spectro-aras.com

I just added an Alpy600 calibration module
to my L-200; see: http://astroimage.info/spectra/L200&CalibModule2sm.jpg

I'm finally getting good flats, although my Ne-Ar calibration line are somewhat
"thicker" than the original DIY Lisa Ne-Ar source I used with the native L-200 calibration-window
for lamp illumination spectra; unlike the LiRESIII, you have to go out and manually flip a
knob to engage a pick-off mirror...like the Alpy module (no manual flip) much more!

I see a new issue, however. The background of my un-calibrated long exposure image show
a wavy interference pattern. At first i thought this was do to the extra 3 X 12V power inputs I'm
using on the Alpy calibration module for remote use (I'm using 2 RF on/off receptacles to control from
inside the warm house). However, after unplug them from the calibration module, I still saw the
interference pattern superimposed on the background of the images. I secondly thought this
was due to my addition of my new Atik Titan guider, but even powering this down and changing to a
separate USB port on my laptop didn't eliminate the issue.

Finally, I changhed the PSU of the Atik 460 and the interference, while not totally gone, was cut by about 75%
Is there any suggestion on how to get the "creamy-smooth" background pattern seen in my old exposures instead
of the wavy-line like patter I'm getting now? Images shown are uncalibrated, cropped, and stretched for clarity:

James,
Certainly looks like some sort of electrical interference.....
Sorry I don't have the answer for you, but I hope other users maybe more helpful.

Yes, I agree with Ken, maybe electrical interference (or maybe your USB Cable ?)
Try with another power supply to check if it come from there ? Or take a battery to check the problem ?

in my set up I have just a single power supply for all my spectrograph set up (LISA or LHIRES III)
- CCD for autoguiding (ATIK 314L+)
- CCD for spectrum (ATIK 414 ex)
- Ar/Ne lamp and Flat lamp
- PC (work on 12 VDC)

a good regulated power supply like this one :
http://elc.fr/devis-en-ligne/alimentati ... -300w.html

I did see this pattern when cooling not operating (12 cable unplugged?).
Seen with my Lodestar X2 guide camera when plugged in a USB cooler for the laptop (summer time), or when used a sort of powered USB hub (5V).

Also recommend to operate your ccd from a fully separate power supply than your mount (mounts can have sudden power demand that a regulated power supply tries to serve - with certain delays...).
In fact, having 2 cheap switching-type regulated power supplies (separate for mount) has always been enough for me.

However, my best bet is your cooling must have gone.

- Peter

RE:"Yes, I agree with Ken, maybe electrical interference (or maybe your USB Cable ?)"
RE:"a good regulated power supply like this one : http://elc.fr/devis-en-ligne/alimentati ... -300w.html"
Thanks Olivier, I changed the location of my USB cable on the computer, but did not
use a different cable on the Atik 460ex ccd. See below regarding a separate PSU

RE:"Also recommend to operate your ccd from a fully separate power supply than your mount "
Thanks Peter! After I wrote my post, I thought of using 1 of my 2 12-volt DC regulated
PSU boxes; see http://img.diytrade.com/smimg/116833/27 ... Y/8d97.jpg

This seems like overkill, and the rating for mine is 5 amps, so I'm afraid it may be
too much for the Atik 460ex to handle (1 amp?). This PSU didn't seem to hurt my
SBIG STL-11K (or AP1200 mount), but those uses 5 amps, especially when its attached
to the AO-L unit which I always have connected.

Whats so strange about this is I didn't add any new components, except the Alpy calibration module and a couple
of more 12V, 1-amp AC-DC power cords; the Alpy calibration module needs 3 of these to work in "remote mode."

One more thing to check-out, is the remote switching PSU I'm using for the Alpy calibration module's flat PSU; see:http://www.frys.com/product/8502549;jse ... IN_RSLT_PG
This is the only other, 'New" set of items added to my usual set-up.
This is my second remote. My first one which I use for turning-on and off the calibration lamp didn't cause this problem, As I've used for
the last 6 months. One thing I noticed on the back of the old remote I used, says in writing: "This device may not cause harmful interference,"
The back of my 2nd remote switch unit makes no such statement........

I want to solve this before I change over to the LISA spectroscope in the next few days after my
Titan guider adapter arrives from Sheylak.

James,
The Amp rating of the PSU has no impact on the actual amps drawn by the camera. The camera will only use what it needs not more.
I use 10A supplies on my gear where the max current draw (according to my power meter) is always less than 2.8A.

To: Ken,

Thanks for the assurance!
(I forgot I use this 12-V regulated box for my Kendricks anti dew system on my 6" secondary mirror)
I moved the Atik 460ex on its own position on the power strip I'm using and moved the "new" remote RC radio PSU
as far away from it as I could. Doing 420 and 300 second darks to test this out. If I still get a background pattern,
the new RC remote will be replaced!

Hi James,

This looks like classic pattern noise to me. You should see it in your bias frames too. If so, the process of elimination is the camera USB cable and power supply and any other sources of noise interference from surrounding equipment. If it persists, then it might indicate that an issue has developed with the camera electronics.

Paul

I think I found the solution to my RC interference problem. I forgot that I had a Technical Innovations Remote Power Module.
see(Euro ver.):

I have Robofocus installed in this laptop for use in the mountains, so I replaced my two radio controlled switches with this RPM that is controlled
by the Robofocus 3.1 software. I assigned buttons 01 and 02 as FLAT and Ar-Ne Lamp after connecting the appropriate 12-V, 1.2 amp PSUs to the
Robofocus RPM. See:

So far after looking at 300 second dark I see none of those wavy-lines of noise in my CCD image background.

I will probably need to buy another RPM and robofocus control box, as the 1st robofocus control box I used did not work with the RPM. I also like to
duplicate working systems, rather than taking one out for both observatory/portable use and something breaking so I cant use it at all.
Thanks for all the help!