is closer EW (16.66 arcmin) though further N (14.5"); however, at least the r-band image at the 1st pointing doesn't match up with the next two in terms of offsets, it looks like it was reacquired between the 1st and 2nd -- there was a change in pointing, due to collimation? The ghost is pretty spectacular on the images 045555 & 052752. Actually in chip 1 (rightmost chip), not 3 -- Olga Kuhn

0430 - Part 2 of A611, doing A611-2.ob: tweaking primary, beautiful pupil images, you can see the cross-struts in the swing arm. wow!
  • Image 1: g 300s - 043325 - 0.56" and not as sharp as before
  • Image 2: g 300s - 043903 - 0.55" and real sharp
  • Image 3: g 300s - 044440 - 0.56" and sharp
  • Image 4: g 300s - 045017 - 0.58" and sharp
  • Image 5: r 300s - 045555 - seems to have picked a glint streak to guide on... huh? weird thing is, it is still guiding. what will the images look like? 0.66" images, and a huge glint from some bright star just off the field in this dither position - worst on chip 3. Great shadow of the swing arm. The dither must be bringing in the star that made the stray ligth on Chip 3 noted above.

0501 - Part 3 of A611, doing A611-3.ob: tweaking primary, Still looking good, only asigmatism and defocus, all <400nm
  • Image 1: g 300s - 050512 - 0.57" and sharp
  • Image 2: g 300s - 051055 - 0.59" and very sharp and round.
  • Image 3: g 300s - 051632 - glint on the guider image stamp ... it still seems able to guide ... must be using other stars, but showing me this junk ... 0.57" and sharp
  • Image 4: g 300s - 052209 - nice star this time, seeing 0.53" - wow!
  • Image 5: r 300s - 052752 - junk on guide stamp view - must be junk from that bright star - 0.56" seeing.

Still lots of scattered light on chip 3, wouldn't surprise me if the bright star isn't on or near the technical chip near science chip 3.

0532 - Part 4 of 4 on A611, A611-4.ob, the Uspec images. Tweaking primary with Bfastextra. Took 2nd iteration since Z4=-1400, but no coma and only ~200nm of astigmatism. All of these are Uspec images, 3 dither locations, 2x300s images at each.
  • Image 1d1: Uspec 300s - 054033 - images here are 3.5pix = 0.8", as expected for U, and just within the PI's spec.
  • Image 2d1: Uspec 300s - 054613 - 0.74" and better images (rounder) - appear better at bottom of chip 2... bet it moves up during sequence.
  • Image 1d2: Uspec 300s - 055151 - autoguider claims no guide star - running open loop - images degraded - 0.95" and not round
  • Image 2d2: Uspec 300s - 055733 - autoguider claims no guide star - running open loop - images badly degraded and trailed (~1")

Same lack of guide star on dither 3, aborted the OB. Images for the 2nd dither position were basically taken open-loop because of failure of the autoguiding algorithm, despite adequte bright stars on both technical chip images (see lbctec.20070317.060202_1.fits and _2.fits).

0606 - To salvage their science, I am repeating the OB for just the first dither position and hoping it works like it did the first time above. *no luck, it didn't repeat the previous behavior - had to abort the exposure*.

Sorry guys, there's nothing we can do... Damn shame in such wonderful seeing conditions. Lost the GUI on the second abort. In fact, lbccontrol appears to have hung. I can't ssh into it. Then after 5 minutes it came back, and the GUI is alive. That was pretty weird (and wasting some lovely observing conditions...)

0614 - Taking a 5s g snapshot to see what the conditions are like - more like 0.75" now. Checking primary w/Gfastextra and a G5sec snapshot to verify. Seeing in this snap is 0.6" and nice and round.

0625 - Next up: COSMOS gSloan shots. Doing gSLOAN_3.ob, tweaking primary with Gfastextra, ready to go (minor correction)
  • Image 1: 063111 - 0.75" seeing and round/sharp images. Not as good as before, so seeing is going soft on us. Tumbling satellite trail across chip 2 & 3
  • Image 2: 063805 - 0.75" seeing, round & sharp images.
  • Image 3: 064505 - seeing a little softer, now 0.9", a little less round then before. Better towards bottom of chip
  • Image 4: 065146 - 0.84" seeing, rounder & sharper than previous.
  • Image 5: 065829 - 0.9" seeing, round & sharp

Seeing is not as good as it was before, and a bit more variable. It was spectacular while it lasted. There is a front of some kind coming in from the south, which is already occluding the sky over Kitt Peak and MMT (judging from their web skycamera).

0706 - M81 V PB for its every couple-night hit. Tweaking primary with offset field - took 2 iterations (big move, big Z4, Z5, & Z6).
  • Image 1: 071744 - more like 1.1" now, not as good as before, but we're in a different part of the sky. Seems to vary a bit across the FOV...
  • Image 2: 071922 - still 1.1", not as round as it could be.
  • Image 3: 072059 - same...
  • Image 4: 072236 - same...

