Mostly, you can't.
The classical astrological signs are "Sun Signs"; that is the constellation that the Sun WAS in about 2500 years ago. Because of the "precession of the equinoxes", the Sun is actually one zodiac sign earlier now; during Cancer, the Sun is actually in the constellation of Gemini.
But even so, at the beginning of July, the constellation Cancer is very low in the western sky at sunset; since none of the Cancer stars are especially bright, you probably won't see it.
You must provide location. It is very important because stars visible in one area does not mean they are visible in others. I live close to the line of the cancer tropic and for example I am able to see the cancer constellation on nightly basis.
In New England (Northeast US) Cancer currently begins to rise in the east roughly 5PM; Acubens (65 Cnc, also alpha Cnc) rises roughly 7:50. Cancer is highest in the south roughly 2:30AM.
09h 00m 00s, +20° 00′ 00″
See link for Wikisky
There is no specific place you have to wait for a specific time and date to see it.
Cancer is visible at latitudes between +90° and −60°.
Best visible at 21:00 (9 pm) during the month of March.
Night time.
Beta Cancri is the brightest star in the constellation Cancer. Its common name is Altarf.
Cancer is a constellation that appears in the northern quadrant of the sky and is visible everywhere except for higher than 60 degrees South latitude. It has a right ascension of 8h 38.96 minutes.
they dont have any specific stars
The Tropic of Capricorn is so named because about 2000 years ago the sun was entering the constellation Capricornus on the December solstice. In modern times the sun appears in the constellation Sagittarius during this time. The change is due to precession of the equinoxes!!
Tarus
You can find a list of them in the Wikipedia article "Cancer (constellation)", under the section "main stars".
it is a star of a crab that reprsents cancer
The constellation of cancer has been around for around 5 millions years. Cancer is a zodiac constellation and is represented by the crayfish or crab.
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If you mean the constellation cancer, there is no such thing as a "distance to a constellation". It just doesn't make sense. A constellation is basically a general direction in space.
Aside from Cancer being the dimmest zodiacal constellation, the planet Mars is in Cancer (as of 4/21/10)
5 stars are there in cancer
Cancer.
It is Cancer.
"The Crab"
The Crab
A constellation has no surface, it is an imaginary pattern of stars.