[LVAS] Observing Report

[roger ivester]

All,

 

I have mentioned on several occasions of the opportunity to observe with severe light pollution, the moon high in the sky, and thin thin clouds. Double and multiple stars can be an alternative to galaxies, star clusters and nebulae. 

 

On Wednesday afternoon a local friend and observer called and asked if I would be interested in observing and evaluating his new 8-inch Takahashi Classical Cassegrain telescope mounted on a heavy duty Astro-Physics 600 mount. Despite the moon, and intermittent clouds we were able to examine a variety of double stars. 

 

If you have never had the opportunity to observe with a Tak refractor or any product produced by this company, the quality and precison are normally superb. 

 

The seeing was fair to poor, but we were still able to get a nice view of the trapezium, seeing the fifth or "E" star. I have always found that a minimum of 200x or more is required to achieve this feat.

 

If seeing had been good I feel sure that we could have seen the sixth star. If you are going to go for six stars use the diagram in Burnham's Celestial Handbook. I have actually seen six stars with my 10-inch f/4.5 reflector on a night of very good seeing. 

 

As you know a rich-field telescope is not designed for close doubles, but I have observed a sub 1.0-arc second separations with this scope on "one" night of exceptional seeing. 

 

When using my 10-inch for doubles I normally use an off axis aperture mask, reducing the effective aperture to 4.25-inches. It has surprised me on many occasions with views rivaling that of an apochromatic refractor...really.   

 

Using the Takahashi scope we also observed Zeta Orionis, and Castor, with both being very easy. I have easily seen the companions of both of these stars with an 80 mm f/15 Japanese refractor, and a Meade ETX 90 mm Maksutov-Cassegrain scope. If you have a small scope take a look at Rigel and it's faint companion. The glare can be a problem with this one. There is also a nice color contrast with this double if you look carefully.

 

When seeing is superb, some doubles can be an absolutely beautiful sight, with some appearing as two ping-pong balls sitting side by side...almost animated. 

 

I would hope that someone might be interested in checking out the trapezium and seeing how many components you can see. Be sure to list the scope, conditions and magnification. 

 

Within a very short period of double star work you will recognize good or bad seeing very easily and "fast". You must also learn to hold your eye very steady without blinking, and you must be seated. Double star work will improve what you see visually on faint details in galaxies and other deep-sky objects. 

 

You do not need a dark site for the above listed multiple stars....

 

Roger

 

 

 

 

 

 

 

 

  
 
 
 
 
 
 
 
 
 

 
    The moon and stars to govern the night.....   Psalm 136:9



 		 	   		  
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