What Finder for an RC-12

[Spookyer (Brett)]

Hi all

Spent a frustrating evening last night trying to polar align my new RC-12. I don't currently have a finder for it and let me tell you if you haven't tried this before with a 2483mm focal length - it is bloody hard.

Because the alignment was quite a bit out I couldn't use alignmaster because it wasn't putting me close enough to the stars for me to find and identify them. So I basically wasted a clear evening which is rare event lately in Brisbane.

The two finders I currently own of course do not fit the finder brackets on the RC which happen to be quite wide.

What is the best way to go? Do I get a finder to fit the RC or a red dot type thing. What do others use on their long focal length setups?

thanks
Brett

[pmrid (Peter)]

Bi Brett,
even without the finder, you can still drift align if you use your guide camera and whack it in the back of the RC12. That'll get you polar aligned.

And then, once Polar aligned, use your main camera to do a good image, plate solve and sync. Then you should be well-enough positioned so that when you Park, you should be able to warm restart and be darned near spot on target.

So forget a finder scope - you won't need so long as your scope is on that mount. Have you got it in a roll-off yet? Or a dome?


Peter

[Camelopardalis (Dunk)]

I feel your pain, I've just started experimenting with my C11 for imaging and has a focal length of 2800mm, I typically have a Rigel Quikfinder and 9x50 RACI on board, but once you start your drift alignment it becomes irrelevant and your gotos should be pretty spot on once you've got good polar alignment.

I'd also recommend plate solving - I've been experimenting with AstroTortilla - it makes any onboard computer/handset irrelevant and does what you tell it

[LewisM]

Get (or make) a finder-guider - put the guide cam in the back (with your main cam in the main scope), and use it as an electronic finder - MUCH better than a visual finder, and you can also guide with it if you really want to.

Not sure on the GSO RC's, but GSO finders use the bog-common/standard Vixen finder mount - you can get the bracket itself for around $20 from MANY sources in Australia. Then you can mount your Tak finder or whatver you have in the Vixen style bracket.

Haven't used a finder in years now since using the finder-guider that doubles as both an electronic finder (more sensitive than my eyes, especially with the Lodestar) and as a guidescope if you want to go that way. Myself, now having gone OAG, will continue to have the finder-guider setup in place of the visual finder, as both an electronic finder and a back up guide arrangement. Redundant, but redundancy is a good strategy.

[glend (Glen)]

Re Finder-Guiders, (thanks Lewis for bringing that up), I just bought an Orion Mulit-Finder and am finding it very useful. At 70mm it's harvesting 50% more light than a standard 50mm finder, and I can hang just about anything off the back. It has a helical focuser at the back, and needs a diagonal to achieve focus, which is ok because you get a right angle finder out of that. I'm running a 20mm Superview EP on a 90 degree diagonal and its working really well for my old eyes. I can also stick my ASI130 guide camera on it to create a video finder - a device I am thinking has real value to me in the future. It can be a guide scope as well. It is a little bit heavier than a 50mm finder but as it can be dual purpose you potentially could ditch the guide scope off the rig. Mount it on a Skywatcher Guidescope mount and it will be easily X,Y adjustable across the sky for guide star locating.

[Spookyer (Brett)]

I don't really use the finder once I am aligned just use pointing and plate solving as part of my imaging. I have never had to drift align before as I have always used Alignmaster as a shortcut with my other scopes and do it all in 15mins. You do need a finder for that though. I tried to use the PHD2 drift alignment function last night but it told me I had to calibrate first. I couldn't get the guider to calibrate because of the polar alignment error so not sure how much use that feature is if you are not quite close to start with.

Any PHD2 users want to tell me what I am doing wrong there?

[Peter.M]

Originally Posted by Spookyer

I don't really use the finder once I am aligned just use pointing and plate solving as part of my imaging. I have never had to drift align before as I have always used Alignmaster as a shortcut with my other scopes and do it all in 15mins. You do need a finder for that though. I tried to use the PHD2 drift alignment function last night but it told me I had to calibrate first. I couldn't get the guider to calibrate because of the polar alignment error so not sure how much use that feature is if you are not quite close to start with.

Any PHD2 users want to tell me what I am doing wrong there?

If you usually use alignmaster with another scope there is nothing stopping you doing your polar alignment with that and then swapping for the RC. I have no finder on my tv scope and use alignmaster

[alocky (Andrew lockwood)]

Originally Posted by Spookyer

I don't really use the finder once I am aligned just use pointing and plate solving as part of my imaging. I have never had to drift align before as I have always used Alignmaster as a shortcut with my other scopes and do it all in 15mins. You do need a finder for that though. I tried to use the PHD2 drift alignment function last night but it told me I had to calibrate first. I couldn't get the guider to calibrate because of the polar alignment error so not sure how much use that feature is if you are not quite close to start with.

Any PHD2 users want to tell me what I am doing wrong there?

You're not doing anything wrong, although it needs to be quite a long way off (10 degrees or so) before it won't calibrate. I find using phd2 I need to recalibrate after each adjustment as well.
Cheers
Andrew.

[Spookyer (Brett)]

Thanks for the responses.

I did think of swapping my other scope on last night and doing the alignment then putting the RC back on but i was a bit tired by then. That might be quicker than attempting to drift align this evening with my limited drifting experience.