Friday, March 9, 2018

When you need a custom scope built fast, contact Dennis at Dobstuff.

John lives in Richmond, Virginia.

Late last year I found an 8” f/4 Ed Beck Enterprise Optics primary and matching secondary on Astromart. (I don’t know the make of the secondary) It has a surface blemish about 1” long that does not affect views. I had never hear of this maker before. I was intrigued by the ideas of vintage optics, wide field, sufficient aperture, and easy portability. My first though was a small dob, but then I remembered seeing some Dobstuff newts with integrated Losmandy dovetail. This allows both alt-az and equatorial use. 

At the star party the ATM guys set up the mirror  in in the Focault tester. It showed smooth figure and no other defects. This was readily apparent compared to  other mirrors were tested. I went ahead and had it recoated by Ostahowski (highly recommended) and then on to Dennis for the build. Many emails  were sent back and forth, and about a month later, the scope arrived. 

It has a simple strut design. The rings have a flat side for direct attachment of the dovetail Its also attached to the aluminum truss. Moonlite focuser and filter slide. Dobstuff secondary holder keeps collimation well and easy to adjust thumbscrews. Dennis provided the mirror cell with fan and three thumbscrews for no-tools collimation. Rubber feet allow the scope to stand upright for storage. Two wood rotating finder bases on the truss next to the focuser. Can accommodate reflex or optical finders. 

Things I added:

I started with a 13” Losmandy dovetail, then changed that to a 26” for wider range of balance.

I forgot to ask for a secondary dew heater. (Duh!) Ordered  the Kendrick split heater and glued it with some silicone. I also added a forward platform for the Telrad. I like it ahead of, not next to the focuser.

I have a Lycra shroud from another scope that fits after minor alteration.

First light was under dark semirural skies. With a Paracorr and 21 Ethos, magnification is 45x and Field  of View around 2.2 degrees. This was plenty to see Orion’s Sword region all at once. Thor’s Helmet nebula was easily seen , and even better with a UHC filter. With a 4.5mm Delos giving 208x , observed M79 in Lepus and planetary nebula IC 418. High power isn’t ideal for alt-az use, but I had no issues. The mount is the highly regarded  Discmounts  DM6. No backlash and easy tracking. First light was a success. I was able to observe a number of DSO’s and double stars. 

Second light was at home under a bright bright waning gibbous moon. I used a binoviewer with 2x OCS, and eyepieces from 32 to 11mm. A Lumicon ND25 filter reduced the glare. The scope again provided excellent sharp views, although the seeing was poor from a cold front. The best feature of the night was Vallis Capella. https://en.m.wikiped...Capella_(crater)  It was so distinct I ran in the house grab the Rukl Lunar Atlas. I’ve seen the crater any number of times, but never the Vallis.

Thanks John...

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