Guidescope Advice Please

[teoria_del_big_bang]

Up until now my imaging rig consisted basically of:

WO Z73 + ZWO1600 MM + SX Filterwheel

Starwave 50mm guidescope + Altair GPCam

All on a HEQ5 with Rowan Belt mod.

I am now upgrading to an Esprit 100ED still with same camera and FW.

The original rig did me well but my early images were fairly short and despite having a guidecam due to issues I have gradually overcome ended up unguided as I was desperate just to get some sort of final image.

Even when guiding I did have issues with the guidescope in that bright stars had huge halos, but so long as I picked a less bright star then it did seem to guide okay throughout the night, My guiding was not perfect and this may have been down to other things beside the guidescope and I really need more sessions to get this tuned in. I am pretty new to a lot of this stuff and guiding and PHD2 is one of them so I have got it working but not yet done a lot to tune it in precisely.

But do I keep this guidescope with my new rig or change ?

Without spending more money my choices are to stick with this 50mm guidescope, or use a scope I did buy with the intention of using it as a guidescope an Opticstar AR90S F5.5, or use my WO Z73 ???

My camera for guidescope is an Altair GP130M.

I am not sure what should be my main aim here to get the best from guiding.

• Keep as light as possible (obvious what advantage this has) which means the 50 mm guidescope
• higher magnification
• Some sort of matching between the guidescope and camera pixel size

Forgive my ignorance in this aspect there is so much to learn in AP and in the short time I have had this has been put on a back burner but I think I need to concentrate on understanding this now and getting it the best I can.

I did get the Opticstar for use as a guidescope but with the Esprit and other bits I think is getting towards the top weight of the HEQ5. Yes I do intend to upgrade the mount but funds prevent this just now. 

The guidescope is 800g, the WO is 2.2Kg and Opticstar 2.4 Kg

Steve

 

 

[Ronclarke]

I have used my finder/guider scope on 3 different scopes and 2 different mounts.

Never had a problem with it but I DON'T use PHD2, I have used PHD 1.4 throughout and 

had no problem. Just my take on it but my guiding has improved since I got an iPolar PA

cam fitted!

Ron

Edited October 13, 2019 by Ronclarke

[ollypenrice]

The main thing is to ensure that everything in and around the guide scope is rigid. I have some parts of mine held solid by epoxy resin (slightly extreme but they are cheap ST80 scopes). The focuser, the guide rings, all the attachments, need to be treble checked for rigidity. Soft stars don't matter, within reason, and PHD prefers them to be in imperfect focus according to its author.

If the little guide scope is really rigid it should be OK. I guide a pair of parallel 140 refractors working at 0.9 arcsecs per pixel with an ST80. As ever, the only way to be sure you're guiding to the mount's capacity is to try one modification at once and see if it helps.

Olly

[teoria_del_big_bang]

1 minute ago, ollypenrice said:

The main thing is to ensure that everything in and around the guide scope is rigid. I have some parts of mine held solid by epoxy resin (slightly extreme but they are cheap ST80 scopes). The focuser, the guide rings, all the attachments, need to be treble checked for rigidity. Soft stars don't matter, within reason, and PHD prefers them to be in imperfect focus according to its author.

If the little guide scope is really rigid it should be OK. I guide a pair of parallel 140 refractors working at 0.9 arcsecs per pixel with an ST80. As ever, the only way to be sure you're guiding to the mount's capacity is to try one modification at once and see if it helps.

Olly

Cheers, yes everything is rigid whichever scope I use. 

So in your opinion, assuming all other things equal regarding such as rigidity, is there no real advantage using what is essentially a better scope, i.e better focus, less halos, higher mag. Because I guess then the choice has to be the lighter option as of course added weight can only make guiding worse.

The halos on the bright stars are really big and bright though but maybe I could help with a filter ?

Steve

[ollypenrice]

1 minute ago, teoria_del_big_bang said:

Cheers, yes everything is rigid whichever scope I use. 

So in your opinion, assuming all other things equal regarding such as rigidity, is there no real advantage using what is essentially a better scope, i.e better focus, less halos, higher mag. Because I guess then the choice has to be the lighter option as of course added weight can only make guiding worse.

The halos on the bright stars are really big and bright though but maybe I could help with a filter ?

