8" SCT

[Joshelerry]

Hi can anyone advise between Celestron 8" SCT on CG5 vs Meade 8" LX90 on alt-az
1) I mean is it easy to align the telescope in sg light polluted area?
2) Possible to do long exposure ap on alt-az motorised mount?
3) Brand comparison between the two?

[ivan]

1. I have used the CG-5 before, and it's quite easy to align the GOTO. All you need is 5 stars (2 alignment+3 Calib) to get a good alignment.
2. Very unlikely. You'll get problem with field rotation, and the tracking will be far worse than an equatorial mount. Even on the CG-5, you probably won't get more than 30 sec of exposure with good polar alignment. Not to mention the long FL of SCTs will magnify tracking errors.
3. Never used the Meade before. OTA wise, the performance should be nearly identical.

[Joshelerry]

Thanks..

Btw how hard is it to get polar alignment in condition in sg.. Do we need polaris or any other stars..?

[bornfree]

polaris is around 1 degree off the horizon and we can hardly see our horizon so it has always been a rough estimation. using star drift alignment, you can correct the star trails and get it as close to polar align as possible.

[orly_andico]

not sure about the 8" but the Meade 10" is really, really heavy - heavier than the C11.

So better to stick to Celestron, a heavier telescope will require a more expensive mount to carry it stably.