PHD question

[kookoo_gr]

i am imaging with a 1200 f/6 newton and i am trying to guide with an spc900nc unmod and a 70/500 refractor at an heq5 pro - eqmod. the issues i am having are these:

my first attempt at imaging the core of m95 was successful a month ago but the last week when i tried to image M95 at leo after polar alignment and a 5 star alignment i tried to find a guide star with phd but i was unable to do so. i know the ccd sensor is not as sensitive as a qhy5 but as i was trying to find ρ Leo i was unable to find it even when i increased the sampling time at 2.5 sec, the screen was completely white (i live at an area with little light pollution and all my equipment was perfectly aligned) also when i centered at Regulus and started calibration i had the message calibration failed the star did not move enough.

the only setting i changed at the advanced screen was the calibration step from 750 ms to 2000 ms

after a 5 hour attempt i centered at Alnitak and i still had the same calibration error. at the end of my disappointing and frustrated photo session i accidentally found that if i have the eqmod running and connect to the telescope via phd it loads another eqmod and i get calibration error. the only way around this is to close eqmod and start phd and connect my telescope via phd. only then i won't get a calibration error. also i changed the compatibility of all the programs to winblows () xp sp2 and run them as administrator at my vista laptop

my questions are how far or at what mag should a star be from my original target in order to find a guide star with my current setup? i am also open to suggestions on how to find a guide star and what settings should i change at phd apart from buying a guide camera which is a bit out of my budget at the time being

thanx in advance

[Glider]

StarPusher, have a look at the last post in the thread, "Dec spikes, what does this mean?" in \Imaging\Discussion.

[Glider]

StarPusher, have a look at the last post in the thread, "Dec spikes, what does this mean?" in \Imaging\Discussion. Euon's worm gears were loose.

[Glider]

kookoo_gr, Google for a program called 'New Astonomy Press CCD Calculator'.

It lets you superimpose the calculated FOV for your camera/scope combination on a library of object images. It'll give you an idea if you should expect to see a star in the guider FOV.

Whether it's bright enough, that's a question someone else may know how you find out.

For comparison, I guide with a 9x50 finderguider. Its FOV is wider than yours, I've never struggled to find a star, plus allowing for its aperture I've also not struggled to find one bright enough.

[kookoo_gr]

glider i already have the New Astonomy Press CCD Calculator and it has helped a lot. anyway when the sky clears i will try with my 9x50 finder scope

[kookoo_gr]

searching for answers for my guiding issues i stumbled upon the videos by stark labs Index of /movies. the most interesting video is the Guiding on the Cheap (NEAIC 2008) its about an hour of presentation (about 100mb) but has interesting info on guiding. i will it a another go when the clouds clear

[starpusher]

Glider /kookoo_gr,

Daft question probably .... but how do you connect your guide camera to the finder scope?

Regards,

Richard

[dark knight]

Kookoo - Does that mean you can't use Stellarium or other planetarium software providing Goto at the same time as PHD??? ...If that is the case it would explain why I also struggle with the same error message you get..

[kookoo_gr]

i connect the camera to my 70/50 guidescope focuser with a 1.25'' adapter and also there is a 90 degree diagonal mirror. its placement is very sturdy.

in order to place the camera at my 9x50 finder i unscrewed the rear lens and i have made an adaptor made out of plastic to place it at the rer of the finderscope, outer diameter 50mm inner diameter 31.2mm, i think, and thickness 3mm. in order to secure the camera i use some bungee cords (still trying to figure this one out on how to make the camera more secure and steady at the finderscope) . as i said before i still haven't tried my fiderscope yet.

[kookoo_gr]

dark knight you can run CdC or Stellarium with no problem along with phd. my issue the last time was that while connected to my telescope with CdC or stellarium i connected to my spc990nc with no problems via phd, when i tried to connect to my telescope at phd it started another EQMod session and i had to terminate one of the two sessions with the command kill eqascom. i checked to see if my telescope run at sidereal and it was ok. when i tried to calibrate i had the calibration error. so what i did was shut down all astro software i run at the moment. i started phd, connected to my camera, connected to my mount and the calibration passed with no problems. then i started CdC and i had no problem to take a 3 min guided frame at orion. I also had all the comatibility options set for win xp sp2 and run them as administrator

[Glider]

As per Kookoo-gr I unscrew the rear lens from the finder tube. I have an adaptor made out of plastic permanently sitting up the inside of the tube bore, outer diameter about 50mm(a tight fit), inner diameter 31.2mm, 40mm long. About 10mm from the end of the tube I've drilled and tapped right through the tube and adaptor. When the camera is in the adaptor I clamp using a long bolt.

If I remove the camera and put the rear lens back in then I've still got a functioning finder scope.

The camera butts up about 5mm from the end if the tube so I've got a few millimeter of manual in/out focus.

This supposes I've removed the objective locking ring and screwed the objective lens assembly as far onto the tube as it will go.

[dark knight]

I removed the whole back lens assembly, I then used a lathe and machined a standard 2" to 1.25" eye piece adaptor so as to be a tight fit in the finder scope tube. My adapter has a compression ring fitting on the 1.25" end and it is into this that I put my guide camera. I can always remove the camera and put in a 1.25" eye piece (preferably an Illuminated cross hair one).

[kookoo_gr]

last night i made another attempt with my 9x50 finder scope and i found that if i set the camera properties to full auto exposure the camera works fine and it finds one star after another, i tried a calibration near m51 and it didn't work (probably because it was near the north) but at leo i had no problem at all after i changed the step at 2000ms and looped the image at 1.5 sec.

[dark knight]

Hi Kookoo, keep increasing the step up to 3000 (think I use up to 4000) or higher when near the pole. Because the star doesn't naturally appear to move very much a higher step is required.

Hope it helps.

[dark knight]

Glider, I ended up cutting 10mm off the finder tube, this allows me to use the front focusing ring for some fine adjustment of focus.

[starpusher]

I tried checking the HEQ5 mount tracking over the weekend. This was with the f2000 newt a 2 x Barlow and the f12.5mm illuminated recticle eyepiece. I selected a relatively bright star, low down in the south. The balance was good, slightly east heavy. I switched on the PEC training and went through the procedure for the required 10.5 minutes until it bleeped telling me that the record was complete. During the training, I had to correct the RA with the hand controller to keep the star in the recticle square. The DEC looked pretty good and the star did not move out of the square in North / South for the full 10.5 minutes.

I then selected “sidereal +PEC” for the tracking and watched the star for about 5 minutes. I was surprised and a bit disappointed to see the star drift out of the recticle square in the RA sense. I expected the PEC to keep the star within the square. I then switched to “sidereal” only and it again it drifted but in the opposite direction and by about the same amount. I repeated the whole procedure but the results were about the same i.e. the PEC does not keep the star in the recticle and drift is reversed when tracking is on sidereal alone. Even more surprising when I operated the DEC (because by this time the star was moving North/South to the edge of the square) the mount not only moved in DEC but it started and continued to move in RA ! This RA movement rapidly moved the star out of the rectcle and only stopped when I operated RA via the hand controller to bring the star back into the recticle.

I experimented further with this and found that this RA “triggering”, on operation of the DEC, did not occur on when the tracking was switched to sidereal, it only occurred when the sidereal + PEC was selected.

I thought that the PEC training may have sorted out my guiding difficulties and this is why I have been experimenting but it seems that there is some fault with the mount tracking and it may well be that fault that is giving the guiding difficulties.

Regards,

Richard