The best (smoothest) mount for unguided astrophotography?

[rocketandroll]

Hi folks

Having dabled with stand alone autoguiders (and failed) and having subsequently realised I'm having pleanty of fun doing unguided imaging... and am about to hopefully upgrade to an even faster refractor... I am considering leaving off going guided until I at least have the ability to image from home/an obsy (which I can't do at present).

So, bearing in mind I need something portable (I'm a fairly big guy so can move fairly hefty kit, but will need to lug it from car to field and back) and a not unlimited budget.... is there anything better available than the HEQ5 or NEQ6 for tracking accuracy?

I am noticing I'm loosing one in every three subs now from trailed stars with the HEQ5 due, I assume, to pereodic errors... certainly it's not alignment as at least half the subs are pin sharp.

So, with a light scope and DSLR (sub 6kg/12lbs total payload weight) are there any other options in terms of mounts in the sub £3K price bracket that could, in future be used for guiding, but are better made and likely to be more consistent for unguided in the mean-time?

Or am I asking for rocking horse doo-doo? :-)

Ben

[Peter Drew]

Astrotrac?

[Whippy]

So, bearing in mind I need something portable (I'm a fairly big guy so can move fairly hefty kit, but will need to lug it from car to field and back) and a not unlimited budget.... is there anything better available than the HEQ5 or NEQ6 for tracking accuracy?

Not for less than 3K and even then, time you take drift aligning and whatnot, you might as well get back into guiding.

Peter's suggestion of an Astrotrac would be the obvious solution IMO.

Tony..

[Deneb]

Personally I don't think your going to get any mount really without tracking errors... even if you spend a few thousands... im about to embark on another unguided experiment ( & thats all im going to say). Personally I would take my time even deciding to guide or not !

Believe me I was looking into this subject as well "Best Mount for Unguided" but did not come up with much....

Some people fine tune the gears in their mounts for better performance as people already know - some chinese manufacturing Quality Control does vary, but I don't know who you could approach for that type of service !

Nadeem.

[Ags]

I thought the HEQ5 had PEC?

[Ben Ritchie]

The only mount that i've ever owned that could do absolutely reliable multi-minute unguided exposures (at 1040mm focal length) was the 1200GTO, which had (measured) peak-to-peak PE of under an arcsecond with PEC on. My G11 wasn't close, ditto the EQ6. But when guided both were/are fine. PEC may help reduce the number of subs you need to throw away, but it's really not a good substitute for guiding.

[Whirlwind]

Depending on what focal length you are looking at there is also the Vixen Sphinx's (SX+SXD)? However they do have some software issues with them trying to autocorrect for poor polar alignment. However people appear to rate them once upgraded with a Nexremote board. They are also light for their weight capacity. I have an SXD and could guide it at 500mm focal length - never tried unguided though.

Ian

[RobH]

You'll waste more time, and become more frustrated, trying to image unguided over longish exposures than any slight guiding issues will make you.

Guiding is dead easy, especially at short fiocal lengths and when using something like PHD as a guide program.

Rob.

[Psychobilly]

You'll waste more time, and become more frustrated, trying to image unguided over longish exposures than any slight guiding issues will make you.

Guiding is dead easy, especially at short fiocal lengths and when using something like PHD as a guide program.

Rob.

Totally agree with Mr H's comments...

For relatively stress free "imaging" chill-out with some unguided widefield... even my EQ3-pro gives good 120s subs at 200mm fl and thats without drift aligning - just PA'd using the polarscope...at 50mm it will churn out 240s subs all night...

A guidecam and PHD is a lot easier to use than a standalone guider (I have a synguider)

Peter...

[rocketandroll]

Cheers all for the thoughts....

I think I'm hitting a bit of a barrier. I think the trouble is most folks who are in to imaging do so from their garden or, even better, a permanent obsy. That's great, and obviously when some or all of your gear can be left set up running guiding is pretty easy and quick to do.

