autoguiding

[ttgib]

Hi all, i.m doing a bit of imaging and setting up a autoguider.

I have a eq6 pro with a 80mm ed skywatcher refracto, i have a old 114mm reflector, can i use it to autoguide with or must i use short tube refractor?

Regards

ttgib.

[RikM]

I would expect you can use pretty much anything as a guide scope provided you can see stars and the tube/lens/mirror doesn't flop around. Short refractors are generally regarded as the best I guess because they give nice round star shapes and don't put much extra strain on the mount.

[ttgib]

Nice one my friend, i give it good clean n give it a go n save some coin.

Kind regards

ttgib

[ollypenrice]

Worth a try but an ST80 is disgustingly cheap and won't create issues from mirror shift. This will be a real risk. But suck it and see.

Olly

[angusb1]

Good luck and let us know how you get on.

[RikM]

What is it about the ST80 that makes it so suited to guiding? Good field of view, no image shift, light and easy to mount, no diffraction spikes, good price, nice paint job...is there anything more technical or is it a case of add up all the desirable features and this little scope ticks all the boxes?

[ollypenrice]

What is it about the ST80 that makes it so suited to guiding? Good field of view, no image shift, light and easy to mount, no diffraction spikes, good price, nice paint job...is there anything more technical or is it a case of add up all the desirable features and this little scope ticks all the boxes?

All true but I think you missed the really big one. F5.

Olly

Oh, you get a free extension tube as well once you have given the barlow lens element to the bin men.

[ttgib]

Worth a try but an ST80 is disgustingly cheap and won't create issues from mirror shift. This will be a real risk. But suck it and see.

Olly

Mirror shift ey, never thought of that when autoguiding, this will cause to much mount correction giving poor images during long exposures, totally opposite to what i,m trying to achieve.

ttgib.

[Psychobilly]

Isn't mirror shift more likely in scopes that are focused by moving the primary like SCT's and Maks ?

[cpartsenidis]

Hello to everyone!

I've been doing my research and need to ask the experts here on their opinion.

I've got a SkyWatcher Equinox 120ED with a CGEM and are looking to get involved in Astrophotography. I've concluded that a separate guide scope with a CCD is my best option for guiding. This will be piggybacked on top of my Skywatcher. A DSLR camera will be used for imaging.

My problem is that I am unable to decide what guiding package I should use. I've read about the telescope resolution and how the CCD camera should have twice of that the telescope has, however I don't know what the best combination would be.

As additional information, I would prefer if the guide camera can also be used for planetary imaging as it would be a plus. For that, I wouldn't mind spending a bit more extra money on the CCD as having a double-role would be a best value for money.

I'd really appreciate any feedback and suggestions by other experienced users who have gone down this path!

Many thanks in advanced.

[ollypenrice]

You can forget about the relative resolution business. Cameras like the Atik Titan, QHY5 etc will all do a good guiding job. Just bung it in the back of a seriously bolted down ST80 (lock the focuser as if it contained Jack the Ripper) and enjoy yourself. Even little finder-guiders can cope at around a metree of FL. Keep well away from expensive and flexible guide rings.

Olly

[cpartsenidis]

Olly,

Thank you for your reply.

Is the ST80 the SkyWatcher StarTRavel 80 you are referring to ?

[Freddie]

Yes ST80 is the startravel 80. As already said, a great little scope for guiding.

[cpartsenidis]

Thanks for the confirmation Freddie!

It seems like a 80mm scope will do the job. Coming to the CCD/Guider the Atik Titan suggested by olly seems to have a larger pixel size in comparison to the QHY5, however the QHY5 has an 8bit converter, while the Atik Titan has a 16bit converter.

Does the converter play a bit role in the camera's performance?

Also, would ther Orion StarShoot Planetary Imaging Camera and AutoGuider be considered an good alternative to the QHY5?

Thanks for your input!

[cpartsenidis]

Oh .. sorry, it seems like the Orion StarShoot Planetary Imaging Camera and AutoGuider has been discontinued! Doh!

[FrankieValley]

Have you thought about making a finder guider? Accessories @ Modern Astronomy have finder guider adapters. I finder guide my Evostar 100ED with a QHY5 and I never struggle to find a star. I use PHD and it guides forever (haven't gone past 10mins as haven't needed longer exposures, but stars are round as round things).

I did use my ST80 for a bit, but it is so much lighter and easier to throw the finder guider on rather than have piggy back this, dual mount that.