By the way, at 1230am it is 8C (46F) outside...

0727 - Zaritsky/NGC3368 - two focus iterations since the move was big, then starting. Seeing not as good as before, the swing arm is not as clearly delineated in the pupil images.
  • Image 1: 073556 - has gs in 16s loop, then lost lock part way into 160s integration. Stars elongated, FWHM 5pixels (1.1") - satellite streak across Chips 1 & 2
  • Image 2: 073934 - has gs in 32s loop, holding it, better image, 1" and less elongation.
  • Image 3: 074326 - has gs in 16s loop, holding... images ~1", except at top of Chip 2. John asked Aaron to dial in +100nm of Z4. after Image 4 is done.
  • Image 4: 074716 - has gs in 16s loop, ~1" on chip 2, nice on chip 1
  • Image 5: 075056 - has gs in 8s loop, Mirror tweaked (maybe, some question) before exposure started. Looks better on chip 2 - 1" and rounder. Still better on chip 1. Top of chip 2 isn't much improved.
  • Image 6: 075426 - has gs in 16s loop - dialing in another 100nm of Z4 during readout - this images is about same as #5.
  • Image 7: 075755 - has gs in 8s loop - dialing in another 100nm after this - looks better overall, but still not so good at top of chip 2
  • Image 8: 080141 - has gs in 32s loop - dialing in another 100nm - looks much the same,
  • Image 9: 080524 - has gs in 16s loop - looks better - seeing more like 0.9". Guide star looked better
  • Image 10: 080909 - has gs in 8s loop - 0.9" seeing. Same change top to bottom.

0815 - working on primary focus for a while, it is giving us difficulty converging to a good solution.

0826 - Trying the first few images in the previous OB set to see if we improved it. Those were the worst, and this will tell us if we're doing this right or something else is an issue.
  • Image 1: 082722 - lost gs lock in 8s loop early in exposure - Images are round, 0.9" much better top-to-bottom, more uniform.
  • Image 2: 083100 - gs in 32s loop - 0.9" images and round.
  • Image 3: 083451 - gs in 8s loop, lost lock 30s in - 1" and round/sharp. uniform across chip 2
  • Image 4: 083832 - gs in 8s lopp, lost lock 30s in - ~1" and round/sharp.

That's enough. Paused OB after Image 4.

0844 - Quasar Point 4. Intending to start with gr, then U. Tweaked primary with Gfastextra, stars too faint, doubling exptime - that helps a little, but still very few pupils contributing to the solution.
  • Image 1d1: r - 085445 - Seeing is a little subarcsec, but kind of ratty in terms of roundness of images.
  • Image 2d1: g - 085727 - lost gs lock - images very fuzzy 1.5" and kind of ratty
  • Image 1d2: r - 090011- seeing is sharper but not round.

Aborted after 3rd image due to problems with tracking and seeing fluctations. Detailed inspection of the images we took suggests we didn't get a very good focus solution, and it slid out during the sequence. Going to try Point 5 and see if there are better stars for pupil imaging and guiding. Note that we had accidentally left the exposure scaling at 2.0 from the Gfastextra shots, and didn't notice it was not reset to 1.0 when we loaded the OB for Point 4. It's a very easy mistake to make because the behavior now is different than when I was using the system in January.

0906 - Quasar Point 5 - starting with focus check Gfastextra. Not converging very fast, not enough good stars to make pupil images. Doubling exptime helped, but it took us longer to get a good solution. Even with John Hill's assistance we're having problems getting things tweaked up to our satisfaction.

0916 - Starting the Point5 OB
  • Dither 1 Img 1: r 60s - 091749 - 1.1" and a little ratty.
  • Dither 1 img 2: g 60s - 091926 - gs bounding around a bit - 1.2" near seeing limit
  • Dither 2 img 1: r 60s - 092104 - 1.2" and a little ratty
  • Dither 2 img 2: g 60s - 092245 - 1.1" and very round
  • Dither 3 img 1: r 60s - 092440 - 1+" but not very round
  • Dither 3 img 2: g 60s - 092617 - gs failed - 1.3" and elongated
  • Dither 4 img 1: r 60s - 092758 - 1.2" and not very round, better at bottom of chip 2
  • Dither 4 img 2: g 60s - 092936 - gs failed - 1.3", but better round.

If we're not getting guide stars very often in g, it's going to be pretty hopeless at U under these conditions. We decided not to proceed with the U filter OB.

Something is not working with focus calculation. We're going to another field with enough stars to take a couple of tests. The systematic change in image FWHM from top to bottom is indicative of a focus offset, even though we're following immediately on a focus adjustment. Why are we systematically wrong each time? No enlightenment. We were looking for some kind of focus hysteresis, but could just be getting hit by atmospheric fluctuations. We spent a little under an hour at this, and while we think we have a possible procedure, we're not convinced we understand it completely. It has been a good thing John decided to stay up here, we'd have been pretty lost otherwise - this stuff is pretty arcane sometimes, especially late at night.

