Qsi wsg off axis

[libraryman]

Hello all, can I ask if anyone uses a Qsi wsg camera off axis?

ive had my 583 for years and always used a guide scope...I’m considering putting my qhy 5Lii mono in the guide port but I’m wondering how my  filters will effect focus when I change between narrow band and lum for focus routines 

anyone knowledge of this?

 

Ray

[geoflewis]

Hi Ray,

I have the 583wsg-5 and use a lodestar x2 in the OAG port. I mostly do LRGB, sometimes adding Ha, but don’t have other NB filters, so don’t know if their focus position is significantly different. I’ve never had any issues with the lodestar going out of focus on filter changes enough to affect guiding, but I do pause guiding when running autofocus routines, as that can take out any dim guide stars that I might have to use with the small FOV of my C14.

Good luck, Geof

[Dr_Ju_ju]

I don't know the camera, but from what I've seen on QSI site, the guider port is pre the filters, so won't be affected....

[sloz1664]

Hi Ray,

Although I don't use the QSI, I do use OAG's on both my Tall 200K and my WO 71 Star. With regards to focal points of various filters, it depends on whose software you are using for your imaging. On both MaximDL & SGPro you can set the focal distance per filter. Once selected the filter will be within the tolerance required for auto focusing. The guiding focus will not be affected by the small focus movements required by each filter.

Steve 

Edited August 26, 2019 by sloz1664

[Guest]

Hello, as DR_JU-JU did already  claim, the PRISM for the AUTOGUIDER (OAG) is in the front part of the CCD, the FILTERS are behind the OAG-PRISM., hence the filters will not effect the OAG functioning.. See the link below and the chapter "A WORTHY QUESTION" 

http://www.astronomy.com/~/media/Files/PDF/Equipment reviews/2011/0711 QSI 583 CCD.pdf

 

Cheers

Martin

[libraryman]

Thanks all for the replies...it is correct to say the prism is in front of the filters, however; when the filter is changed, the focuser offset means that the focuser May travel in...or out...and it’s thisaspect that changes the guide scope focus!

ive fitted it for a trial tonight...I’ll set it up when thescope is infocus for the ha filter, the Astrodons I have are not perfectly par focal, but close enough...it’s the Lum filter that I use for focusing that might be the issue.....if focus is out by a good margin on the lum, it won’t matter...but yes...I agree...pause guiding during auto focus...if it actually works in sgpro!,,

 

thanks again all

 

Ray

[Dr_Ju_ju]

For guiding, as long as you've adjusted the guide camera to be roughly focussed with the main camera, small deviations won't matter.... in fact there's a train of thought that says the guide camera should be slightly de-focused..

[steppenwolf]

I don't think this will give you any problem at all  - autoguiding doesn't require perfect focus, in fact, there is a strong argument for using a slightly de-focused guide star as this can make it easier to determine the star's centroid. I use from 3nm Ha through to Luminance using three different makes of filter with my QSI 683 WSG 8 and autofocus using the OAG is very straightforward.

[libraryman]

Hi all, indeed it was so easy to convert, I had some 2 years ago tried a brief foray into using my qhy5Lii on the QSI but abandoned it.....why oh why did I do that?

The Caméra was actually very close to focus and with the longer fl....Tak reduced to F/3.8...it has improved the accuracy of my guiding....

the out of focus Lum filter is still used for auto focus and SGpro allows me to pause guiding during focus routines!

Ray

[geoflewis]

Excellent news Ray, OAG makes a big difference in guiding accuracy, so glad you got it working 

[libraryman]

Cheers Geof

Ray