[Aavso-photometry] RE: Where do the professionals source (arne)

[David Higgins]

I agree, you have an awkward setup so have good reason :-)

The simplicity of the SCT backend on the LX200GPS makes the setup very quick
and easy for me.  10 minutes and I have the cameras connected (2),
observatory openned, computers time synched, telescope pointed and focused
and ready to start a run on my next NEO lightcurve target. (I run with ACP4,
MaxIm, FocusMax).  

In the last 3 yeasr I've never actually run into any thermal equalibrium
problems with any of my cameras but I've only been using the SBIG for a
short time.  My SX cameras have never had an issue (and I've imaged while
the scope is covered in 1/4" of frost and ice).  However my temperature
ranges (extremes) are +25c (Summer) to -12c (Winter) with a typical nights
temperature variation of only 5-6c but this differential can be as high as
15-20c which makes refocusing a must.

Cheers

David


-----Original Message-----
From: Michael Koppelman [mailto:lolife at bitstream.net] 
Sent: Sunday, 25 September 2005 11:33 AM
To: David Higgins
Cc: aavso-photometry at mira.aavso.org
Subject: Re: [Aavso-photometry] RE: Where do the professionals source (arne)


To each his or her own, David. My camera is not so easy to remove. It  
is screwed on to the corrector of my Tak E-160. I do not focus every  
night -- I focus every couple of months. I'm not taking pretty  
pictures and because I am undersampled a little misfocus can actually  
be an advantage. It would probably add at least an hour if I had to  
reattach and refocus every night. (I do not have a robotic focuser.)

I also don't want to deal with thermal equilibrium problems so all my  
gear is at ambient temperature all the time. Here in Minnesota, in  
the winter, my unheated (but attached) garage is still 20 degrees  
warmer than ambient.

Finally, someone once gave me what I consider a very good piece of  
advice: the purpose of an observatory is to protect your equipment!  
He suggested, and I agree, that one should leave everything set up  
and ready to go. I can be taking data within about 15 minutes of  
arriving at my observatory. With a full-time job, taking classes,  
doing research, playing in bands and spending time with my wife and  
kid, an hour here and there makes a difference.

I can live with a little suspect data every 3 or 4 years. Because I  
enjoy error analysis, I noticed this pretty much right away. I had  
some problems with frost this summer because my desiccant needed  
recharging. I think the combination of high heat and high humidity is  
probably the culprit.

Cheers,
Michael

On Sep 24, 2005, at 8:01 PM, David Higgins wrote:

> 'Not practical for a working observatory'???  Of course this
> depends on what
> you classify as a working observatory but I remove my cameras every  
> night
> simply because they are small and easily transportable items for  
> thieves (a
> 14" telescope isn't).  The camera always goes back to within 0.4  
> degree
> rotation (camera/scope mount adapter takes care of that) and I always
> perform a focus (as should any observatory) before the imaging session
> begins.  I've done this for 100+ sessions over the last 3 years  
> with no ill
> effects.
>
> I can understand why observatories with LN DEWARs etc will not
> remove the
> cameras but there really isn't any valid reason otherwise if you  
> want to
> maintain the integrity of your filters.
>
> If the filters are degrading and you have to change them then your
> data then
> becomes suspect because you have no idea at what point they become  
> suspect!
> Whats more important - data integrity or a small inconvenience each  
> session?


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