Jay Soso has taken the first legal steps in a bid to overturn a 12 years and eight months term imposed last month.
Soso, 20, admitted rape and culpable homicide after he attacked 63-year-old Marie Reid in her sheltered home in Easter Drylaw Way in November 2010. Mrs Reid lay dead for up to four days before her body was discovered.
Soso was initially charged with murder, but admitted a reduced charge of culpable homicide.
Marie’s son Paul, 31, said the appeal had left him devastated.
He said: “I am so angry. It’s like a kick in the teeth.
“I was hoping to put everything behind me but now it’s going to be dragged up again and it could go on and on.
“I’ll just need to see what happens but I’m hoping it will get flung out.”
At the High Court in Edinburgh in June, judge Lady Dorrian said Soso had been aware that his victim, who lived alone and suffered from poor health, was vulnerable.
Passing sentence she told him: “You have pled guilty to the rape and culpable homicide of an elderly lady in her own home. You knew her and there was an element of trust in the relationship you had with her.
“The rape was clearly forcible and violent, causing injuries to her and leading to her death.”
A Scottish Courts spokeswoman confirmed the appeal application had been lodged earlier this week.