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Henden Calibration Fields for Comet Observations

steveehlert's picture
steveehlert
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Joined: 2014-06-03

Hello all-

I am a professional astronomer at Marshall Space Flight Center working in the Meteoroid Environment Office (MEO), having started this job just a few weeks ago. One of my first jobs has been to put together a new analysis pipeline for our observations of comets, and I think I have managed to put together an almost entirely automated end-to-end pipeline that automatically does photometric calibration. However, I now need to do some diagnostic tests on how well my photometric calibration works. The MEO has been getting observations of two Henden start fields every night we get comet data, so I would like to use those to determine the accuracy and precision of my photometry. However, I cannot seem to find good catalog of the Henden star fields/objects online thus far. I know of the old ftp site that used to have them but I gather that is out of date now.

So my question is: Is there any place on AAVSO or elsewhere where I can download the entire catalog of Henden star fields, ideally in a FITS format? I would like the entire survey catalog if possible, as I will be using a large number of Henden fields over the course of the year to maintain the photometric accuracy of my own pipeline.  Specifically, I am doing observations in R, B, V, and I band of the comet that I need to calibrate

 

Thanks

Steven Ehlert

Henden sequences
HQA's picture
HQA
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Joined: 2010-05-10

Hi Stephen,

Those sequences were moved to

ftp://ftp.aavso.org/public/calib/

The all-field calibration files have a ".dat" extension; if you drill down to the sumner directory, you will find ".seq" files that Bruce Sumner created from those files.

You might also consider using APASS:

http://www.aavso.org/apass

which covers most of the sky with decent photometry, so that you don't need to take special calibration exposures.

Arne

FTP Site Henden Sequences
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WBY
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When I tried to access the FTP site you posted it required a password and log in. My AAVSO ID and password didn't work. Needing a password for a public FTP seemed odd and my AAVSO log in not working seemed even more odd. Is something broken?

I sent an e-mail to Sara but thought I should also make a post here in case anyone else had the problem. 

Brad Walter, WBY

ftp site
HQA's picture
HQA
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Joined: 2010-05-10

Hi Brad,

Yes, the ftp site is not publicly accessible right now, one of the last things to be brought up after the computer breakin.  It should be available sometime soon; I'll post here when it happens.

Arne

If you want to observe comets
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FRF
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Joined: 2010-08-09

If you want to observe comets I'd also recommend to use APASS. The APASS photometry actually is also included in the UCAC-4 catalogue and can be accessed via Aladin.

Access to FTP
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WBY
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Thanks, Arne.

ftp site
HQA's picture
HQA
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anonymous ftp is back.  The path has changed slightly to improve security.  For the Henden calibration fields, go to

ftp://ftp.aavso.org/calib/

and for the Sumner extracted sequences:

ftp://ftp.aavso.org/calib/sumner/

Enjoy!

Arne

ftp site
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WBY
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Thanks, Arne.

Can't connect to new ftp sites
WBY's picture
WBY
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Well, I tried connecting to the news sites this morning and couldn't connect with Google chrome or IE11. Perhaps the site was just off-line for maintenance. I will try again during the week. 

Brad Walter, WBY

ftp site
HQA's picture
HQA
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Joined: 2010-05-10

Doc restarted the ftp process this morning, so you should be able to connect to our ftp site.

Arne

AAVSO 49 Bay State Rd. Cambridge, MA 02138 aavso@aavso.org 617-354-0484