First night with guiding - what a waste of time

[bamus]

Yesterday I got finally clear sky (despite Met office forecast) . First time for weeks in Essex and unfortunately it was wasted as from 2000 to 2300 I have tried to get guiding working without any sucess.

I think I may have done something wrong. Let me describe my procedure:

- Polar align my telescope

- 3 star alignment using Hand Controller

- Choose M45

- Connect mount to my netbook through Hand Controller (USB to RS232).

- Choose Direct PC mode on my Hand Controller

- Start Metaguide software

- Connect to mount through Metaguide - connection successful

When I tried to calibrate star, calibration was taking ages – 20 minutes and progress bar was not moving, then I have switched to PHD guiding. Calibration was not successful and error message showed up – NOT ENOUGH MOVEMENT IN RA.

I have got few ideas why it might went wrong, would like to ask you for a help – I do not want to waste another clear night (if we will have one in February L )

- I think that I should not do 3 star alignment using my Hand Controller because ASCOM is not reading current position of mount/telescope while trying to calibrate PARK position coordinates were used (declination close to 90 might caused problems)

- Because I am using SW finder scope I was thinking that maybe focal length is not long enough, but on the other hand, many other users are using finderscopes and it was working fine.

- Shall I do alignment using Stellarium so ASCOM and guide program will know correct coordinates?

Thanks in advance for any advise

Brg

adam

[SteveL]

for PHD, increase this setting, which moves the mount further per step. The not enough movement error indicates this is probably the issue here. You may need to increase it QUITE A LOT.

(The star you selected was actually moving while calibarting, albeit it very slowly, right?)

[bamus]

for PHD, increase this setting, which moves the mount further per step. The not enough movement error indicates this is probably the issue here. You may need to increase it QUITE A LOT.

(The star you selected was actually moving while calibarting, albeit it very slowly, right?)

yes, it was moving little bit. I have to try your recommendation.

Does it mean that alignment is not an issue here?

[SteveL]

probably not an alignment issue, it just meant that the star you selected to calibrate on didnt move far enough to give PHD a better idea of how to guide the mount.

PHD is telling the mount to move "at guide rate" for so many milliseconds, and then working out how the star has moved. It then repeats this until it is satisfied it has enough information (I believe with PHD it needs the star to move at least 5% of the chip area, or might be 10%).

The shorter the guide scope (i.e. the wider the FoV), the higher the calibration step number will need to be. I had 1700ms when I had my William Optics 66, but have seen much higher figures with finderscope guiding.

Also, it is dependent on what guide rate you have selected in your handset. Slower guide rates will require a higher calibration step size.

[lukebl]

As you're using a finder scope for guiding, I'm guessing that it has a pretty short focal length. I'd therefore suggest setting the calibration step as 2000 or even higher. I suspect that's the problem.

[r3i]

+1 for Steve's & Luke's suggestion. You need to crank that value up - try at least 2000.

Before getting my EQ6, I briefly tried using a finder-guider arrangement on my LX90: I recall having the same problems you did with both PHD & MetaGuide. Bumping up the calibration step in PHD sorted it out. For MetaGuide, I'm sure there'll be some setting or other to do a similar thing, but I never got round to sussing it out.

When first getting to grips with imaging & autoguiding, you can end up spending quite a while with little or nothing to show for it, whilst you're getting everything working together, I know I did. Once you've got the parameters and your setup sequence sorted out, things should improve.

If you're like me and have to set up & tear down for every session, I would suggest writing up a checklist to help you remember each time what you need to do and in what order to get everything up and running. It's all too easy to forget a step, especially if your imaging sessions are few and far between.

[bamus]

thanks a lot for all for all suggestions!

Just checked PHD set up and calibration step was 750 only. Next time will set it to 2000 and will see what will happen.

While we are on PHD subject. I was little bit surprised that I do not have to provide focal length of guide scope and pixel size, but I guess PHD can calculate it self basad on star movement?

[SteveL]

that is correct, it moves + watches + learns... and a great way to start the guiding process.

[dlp]

Just one thing - if you want to connect other progs that use EQASCOM (eg CdC, stellarium), make sure you connect the first (eg PHD) through 'Generic Hub' and then select the mount. When you run an additional prog, just use generic hub. I think that avoids any conflicts between who's got control of the mount.

David

[r3i]

One other thing I forgot to mention about PHD and calibration step size: I've read in various places that you should tweak the step size so that calibration is achieved in around 15 steps.

[Demonperformer]

Don't feel too bad about it, Adam

OK, so first time out trying the equipment you didn't get any images. But based on that evening's problems you have gained some good advice from others and this will should make your next evening's efforts better. View it as part of the learning curve and it won't be a complete waste of time.

[bamus]

Don't feel too bad about it, Adam

OK, so first time out trying the equipment you didn't get any images. But based on that evening's problems you have gained some good advice from others and this will should make your next evening's efforts better. View it as part of the learning curve and it won't be a complete waste of time.

True, I have learned a lot actually. Imaging with guiding is completely different story comparing to simple no guided session. Need to learn new set up and way all connect to each other and procedure what needs to be done first (earlier mentioned check list seems like a good idea).

During that night I also have lost a lot of time trying to get Stelarium and EQASCOM to work together. In the end I have gave up and start trying guiding without alignment. Yesterday I have downloaded Cartes du Ciel and get no problems what so ever with controlling mount.

Tonight looks like clear night, so I will try get some results on guiding again.

brg

adam

[skywatcher1701]

hi there folks, not to hijack this thread, but i to was out the other night and had problems with phd to.

when i got all set up and done the 3 star alignment and chose my target( lets say m45) and chose a star for phd to guide on, its does the calibration and once it says guiding i take it that it should now follow that star....right????? wrong, the star moves out of the 2 lines that appear with in a few secs and then every thing starts flashing at me, the bar at the bottom of phd window, so what am i doing wrong???

have looked at older threads and seen what some of you suggest and i have done them, but when i look at the diagram that STEVE L posted, my list has a few more options???? any help would be very welcome:iamwithstupid:

[swag72]

I am a real newbie with guiding and PHD, but have encountered the problem you mention at times. When this happens, it is something to do with the signal to noise ratio being too low. Stop the guiding, and change the exposure setting that is on the right of the 'stop' button. I have found that I use it at around 1.0s but will change that if it loses the star.

Hope that helps and makes sense - From one newbie to another!

[Digz]

Great thread to read and a lot of information there. Perfect for me as I am waiting to get out and try guiding with my finderscope as soon as the sky clears.

[bamus]

hi All

last night I have finally managed to calibrate PHD in RA , but have failed to calibrate in Dec. Is there anything else what should be changed in setting?

So, I have guided in RA only and 180 sec exposures looked good to me.