Weather

Warm and somewhat hazy.  High today was 85 – predicted low 65.  Medium to high humidity.

Rig #1: Deneb & P-Cyg

I focused the collimator lens and set the grating micrometer so that the Neon 6532 line was a close to column 558 as possible.  That is where it was located a few nights ago when I did lamp flats.  To measure – show the crosshairs and measure at the central Y position.  Micrometer reading is 1578.0.  I also re-focused the guide camera, looks like the best focus spot on the slit is around x=115.  For the Si lines in Deneb set the micrometer to 1511.2 – place the Ne 6334 line at around 559.

I need to come up with a good cadence.  Basically need to start with Zeta Aql (ref star) in Ha – then to P Cyg, then to Deneb.  Change grating micrometer for Si lines – get Deneb, then back to Zeta Aql.  Then change micrometer back for H-alpha and back to P-Cyg.  Noel says he needs 3 to 4 sets of P-Cyg images around H-alpha – but I’m not sure what sort of time separation is needed for each set.  Tonight I got two sets – though I almost forgot to get Zeta Aql at the setting for the Si lines!  Done at around 2:30am.

Rig #2:  UX UMa

I got the first sequence started for UX UMa around 9:35pm – gotta love those late summer sunsets!  Seeing is around 2.0 arcseconds, perhaps a bit better.

Guidestar Fade Issues

One thing that is still and always has been a PIA with Maxim – the dreaded “guide star fade” issue.  Despite the star being clearly visible in the guider image with reasonable s/n (in this case s/n was about 10) the guider function cannot find the star in the image.  I lost about 15 minutes of imaging (right during eclipse, of course) due to what is a way too common problem.  Lots of discussion about this on the Maxim Yahoo group site as there is every time there is a new release for Maxim DL (I just installed 6.03 on the main computer – though the observatory computer is running 5.24).  But it’s been a problem for as long as I’ve used Maxim – which is about 8 years now!

Out at about 2:30am.  Excellent night overall.

 

Weather:

Clear and cool – almost perfect night.  Seeing is not quite as good as last night but close – and I think transparency may be better.  Low 50F, fairly low humidity but dew will be strong by sunrise, no wind.  Seeing around 2.0 arcseconds.

UPDATE:  3:10am – a few clouds.  Getting worse – out at 3:50am.

Rig #1:  Spectra of Nova Del (=v339 Del) – and guider focusing issues return.

More frustration focusing the guide camera.  It seemed that everything last night was in good order – so of course I tried to improve things.  I rotated the main camera so that the spectrum is as horizontal as possible.  And since the guide camera seemed to be moving around a bit I tried focusing it on the slit using daylight to illuminate the field.  I got the slit as focused as I could – the fwhm was around 3 pixels.  Usually in order to get the best focus I simply get maximize the maximum value in the psf, then move the star onto the slit and turn on the guider.   The normal location of the slit center was near the center of the image; last night at x=160, y=103.  Tonight, after focusing the slit earlier in the day, it seemed the location of the slit in the camera had moved to around y=125.  And when I used Altair to peak up the focus by taking a series of 10-second spectra the resulting image seen in the guider was decidedly not right.  Basically it looked like an arc.  But I figured what the hey – it was sharp in the main camera so off to Nova Del.  The first spectrum was certainly sharp – measured by taking a vertical cut through the profile, but the overall level was down by almost a factor of two from the previous night.   I’d seen that before and really have no clue how it happens except that I knew the only thing that had changed was the guide camera positioning.  I tried a few simple things but just decided to get what I could.  Finally, once Nova Del moved out of range (behind the maple tree!) I went to Alpheratz to work on getting things aligned again.  I think the guide camera is too loose in the holder and so moves around a bit.  And it can get out of alignment – the camera’s chip can become non-coplanar with the image “plane”.  Once I got it moved so that the slit was back to y=107, and where the image looked round when located near the slit and x=160 (near chip center) I went to Alpheratz and ran a sequence of spectra tweaking focus on the telescope until, with the star on the slit at x=155, y=107, the peak intensity was maximized and the FWHM of a vertical cut through the spectrum was minimized.  I then found a nearby 6th-mag star and looked at the image in the guider and it was what I am used to – a fairly tight “spot” with no artifacts other than the ghost image just below the main image – and the ghost image slightly out of focus.  Taking an image of the 6th mag star the FWHM of a cut through the spectrum was 3 pixels, which is great.

I’m going to see if I can find something to “shim” the guide camera in it’s holder.  It sits about 1 or 2 mm off of the “shoulder” of the guide camera port.  Something that would keep it square and less easy to move if bumped.  Perhaps a 1.25-inch gasket of some sort?

Flat Fields

Last night I attempted to get flats for each of the micrometer settings, but in the middle of the first flat image the bulb blew out.  Interestingly, when it did it left emission lines.  Might be fun to see what they were.  Anyway, bought a couple of new bulbs today and am running sequences of flats for all three settings.

Rig #2: OT J004527.52+503213.8  (=new CV in Cas)

Another night of images of this very interesting newly-discovered CV in Cassiopeia.  Joe Patterson thinks this may be a WZ Sge type – based on it’s huge brightness increase of at least 7 magnitudes.  The star is exhibiting huge superhumps (see last night’s log).

 

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.

Weather

Really nice and clear – until around 11:pm – when some high clouds passed through.  Low temp around 55, low humidity, very little wind, seeing around 2 arcsec, perhaps better.

Rig#2:  V1101 Aql

The final night on this object.  Sequence cut short by about 10 minutes due to clouds – also one short cloudy period during the sequence.  Done by 11:30pm.

