Help with Solar Tracking on a Sky-Watcher Star Adventurer

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Help with Solar Tracking on a Sky-Watcher Star Adventurer

Postby cloudwalker_3 » Fri May 06, 2016 3:06 pm

I would have really liked to include links in this post, but unfortunately, when I tried to the website just kept saying that the post looked too 'spammy' for a new user, which is deeply frustrating, but here goes anyhow...

I'm a photographer who has recently invested in a Sky-Watcher Star Adventurer kit. The reason I've brought this is primarily to capture the forthcoming transit of Mercury across the face of the Sun. I've also brought a solar filter for the end of my lens so no burnt out eyeballs! (The solar filter for the Meade-ETX125 - is a good fit for a Nikon 300mm f/2.8 VRII, FYI)

Having seen some of the online set videos (I think...) I'm fairly clear about setting up the equatorial wedge onto my tripod to capture the latitude: You point the adjustment knob twowards the north, then adjust the latidude indicator to your latitude (which for London is 51°30′N).

There are a couple of things that aren't clear to me however (essentially I'm a newbie, and a dycalculic/dyspraxic/dyslexic one at that, so I'm finding the learning curve pretty steep at the moment!)

1. If you're aiming to capture the transit of Mercury, do you still need to polar align? I've brought myself a copy of an app for my iPhone called PolarAlign just in case. How do you do this during the day? Or is it just a matter of adjusting the time graduation circle, the date graduation circle and the standard meridian offset scale to match the information within the app?

2. Assuming that you've now set up the mount, how do do you get it to solar track? I know where the selector is on the mount, but is this essentially just the speed of movement? Is it the polar alignment that makes it follow the correct arc of the sun?

3. As mentioned above, I'm planning on mounting a Nikon D700, with a Nikon 300mm f/2.8 VRII onto the mount. The kit comes with a counterweight, to balance off the weight of whatever you place onto the mount. How do you know where to locate the counterweight (it slides up and down a rod)?

Obviously, since the transit is on Monday, there is a bit of urgency, either way, thanks in advance for any help that you can give me.
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Re: Help with Solar Tracking on a Sky-Watcher Star Adventure

Postby Aratus » Fri May 06, 2016 8:40 pm

I wouldn't worry too much. Although the sun is 'moving', the brightness of the sun - even with a filter on it - means that it it won't move enough to cause problems with the kind of exposures you will be using.

This device would of course track the sun if set up correctly, but the sun isn't a difficult target to locate! :D
I imaging that it has a solar setting to enable someone to automatically take eclipse photos while watching the eclipse themselves, but since this event will be on all afternoon you will easily be able to move your camera manually and not miss anything. (Unless you want to set it up and then leave it for 7 hours)

If you still want to set it up, then I am certain you will need to polar align it. You may need to align it at night and keep it in position for the next day. A counterweight is literally that. Mount your camera and slide the weight across until the balance in on the unit itself. With such a small unit you could lift it by hand and move the weight until it balances on your hand.

If anyone here has got one of these, hopefully they could give you more precise advice.

Sorry about the 'automatic moderator' on this forum software. It restricts the things you can do until you prove to it that you are a genuine contributor. It is a bit paranoid until you have made a dozen or so posts! :D
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: Help with Solar Tracking on a Sky-Watcher Star Adventure

Postby cloudwalker_3 » Sat May 07, 2016 7:02 am

Thanks for the reply Aratus, I really appreciate it.

My plan is to try to capture around 37 images of the sun and then combine them so that I have a composite showing the transit of Mercury across the face of the sun.

Although I will be controlling the exposures (sitting in a deckchair for seven hours basically on Primrose Hill in London) I do want it to move automatically and track so that the sun stays centered perfectly in the viewfinder.

Because London has such bloody awful light polution at night, combined with the current cloud cover, I'm still stumped as to how I do the Polaris alignment thing (most nights I can't even find Orion - one of my favourite constellations) so if you or others can offer any help on this, I'd be very grateful.
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Re: Help with Solar Tracking on a Sky-Watcher Star Adventure

Postby Gfamily2 » Sat May 07, 2016 10:56 am

cloudwalker_3 wrote:Although I will be controlling the exposures (sitting in a deckchair for seven hours basically on Primrose Hill in London) I do want it to move automatically and track so that the sun stays centered perfectly in the viewfinder.

