Posts Made By: Eric Loomis

Geoff,

I've had better luck picking stars that are both on the same side of the meridian. With two star alignment at this time of year at my location, I use either Altair and Deneb if it's early in the evening and they are still above 20 degrees, or Capella and Rigel if it's later. Generally this gives me decent results, i.e., targets are always within a 40mm plossl, and usually within a 25mm. I don't have a wedge.

I read somewhere to avoid using Polaris as the first star; not sure if this is true, though.

I don't notice any difference between 2-star and auto align, FWIW.

I don't think it's necessary to be super accurate levelling the base, but it should be pretty close. I check with a small level along each of three axes, on the diagonal across from one tripod leg. I think what is important is that the OTA be orthagonal to the azimuth axis of the tripod, which is easiest to do if the tripod is already level and then the OTA is levelled on it.

Because of backlash, it seems to be important that the final movements in aligning the star mimic the final goto movements when the scope is slewing itself. Since direction changes between slew settings 1-6 and 7-9, you have to figure how to mimic the scope's final slewing behavior with the keypad (this varies depending on whether you use a diagonal, etc.). Experiment a bit and you'll quickly figure it out.

Is there any chance the clutch is slipping on your scope? This will ruin alignment.

HTH, Eric

Mars still looks good. Saturn will be above 25 degrees there at around 20:00, but better later. Uranus will be out early. M31 will be up near the zenith early, as will M33 and M45. M42 will be viewable around 21:00.

Have you downloaded Cartes du Ciel? Superb freeware astronomy package.

Eric

Jeffrey,

I hang Denk standards on the back of my 8" Celestron SCT also; no problems.

I think it's very likely that Russ would refund your StarSweeper purchase if it didn't work out. I asked him the same thing when I bought mine. You can call and ask him. On an 8", the Starsweeper gives f/5. The 2" version that some 9.25 users apparently need still gives f/7 (I think), which might be pretty nice to have.

Eric

Jeffrey,

Since no one else has answered, I'll say this; on my N8 with stock focuser and 2" WO diagonal, there was not enough back focus for the standard f/5 starsweeper. Russ at Denkmeier seemed to think this was the first time this had happened on an 8" SCT. Apparently it has happened on some C9.25s; I infer from the Denkmeier website that some C9.25s come to focus and some do not. If yours doesn't come to focus, Denkmeier has an f/7 starsweeper that requires less backfocus, which they swap for the f/5, (plus $30 in my case, since the f/7 is 2", not 1.25").

Russ was very helpful with my little focus problem, FWIW.

Eric