 

Weather:

Unbelievably – a fourth consecutive clear night during new moon.  Sadly I can only use the first part of the night because I have a show at the studio tomorrow and need to get some sleep.  Beautiful day today with highs in the mid-upper 70s – low tonight around 58F – low humidity, no wind, seeing is quite good at around 1.8 arcsec.

Rig #1:  WR134, 135, & 137

Pushing it to get two full cycles through the three objects, perhaps a third on one of them.  As noticed last night the intermittent power cycles have disappeared (at least for two full nights so far).  Got three of WR134, two of each of the others.  Also new bias and darks

Rig #2:  V1101 Aql

Since I’m staying to early objects tonight and since I missed it last night due to early clouds.  New -15C bias and darks as well.

About last night…

I decided to add a couple of new comparison stars, designated Comp #4 and Comp #5, neither of which are AAVSO field stars.  In fact I used Comp #5 as the PSF model star as it was the brightest of the bunch.  Again it isn’t clear what caused the strange looking curves I got the previous night, but these data seem to be just fine:

Theories?  Well, perhaps the originally selected PSF star was a close double?  On previous nights the PSF star used ws also the second comparison star.  Maybe I should make sure the PSF star is not one of the comparison stars?  In any event I’m going to re-reduce the previous two nights’ data using the new comp stars to see if it makes a difference.  There’s obviously still a small jump in the comparison star light curve at the meridian flip – but much less, for whatever reason, than for previous nights.  Standard deviation was around 0.011 mag.  There also seems to be a little more happening as far as variation in the target object; maybe about 1.3 hour period?

Weather

Started warm and humid – but a cool front passed just around sunset.  Clouds were a problem early on – after about 9:30 local time mostly clear, very occasional high clouds, low temps in the upper 50s, humidity around 50%, very little or no wind.  Seeing is not great – maybe 2.2 arcsec.

Rig #1: WR134,135, & 137, also WR1

I got the declination assembly back this afternoon and installed on the AP1200.  The motor is now much quieter, and so far I’ve noticed none of the intermittent power interruptions.  Not sure how that could be related, just an observation at this point.  The new motor runs much more smoothly.  I setup on WR134 and began the sequence.  Some clouds were passing through throughout the first cycle – the second time through was better with only very occasional or no clouds.  Note that I only just barely had time to finish two cycles before getting into the maple tree.  Noel Richardson preferred that I still try to get two cycles if I can – once that is impossible go to longer exposures for a single pass through.  I got somewhat of a late start, but really only going to have another week or so where I can do two full cycles.  Once finished (at around 12:30 following Beta Aqr image) I decided to try WR1 in Cassiopeia.   At V=10.11 it’s likely too faint, but I’ll try a set of three 1-hour exposures to see what I get.

Rig #2: ASAS-SN 13ck

The clouds kept me from starting a sequence on V1101 Aqr – so I skipped it once it cleared and went straight to ASAS-SN 13ck.  It is definitely fainter tonight, going with 1-minute integrations.

Some more ratty data!

Last night’s results were interesting to say the least.  The data for ASAS-AN 13ck were a total mess:

I have no idea what caused the discontinuities in the light curves.  My usual suspicion of scattered light just wouldn’t do that.  It almost appears that the curve changes each time I stopped the sequence to focus.  But plotting the image fwhm against the magnitude difference (shown in the blue curve) did not show a correlation.  The thing is, the V1101 Aql data came out looking great, where the previous evening’s plot showed a 0.04 mag jump at the time of meridian flip.

Note there is no “jump” in the comparison star curve – in fact the standard deviation for the entire run is 0.007 mag.  The thing that I noticed was that, for the September 4/5 data, looking at sample images before and after the meridian flip, the objects fell close to the same location on the before and after meridian flip image sets.  But that is after having flipped the post-meridian images so that all images were East-Left and North-Up.   In the case of the V1101 data from the previous night the objects were shifted by quite a long way, particularly in X. But, in the case of the ASASAN data, the images from Sept 3/4 were shifted by a lot, while from Sept 4/5 they were pretty close.  Yet it is the September 4/5 data that is screwy.  So exactly the opposite of what I’m seeing for the V1101 data.  So what is up????

One thing for sure is that I am not going to figure it out tonight!  Fading fast – nodding off.  Out at 4:20am

Weather

Two solidly clear nights in a row – and tomorrow is supposed to be more of the same!  Best stretch of weather since at least May and likely longer.  70 degrees for low tonight, almost no wind.   Humidity 40% now, rising to 60% as temp drops.  Seeing about typical, perhaps slightly better.

Rig #2:  V1101 Aql early, ASAS-AN 13ck late

Same two targets as last night.  V1101 looks a little fainter tonight – as does ASASAN 13ck;  25-second exposures for V1101 and 45-second exposures for ASAS-AN 13ck.

From last night – thoughts on variable PSFs and scattered light.

Reduced data from last night was actually pretty ratty, not really sure why.  All three stars (variable, comp, and check) had S/N well above 100.  But the biggest problem is what I’m guessing is variable PSF shape as a function of position on the chip.  Enough that when the telescope is flipped when crossing the meridian the “curve” for the two comparison stars is different by about 0.04 magnitudes.   The effect is easy to see in the plot from last night, below.  The “drop” in comparative brightness is around 0.04 magnitudes.  Outside of that drop the standard deviation is around 0.008 magnitudes.

It could also be due to scattered light getting into the flat fields, so not totally convinced that changing PSF shape is the problem.   I’ve been thinking of a couple of different tests to try.  One would be to pick a small region of the image plane and arbitrarily designate the flux of stars seen at that location as being “unity” and then seeing what the difference is for the same stars at their new location after the meridian flip.  I have a number of nights now so could probably create a very crude map of improper flux levels due to scattered light in the flats.