Bolton Astronomical Society

Red spot finder
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Author:  bchamberlain [ Mon Sep 24, 2012 2:59 pm ]
Post subject:  Red spot finder

Hi. First, thanks for the advice last Tuesday on alignment. I'll try 2 star rather than 3 star when I get a clear night. I previously made a stupid mistake By taking longitude from an O.S. map, reading 53.31 as a percentage rather than degrees and minutes. It should have been 53.52%. An error of 44 kilometers. I got my scope in June with the idea of familiarizing myself with it in comfortable temperatures. Pity there have been so few clear nights.
An opinion please. Is it a good idea to buy a red spot finder and if so, is there a great difference in quality as the prices seem to suggest?

Author:  rwilkinson [ Mon Sep 24, 2012 3:37 pm ]
Post subject:  Re: Red spot finder

Bill, you'll find that there are three ways of expressing lat & long:
DD.DDD (degrees/decimal degrees);
DD.MM.MM (degrees/minutes/decimal minutes);
DD.MM.SS (degrees/minutes/seconds).
The latter is the most common, and is used by Celestron GoTo systems.

As an example, the location of our meetings at Ladybridge is marked on this map:

I find that the red-dot finders are much more useful at dark-sky sites (e.g. Kelling Heath) - as you need to be able to see your targets with the unaided eye.
Here in Bolton, I need a 9x50 finder-scope in order to stand a chance of finding anything!

But if you are going to get a RDF, look out for one with auto shutdown - then you don't find that you need fresh batteries every observing session!
We found three of these for a tenner each on AstroBoot earlier in the year (but there are none there at the moment :( ).

Author:  bchamberlain [ Mon Sep 24, 2012 7:42 pm ]
Post subject:  Re: Red spot finder

Thanks Ross. I think your first option is the one used by Skywatcher Syncscan although the book doesn't clarify that. I have a reading of 002`51W 53`52N I'll need a clear sky to check it out.
I'll look out for a red spot finder following your advice. Thanks again.

Author:  rwilkinson [ Mon Sep 24, 2012 9:26 pm ]
Post subject:  Where on Earth am I?

No Bill, I think that the SynScan just omits the seconds, so enter your co-ordinates in DD MM format, rounding up to the nearest minute.
Taking the example of BAS HQ, this would be 002 29' W, 53 34' N.

See this rambling discussion in the StarGazers' Lounge:

Author:  bchamberlain [ Tue Sep 25, 2012 10:26 am ]
Post subject:  Re: Red spot finder

OK Ross. I'm back to my original settings so I'll see how the 2 star alignment works if we ever get a clear sky.

Author:  Amartin [ Sun Sep 30, 2012 4:48 pm ]
Post subject:  Re: Red spot finder

Hi Bill,
I only live in Leigh so if you want I can come over to have a look for you - I've made/still making some of the mistakes you are making/will make!!!

Author:  bchamberlain [ Thu Oct 04, 2012 3:22 pm ]
Post subject:  Re: Red spot finder

Great offer Andy. Many thanks. I've just picked my polar scope up From Brian so I know that's accurate. Thursday and Monday evenings are tied up for me but otherwise any clear night I'm on 884135

Author:  Amartin [ Sat Oct 06, 2012 12:27 pm ]
Post subject:  Re: Red spot finder

No probs, lets wait for a clear(ish) night then we can see what's what.

Author:  bchamberlain [ Sat Oct 06, 2012 4:51 pm ]
Post subject:  Re: Red spot finder

Thanks Andy. Look forward to that

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