Hi,
To be honest, I think most 'simple' mounts would find it a push to remain centred exactly over 7 hours, so I think it would be more realistic to assume you'll be manually aligning the images afterwards.
Because London has such bloody awful light polution at night, combined with the current cloud cover, I'm still stumped as to how I do the Polaris alignment thing (most nights I can't even find Orion - one of my favourite constellations) so if you or others can offer any help on this, I'd be very grateful.
.

If you can get your tripod leveled and the angle more or less right on the equatorial mount, and a compass to find north, you should find that you'll only need to make small alterations before each image.

Good luck though. We're at Astrocamp in S Wales, and the forecast isn't great for Monday. :(

We may well set off early and try and catch our friends at Mid Cheshire Astro Group who are meeting in the Old Pale car park in Delamere Forest (not so subtle club promotion)
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: Help with Solar Tracking on a Sky-Watcher Star Adventure

Postby Aratus » Sat May 07, 2016 8:52 pm

cloudwalker_3 wrote:
Because London has such bloody awful light polution at night, combined with the current cloud cover, I'm still stumped as to how I do the Polaris alignment thing (most nights I can't even find Orion - one of my favourite constellations) so if you or others can offer any help on this, I'd be very grateful.


Learning your way around the sky is a slow but rewarding process. Finding polaris is fairly easy. Orion is not always in the night's sky but another constellation will help you. 'The Great Bear' has a collection of stars sometimes called 'The Plough'. This is always visible in the clear night sky. You use the 2 stars at the end to 'point' to the Pole Star.
This image shows how to do that.
Image
and this web page explains it.
http://popastro.com/youngstargazers/skyguide/bearings/

All the best for Monday everyone!
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: Help with Solar Tracking on a Sky-Watcher Star Adventure

Postby cloudwalker_3 » Sat May 07, 2016 9:22 pm

Thanks for that information Gfamily2, very helpful.

I've seen a video on setting it all up it's on YouTube (after the web address typ a slash / watch?v=g58TqYUbhWY and you'll find it).

I'm using the wedge seen in this video which I've set to the London latitude (51.5º N). In terms of finding Polaris, given that the light polution here is so awful, having done this, and based on the fact that I'm tracking the Sun is it now just a matter of aining the mount north and turning it on?

Or am I missing something in your reply?

Good luck with Monday, either way.
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Re: Help with Solar Tracking on a Sky-Watcher Star Adventure

Postby cloudwalker_3 » Sun May 08, 2016 4:37 am

Thanks for the chart Aratus, that was really helpful. After looking at it I downloaded an iPhone app that helps you track down polris called SkyView (which was rather good)

Having found it however (with the augumented reality part of the app it just points you towards it in the sky) it was pretty faint (due to the light polution) but I definitely found it. It was pretty easy with the app.

I also have the PolarAlign app on my iPhone.

I figured by using both these apps together I've got to be able to work out how to set up the alignment, right?

Nope! Just much more confusion...

Firstly the reticle diagram in the app is numbered from 1 to 24 and the reticule in the Sky Adventurer is numbered just has 0, 3, 6 and 9 on it. I looked at the options for the in app reticule and a whole bunch come up:

PolarAlign 2010, 2020
Takahashi 1975, 1983, 1990
Takahashi 1975, 1985
Takahashi 1985, 2000, 2015
Takahashi 2010-2050
Astro-Physics RAPAS

I picked the first one, 'PolarAlign 2010, 2020' and then another bunch of options come up under the heading 'Set Orientation':

Inverted
Corrected
Inverted Right Angle
Corrected Right Angle

Looking at all the stuff and trying to work out the manual (which is fairly difficult) has just left me utterly confused. It's probably not aided hugely by the fact that I'm dyslexic and dyspraxic either.
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Re: Help with Solar Tracking on a Sky-Watcher Star Adventure

Postby Aratus » Sun May 08, 2016 9:41 am

I'll do my best with this. (is the manual on the internet?)

Numbers 1 - 24 will be what is known as 'Right Ascension'. It is equivalent of 'Longitude' in the night's sky. 0,3,6,9 might be 'declination' which is the equivalent of 'latitude'. (actually 0 - 90 degrees) So these are different coordinates.

The orientations look as if they are the various possible views through a telescope. If you are using a camera lens then I'm guess you need to use 'corrected'. In other words the image is 'the right way up and not 'flipped''.

This is an educated guess, and may be wrong, but I figure it is worth a try. If anyone else can understand this better then please chip in.

Remember that you will be able to take photos of the transit without the mount so it is not urgent. Once you have mastered this mount you will be able to image plenty of deep sky objects which require a long time exposure.
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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