Steve

I guess I'd be inclined to try an alternative scope. It's the only way to know for sure, unless you know you don't have a problem (as in the case of a system guiding with an RMS in arcseconds which is reliably less than half the imaging scale.

Olly

[Adam J]

I would say that a smaller 50mm guide scope does not need to be as ridged as the forces placed onto it are so much less than a larger heavier scope and hence it flexes less not because its rigid but just because it has less mass.

[Adam J]

2 hours ago, teoria_del_big_bang said:

Up until now my imaging rig consisted basically of:

WO Z73 + ZWO1600 MM + SX Filterwheel

Starwave 50mm guidescope + Altair GPCam

All on a HEQ5 with Rowan Belt mod.

I am now upgrading to an Esprit 100ED still with same camera and FW.

The original rig did me well but my early images were fairly short and despite having a guidecam due to issues I have gradually overcome ended up unguided as I was desperate just to get some sort of final image.

Even when guiding I did have issues with the guidescope in that bright stars had huge halos, but so long as I picked a less bright star then it did seem to guide okay throughout the night, My guiding was not perfect and this may have been down to other things beside the guidescope and I really need more sessions to get this tuned in. I am pretty new to a lot of this stuff and guiding and PHD2 is one of them so I have got it working but not yet done a lot to tune it in precisely.

But do I keep this guidescope with my new rig or change ?

Without spending more money my choices are to stick with this 50mm guidescope, or use a scope I did buy with the intention of using it as a guidescope an Opticstar AR90S F5.5, or use my WO Z73 ???

My camera for guidescope is an Altair GP130M.

I am not sure what should be my main aim here to get the best from guiding.

• Keep as light as possible (obvious what advantage this has) which means the 50 mm guidescope
• higher magnification
• Some sort of matching between the guidescope and camera pixel size

Forgive my ignorance in this aspect there is so much to learn in AP and in the short time I have had this has been put on a back burner but I think I need to concentrate on understanding this now and getting it the best I can.

I did get the Opticstar for use as a guidescope but with the Esprit and other bits I think is getting towards the top weight of the HEQ5. Yes I do intend to upgrade the mount but funds prevent this just now. 

The guidescope is 800g, the WO is 2.2Kg and Opticstar 2.4 Kg

Steve

 

 

You honestly dont need anything more than the 50mm mate, all you will do is make it heavy and if you can keep the weight down you will have no reason to need to upgrade the heq5.

[Laurin Dave]

Hi Steve,  does your guidescope have the "non rotating helical focuser"? if so then I'd check it for slop/rotation as I had a 60mm Altair guidescope and the helical focuser on that had a load of slop and caused guiding issues. I  replaced it with Altairs "precision autoguiding focuser" which eliminated them.

Dave

[jimjam11]

3 hours ago, teoria_del_big_bang said:

Up until now my imaging rig consisted basically of:

WO Z73 + ZWO1600 MM + SX Filterwheel

Starwave 50mm guidescope + Altair GPCam

All on a HEQ5 with Rowan Belt mod.

I am now upgrading to an Esprit 100ED still with same camera and FW.

The original rig did me well but my early images were fairly short and despite having a guidecam due to issues I have gradually overcome ended up unguided as I was desperate just to get some sort of final image.

Even when guiding I did have issues with the guidescope in that bright stars had huge halos, but so long as I picked a less bright star then it did seem to guide okay throughout the night, My guiding was not perfect and this may have been down to other things beside the guidescope and I really need more sessions to get this tuned in. I am pretty new to a lot of this stuff and guiding and PHD2 is one of them so I have got it working but not yet done a lot to tune it in precisely.

But do I keep this guidescope with my new rig or change ?

Without spending more money my choices are to stick with this 50mm guidescope, or use a scope I did buy with the intention of using it as a guidescope an Opticstar AR90S F5.5, or use my WO Z73 ???

My camera for guidescope is an Altair GP130M.

I am not sure what should be my main aim here to get the best from guiding.

• Keep as light as possible (obvious what advantage this has) which means the 50 mm guidescope
• higher magnification
• Some sort of matching between the guidescope and camera pixel size

Forgive my ignorance in this aspect there is so much to learn in AP and in the short time I have had this has been put on a back burner but I think I need to concentrate on understanding this now and getting it the best I can.