1024 - Doing Dwarf/Herc V - because of time, seeing conditions, and it will let us see if we can get this scope focussed right now. Adjusting primary, then taking a 10s V snapshot to see if we're good. Now we're good on Chip 4 and top of Chip 2, but not good at bottom of Chip 2. Aaron dialing in -150nm of Z4 to correct. Taking another snap. That kind of evened it out in the right direction, but images are not as round/sharp as previously. We're as close as we'll get, and it took us long enough. Firing off the OB (Herc_V):
  • Image 1: 104039 - seeing back to being good - 0.6-0.7" seeing, in lower third it is more like 0.8" towards bottom. Still some residual focus offset that we're sensitive to in good seeing conditions.
  • Image 2: 104618 - 0.7" seeing, maybe a touch better, but still a gradient, maybe getting less (mirror sliding through focus in our favor).
  • Image 3: 105203 - 0.66" seeing, sharp and round, good towards bottom,
  • Image 4: 105800 - 0.6-0.7", worse at bottom third. Gradient seems worse.

1104 - Dwarf/Herc B
  • Image 1: 110451 - 0.8" in the good parts (Chip 4, top part of 2 et al.) - dialed in -200um of Z4 before Image 2 to balance out
  • Image 2: 111037 - that flattened out the gradient, best images are still on Chip 4, but not as big a difference, seeing about 0.8"
  • Image 3: 111622 - Satellite streak across 1/2/3, 0.75" seeing, worse as you go down Chip 2.

1122 - Tweaking up using Bfastextra32, then 5s Bsnap, then adjust focus by hand if necessary and Dwarf/Herc B2
  • Image 1: 113128 - 0.8" , round but not super sharp
  • Image 2: 113714 - 0.8", round & fairly sharp, - dialed in -300um after this to correct any slide
  • Image 3: 114308 - 0.85" and a little ratty - didn't make much difference, maybe seeing got a little worse?

Completed the Dwarf/Hercules program. Pretty good seeing, but images aren't as round as uniformly across the detectors as we'd like (or as good as we'd achieved earlier).

1154 - We're out of end-of-night program and we're not photometric, so not much else to do in the remaining half-hour of darkness before flat fields. In the last half hour we're doing some engineering tests for tomorrow-night's scheduled Pluto occultation configuration.

1155 - Turn on camera with Pluto version of bluechannel.conf; Trackers Client/Host RPC error. Reboot CMU.

1213 - Pluto Rfastextra 15 sec --> more pupils than you can imagine

1218 - Pluto_RTech1 x0.06 1sec exposures at 4 sec intervals; fails by ramping up to 32 sec. Need more tests in the afternoon.

1222 - Pluto_RVB1 - 3color, 1 sec dithers on the Pluto field in center of science array.

1233 - Setting up for twilight flats
  • V sky flats - SkyFlatV_5 scale 8x, imgs 124147-124609, Range 4K-8K
  • r sky flat - SkyFlatRrot180_5, scale 4x, imgs 125527-125908, Range 20K-42K, last one prob nonlinear - lost connection to instrument for ~10min, very disconcerting while racing twilight,
  • B sky flats - SkyFlatB_5, scale 1x, imgs 130220-130342, range=30K-43K. Getting too bright. 130822 and 13090 saturated.

Night Summary

Started out great, no problems on telescope or instrument startup, and seeing was spectacular. As the night progressed, we started having problems achieving good focus using the standard methods. We're still not sure why. Seeing towards the end was subarcsecond, but not as good as earlier in the evening. Thin clouds were apparent at dawn.

  • GRB070311 - observed at about 25th mag in r in 0.7" seeing, clean detection but no visible host. Object is low in the galactic plane, and in our deep images the foreground has whisps of galactic emission-line clouds.

  • Weak lensing field A611 g&r images completed in 0.55-0.6" seeing (yow!), but Uspec observations had to be aborted because the guider kept losing stars and went open loop, ruining the image quality.

  • COSMOS gSLOAN_3 shot in 0.7-0.9" seeing

  • M81V shot in 1.1" seeing

  • Attempted Zaritsky/NGC3368, but started having problems with getting proper mirror focus. Very puzzling and frustrating, we think we got enough data, but PI will need to inspect and inform us.

  • Attempted Quasar Point4, but the pupil stars were inadequate and seeing/tracking degraded badly.

  • Attempted Quasar Point5 and got better results at first, but we started having changing seeing and guide-star lock problems and had to give up doing U. Seeing was marginally within project limits at the end, possibly past them. PI should advise.

  • Spent a fair amount of time with John Hill examining our focus problem, we have no solutions, but managed to get it focussed OK.

  • Dwarfs/Herc field shot in V, B, and B2 in subarcsec seeing with reasonably good image quality across the images. That was our last major target of the night.

-- RichardPogge - 16 Mar 2007
Topic revision: r9 - 21 Jul 2009, NormCushing
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