From ALT-AZ to EQ*

[budgierless]

Hi,

I have an Skywatcher 130P with az goto mount, If i wanted to buy the eq3 pro goto mount to use with my 130P would that be possible or is their extra things I would have to buy to make it compatible?

any advise or a better suggestion would be most welcome, as I intend to do astro-photography.

thanks

[jambouk]

How does the 130p attach to the current mount? If it uses a dovetail, then it should just fit in a similar fashion.

Why are you changing mounts?

If you are doing it as you want to do "astrophotography" then make sure you ask people on here about that, as i would be worried you may be limited to similar length exposures with the new mount as you are with the alt-az one (even taking into account field rotation). Get some sound advice before splashing the cash.

James

[budgierless]

How does the 130p attach to the current mount? If it uses a dovetail, then it should just fit in a similar fashion.

Why are you changing mounts?

If you are doing it as you want to do "astrophotography" then make sure you ask people on here about that, as i would be worried you may be limited to similar length exposures with the new mount as you are with the alt-az one (even taking into account field rotation). Get some sound advice before splashing the cash.

James

The field rotation is a big issue yes, indeed astro-photography can be accomplished using the AZ mount but it is limited with 25 to 35 sec exposure times.

yes my 130P version uses a dovetail to slide on the single arm of the AZ mount.

[jambouk]

Ascertain from other owners of the EQ3 how long they can do subs for before trailing or non pin-point stars start appearing; unless it is 50-100% longer than your current set up, it might be worth a re-think.

[budgierless]

Ascertain from other owners of the EQ3 how long they can do subs for before trailing or non pin-point stars start appearing; unless it is 50-100% longer than your current set up, it might be worth a re-think.

what would you suggest as an alternative?

[russ.will]

Not that I'm a touchstone on the issue, but a well tuned EQ5 class mount seems to be the bare minimum I've seen good images produced from (some people have determination above and beyond the call of duty) and an HEQ5 the de riguer minimum recommendation.

Based on my old HEQ5 Pro, I'd say they will still need some work, but it's also probably true that successful AP starts with an innate understanding of your mount and how it works. That means taking it apart and learning how and what affects it's operation through re-assembly - None of them at sub £1k level will work as advertised from the box.

The alternative is to have a look at a really well tuned second hand Japanese mount from the likes of Ade Ashford on UKABS.

Russell

[jambouk]

I am not by any means knowledgeable on this topic but time after time i have read posts on here and elsewhere where people have asked advice about mounts for astrophotography and the overwhelming consensus seems to be HEQ5 as a minimum, and from owners of mounts with sub HEQ5 specifications asking how they can get longer subs without guiding or without poor-tracking artefact.

The going second hand rate for an HEQ5 is about £500. Howevere they hold their value well if looked after (which isn't hard to do), unlike the lower specification mounts (personal observation from the prices on astrobuysell). Yes £500 is a lot of money but for astrophotography the mount appears to be overwhelmingly the most important part of the setup.

If you can find one which has had the belt conversion modification done, then that may well have reduced periodic error, less backlash and better overall unguided tracking. Though having said that many engineering-minded individuals have stripped down mounts and cleaned and tunes and replaced parts which possibly, i believe, do a better job overall than a simple belt conversion.

This thread title may not be attracting the sort of people you need to hear from on this topic, so i'd suggest looking at related threads on here and potentially starting a new thread with your dilemma (eq3 vs heq5 or whatever).

Even if there are no heq5 mounts advertised on ABS, just post a wanted add as there may well be people out there with perfectly good mounts who just need a nudge to sell.

And as always, ideally go and look at, and play with the two mounts; you will instantly see the difference in robustness (not sure that is a word) of something like the heq5 in comparision to the eq3.

The next issue will be addressing issues with the scope: collimation; focus; coma abberation; secondary dewing up...

Good luck, but get some better advice before clicking "pay now"

James

[JG777]

Not to mention payload weight which by current standards appear to be about half of what the mount can handle. Factor all your add ons, camera, guide scope etc etc