Astroguy99

Hi guys, I'm looking to buy a guide scope pretty soon, up to maybe £70-80 at the top end. I have a Skywatcher 130PDS OTA on the Celestron LCM goto mount from my first scope, with the ZWO autofocuser, and there's two camera options, the Altair GPCAM BASIC Colour one here, or my mono GPCAM2 (which I plan to use on the guidescope until I can get a filter wheel). I'm guessing you can just whack one in on the finder scope dovetail? What size do you guys think would work best for me? On a bit of research, 50mm looks good enough, but my concern is with getting focus onto the sensor. Would appreciate any input on that. Also, I have a SERIOUS problem with backlash. In the software and CPWI, the maximum is 99, but the actual backlash appears to be substantially higher than that, and has been since I bought it a year and a half ago, and things almost always drift, but actually not that much for say 4-8 second subs. I am looking at getting the SW AZ-GTI and a rotator at some point. Is this as good an option as just going for an EQ mount? I don't actually have a garden, so I'm lugging it to my sister's place once a week or so to get images (which I haven't actually managed yet due to still learning - and probably picking the wrong kind of things - and alignment can be tricky). I'm hoping with the guide camera at a larger FOV that it will pick up much more and be able to plate solve and sync better (as well as acting as the tracking). I'm very happy at the moment to get 100s of subs at sub-minute exposures, so that part isn't an issue for me for quite some time. I'm just thinking fund-wise and doing it in upgradeable parts rather than spending out like £500-£1000 on a really complicated and expensive mount. Will this extreme backlash be an issue, or will PHD2 compensate for that? If not, is there any other guiding software that might? Apologies for the 500 questions guys, but felt the need to explain as much as possible. Thank you

Yeah I think I understand, adds compensation on top. Which is then counteracted by the pointing model in CPWI (I assume), so it all works out. Would be nice if Celestron actually explained this stuff, especially knowing that people with little to no knowledge will be buying these cheap scopes. Was tempted to return as well! Glad I didn't!

Just an update. Slewing is within 2 arcminutes now and tracking is pretty decent, for a cheap scope anyway. Turns out it was either backlash or poor alignment...or both. Spent a few hours tonight slewing to various stars and adding them to the pointing model in CPWI and I'm really happy with the result. I've set the backlash to 90 in every direction. No idea how it works but it's working. There's still a fair amount of drift but objects are still in frame after an hour or so, which I can't complain about for the price I paid. Just thought I'd update as you guys were decent enough to reply to a relative noob to astronomy. Thanks again!! ☺️

All fantastic replies guys, thank you. The EQ N/S is for a wedge, yeah. I've actually put a spreadsheet together to calculate the field rotation rate for any given latitude, alt and azimuth, which is really helpful for seeing the maximum exposure. As someone said, the f-stop is a bit of an issue, but with a highly sensitive imager I assumed that'd help reduce the time needed. Light pollution is a bit of an issue here, but I have a screw in filter coming today which I hope helps to some degree. I've been a bit iffy about using the eyepiece to centre for alignment and used the finder scope instead. I guess that's probably a no-no thinking about it but changing focus to put the camera back in every night probably won't work for me. Also imaging from indoors without a garden seeing only 30° in alt and 50° in az probably isn't helping getting a decent alignment *anyway*. I'll do as suggested and learn to hone these skills, following some of those suggestions about how to get better - the handset is set perfectly other than that. Thanks again everyone, really appreciate it

Bit of everything really. Mainly stars and clusters at the moment since they're the only things that will plate solve and then track well enough. Maybe that's the issue, alignment error?

Thanks for the info, appreciate it. I've really only just started, I don't have the budget for more gear after only a week. I'll certainly keep the suggestion in mind for a few months down the line. I was really only trying to find out if maybe there's a hardware or driver problem since it won't even reliably track for more than a few seconds with a DSLR

Hi all, been looking around here for a few weeks now trying to get my head around how to get started. I have a Celestron 60LCM refractor and an Altair 130 mono camera which I'm loving using and seeing things I'd never see with my own eyes in suburbia. My question.... I'm not sure why, but the mount really doesn't track well at all. I've got it connected to Sharpcap and Stellarium for slewing both through the POTH hub driver, but for whatever reason, it really has a hard time. In fact, I can see the RA and Dec drifting in Stellarium when it does this. I've tried one, two star and three star alignments but nothing seems to keep it on track. I can't use plate solving very well either because I can't get enough exposure for enough stars without the trails (I'm aware there's field rotation, that's not the issue here). The mount I definitely tracking as I can hear it, and the trails are a lot less than when it's not. I had it working perfectly one time but for the life of me I don't know why slewing afterwards without changing anything else it just went again. I'd appreciate any help anyone can offer to a real noob, but I'm seriously hooked and want to learn :)