Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Rocket Pooch on Jun 01, 2004, 20:50:00

Title: June the 8th dry run
Post by: Rocket Pooch on Jun 01, 2004, 20:50:00
Hi,

Now I have my solar film etc, I have a couple of questions.  

Firstly (don't laugh) does the Sun track at the same rate as the stars?  Will I be ok with a normal slew rate on my telescope?

Will notmall Polar alignment be ok for this?

Also has anyone tried to autoguide on the sun?  I was thinking of pointing the LX90 at it and autoguide through my SkyWatcher 80mm?  I believe this should work providing I use the LPI?  Anyone done this sort if thing before?  I was wondering if there was enough detail on the Sun for this to work?

Lastly, anyone fancy a dry run down the field later this week 4am ish to see where the sun will rise?

Bye
Title: June the 8th dry run
Post by: Rick on Jun 01, 2004, 21:30:00
QuoteFirstly (don't laugh) does the Sun track at the same rate as the stars?  Will I be ok with a normal slew rate on my telescope?
Near enough. The difference is about 4 minutes in 24 hours.
QuoteWill notmall Polar alignment be ok for this?
Yes.
Title: June the 8th dry run
Post by: Greg on Jun 02, 2004, 20:23:00
Yes, agree with rick about one degree of celestial motion per day. It should make any difference for the type of observation you are doing.
Title: June the 8th dry run
Post by: Rocket Pooch on Jun 03, 2004, 14:27:00
Ok, thanks for that, so all I have to do is setup the kit and wait, in the, field for dawn.

Title: June the 8th dry run
Post by: Mike on Jun 03, 2004, 21:37:00
Who's Dawn?!

If we get down to the field early enough on the obs. session the day before we would see were the sun would rise nicely ! We could always go back to the pub of course (presuming it isn't cloudy and we can SEE the sun of course).


Title: June the 8th dry run
Post by: JohnP on Jun 03, 2004, 21:44:00
OK -So what's the plan for next Mon/ Tues - are people planing an all night session at the field or is it meet at the pub & head on down after closing time? Also, I've never been to the field before - Is there any possibility of having access to 240VAC? The problem I have with my TAL is that the motor is a 12VAC 50Hz - If no mains is available I'll have to fork out on one of those DC to AC converters that maplin sells & get a 12VDC car battery (or use the one in my car I suppose).

Thks,  John
Title: June the 8th dry run
Post by: Rick on Jun 03, 2004, 22:28:00
I don't think there's any 240V AC in the field. There's a "normal" observing evening on Monday, so, sky being clear, folk will be going to the field around sunset. Some folks will stay overnight. Others will retire to bed and return around sunrise. All assuming it isn't chucking it down, of course....
Title: June the 8th dry run
Post by: Mike on Jun 04, 2004, 06:12:00
John, you'd be better of with a low voltage 12v ac to 12v dc convertor as you will lose power using the 240v convertor. Can't it also take 12v DC??
Title: June the 8th dry run
Post by: Ian on Jun 04, 2004, 18:13:00
if you're feeling brave, you can get 12V AC out of an 12VDC to 240VAC invertor if you tap off before the transformer.

All usual disclaimers apply, including the fact that I've never actually tried it, but if you want me to, I can take a look at the invertor I have at home.
Title: June the 8th dry run
Post by: JohnP on Jun 05, 2004, 06:08:00
Unfortunately, the Tal-2m has an AC motor that runs off 12V, 50Hz for driving the RA axis. It won't work off 12VDC. I actually made a little invertor from a diagram I found on the web that converts from 12VDC to 12VAC however, I won't have time to install it before Mon/ Tues. I figured the easiest solution would be to buy a 12VDC to 240VAC invertor from Maplin - this way I can plug in the 240VAC to 12VAC transformer that I currently use (came with the scope) I could also use it to plug in my laptop when the batteries die. It'll also be useful if I ever take the kids camping sometime in the future.....!

Thks for all your help - John
Title: June the 8th dry run
Post by: Mike on Jun 05, 2004, 07:23:00
John, I have one you can borrow if you like as i won't be using it.
Title: June the 8th dry run
Post by: JohnP on Jun 07, 2004, 17:19:00
Hi Mike,

That would be excellent thanks - John