Most reported supernovae turn out to be false alarms. There are lots of checks and balances put in place to prevent false discoveries from getting posted on CBET Circulars, but sometimes a bad ones still gets through. The IAUC guidelines
It is possible to have a hot pixel on your imager. The way you can tell is to compare the size of the suspect to the size of a star of a similar brightness. The hot pixel will be smaller then the foreground star, a supernova would be about the same size.
The supernova hunter's first line of defense is the CfA Minor Planet Checker. However, don't think that this is the last word. There are lots of uncharted asteroids out there, particularly on the ecliptic. This is why you want to take two images of any suspect. If the object has moved, then it was an asteroid. A very famous case is the case of 2003lr (local link).
See the AAVSO online list of variable stars. Here you can check for variable stars near the location of galaxies.   Also, look for high proper motion stars 2003aw
An HII region can often produce a bright pixel in an underexposed image. A second exposure can often verify this.
Luminous Blue Variable stars are like Eta Carinae these are sometimes called "supernova imposters". They are still worth reporting due to how rare these objects are.
|Host name||Location||Associated object|
|NGC 300||R.A. = 00h55m04s.86, Decl. = -37°41'43".7||2010da|
|NGC 1511||R.A. = 03h59m38s.07, Decl. = -67°37'54".6||Variable star in NGC 1511|
|NGC 3184||R.A. = 10h18m19s.89, Decl. = +41°26'28".8||2010dn|
|NGC 7259||R.A. = 22h23m08s.26, Decl. = -28°56'52".4||2009ip|
|MCG +06-49-68||R.A. = 22h39m58s.36, Decl. = +34o23'05".5||Variable star near Pegasus|
2001bn IAUC 8624 BV anon 2001bh 7622 K star ugc11635 2001dh 7482 M star ic5374 1999db 7227 QSO anon 1999dc 7227 AGN anon 1999cx 7210 AGN anon 1999cu 7210 AGN anon 1999bs 7141 cat var ugc11093 1998di 6982 dwarf nova anon 1993U 5818 QSO anon 1993V 5818 QSO anon 1992W 5517 M star mcg 8-23-96 1992X 5517 M star mcg 6-32-24 1991ap 5327 QSO anon 1989Z 5162 var ngc4013 1985J 4059 CV ugc6274 ? var ugc10700 - CBET 184 var ugc11800 - 197 var ugc2495 2010db 2290 M star ? 2005md ? CV ngc2274 2007sv ? BV ugc5979 2006gy ? AGN? ngc1260 2006fp ? BV ugc12182 2006bu ? AGN anon
If you want to search this page, the easiest way is to do a "view source" (Ctrl-u in Firefox), then do a find (Ctrl-f in Firefox) and look for "-00°" for any SN at -00° Declination.
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