Need - no, should - yes. You could do it without one but your alignment is going to be less accurate and it's going to take you longer to achieve that worse alignment (1-2 hours vs 30mins).
Originally Posted by DJVege
B) Do you have any suggestions on which ones to get?
Best suggestion I have is to get on with movable crosshairs. That will make your life a bit easier, especially if you don't have a top notch accuracy mount. I have the Meade one, one I bought about 8 years ago, so probably different to what's out there now. I doubt brand matters much as long as the functionality is there, the optics will be average in all of them I expect (and that's OK).
I bought a Meade astrometric reticle eyepiece last year, and just learned how to do drift alignment at Astrofest this year. Can't imagine trying it without a reticle. Best thing I think I have purchased. A drift aligning is easy if you get the right (simple) instructions!
I have the Celestron "double cross" one. So much easier for aligning the GoTo. The biggest problem I have found is remembering to turn the light off when I have finished. Several times I have put it in the next night to find the light still on! I can assure you they don't last for a week though...
Thanks guys! I'll wait a bit then. Once my rings arrive, I'll just have a few viewing sessions with rough alignment. Once I've learned the sky a bit, I'll get a reticle (12mm) then work on drift aligning (and imaging with my TouCam!).
You could always do what I do and that is after getting an inital rough drift with the reticle (a high power eyepiece would do well enough) I then finish my drift using the webcam and K3 CCDTools. As you can see from the attached image the dec drift was almost neglible (just over 2arc") for the first 1000 sec or so (bit of up and down in some areas for some reason ), and this is on a light EQ4 mount. On a good mount like my G11 I can get negilible drift in Dec for over 2000 sec (with no bumps) if I set my mind to it when drifting. Fortunately I don't need that sort of time frame for imaging normally. Consequently I don't have to autoguide in Dec normally and only have to worry about the RA.
I have a 13mm reticule and to be honest never use it. I align using the polar axis finder and the main scope aimed at the south pole. If I need to drift align I would use my webcam or QHY guider to give a much more accurate image of a stars movement than I would ever get with my reticule.
Just my opinion.
If you can get yourself up to Astroron's for the next dark sky night I can show you how to use K3CCDTools to drift align in about 15 min. It is easy as and you will drift align to a VERY good alignment in about 20 -30 min once you have learnt how and had some practice. If you set up at home in the same spot all the time there are some short cuts you can use as well.
Yep, just keep an eye on the Observing sessions and Star party forum. There will most likely be a get together in two weeks time, maybe even Saturday week as well as Saturday fortnight seeing the new moon falls in the middle of the week. Maybe you could even drag Rowena along as well. I hear she might be a bit toey to get out under some dark skies as well