All-sky Camera Images at McDonald
Last updated: May15,2019
I am keeping a variety of notes on all-sky camera available at McDonald.
Note: I am storing a lot of these emails in HET_Stuff and astro_frineds.
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Brian Haworth bhaworth@lco.global
Wayne Rosing wrosing@lco.global
Hi Steve,
You can access our allsky images here https://lco.global/camera/elp/allsky/archive/
We only keep the last 24 hours of images but you can probably write a script to
scrape these as and when required. We use two cameras, an SBIG 340C colour is
only used during daylight with the dark sky images being taken with the SBIG 340.
Regards,
Brian
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Hi Steve - you have the correct address for Rick - not sure why it's bouncing...
I can answer your question:
We retain 30-days of image frame data from the MONET all-sky camera, on a rolling
basis. We can make the data available if you need it.
John Kuehne and Darrin Crook are CC'd here as well.
On an informational basis, LCO has an all-sky camera, and they may retain
data as well - I can ask to see about availability.
On Mon, Apr 29, 2019 at 10:55 AM Stephen Odewahn wrote:
Hi Coyne:
I sent a note to Rick Hessman at:
hessman@astro.physikuni-goettingen.de
but it bounces.
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Note from Bill Wren:
Hi Wayne,
Steve Odewahn (HET resident astronomer) didn’t have your email address so asked me to forward this query to you.
And, Steve, you might also checkout the all sky imaging Boston University collects from their site on Mt. Locke:
http://sirius.bu.edu/dataview/
Good luck! Bill
A good example:
http://sirius.bu.edu/dataview/
Note: RAs and Bill:
Hey guys:
I have been computing acm sky surface brightness values from various nights of
HET data. The rms scatter in the photometric calibrations using PANSTARRS look
very good (0.01-0.03 mag in g and i). One thing that had been hampering my work
was the ability to know the whetehr the night was cloudy! I have been writing to
various folks about the MONET and LCOGT allsky camera data. Yesterday at Taft's
talk Bill Wren reminded me that he had sent a link to the Boston University site.
This is a fantastic resource for us, and I am sending on the link:
http://sirius.bu.edu/dataview/
I am still trying to find a paper that describes the filter curves, but they have
7-bands taken nightly at a cadence of a few minutes. What ever the filter shapes, we
see stars, the Wilky Way, and clouds! They have the indicidual images and a nice
movie stream for each filter and night.
I'll let you know if I find more, but this is clearly an extremely well-built
and well-maintained web resource.
-Steve
Later, on May15,2019 I got a ton of useful info from the Boston people.
First I give my early morning notes from tests at the HET, then I give
their confirming and informative emails.
Summary:
I conclude tha Boston nights are labeled by UT date. I did this by
going to multiple nights of HET RA night reports. There I could determine
from the Activities section when we went idle for clouds. I could confirm
that the Boston images images show clouds around the same time. Second, I
could use the moon rise/set times reported in the HET NR. When it is clear,
the Boston images show a very washed-out, harder to see Milky Way. When the
moon has set the MW becomes much clearer. I use this to judge moon set/rise
times on the Boston images. I could use this as a second check to confirm
that the Boston nights are labeled by UT Date.
There is one caveat. The Boston 6950 angstrom images often show cloudy,
"ciirus-like" features on nights we seem to call very clear. I'll have to
do some mor research to see if this is a band that they user for arouroal
or "sky glow" properties. There may be surface brightness features in barrow
bands that we do not see in the MONET or LCOGT all-sky cameras or would detect
in the OCD transpareny values. On one of these "cirrusy" nights I checked
other bands (7744, 6300) and they showed such features. Of interest: the
6050 images were very clear and showed stars and the MW very well. On cloudy
nights the 6050 images show clouds well, but are also more adversley affected
by bright moonlight. It seems that using 6050 may be slightly prefereable to
using the 6950 image for judging phtometric quality of a night.
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Sorting out some questions about all-sky cameras at McD
The time NOW (as I type this) = Thu May 16 13:55:55 UTC 2019
The time on the LCOCT allsky image is: 2019-05-16 13:50:01 (both UT)
The time on the MONET allsky image is: 2019-05-16 13:55:09 (both UT)
Possible site URLs:
http://lcogt.net/camera/data/elp/allsky/lastsnap.jpg LCOGT
http://monet-n-sky.as.utexas.edu/mjpg/video.mjpg Monet
These seem to give just the last snapped image.
Going to the Boston site around this same time (Thu May 16 14:16:05 UTC 2019)
http://sirius.bu.edu/dataview/
Going to the 6950 archive, the last image set is for: May15 (civil or UT?)
In the sequence of images I see the moon has set by 10:23UT
From the RA night report of last night I see Moon set = 10:48 UT (for 20190516 UT = May15 civil)
From the previous night's RA report I see Moon set = 10:11 UT (for 20190515 UT = May14 civil)
Hence, I conclude that:
1) the Boston nights are labeled by UT
2) the page for last night (20190516) has not been processed and displayed in the Boston webdoc.
Maybe a second approcah? What was the last cloudy night?
