User`s guide

9
SECTION 4.0
TROUBLE-SHOOTING GUIDE
The following common problems and solutions have been collected over the years
from our customers and our attempts to solve their instrument problems. Before
calling us, read through these and relevant sections of this manual to see if an easy
solution exists for your errant photometer.
The CCD photometer seems to produce erratic results with the I and R filters but
appears to work OK with the B and V filters.
Read section 3.1 again. In addition to observatory or nearby incandescent light causing
problems, high cirrus clouds not visible with the naked eye or an active aurora can cause
havoc in the far red and infrared portions of the spectrum and be invisible in the visible
portion.
The night appears clear but the star count is diminishing with time faster than
expected due to changing extinction conditions.
A common problem specially with Celestron and Meade telescopes is that a nearly invisible
film of condensed water will develop on the corrector plate or main mirror during the night if
the dew point is high enough. Usually this fog film can only be seen when a strong light is
projected down the front of the telescope and the optics carefully inspected. A hair dryer is a
good cure.
When using the PFE-1A and moving the filter slider, a clicking noise is heard but the
filter slide does not actually move.
If the filter slider covers have been removed for any reason, they may be binding against the
slider. To check, simply loosen the two pan head screws on either of the covers and move
the filter slider from the keyboard. Carefully tighten the screws while ensuring that the slider
continues to move. If this does not cure the problem, a return to Optec may be required.
The long term performance of the CCD seems to be seasonal. The limiting magnitude
during the summer months cannot seem to match the limiting magnitudes during the
winter months.
This phenomena is due to the nature of the TEC cooler. The coolers on some CCD cameras
are not regulated. The operating temperature is much lower during winter nights than during
summer nights because ambient temperatures during the summer months may be 20° (or
more) higher than typical winter ambient temperatures. With lower operating temperatures,