Guiding with a Finderscope and ASI120MM

[BarnMiguel]

Hi all,

I had a go at imaging M45 last night and thought I would try my using my finderguider as its quite bright and should be easy to find a guide star. I polar aligned with EQmod which worked really well but when I fired up PHD and increased the calibration step to 2500 I got the error "Star didn't move enough". I've used these settings before and got further in the calibration (although dew put an end to that) but not this time. My polar alignment was pretty poor the previous time but no matter what I tried by increasing the steps further it wouldn't work. Is this a case of using different settings or should I decrease the sensing area size on the ASI? I've been using the full sensor and I so I tried 1280x960 first and then 800x640 but before I could try anything else dew stopped that try as well.

Here's the settings I use at the moment. I've seen a few tutorials around about guiding with a finderscope which is why I've used these settings but could do with some advice in case I'm forgetting something important!

Thanks in advance,

Mike

[JamesF]

I don't think changing the resolution will help because you're just using a smaller area of the camera sensor. No idea why it would refuse to calibrate though. You weren't attempting to guide on a hot pixel?

James

[BarnMiguel]

Thanks James that makes sense. It wasn't a hot pixel as I was guiding on Alcyone! It did move, just not enough to reach the edge of the green square. Would it make sense to reduce the size of the search region? To be honest I haven't a clue.

[lensman57]

Hi all,

I had a go at imaging M45 last night and thought I would try my using my finderguider as its quite bright and should be easy to find a guide star. I polar aligned with EQmod which worked really well but when I fired up PHD and increased the calibration step to 2500 I got the error "Star didn't move enough". I've used these settings before and got further in the calibration (although dew put an end to that) but not this time. My polar alignment was pretty poor the previous time but no matter what I tried by increasing the steps further it wouldn't work. Is this a case of using different settings or should I decrease the sensing area size on the ASI? I've been using the full sensor and I so I tried 1280x960 first and then 800x640 but before I could try anything else dew stopped that try as well.

Here's the settings I use at the moment. I've seen a few tutorials around about guiding with a finderscope which is why I've used these settings but could do with some advice in case I'm forgetting something important!

Thanks in advance,

Mike

Hi,

I use both the MC and MM with a 50 mm guider scope with my 80 ED, 100 ED and I have had good results up to 1200s guiding with GPUSB and EQ5 pro provided the balance is spot on. I attach an image of my settings but you need to experiment with them and fine tune them to your set up. Hope this helps.

Regards,

A.G

PS: I use the 640 480 setting in the driver dialog with phd capturing at between 1s~2s depending on the seeing. Both the scope and the finder have anti dew heaters even in the summer.

[JKB]

Hi

Are you using EQMOD for control or just polar alignment? I only ask because I have had the same problem for ages. Just needed to tweak the Pulse guide setting (top right hand corner of EQMOD) up a bit

Cheers

Jamie

[orion69]

Did you tighten the axis clutches?

[JamesF]

Did you tighten the axis clutches?

Oooh, you'd feel such a fool, wouldn't you?

James

[BarnMiguel]

I used EQMod for polar alignment but use the handset for star alignment and then go back to EQmod control so I'll try tweaking the pulse guide setting.

I did tighten the clutches yes. At least I'm pretty sure i did

Looks like I have some things to try for next time, fingers crossed as I've been trying to get guided images for what seems like ages! Thanks again for the suggestions.

[JKB]

Yea I couldnt get the thing to calibrate at all. Heard all the right noises but nothing happened.

Ill go take a screenshot and post up in a bit

Cheers

Jamie

[JKB]

Heres my EQMOD screen.

Numbered 1 is the Pulse Guide settings that I had to up to x0.40 and x0.50 to get the star to move at all. Number 2 I use after everything settles down and guiding. These sliders adjust the amount of guiding sent to the mount and I usually tweak them to get a flat line (ish) in RA and DEC. (normally around 40 to 60%)

HTH

Cheers

Jamie