Subject: Re: [sdss3-25mlog 1632] 2.5m obslog 20140212 (MJD 56701)
From: "John K. Parejko"
Date: Fri, 14 Feb 2014 16:35:02 -0500
Mea culpa:=20
After further reviewing the code, and testing it last night, it looks =
like I was incorrect (thanks also to a poke from Craig): the FFS bypass =
doesn't affect the actual behavior of the FFS. When we tested the new =
SOP's apogeeDomeFlat command last night with the FFS bypassed, it did =
close the FFS.=20
This does leave the excellent question as to just *why* the FFS didn't =
close for this particular dome flat. I looked in the logs too, and =
didn't see the actual command sent. So, that's rather perplexing.
Apologies for my mis-statement.
John
On 13Feb 2014, at 18:37, Daniel Oravetz  wrote:
> Thanks for the clarification, John. That actually was not clear to us. =
We
> had been under the assumption that having FFS bypassed in SOP was =
actually
> only bypassing the _status_ of the FFS, but commanded _moves_ would =
still
> get through. In fact, wasn't the motivation to include the FFS bypass =
in
> SOP originally a product of windy conditions and failed guiding?
>=20
> I can certainly see from a developer's perspective the utility in
> bypassing everything for testing purposes, but I think you can =
appreciate
> that from an observer's chair, having only the status of the FFS =
bypassed
> so that we could guide in windier conditions while still allowing
> commanded moves to get through so that we can proceed with normal
> observing, would be beneficial.
>=20
> I think this is another one of those situations where having an =
observer's
> perspective (as opposed to taking a developer's approach) may have =
skewed
> our expectations. I wonder if our understanding of other bypasses are
> misaligned with what actually happens for this very same reason?
>=20
> Dan
>=20
>=20
>>=20
>> Yes, having FFS bypassed in SOP means FFS commands from SOP don't =
happen
>> at all. That bypass lets us, e.g., run commands that require moving =
the
>> FFS while the dome is closed. It does mean that if you do want to =
move the
>> FFS, you have to either clear the bypass or command the move manually =
via
>> the mcp.
>>=20
>> I suppose a more general system for dealing with flapping FFS might =
be
>> better than the current, rather crude, "ignore anything to do with =
them"
>> method. I'll have to give this some thought, though, since it impacts =
on a
>> number of different subsystems.
>>=20
>> John
>>=20
>> On 13Feb 2014, at 09:10, doravetz@apo.nmsu.edu wrote:
>>=20
>>>                      APACHE POINT OBSERVATORY SDSS 2.5M
>>>=20
>>>                                OBSERVING LOG
>>>                         Wednesday February 12, 2014
>>>=20
>>>                                 (MJD 56701)
>> ...
>>> When we look at the image, it doesn't look like a flat; it looks =
like a
>>> 5-read
>>> exposure of the sky, which suggests that having FFS bypassed in SOP =
to
>>> accommodate guiding in windy conditions also prevented the FFS from
>>> closing for
>>> the dome flat.
>>=20
>> --
>> *************************
>> John Parejko
>> john.parejko@yale.edu
>> http://www.astro.yale.edu/~jp727/
>> 203 432-9759
>> JWG 465
>> Department of Physics
>> Yale University
>> New Haven, CT
>> **************************
>>=20
>>=20
>>=20
>>=20
>>=20
>>=20
>>=20
>=20
>=20
--
*************************
John Parejko
john.parejko@yale.edu
http://www.astro.yale.edu/~jp727/
203 432-9759
JWG 465
Department of Physics
Yale University
New Haven, CT
**************************