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Help With Guiding Please........


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I am looking to get some advice on choosing a guide scope and guide camera to help me image DSOs with my Celestron 9.25 Edge HD using an unmoded DSLR. I am working to a budget of upto £600 but will flex if needed.

With regards to guides scopes, my current thoughts centre on either a dedicated guide scope or a short doublet.

Guide scopes options - all 80mm Aperture:

- Orion short tube 80 FL:400mm f/5.0 (£100)

- Skywatcher Startravel 80 FL:400mm f/5.0 (£97)

- Celestron 80mm Guide Scope FL:600mm f/7.5 (£188) includes all attachments except dovetail

Alternative - short doublet

- William Optics Zenithstar 71 FL: 418mm f/5.9 71mm Aperture (£360)

Moving to guiding Cameras, my current thoughts centre on either an all in one Auto-guider or a guide camera connected to laptop utilising PHD, unless other options are better? (currently have a laptop connected to setup using backyardEOS).

Auto-guiders

- Orion Starshoot Autoguider (£250)

- Sywatcher Synguider (£220)

- Celestron NexGuide AutoGuider (£300)

Guide Cameras

- QHY5-II (£200)

- Starlight Xpress Superstar Autoguider (£400) or Starlight Lodestar - £345 or Starlight Xpress Costar - £270

- Atik GP Guider/Planetary Camera - £320

I would really welcome your thoughts on the options I am considering any alternatives and a setup for me still an improving novice. Thanks

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I would strongly recommend that you go for an Off Axis Guider at that focal length. I tried to guide my EdgeHD 800 with the finder and it almost worked, but I never got perfect results. As soon as I connected up an OAG it worked pretty much perfectly. As for guide camera, I would go for the Lodestar X2 - it's fab! Use PHD2 (free) software to guide. You have your laptop in use already, so you may as well use it for everything! What mount are you using?

Price wise:

Celestron OAG = £195

Lodestar X2 = £449

Just over budget!

There is a bit of a learning curve with the OAG, but well worth going that route.

Good luck!

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Thanks for your help and advice.

My mount is a neq6 pro currently using a synscan and want to move to EQmod as some point.

What are the advantages of the OAG over guide scope at this long focal length of 2350mm.

Also new to using a laptop - currently using backyardEOS to capture with my DSLR (unmoded 350d and 700d).

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Perfect mount. Definitely spend time to get EQMod up and running. It is well documented on their website. It will be a cloudy evening very well spent. It will help massively with polar alignment and basically everything! I use Cartes du Ciel in conjunction with it and while there is the usual learning involved with new software, it integrates very well and does away with the need for the handset other than as the connector from laptop to mount.

The OAG means that the guidecam can track the movement of the main scope and the guiding will keep it on target. If you attach a separate scope you are essentially keeping the guidescope on the target and not necessarily the main scope! The long focal length only serves to amplify the slightest misalignment or flexure between the two scopes. It is possible to guide with a separate guide scope, but will take some luck to get it working perfectly. The OAG will work, full stop. Long subs will be a reality, not just a dream...!

It's worth checking out APT (http://www.ideiki.com/astro/Default.aspx) for camera control. That's what I used with the DSLR and continue to use with the CCD now.

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I've looked and there are 2 versions of the Celestron OAG, an updated one coming out this year but I read spacing it correctly with a DSLR can be tricky.

Not sure what the basic setup would be to get this working?

Can you advise on setting this up? Is this what you refer to in the initial learning curve?

It sounds like this is the way to go, any additional help would be great. Do you use APT to guide and capture?

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This is the version that I used successfully: http://www.firstlightoptics.com/off-axis-guiders-oag/celestron-off-axis-guider-sct.html . Not sure about the new version on its way - might be worth waiting for it if it's going to be better and the price is not silly.

Yes, I couldn't use it with the DSLR and the reducer as the spacing was not right. I think that there was going to be a new adapter that would allow the correct spacing. I moved to a CCD before that arrived. The OAG comes with all the correct bits and pieces to choose from to get the right spacing for your system. Have a look on the Celestron website for the OAG manual and you will see what comes with it.

The initial learning curve is indeed just getting the set up right, then there is a bit of faffing to twist the OAG around with the guide cam active to actually find a guide star. I used a QHY5-II mono camera and always managed to find a star, but did have to move the guide cam around the OAG to get to a star. I think that a more sensitive guidecam, such as the lodestar x2, would find more guide stars without moving it. In fact, my current set up of a QSI with inbuilt OAG and a lodestar x2 has presented many possible guidestars without moving anything. I think that is down to the guidecam.

I use PHD2 to guide and APT for capture.

Hope that helps.

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Thank you both, this is very handy, it's seems like the OAG with a lodestar 2 seems like a good option but only with a dedicated CCD not a DSLR.

At present the 9.25 edge HD doesn't have a focal reducer as it's still being made so could try the latest OAG until I am able to get the Focal reducer but not ideal as might have to change this set up once this happens. Nothing in life is straight forward.

Any tips on getting the guide camera and DSLR both in focus on a OAG?

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Set up the OAG during the day on a distant object.....

Get the imaging camera to focus then don't touch the telescope focus again until you're finished!

Move the guide camera in/ out of the guide port until you can get an image...slowing tweak the positioning until it looks good.

This may require adding spacers etc.

You may find the guide camera needs to be closer to the OAG and run out of space....if this happens add a spacer between the OAG and the imaging camera - refocus the imaging camera then try again with the guide camera.

Once the guider is focused you shouldn't have to touch it again - unless you change the imaging camera...

(Not my images but ones taken from an earlier post)

post-2614-0-63222200-1414094414.jpgpost-2614-0-70295800-1414094514_thumb.jp

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