[cpartsenidis]

David,

Funny you mentioned using the finderscope. A friend had suggested it a couple of months ago with a QHY5 It seems like it is a popular and recommend choice. I have a Explore Scientific finder scope 9x50 (Explore Scientific Illuminated 8x50 Finder Scope - OPT Telescopes) - do you recon it can be adjusted to fit a QHY5 on it ?

[FrankieValley]

David,

I have a Explore Scientific finder scope 9x50 (Explore Scientific Illuminated 8x50 Finder Scope - OPT Telescopes) - do you recon it can be adjusted to fit a QHY5 on it ?

Your best bet is to call or drop a line to bernard@modernastronomy.com. I don't see why it wouldn't work with one of his 'T Mount Adapter for Straight Through Finders'. It looks like it probably has a standard barrel. I'm sure Bernard will accept the adapter back within 7 days if it doesn't fit

[cpartsenidis]

David,

I've already sent and email - I'm hoping for a positive answer as this will most probably be my solution.

Thanks for the tip - I'll post my findings.

p.s Will I also be able to use PEMPRO v2 with the QHY5 as well?

[FrankieValley]

p.s Will I also be able to use PEMPRO v2 with the QHY5 as well?

I don't know, but after listening to a (web posted) presentation by Craig Stark (PHD) on guiding, I don't worry about PE. He said that PHD (and other good guiding applications) will guide out PEC..... and he should know. I've certainly never seen any periodic problems - either watching my PHD graphs when guiding or in the results.

By the way, I use the Ascom drivers for my QHY5 with PHD. I had problems if I tried to use the Win drivers and the QHY selection in PHD. You can install both types of driver and use them for different apps, but just to say I use the Ascom ones for PHD.

Another thing I learned the hard way is that the 'tracking rate' set for your mount is important. The setting is x.25, x.5, x,75 or x1.0 of the sidereal rate. PHD has to 'calibrate' and find out how far the mount moves when it tells it to. If calibration takes longer than 20 steps, then increase the tracking rate until you get calibration done in 12 steps +/- 5 or so. basically, you don't want the mount moving very fast and far for a guide pulse and similarly you don't want it moving slowly and hardly anywhere.

[cpartsenidis]

David,

Further research shows that the QHY5 is the same product as the Orion Starshoot Guider. So either choice would be pretty much the same product, right?

Any suggestions?

p.s I've also taken note about the tracking rate issue. I'll certainly check this up once I have my setup ready.

[FrankieValley]

David,

Further research shows that the QHY5 is the same product as the Orion Starshoot Guider. So either choice would be pretty much the same product, right?

Hi Chris,

I think you are right in that they are basically the same hardware. PHD supports the Starshoot camera, so it should be fine. Orion actually make a finder guider for the Starshoot, but it looks like this would need a 1.25" nosepiece attaching to the camera to fit their particular finder guider Orion Mini 50mm Guide Scope - SCS Astro

[FrankieValley]

I have a Explore Scientific finder scope 9x50 (Explore Scientific Illuminated 8x50 Finder Scope - OPT Telescopes) - do you recon it can be adjusted to fit a QHY5 on it ?

Chris,

If you have a SW or Celestron findercope and the eyepiece portion will screw into your illuminated finderscope barrel, then you should be ok for thread sizes and the adapter will at least fit.

[cpartsenidis]

David,

Considering a guide scope, would you believe there would be any benefit using a APO type scope? I was considering the William Megrez 72 f/6 Doublet APO with 2" DDG focuser.

Would this be a pure wait of money or are there some real benefits ?

I could possibly also use this as an imaging scope if I got tired of carrying around my 120ED

I'd like to hear your thoughts on this.

Thanks!

[FrankieValley]

David,

Considering a guide scope, would you believe there would be any benefit using a APO type scope? I was considering the William Megrez 72 f/6 Doublet APO with 2" DDG focuser.

Would this be a pure wait of money or are there some real benefits ?

I could possibly also use this as an imaging scope if I got tired of carrying around my 120ED

I'd like to hear your thoughts on this.

Thanks!

Hi Chris,

You really want a mono guider, although colour will work, mono is better as you will get a better 'core' to the guide star without any colour distortion from the guide scope optics. An APO will be better if the guide scope camera is colour, but if budget is a factor then a mono guide camera and an achromat will work very well.

That said, a William Megrez 72 f/6 Doublet APO with 2" DDG focuser would make a superb wide field imager and an excellent guide scope for mono or colour guide camera, I would think.

I've never guided with a colour guide camera, this is what I have read and it makes sense and it is a good question you ask.