I'm looking for a 1970s book about a young girl who looks through her
inventor father's telescope one day to see someone on another planet
looking back. She's then transported to that planet and has a series
of adventures. I remember one chapter being called "Beware Bad
Habits".
Possibly translated from French original?

Hi corner_surfer,

I believe the book you are looking for is called "Rebecca's World" by
Terry Nation.

From an Amazon user's comment:
"Rebecca is mysteriously transported to a distant planet as she looks
through her father's astral telescope."

http://www.amazon.com/exec/obidos/tg/listmania/list-browse/-/8D176LAVTOF/002-3363765-0877659


Author: Terry Nathan
Title: Rebecca's World
Theme: Adventure mystery fantasy

"This book about a girl called Rebecca who is bored  half way through
her Summer Holidays. But then when she goes into her dad?s study room
with she is not supposed to be in she looks through her dad's special
telescope and her adventure begins.
She is suddenly transported into another world and is told she will
have to wait and explore a little bit before the transporters is
fixed.
She meets new friends and discovers she has to unravel mysteries to
find the last living ghost tree before the horrid Mr Glister who has
chopped all the rest down so that she can plant it's seeds and restore
new ones so that the horrid ghosts will go away and hopefully she can
do it before the horrid ghosts and Mr Glister or else the mysterious
planet will be destroyed..."

Beith Book Sp@ce
http://www.learning-north-ayrshire.com/Beithbookspace.htm


Rebecca's World is available for purchase at Amazon:
http://www.amazon.com/exec/obidos/tg/detail/-/0814907792

Also available at Abebooks:
http://dogbert.abebooks.com/servlet/SearchResults?y=9&tn=%22Rebecca%27s+World%22&x=29


Search criteria:
site:.amazon.com intitle:books children's book girl telescope planet
"Rebecca's World" telescope planet

I hope this is helpful. If you have any questions regarding my answer,
or believe this is not the book you remember, please don?t hesitate to
ask for further assistance before rating.

Best regards,
Rainbow

Thankyou, you've just ended several year's of searching.

I'm glad I could help. Thank you very much for the rating and generous tip.
Best wishes,
Rainbow