From HET RA NR
--------------------------------------
20190514 UT cloudy at start of night, sci (clear) around 8:15UT) Moon set = 9:34
**** Boston shows clearing around 8UT moon set around 9:48
20190513 UT eng work at start of night, idle to clouds by 4:41 Moon set = 8:55
**** Boston shows patchy clouds at star of night, MOSTLY cloudy at 4:50 UT and onward, hard to judge moon set
20190512 UT idle clouds a 8:43 UT, moon sets at 8:13UT
**** Boston shows heavy clouds in east at 8:41 UT , can not judge moon set time (clouds)
20190510 UT idle at start, sci at 3:43 UT, clouds at 4:05 onward
**** Boston shows some clearing around 3:42 to 4UT, heavy clouds at 4:26 UT onward.
20190504 UT clear all night, moon rise at 12:12
**** Boston shows some light cirrus, but mostly clear; could not judge moon
20190501 UT clear all night, moon rise at 10:35
**** Boston shows clear all night (some cirrus), hard to judge but moon rise aroudn 10:20 UT
20190428 UT clear all night, moon rise at 08:56
**** Boston shows clear most of night (some clouds aroud 6:43), moon rise around 9:02 UT
20190425 UT clear all night, moon rise at 06:48
**** Boston shows clear most of the night (some clouds at start), moon rise around 6:37 UT
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Later useful notes from Boston folks:
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On 5/16/19 10:26 AM, Wroten, Joei wrote:
Hi Steve,
Yes, both date and time are in UT. I will make that more
explicit on the website.
It's great to hear that our data and website is a useful
resource for you and potentially other observers at McDonald.
Do you think a link to our all-sky data somewhere on the
McDonald Observatory website would be useful for other
astronomers? I guess I hadn't considered our *archived* data
to be of interest to observers as much as real-time images
might be. For example I just found:
https://hydra.as.utexas.edu/?a=help&h=68
Or perhaps:
http://www.as.utexas.edu/mcdonald/observers/mcdobserver.html
Observer Information - Astronomy
www.as.utexas.edu
MUC Reports. McDonald Users' Committee reports (access restricted
to McDonald Observatory and Astronomy Departemnt personnel). The
McDonald Users' Committee meets at least quarterly to discuss issues
of importance to observers at McDonald Observatory, and to recommend
solutions to problems.
If there's someone you know that I could reach out to, please let me know.
Best,
Joei
Hi Steve,
The sky monitoring filters we use are 6444 or 6050. This is outside
my area of "expertise", so I'm going to be general here, but 6950
can show some mesospheric activity that could be deceiving on a
clear night. I'm going to attach an image from one of our other
sites that illustrates this nicely (southern hemisphere sky).
The image on the left is 6444 and is clear with lots of stars visible.
The image on the right is 6950 and taken just a couple minutes earlier.
That's the mesophere, not clouds, in 6950. But it's true that certain
clouds can look very obvious in 6950.
Joei
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From Jeff Baumgardner jeffreyb@bu.edu
Hi Steve,
The 6050 filter is ~18A wide. the 6950 fiter is a RG695 long-pass filter to get
everything from 6950 red-ward to the limit of the detector sensitivity in the
red, (to get all of the hydroxyl and O2 emission lines).
Jeff
Jeff Baumgardner
Senior Research Scientist
Center for Space Physics
Boston University
617 353 5639 O
978 443 5294 H
Also from Jeff:
Hi Steve,
The times are indeed UT date and time.
Over the years we have had equipment changes for our all-sky
camera at McDonald. ~May 26 2015 we changed the detector and
also installed a different "off-band" filter. We monitor the
sky at a wavelength not associated with any (bright) nightglow
spectral lines. Prior to may26 2015 this off-band filter was
6444A. After that we use 6050A. Both of the filters "see" some
Hydroxyl (OH) but they primarily sample the continuum (scattered
starlight, moonlight etc.) We use these offband images to access
transparency. fog, clouds etc. In the nightglow wavelengths
(5577, 6300, 5893, 6950) there is a lot of structure to the images
and we want to disambiguate real geophysical (ionospheric) effects)
from clouds. For a few years 2009-2010 we had an H-Alpha filter
in the all-sky camera. I was going to make an all-sky map of
large/low brightness H-alpha features. I was ultimately limited
by the highly variable hydroxyl nigtglow that also is seen in our
14A wide H-alpha filter.
For a couple of years we have had a spectrograph operating at
McDonald (it is still there but it has some issues and has been
off-line for a few years). This low resolution (R~1000) device
sampled two regions of the spectrum ~6700A-7800A and 7700A-8800A.
This data is not on our public web-site, but can be made available
(I think!).
Jeff
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Hi Steve,
An other thought about using the 6950 filter for clouds. If you see
structure moving through the 6950 images and not in the 6050 images
you are probably seeing gravity wave activity in the Hydroxyl layer
at ~85 km. Structure in the 5577 filter (O1S) will highly correlate
with the OH images if it is gravity waves activity in the 85-95km
Mesosphere region
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