Finder scopes

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Re: Finder scopes

Postby Aratus » Mon Jan 16, 2017 9:54 pm

I suppose that modern cameras and sky map software will eventually get sophisticated enough to line up the telescope automatically. Celestron has 'sky sense' but it seems more trouble that it is worth - at the moment. Perhaps a mirror behind the red dot at 45 degrees would do it.
I use an 11" Celestron SCT (CPC 1100) on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI1600MC and Canon 500D for imaging.
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Re: Finder scopes

Postby Gfamily2 » Mon Jan 16, 2017 10:10 pm

Aratus wrote:I suppose that modern cameras and sky map software will eventually get sophisticated enough to line up the telescope automatically. Celestron has 'sky sense' but it seems more trouble that it is worth - at the moment. Perhaps a mirror behind the red dot at 45 degrees would do it.

Plate solving is standard already in several software packages - and with ASCOM can be used to determine the alignment of the telescope. Also, as you say, Celstron's Sky Sense and Meade's LS mounts use cameras to auto-align, with more or less success.
Scopes: Meade 8" SCT, Skywatcher 127mm Mak, Raffle winner of SW ST80
For imaging: Pentax K5, Asda webcam, Star Adventurer (new toy)
For companionship: Mid Cheshire Astronomical Group.
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Re: Finder scopes

Postby dave.b » Fri Jan 20, 2017 5:58 am

A 2 star alignment with 2 additional calibration stars usually produces a good result for me. You do need a level scope that isn't too far off polar alignment though. When I've started a session with a single object alignment, such as Venus of the Moon, then you do pretty much have to use the finder to get other objects into the FoV. It's almost always worth stopping and reinitialising the mount to get better assistance from it.
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Re: Finder scopes

Postby Aratus » Fri Jan 20, 2017 2:00 pm

My main problem with 'sky-sense' is that it cannot align a telescope any quicker than I can do it manually. Fair enough, I know my way around the sky, but that is just a matter of learning and practice. The other reason I don't bother, is having the telescope in a dome makes something like 'star sense' useless, since the telescope doesn't have access to the whole of the sky. Generally speaking it is 'the future', I'm sure, but it is a lot of cost and technology for what is, with a little practice and care, quite a simple process.

If the telescope is perfectly level, then even a one object alignment can be sufficient if it is done carefully. On the day of Mercury's transit, last year, I aligned on the sun (with correct filters, of course) and it stayed with it for the rest of the day without any adjustments. That is probably the longest I've stuck with a single alignment - about 7 hours. That is with an alt-azimuth mount too. A 2 object alignment, is likely to be better though.
I use an 11" Celestron SCT (CPC 1100) on an equatorial wedge, housed in a 2.2m Pulsar observatory. I use a ZWO ASI1600MC and Canon 500D for imaging.
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Re: Finder scopes

Postby Gfamily2 » Fri Jan 20, 2017 4:50 pm

Aratus wrote:My main problem with 'sky-sense' is that it cannot align a telescope any quicker than I can do it manually.


That may be true, but it does mean you can take your scope out, and leave it aligning itself while you're getting out your EP box, dew shield, planisphere, laptop, etc. By the time you're ready, it is already aligned.


* if all goes well anyway.
I bought a self-aligning Meade LS8, which has the benefit of being self-levelling and capable of finding its own location and North by means of GPS and internal compass. Yes, it added about 25% to the cost of a comparable 'standard GOTO' scope, but I don't regret it. Would I replace it with the same type now? No, because I've now got more experience, but I wouldn't necessarily have that if I'd not started that way.
Scopes: Meade 8" SCT, Skywatcher 127mm Mak, Raffle winner of SW ST80
For imaging: Pentax K5, Asda webcam, Star Adventurer (new toy)
For companionship: Mid Cheshire Astronomical Group.
(Not a moderator)
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Posts: 452
Joined: Thu Jun 25, 2015 10:38 pm

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