Best competitive priced mount for unguided tracking

[bomberbaz]

This is more a curiosity query than purchasing at this moment in time but it's good to know these things.

There are loads of mounts out there ranging from a few hundred quid for an EQ3 Pro goto to 10micron GM 4000 HPS II at £22K 😳

I have only used basic goto and don't get fully understand these mounts where I have read they turn the encoder system off and let it track on it's motor or something akin to that. Someone can hopefully explain better than I just did !

Weight wise I have a 127 mak for planetary eeva (3kg) and my 130 p-ds (4kg). I also have a good solid steel tripod.

I was looking at unguided because I really don't want it to get too involved although @vlaiv has explained to me you need a very good unguided mount to get better EEVA results.

So really I am asking is how does it actually work and which is giving the best stability / tracking for your cash.

[vlaiv]

I'm sorry if I mislead you in thinking that you need better mount for EEVA.

I was just pointing out that if you want to achieve certain resolution in your images - and by term resolution I mean sharp enough image at your wanted pixel scale - then you need certain gear / sky conditions.

What I failed to emphasize is that for good EEVA - you don't need high resolution, and if you revisit what I've written - you can achieve that with very basic mount and short exposures.

Quote

3-4"/px - wide field imaging with telescopes - good resolution in almost any seeing, any decent mount should be able to do it unguided with relatively short exposures - any mount guided will be ok. Aperture of 50 or above

This is where I would start off - by keeping AzGTI - even in AZ mode, although you can use it in EQ mode - and switch is rather simple to do (involves flashing suitable firmware, getting wedge and counter weight shaft).

Question then is rather - how to achieve 3-4"/px resolution rather than what is suitable larger mount.

Just as a side note, ASI294 with 130PDS in super pixel debayering mode will have ~3"/px, and so will ASI183 if you super pixel debayer it and then bin it 2x2 in software.

Using x0.5 reducer with ASI224 will also give you sampling rate that you need if you debayer it in super pixel mode (~4"/px depending on how much reduction you achieve by careful distancing of reducer to sensor).

[Davey-T]

I have a 10Micron GM1000HPS than runs "unguided" it does this by taking anything from 25 to a 100 images across the whole sky then stores a model of the sky in its onboard computer, preferably needs to be on permanent setup to avoid modelling every time you set up although it will do it unattended as soon as sky is dark enough.

This is obviously not necessary for short exposures or videos.

Dave

[bomberbaz]

10 minutes ago, vlaiv said:

I'm sorry if I mislead you in thinking that you need better mount for EEVA.

I was just pointing out that if you want to achieve certain resolution in your images - and by term resolution I mean sharp enough image at your wanted pixel scale - then you need certain gear / sky conditions.

What I failed to emphasize is that for good EEVA - you don't need high resolution, and if you revisit what I've written - you can achieve that with very basic mount and short exposures.

This is where I would start off - by keeping AzGTI - even in AZ mode, although you can use it in EQ mode - and switch is rather simple to do (involves flashing suitable firmware, getting wedge and counter weight shaft).

Question then is rather - how to achieve 3-4"/px resolution rather than what is suitable larger mount.

Just as a side note, ASI294 with 130PDS in super pixel debayering mode will have ~3"/px, and so will ASI183 if you super pixel debayer it and then bin it 2x2 in software.

Using x0.5 reducer with ASI224 will also give you sampling rate that you need if you debayer it in super pixel mode (~4"/px depending on how much reduction you achieve by careful distancing of reducer to sensor).

I have already flashed my Gti Wifi and have it on a wedge so that's a start 😅

I understand binning but what is super pixel debayer, is this something available on standard capture software or is it a physical thing added to your capturing gear. 

[bomberbaz]

Ok I just read a little about super pixel debayer. I think I would have to look at a lot of tutorials for both that and also binning as I have never really tried that either.

 

[PEMS]

Overall I would have said the EQ5. Maybe on the smaller side but the mount is a manageable size and will take 6Kg imaging and in reality that should be enough for a reasonable small reractor ED variety A WO ZS81 is 3.5Kg, DSLR estimate 1 Kg upper end and the flattener how about another 0.5Kg. So a total of around 5Kg. Agreed at the upper end of the capacity, but should be OK.  Could simply get a smaller scope the ZS73 is 2.8Kg so a saving of 0.7Kg, and down to around the just under 4.5Kg.

In an odd way the 81 size is likely more use as you can use it for a greater range of visual objects.

Above the EQ5 mounts get big and heavy, and more expensive. The possibly lighter physical weight iOptrons are more costly, and as the question is "competitive priced" I would say the EQ5.

Will depend on the amount of weight that you expect or intend to put on a mount, and also the exposure length. The most competitive mount if you want to out 18Kg on it and take 180 to 300 second unguided exposures is not an EQ5.

If you are thinking 4.5Kg to 5Kg and 45 seconds to 60 seconds maximum then it should do you fine. You will need to set it up reasonably well.

[bomberbaz]

I haven't seen this mount before but on the surface of it, it does sound a very well priced, well thought out and hopefully well constructed bit of kit.

Sky-Watcher EQM-35 PRO Go-To Modular Astronomy Mount | First Light Optics

It carries slightly more than the EQ5 for imaging (7kg over 6.5kg) and has modified gearing in RA to improve accuracy although they both state within 1 arc-min.

The sky at night review makes good reading although I do realise these tend to be glammed up a little Sky-Watcher_EQM-35_review_Sky_at_NightReview.pdf (firstlightoptics.com)  That said, if it does manage 25 minutes before any noticeable drift then it would be excellent. Personally I would be happy at 10 minutes. 

Overall though it seems a good mount.

Has anyone used or got one?

Steve