ETX TECHNICAL TIPS Last updated: 12 January 2002

ETX90 Solar Scope

Sent:	Tuesday, January 8, 2002 06:13:03
From:	MaserD@tuhs.temple.edu (Maser, Drew)
Just to add my 2 cents and possibly help others. Without making any
modifications, I have made my ETX90 into an H-Alpha solar scope. If you
think appropriate you can add to your site.

REMEMBER, DO NOT LOOK AT THE SUN WITHOUT PROPER ERF FILTERS.

Those who own a Daystar H-alpha filter can do the following. Purchase
(1) Full aperture ERF (red glass that meets specs), (2) the ETX to 1.25
adapter for the back end of the scope, and (3) a 2.5x POWERMATE from
Televue (not a barlow).

Screw the 1.25 adapter onto the back end of the scope, insert the
Powermate into the adapter, insert the Daystar H-alpha filter in the
Powermate and insert your eyepieces.

It is important that you use a Powermate and not a barlow when using the
Daystar units. Daystar requires an F30 light path and regular barlows do
not provide this. The Powermate does. Using this set up and a Televue
40MM Plossel, I was able to get full disk view.

Once this setup is completed, you will need to balance the scope with
weights up front as the back end is now extended out about 10 inches.
This is also where you will notice any rocking in the RA axis.

This does not apply to the Coronado or other prominence brands of
H-alpha filters.

Note - I can supply the source for the ERF's upon request. DO NOT USE
ANY RED PIECE OF GLASS. THE ERF'S ARE MANUFACTURED TO SPECIFIC
TOLORANCES.

Good luck.

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