I did get the Opticstar for use as a guidescope but with the Esprit and other bits I think is getting towards the top weight of the HEQ5. Yes I do intend to upgrade the mount but funds prevent this just now. 

The guidescope is 800g, the WO is 2.2Kg and Opticstar 2.4 Kg

Steve

 

 

What is the problem you are trying to solve? It doesn’t matter what phd looks like as long as it is working. If you tell phd to auto select a guide star it will pick the best one so you don’t need to worry about them being too bright.

A 50mm guidescope will easily be enough for 550mm with an asi1600...

[teoria_del_big_bang]

3 minutes ago, jimjam11 said:

What is the problem you are trying to solve? It doesn’t matter what phd looks like as long as it is working. If you tell phd to auto select a guide star it will pick the best one so you don’t need to worry about them being too bright.

A 50mm guidescope will easily be enough for 550mm with an asi1600...

I think due to lack of understanding I was thinking a better guidescope (better in respect of clarity and maybe magnification) would improve the guiding itself. Sounds like I need to stick with the lightweight 50mm and look at other things that can improve guiding.

[teoria_del_big_bang]

17 minutes ago, Laurin Dave said:

Hi Steve,  does your guidescope have the "non rotating helical focuser"? if so then I'd check it for slop/rotation as I had a 60mm Altair guidescope and the helical focuser on that had a load of slop and caused guiding issues. I  replaced it with Altairs "precision autoguiding focuser" which eliminated them.

Dave

Yes it does - I will look into this.

Steve

[teoria_del_big_bang]

29 minutes ago, Adam J said:

You honestly dont need anything more than the 50mm mate, all you will do is make it heavy and if you can keep the weight down you will have no reason to need to upgrade the heq5.

Thanks I think that makes me a lot happier and will stick with this.

Cheers

Steve

[jimjam11]

6 minutes ago, teoria_del_big_bang said:

I think due to lack of understanding I was thinking a better guidescope (better in respect of clarity and maybe magnification) would improve the guiding itself. Sounds like I need to stick with the lightweight 50mm and look at other things that can improve guiding.

Next time you are out, use the guidescope and run a new calibration. Once complete run the guiding assistant for 7+ mins and it will give you a wealth of information you can then act upon...

[teoria_del_big_bang]

Just now, jimjam11 said:

Next time you are out, use the guidescope and run a new calibration. Once complete run the guiding assistant for 7+ mins and it will give you a wealth of information you can then act upon...

I have run this but probably not for over 7 minutes, usually around 3 to 4 minutes.

I think I will stick with the 50 mm and run the calibration then the guiding assistant and post some of the graphs I get so I get some comments on what I am achieving and what I should be able to achieve.

This is pretty typical of what I am achieving.

 

[Thalestris24]

3 hours ago, teoria_del_big_bang said:

Up until now my imaging rig consisted basically of:

WO Z73 + ZWO1600 MM + SX Filterwheel

Starwave 50mm guidescope + Altair GPCam

All on a HEQ5 with Rowan Belt mod.

I am now upgrading to an Esprit 100ED still with same camera and FW.

The original rig did me well but my early images were fairly short and despite having a guidecam due to issues I have gradually overcome ended up unguided as I was desperate just to get some sort of final image.

Even when guiding I did have issues with the guidescope in that bright stars had huge halos, but so long as I picked a less bright star then it did seem to guide okay throughout the night, My guiding was not perfect and this may have been down to other things beside the guidescope and I really need more sessions to get this tuned in. I am pretty new to a lot of this stuff and guiding and PHD2 is one of them so I have got it working but not yet done a lot to tune it in precisely.

But do I keep this guidescope with my new rig or change ?

Without spending more money my choices are to stick with this 50mm guidescope, or use a scope I did buy with the intention of using it as a guidescope an Opticstar AR90S F5.5, or use my WO Z73 ???

My camera for guidescope is an Altair GP130M.

I am not sure what should be my main aim here to get the best from guiding.

• Keep as light as possible (obvious what advantage this has) which means the 50 mm guidescope
• higher magnification
• Some sort of matching between the guidescope and camera pixel size

Forgive my ignorance in this aspect there is so much to learn in AP and in the short time I have had this has been put on a back burner but I think I need to concentrate on understanding this now and getting it the best I can.

