Leave finder attached?

[buddym]

Hello:

I am a new member and a newcomer to astronomy and i have what is probably a pretty basic question but first, let me thank all those who responded to my intro post the other day.

I did a quick search and didn't find my question in a previous post but apologies in advance if i am duplicating.

I have a Celestron C6 SCT OTA on a CG4 mount, all manual.  I also purchased the Celestron RACI 9x50 finder to replace the cheesy 6x30 that comes with the OTA and a Telrad so i have something with a wider FOV to get in the vicinity.

Today i took the scope out and did an approximate alignment on the RACI finder in the daytime.  I say "approximate" because the furthest target i could conveniently sight that was not toward the sun was only a few blocks a way.  The sun was too bright to see the Telrad bullseye so i broke everything down and put it away.  Then late in the day i went back out and was able to sight a target about 1/4 mile away.  When i checked the RACI alignment it was off noticeably so i adjusted it again.

Here is my question.  Once a finder like the Celestron RACI is aligned should i leave it attached to the OTA or is it reasonable to expect that the mounting foot and set screws will orient the finder exactly the same way each time it is installed?  The RACI finder is a little precarious and i would prefer to take it off the OTA each time i break down but not if that means having to realign it each time, especially in the dark.

Thanks in advance for the advice.

[baggywrinkle]

You could take it off but when you remount it do a quick check on a star or planet just to see if you are close. Having a proper foot with set screws is good as it should relocate with no problem. Of course any small misalignment will show up pretty quickly.

On my 6se I would use the RDF on as they do not like being taken on and off the OTA.

[brantuk]

Any finder that is removed will not go back in exactly the same position later when re-attached. So no it won't be aligned exactly as previously set. If you are leaving the scope outside in a fixed position however, you can leave the aligned finder on the scope until darkness falls. Other wise you'll have to re-attach and realign after transporting or moving the scope somewhere else.

With experience you'll find you can attach and align the finder with the ota in the dark on a bright object in the sky at night. It only takes a few mins to do this. You really only need to practise during daylight as a beginner until you get the hang of it.

The Telrad is usually pretty close when re attached so it'll just need fine tuning - but the raci's do have a tendency to go way off the mark.

[Stu]

I normally find mine to be pretty close when I put it back on. If the finder shoe is good, and the adjustment screws reasonably firm then it should hold reasonably well if removed with care.

I agree with Brantuk though, they are designed to be adjusted easily, not necessarily to maintain alignment once removed so a quick adjust each time is worthwhile.

Stu

[buddym]

OK, that makes sense. We had a cold front yesterday and it should be clear (and cold) tonight so I'll have a chance to practice alignment on a star or planet. Thanks for the help.

[Astro Imp]

I find that the Telrad stays pretty close when re-mounted but my RACI I leave on the OTA and even then find it sometimes need a little tweak.

Good luck to-night, hope it stays clear and not too cold for you.