I am having trouble with oblong stars away from the centre again so I am wondering about getting an OAG. Can anyone recommend a suitable OAG and guide camera for a Skywatcher 200pds and 130pds with Explorer Scientific coma corrector? My main camera is a ZWO ASI 2600MM-pro. ZWO types would be preferred but others considered. Thanks for an advice.
Suitable OAG and guide camera for 1000mm Newtonian
Oooh Man,
isn't this a loaded question 🤔
I was thinking of going down the same road myself with a 130pds on a Az-eq6.
After a lot of research, I don’t think I’d benefit by much.
The science behind Phd2 and how it works, you should have no issues with your setup.
I realise that you probably did a lot of head scratching before post this query.
There’s better people able to answer what’s going on with your star shapes.
At first reading your post , I thought coma. But had a look at your latest image of the Leo Triplet and now not so sure if it represents coma because they don’t seem to be elongated from the center. ?
( Great image though 👍)
If guiding was poor , would your stars not be more bloated than oblong?
Theres lots of resources that can check for tilt, collimation , focal length check etc…
Here’s one…
https://astrometry.net
I’m sure others will chime in and point the way forward before spending Dollars 💵
regards,
Padraig
isn't this a loaded question 🤔
I was thinking of going down the same road myself with a 130pds on a Az-eq6.
After a lot of research, I don’t think I’d benefit by much.
The science behind Phd2 and how it works, you should have no issues with your setup.
I realise that you probably did a lot of head scratching before post this query.
There’s better people able to answer what’s going on with your star shapes.
At first reading your post , I thought coma. But had a look at your latest image of the Leo Triplet and now not so sure if it represents coma because they don’t seem to be elongated from the center. ?
( Great image though 👍)
If guiding was poor , would your stars not be more bloated than oblong?
Theres lots of resources that can check for tilt, collimation , focal length check etc…
Here’s one…
https://astrometry.net
I’m sure others will chime in and point the way forward before spending Dollars 💵
regards,
Padraig
Respectful Engaging Supportive
I am having trouble with oblong stars away from the centre
If it is getting worse away from a point tracking and/or guiding got nothing to do with, it's collimation the issue.
Padraig,
The image you looked at comprises 2 images, one with rounder stars than the other so the effect is reduced. I know polar alignment according to Sharpcap is <1 arc min out and the mount is as vertical as I can make it. Collimation is as good as it can be with a Cheshire eyepiece. Star shapes have suddenly got worse since I moved the gear to the garage and back. Tilt is an issue with my make of camera but in the past I thought it was OK. Guiding is OK I think with multi star guiding with Lacerta MGEN 3 but flexing could well be an issue. Thanks for looking.
The image you looked at comprises 2 images, one with rounder stars than the other so the effect is reduced. I know polar alignment according to Sharpcap is <1 arc min out and the mount is as vertical as I can make it. Collimation is as good as it can be with a Cheshire eyepiece. Star shapes have suddenly got worse since I moved the gear to the garage and back. Tilt is an issue with my make of camera but in the past I thought it was OK. Guiding is OK I think with multi star guiding with Lacerta MGEN 3 but flexing could well be an issue. Thanks for looking.
Moorefan
“Collimation is as good as it can be with a Cheshire eyepiece”
I do the same myself and tried a hotech laser but still I see a small bit out which for visual astronomy can be dialled out with high power eyepieces. But if your on the second night imaging a DSO, I rather live with, rather than taking the camera off to check again.
I need to figure out a way using maybe sharp Cap.
“Collimation is as good as it can be with a Cheshire eyepiece”
I do the same myself and tried a hotech laser but still I see a small bit out which for visual astronomy can be dialled out with high power eyepieces. But if your on the second night imaging a DSO, I rather live with, rather than taking the camera off to check again.
I need to figure out a way using maybe sharp Cap.
Thanks for the advice so far. The original question remains though. Can anyone recommend a suitable OAG and guide camera for a Skywatcher 200pds and 130pds with Explorer Scientific coma corrector? Which coma corrector may not be relevant.
If u've the ZWO EFW then u can take a ZWO OAG M68 (small prism) anche the ASI290MM. I used this combo for 1 year with a 115/800 without problems and with 0% of wrong light.
OAG is another level of guiding.
Actual with the RC8 i'm using the OAG-L (big prism) with an ASI174MM.
At 1000 mm with ASI290MM u've no problem to find guiding star, of course with OAG-L and ASI174MM u see more and more stars (at 1600 mm i see 8-12 stars each time).
OAG is another level of guiding.
Actual with the RC8 i'm using the OAG-L (big prism) with an ASI174MM.
At 1000 mm with ASI290MM u've no problem to find guiding star, of course with OAG-L and ASI174MM u see more and more stars (at 1600 mm i see 8-12 stars each time).
Thanks for the advice so far. The original question remains though. Can anyone recommend a suitable OAG and guide camera for a Skywatcher 200pds and 130pds with Explorer Scientific coma corrector? Which coma corrector may not be relevant.
I've just ( in the last 2 weeks) installed the ZWO OAG V2, the ZWO helical focuser (makes life much easier when setting up) and a ZWO ASI290MM MINI on my 200PDS with skywatcher 2" coma corrector. My guiding has gone from just over 1 arc secs to about 0.5 arc secs. I haven't had any problems finding guide stars so far. If the guide camera sensor was any smaller than the 290MM, then I think it may be more of a challenge.
Helpful Concise
Thanks for the help everyone. Much appreciated.