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27 February 2004: Zeta Cancri, Iota Cancri, Algieba, NGC 2903, M 53, M 3, M 13 and La Superba


About 7pm (UT) the Moon had disappeared and it was time for a night of deepsky observing. To warm up I first visited a few "old friends" like the Pleiades, M 42, Orion's Belt, M 44, and M 35. After that I started to hunt down a few new objects, 3 double stars, a galaxy, 3 globular clusters and a carbon star. I sketched the field of view of the double stars and the carbon star, to verify them next day (just to be sure it where the one's I was looking for). I also made a sketch of the galaxy and it's surrounding star-field, to see if I got the orientation and its size right. The sketches are all included in this report.

1. Zeta Cancri

This is a triple star in Cancer. I could only detect split two components (already at 100x). I could not split the AB pair. They have a separation of 0.8", while the AB and C components are separated by 5.7". The colour of both components was yellow. They are easy to locate. In Gemini, go from Castor to Pollux and extend this line with two times the same length. Then you are in the area of Zeta Cancri. With its distinct colour, you cannot miss it.

Zeta Cancri

Zeta Cancri, 133x, FOV 22'


2. Iota Cancri

This one is also easy to locate, Just have a look in your star atlas at the constellation of Cancer. There is one line of the constellation that stretches north, passing M 44. At the end of this line you will find Iota Cancri. I never had seen it before, but when my telescope came across it, using a 62.5 magnification I was stunned. It almost looks like Albireo, a bright yellow, accompanied by a somewhat fainter blue star.

Iota Cancri

Iota Cancri, 62x FOV 47'


3. Algieba (Gamma Leonis)

This wonderful double star lies at the centre of "the Sickle" in the constellation of Leo, 8 degrees north-northeast of Regulus (Alpha Leonis). Both companions are bright yellow, with magnitudes of 2.2 and 3.5. the separation is 4.4". The B component lies in a position angle of 127 degrees.

Algieba (Gamma Leonis)

Algieba, 133x, FOV 22'


4. NGC 2903

From my backyard, which is heavily light polluted, I cannot see too much galaxies. In an article in sky and telescope I read that NGC 2903 was even brighter than M 65 and M66, but for an unknown reason was not included in the Messier catalogue. I decided to go for it. Again, this object is easy tot locate, because there are some bright stars in the Lion's head that will guide you to NGC 2903. In the lion's head, locate 17 Epsilon Leonis. From there go about three degrees to the west to 4 Lambda Leonis. NGC 2903 lies only 2 degrees south of this star.

I immediately spotted the galaxies bright core, without averted vision. Using averted vision it showed up as an elongated, faint smudge of light. Apart from the bright core, I could not detect any details. Later, when comparing my sketch with my sky atlas, I noted that it was even bigger. The two stars south of this galaxy, actually lie right near the southern tip of NGC 2903.



NGC 2903, 100x, FOV 29'


5. M 53, M 3 and M 13

Now it was time for some globular clusters. First I had a look at M 53, which lies only 1 degree to the north-west of Alpha Coma Berenices. With the 8-inch telescope at 80x I only saw it as a nebulous smudge of light. At 166x I could partially resolve the stars around the edges of the cluster, but I had to use averted vision to do so.

Next on the list was M 3, lying about halfway between Arcturus in Bootes and Cor Caroli in Canes Venatici. You immediately see the difference with M 53. M 3 is a big bright globular cluster. At 100x I already resolved stars on the edges of the cluster. When using averted vision, it became even bigger and brighter. At 166x to 200x, individual stars could be seen almost to the middle of the cluster. Now it was time for M 13.

M 13 is the best (in the northern hemisphere). It is located in Hercules, halfway between Zeta and Eta Herculis in "the Keystone". At 100x I could detect some arms (or chains) of stars coming out of the cluster. At 166 it looks like a giant spider. The cluster is resolved right to the middle, but there is a glow of many more unresolved stars.

My advice, view at these three globulars in the same order I did. The views get better and better this way!


6. La Superba

In Canes Venatici lies La Superba ( Y Canum Venaticorum, variable star), a carbon Star. Carbon stars are cool red giants with a lot of carbon molecules in their atmosphere, causing absorption of blue light. That's why these stars look "deep red". La Superba again is easy to spot. From 12 Alpha Canum Venaticorum ( Cor Carolis) go to 8 beta Canum Venaticorum (Chara). From Chara go about north-northeast. There you will find the "red" star. At 100x there where only four other stars in the field of view (about 30'). The limiting magnitude was about 12 to 12.5 at that moment. The colour was deep orange at the moment. It really stood out from its surroundings.

La Superba

La Superba, 100x, FOV 29'





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