I did get the Opticstar for use as a guidescope but with the Esprit and other bits I think is getting towards the top weight of the HEQ5. Yes I do intend to upgrade the mount but funds prevent this just now. 

The guidescope is 800g, the WO is 2.2Kg and Opticstar 2.4 Kg

Steve

 

 

You shouldn't have any problems with that guidescope provided it's securely/rigidly mounted. Make sure you're properly balanced - the heq5 belt drive is sensitive to any imbalance. Take the time to learn PHD2 properly - there are plenty of video tutorials about. Make sure  you choose a suitable  guide star and exposure  -  2 to 3 secs is usually good.

Louise

[teoria_del_big_bang]

18 minutes ago, Thalestris24 said:

You shouldn't have any problems with that guidescope provided it's securely/rigidly mounted. Make sure you're properly balanced - the heq5 belt drive is sensitive to any imbalance. Take the time to learn PHD2 properly - there are plenty of video tutorials about. Make sure  you choose a suitable  guide star and exposure  -  2 to 3 secs is usually good.

Louise

Thanks Louise, I think you are right I need to learn more about PHD2. I have read a lot of tutorials and slowly bits are sinking in but unfortunately till I actually have clear skies and actually using the guiding I don't think I can jump this final hurdle wrt guiding. I will keep trying though. I tend to work one bit out and maybe make a small improvement then start imaging rather than spending all night messing about with the guiding.

Steve

[Thalestris24]

3 minutes ago, teoria_del_big_bang said:

Thanks Louise, I think you are right I need to learn more about PHD2. I have read a lot of tutorials and slowly bits are sinking in but unfortunately till I actually have clear skies and actually using the guiding I don't think I can jump this final hurdle wrt guiding. I will keep trying though. I tend to work one bit out and maybe make a small improvement then start imaging rather than spending all night messing about with the guiding.

Steve

The 'getting the most out of phd2' video tutorial is quite good. Sit and watch it (several times) on a cloudy night!

[teoria_del_big_bang]

6 minutes ago, Thalestris24 said:

The 'getting the most out of phd2' video tutorial is quite good. Sit and watch it (several times) on a cloudy night!

I will as we get plenty of them 🙂 

Steve

[michael8554]

Your 200mm FL guidescope is fine, but focus wise you should aim for an HFD of 3 to 4 in PHD2 for your autoselected star. 

Defocusing was fine for PHD1, which back then was usually used with long FL guidescope yielding tiny stars. 

The PHD2 developers say not to defocus, or saturate which gives flat tops to the profile, and often cite poor guidescope focus in their fault-finding.

If you're not getting that HFD with autoselected stars, then perhaps an IR filter is required.

Michael

[jimjam11]

52 minutes ago, teoria_del_big_bang said:

I have run this but probably not for over 7 minutes, usually around 3 to 4 minutes.

I think I will stick with the 50 mm and run the calibration then the guiding assistant and post some of the graphs I get so I get some comments on what I am achieving and what I should be able to achieve.

This is pretty typical of what I am achieving.

 

If that is typical then you are already pretty close? Assuming a guidescope your MnMo looks high, I would expect 0.2 or below with a typical 180mm focal length. Also not sure what a realistic expectation is for a heq5, I suspect around 1”...

[michael8554]

You aren't displaying the PHD2 guide pulses on your graph so it's impossible to say if the guiding is optimum. 

Michael 

[teoria_del_big_bang]

9 hours ago, jimjam11 said:

If that is typical then you are already pretty close? Assuming a guidescope your MnMo looks high, I would expect 0.2 or below with a typical 180mm focal length. Also not sure what a realistic expectation is for a heq5, I suspect around 1”...

Thanks for that and yes it is a big improvement over what I had before doing a run in guiding assistant. Although not shown I am sure I occasionally do get spikes up to 3".

Steve

[teoria_del_big_bang]

9 hours ago, michael8554 said:

You aren't displaying the PHD2 guide pulses on your graph so it's impossible to say if the guiding is optimum. 

Michael 

Yes, sorry I will ensure this is enabled next session (if the clouds do ever go)

Steve

[teoria_del_big_bang]

Many thanks to all who have replied the help is much appreciated.

Steve