Celestron fastar

[MartinB]

Those of you who have visited Roger Warner's (Celescope) web site will have seen some of the images he has obtained using a Celestron NS GPS 8" scope equiped with the fastar system and the little Atik 2HS modded webcam. This set up allows the fork mounted NS8 to produce great results in alt az mode. In other words it is probably the easiest imaging system on the planet!!

I finally got to use my new fastar assembly this week. I was lucky to get it since Celestron, for some strange reason are no longer making it. A very similar set up called hyperstar is still available from the US.

The fastar system consists of a lens which slots into the housing for the secondary mirror. A housing is supplied for the secondary so that it is kept nice and safe. An adaptor allows easy connection of camera to lens. the housing and secondary are aligned by a small notch so that collimation isn't lost when it is replaced. With the fastar in place the F ratio of the NS8 is reduced from 10 to 1.95 - put another way - a 1 minute exposure with the fastar is equivalent to 30 mins at F10!!! Well, thats according to the blurb. This means that good exposures can be obtained in alt az before the dreaded field rotation becomes an issue (60 secs isn't a problem).

A big plus for the fastar is the widening of the field of view. This is a great bonus with the very small chip on the 2HS

Its a bit nerve racking removing the secondary in the dark, it has to be pulled out by gripping the small central knob. You also have to be careful not to leave the corrector covered in thumb prints. the housing is very secure and set up after removing the mirror is a cinch.

I had a little play using the goto and managed to get targets on the chip without much bother which helps a lot!!

First impression is a major jump in image quality compared to the meade F3.3 FR which I have been using up until now. At £280 it's not cheap but for the use it's going to get I reckon it's going to be good value in the long run. One concern I had was that it doesn't work well with a lot of larger pixelled larger format CCD cameras. However it does work well with the SXV H9/H9C. So there's scope for the future (if it's good enough for Prof Greg Parker it's good enough for me!!)

Incidentally, not all Celestron SCTs are fastar compatible.

[daz]

Very much looking forward to the first results, Martin!