Alpy+Atik314L+ guiding and imaging problem

[Jacques Montier]

Hello,

I recently got an Atik314L+ camera for Alpy guiding.
I use the guiding soft PHDGuiding-1.14 as it is able to natively manage the Atik cameras.
My first try was with a bright star (~5) and i could guide a 10-micron hps 2000 mount without any problem.
The problem raises with fainter stars as SN2014J supernova or any other faint star.
With 1s exposure, i could not even see nor star nor M82 galaxy.
It was getting worse when increasing the exposure time !
Increasing the camera gain in the PHDGuiding configuration had no effect at all.
So did some of you encountered that problem ?
What's the best configuration for efficiently using PHDGuiding ?
I also tried the Audela autoguiding function, but it does not manage ST4 port and asks for COM port.

Thank you very much for your help,

Cheers,

[Ken Harrison]

Jacques,
I use a Lodestar for guiding my Spectra-L200 on a C11/ NEQ6pro mount....
The recent upgrade to PHD 2.2 has a neat "nudge" feature for spectroscopy, and will support the ATik314.
I'm still guiding on nova Cen - 8mag with 1sec exposures, I would think 3sec guide exposures would do the job.....
Which scope are you using? It the slit gap and target star in focus?

[Terry Bohlsen]

You should be able to guide on much dimmer stars than that. I assume the guide system for the Alpy is similar to my LISA. I use a STi and can guide on a mag 13 field star with a 2 sec exposure. The 314L+ is just as sensitive. Guiding on the slit depends on how much of the star overlaps the slit. I can guide down to about mag 10 but don't usually bother and just use a field star. Idon't use PHD though. I have tried it but find it less user friendly than CCDSoft which I also use for aquisition with my 314L+. A single program running rather than 2.
Terry

[Robin Leadbeater]

I use a Celestron C11, ALPY and PHD. I am able to guide on SN2014J on the slit at ~mag 12 using a very noisy DSI pro and 2 sec exposures. It does sometimes lose lock when the star is exactly on the slit but as soon as it move partly off the slit PHD immediately picks it up again and moves it back (I can also see the galaxy core in 2 sec but only faintly)

Robin

[Paolo Berardi]

Hi Jaques, did you try to use (subtract) a dark frame in PHD? Resulting image can appear much better if there are hot pixels/columns.

Paolo

[Jacques Montier]

Hello,

Thanks to all of you for your answers.
Paolo, i do not substract dark frame ; next time i'll have a try.
Last night, i guided on some 9.3 and 9.4 stars with 1s exposure and without any problem but i did not try fainter stars.
I made some tests :
PHDGuiding and CMOS Orion PL1 :
Increasing exposure time brings up fainter stars, so ok.
PHDGuiding and CCD ATIK314l+ :
when i increase the exposure time(2s, 5s or more) in PHDGuiding configuration, i don't see any change...

[Robin Leadbeater]

Hello Jaques,

My imaging camera is the ATK314L+ so I tried connecting it to my PHD. (v2.2.0) It gave increasing sensitivity as I increased the exposure from 0.1 to 15 sec. The average brightness of the image does not change much as PHD automatically adjust this but when I imaged the ALPY calibration lamp, I could see the background (unsubtracted bias level) becoming darker, the strong lines becoming saturated and the weaker lines appearing. Perehaps there is a problem with the installation of PHD or the camera drivers. Does your ATK314 work ok with Artemis capture ?

Cheers
Robin

[Christian Buil]

Jacques, d'abord bravo pour ta super séquence sur symbiotique !
Je ne connais pas PHD, donc peu pas aider.
J'exploite Audela, mais il semble que tu a un problème
d'interface avec ta monture via ce soft, c'est bien ça ?
Faudrait interroger la communauté Audela, je suis persuadé
qu'il y a une solution.

Pour ma part, dès que l'étoile observée est plus faible que la magnitude 9-10
en gros, je me refuse de guider sur la fente. Il y a toujours une étoile du champ
qui peu aider pour celà. Il est très rare avec une Atik314L+ que je sois ammené
à guider plus de 2 secondes dans ces conditions. Sinon, bien sur,
il est impossible de faire des objets de magnitude 15-16 (on les centres
sur la fente au jugé et on ne les voit jamais lors de l'acquisition - de temps
à autre je fais une pose de 30 sec. pour controler que l'objet est en bonne
position, c'est tout).

Christian

[Jacques Montier]

Merci Christian pour tes encouragements et tes conseils.
J'étais un peu inquiet voyant dans des compte-rendus des images montrant une belle fente de spectro avec un champ riche en étoiles.
Chez moi, à part en spectro de nébuleuse, je ne vois quasiment pas la fente avec 1s de pose.
Heureusement avec l'habitude, on repère vite la bonne position de l'étoile sur la fente à son changement d'aspect.
Je met aussi un réticule qui est bien commode pour repérer la position de la fente du spectro.
En tout cas, c'est un vrai plaisir de travailler avec l'Alpy600 ; il y a tellement de choses à faire...
J'ai pu guider efficacement avec PHDGuiding-v2, mais je vais explorer la piste autoguidage d'Audela.

Robin, i also tested PHD v2 with Atik460EX on calibration light and you are right.
With 1s, 2s, ....15s exposure, the brightness did not change much but the background was getting darker.
Here are some results :
PHD did not give me any information about CCD temperature.

test_audela.png (666.38 KiB) Viewed 8165 times

test_phdguiding.png (43.96 KiB) Viewed 8165 times

Cheers,

[Ken Harrison]

Paolo and I have been working with Fabio at AstroArt and Andy at PHD to make improvements to their guiding software...
Both now include a "nudge" function which allows you to set up the guide cross-wire on the slit gap and tweak the target star onto the slit.
Not exactly split-star guiding (yet) but does help.