Collimating C8 inside with metaguide

[festoon]

Hello everyone

I have an old C8 which I'm hoping to collimate by using metaguide. I have a QHY5L-ii camera and a HEQ5 pro synscan mount or my EQ6 pro synscan.

What I'm hoping to do is to carry this out indoors so I at least get used to the process before trying it on real stars outside.

I've downloaded and installed the program on my laptop and also taken a good read of the instruction manual. The laptop does have a serial port.

Does anyone have experience of doing this, and can give me a bit of advice? To do this in a normal size room, from what I understand I will need a convex mirror and an artificial star or small LED. I should plug the St4 connection from my QHY camera straight into the autoguider port of my mount. And the QHY will be connected to the PC by USB. Is this correct?

Alternatively the manual talks about it being better to use ASCOM as this automatically reads the RA and DEC values. The difference being I have to connect the serial port from my laptop to the mount.

One question is how do I connect the serial port to the mount (whether it be EQ6 or HEQ6)? On the HEQ5 would I need a serial port to ST4 cable and plug this into the autoguider port?

For the EQ6 would I use a Serial to serial cable and connect the Serial port of my laptop to the hand controller port of the mount, or, as with the heq5, would I need a serial port to ST4 cable and plug this into the autoguider port of the mount?

[festoon]

Hi, if there are any moderators out there...is this in the right place? Cheers ?

[knobby]

It's quite a deep question, only but I can answer is about the led and mirror, if you Google artificial star I believe that's what your aiming for... It will need to be a long way from the C8 to achieve focus though.

If you're using the artificial star then the tracking isn't neaded, just a solid stable mount.

Hope you get some more answers.

[festoon]

Thanks for the advice knobby ? I've been through the calculations for how far the light source needs to be so that it is smaller than the resolving power of the telescope in combination with the lens. 

Advice I've had previously is to perform final collimation around x500 or higher magnification. This is where I thought tracking would be useful as very small tweaks of the collimation would move the image potentially out of the field of view. Maybe the tracking is not necessary but I expected it to be the case ?

[newbie alert]

The true test is on a real star.. unless its been bumped or on a long bumpy journey it shouldnt be too far out..  i start with a 25mm ep and then work my way through to a 7mm if the seeing is good enough..i think tracking will be a waste of time,will it track in the same rotation as youre putting pressure on it,not sure on that myself..id also wonder if you can get the false star far enough away to get an accurate reading...i wish you all the best,at least youre trying to collimate..most dont bother..

[Dave In Vermont]

I've not heard of needing 500X for collimating a telescope. That sounds wrong. Around 200X is considered fine by most - myself included. As for an artificial-star, several are available. I have one I like a great deal - inexpensive too:

https://www.amazon.com/Hubble-Optics-5-star-Artificial-Star/dp/B00C38A8TU

I'm sure that the UK - version of Amazon will have these as well, if you decide to go this route. You can also order directly from the manufacturer:

http://www.hubbleoptics.com/artificial-stars.html

A good star to use for the real thing is Polaris, alpha-Ursa Minoris. A 2nd magnitude star is best, which Polaris is (1.99), and it doesn't really need tracking as it pretty much stays put. Being the ultimate for an example of 'circumpolar.'

Hope this helps a bit -

Dave

 

 

[festoon]

Thank you very much the advice Dave and Newbie alert. The article I was basing my setup on was from this cloudynights webpage

http://www.cloudynights.com/page/articles/cat/user-reviews/the-easy-way-to-align-your-telescopes-optics-indoor-artificial-star-collimation-r2798

Here they use a set up like what I'm trying to do (and also the hubble optics artificial star). For final collimation this is at x500 mag.

Having tried collimation a few times before using real stars I've found it very difficult at high magnifications. So I thought metaguide would help based on reading about it and advice from another thread

But as you say Dave...Polaris is a good one

[Dave In Vermont]

If this is a first, or close to a first, time collimating, you'd be well advised to do it the old and true way. Me thinks you're making this waaaaay over complicated. And using advice that might result with one wearing a straight-jacket in a room with rubber-walls.

If you're already quite proficient at collimating reflectors & cassegrains, then go ahead and knock yourself out!

There's many people in these forums with lots of experience in collimation - including some who actually enjoy it! Personally I'm rather new at collimation of cassegrains, but have done this deed several times with no trouble. I use a simple Cheshire sighting-tube. And if I'm employing an artificial-star (my trusty Hubble Optics I ordered straight out of Hong Kong arrived in a week), I place it down the street on top of a neighbor's porch with some duct-tape.

500X and inside your house? What?! Ohhhhhh - CloudyNights, eh? Now I understand.....Me thinks some village's clock is missing it's bird...

Dave

 

 

[festoon]

Just wondering if anyone is able to answer the ascom question from earlier on in the post...

how do I connect the serial port of the PC to the mount (whether it be EQ6 or HEQ6)? On the HEQ5 would I need a serial port to ST4 cable and plug this into the autoguider port?

For the EQ6 would I use a Serial to serial cable and connect the Serial port of my laptop to the hand controller port of the mount, or, as with the heq5, would I need a serial port to ST4 cable and plug this into the autoguider port of the mount?

[newbie alert]

11 hours ago, festoon said:

Having tried collimation a few times before using real stars I've found it very difficult at high magnifications. So I thought metaguide would help based on reading about it and advice from another thread

But as you say Dave...Polaris is a good one

Work your way through your eyepeices,starting with say a 25mm..polaris is a great star as you can do it before you start the evenings events..just make sure its in the center of field of vision and your ota is cooled for long enough