EQ Mount Tracking

[twelly27]

Hi All

Im saving my money to buy a EQ3 GOTO mount im wondering how long they track for? or is that a silly question, i dont really understand the tracking on any EQ mount tried stacking about half an hours worth of orions nebula but tracking on my mounts is not good enough anyone have any thoughts?

Regards

Chris

[nephilim]

I suppose it all depends on the accuracy of your PA.

Steve

[sgazer]

Don't know how much you already know, but the SynScan Az GOTO has to track in 2 directions, left/right (AZ), up/down (ALT), so it sort of tracks in a very fine zigzag to counter the rotation of the earth, which is along it's polar axis. The ALT/AZ tracking is dependant on the software map of the sky, star alignment and both axis tracking motors, so you'll only generally get 30-60s exposure with say a 250mm lens. But with ALT/AZ, you'll also get field rotation, where the stars rotate around the centre of the image, at the earth is rotating and not going in a zigzag!

The EQ mount has the advantage, that as long as you've aligned it precisely with the earths axis (polar aligned), it only has to track in one axis (RA) at the same speed the earth is rotating. How long it will track satisfactorily is depending on the polar alignment, tracking motor/gear accuracy and scope focal length (the longer, the more obvious errors will be).

Your Mak 127 has a very long focal length 1500mm and a slow focal ratio (making images dark). It's ideally suited to planets with a webcam, but not so good for DSOs, requiring extremely accurate tracking and very long exposure times (nearly 6 times longer than a F5 newt or lens). With a shorter focal length, eg a 150pds scope at 750mm, you should be able to get 1-2min, maybe 3min exposures with good polar alignment on the EQ3. with a 200mm camera lens, maybe up to 5 mins.

[twelly27]

Don't know how much you already know, but the SynScan Az GOTO has to track in 2 directions, left/right (AZ), up/down (ALT), so it sort of tracks in a very fine zigzag to counter the rotation of the earth, which is along it's polar axis. The ALT/AZ tracking is dependant on the software map of the sky, star alignment and both axis tracking motors, so you'll only generally get 30-60s exposure with say a 250mm lens. But with ALT/AZ, you'll also get field rotation, where the stars rotate around the centre of the image, at the earth is rotating and not going in a zigzag!

The EQ mount has the advantage, that as long as you've aligned it precisely with the earths axis (polar aligned), it only has to track in one axis (RA) at the same speed the earth is rotating. How long it will track satisfactorily is depending on the polar alignment, tracking motor/gear accuracy and scope focal length (the longer, the more obvious errors will be).

Your Mak 127 has a very long focal length 1500mm and a slow focal ratio (making images dark). It's ideally suited to planets with a webcam, but not so good for DSOs, requiring extremely accurate tracking and very long exposure times (nearly 6 times longer than a F5 newt or lens). With a shorter focal length, eg a 150pds scope at 750mm, you should be able to get 1-2min, maybe 3min exposures with good polar alignment on the EQ3. with a 200mm camera lens, maybe up to 5 mins.

ahh I understand I think, so it i get an EQ mount with GOTO will it have to track with theAZ and ALT? If I want to track without the AZ and ALT will I be better off getting just a normal EQ mount? The one I'm saving for is £399 but and EQ 5 from the shop I use is about £250 I think would I better getting the EQ 5?

Regards

Chris

[sgazer]

Hi, an eq with goto will still track in ra only, goto will just allow it to find stuff easier. Eq5 will definitely be more stable than eq3 so get this if you can.

Sent from my AT300 using Tapatalk 2

[Galilean]

I love my EQ5 with Synscan.

[twelly27]

Ah I'm glad then I though I'd loose the EQ tracking if I got GOTO with it but know you have said that I understand in a perfect world I would go for the EQ 5 with GOTO aswell it's a lot of money though ill have to think about it, thanks for your comments and clearing that all up for me

Regards

Chris