Because I can only grab short spells of imaging from remote sites I have to drive to, generally with no facilities, no power and nowhere to stick a computer I am drawn towards whatever is the simplest, quickest and easiest to set up and take down.

I have got it down to about 15 - 20 mins max to get set up now for an unguided imaging run... completely from scratch. Adding in guiding will invariably at least double that... and when my window for imaging is perhaps a couple of hours at a time... that's a big extra chunk of time to loose.

I think there's an overall feeling that unguided imaging is something unfortunate you only do in extreme circumstances because you can't guide... maybe some people actually prefer the simplicity of NOT guiding?! :-) I really enjoy just aligning the mount, starting the camera running and leaving it going... am I WRONG to enjoy unguided imaging?

I wasn't planning to get longer exposures than I already have achieved... at 400mm fl or so I can get 90 - 120 second exposures. With a faster scope at f5 or below that will be more than enough for a lot of what I want to do.... the only thing I'm trying to do is find a way to get rid of the periodic error which seems to have crept into my HEQ5 in the last couple of months so I don't get 35 minutes of useable subs for every hour I spend imaging.

I just wondered if there was a mount less likely to have those issues which I could use for unguided stuff at remote locations, then, when I move house and can image properly from home next year... I can look at an alternative rig for guided work.

Anyway... still thinking about which way to go, I just kinda feel those who can image from home are less aware of the issues and priorities when EVERY imaging session is done from a remote site in a small time window. I think that's a different set of needs.

Cheers!!!

Ben

[Ben Ritchie]

I really enjoy just aligning the mount, starting the camera running and leaving it going... am I WRONG to enjoy unguided imaging?

No, of course not - simplicity is great, especially when you're short of time and have to setup each night out. You just need to balance budget and focal length so that tracking error and image scale are roughly equal.

As has been said, an Astrotrac seems like an obvious choice for an unguided setup, or just use your current mount with a DSLR and 200mm FL lens - that'll work just fine unguided. But at longer focal lengths there isn't really an easy answer

[Deneb]

Ben, There's nothing wrong with doing unguided work, so I shouldn't feel that way, regardless what people say...I found unguided work to be a good way of pushing my gear to the extremes especially when it came to processing your images afterwards.

I think Unguided work is a lot more difficult then guided work, you certainly have to factor in a lot more things into it, believe me .... My last unguided work was with the MN190 with a focal length of 1000mm with a 450D, those images can be seen on my website or my MN190 SGL Album.

Something just tells me you've only just touched the tip of the iceberg...Have Fun..

Nadeem.

[Ags]

Cheers all for the thoughts....

...

Because I can only grab short spells of imaging from remote sites I have to drive to, generally with no facilities, no power and nowhere to stick a computer I am drawn towards whatever is the simplest, quickest and easiest to set up and take down.

I have got it down to about 15 - 20 mins max to get set up now for an unguided imaging run... completely from scratch. Adding in guiding will invariably at least double that...

.... the only thing I'm trying to do is find a way to get rid of the periodic error which seems to have crept into my HEQ5 in the last couple of months so I don't get 35 minutes of useable subs for every hour I spend imaging.

Ben

Just a thought - unguided you are losing 25 minutes of imaging in the hour, while you think guiding will take you an extra twenty minutes to set up... If you image for just one hour guided, you're already in profit!

[ollypenrice]

While I guide (and like gudiing) I can see where you're coming from. If you really don't want to guide then you need to think along a different line; short focal length and fast focal ratio. Think camera lens. Although I don't use it a great deal I have a couple of big projects for my Canon EF200L this winter. It can work down to F3.5 and give tight corner stars on my setup, so... focal length of 200mm and f3.5 means tolerance of tracking error and very short exposures. (1 minute at F3.5 = 4 minutes at F7.) Just what you're looking for. I paid £500 for mine second hand from London Camera Exchange.

You said £3000 for top whack on the mount. Up that to £4000 and there is the Dutch Mesu Friction Drive which claims a very low PE indeed.

For fast setup the expensive Takahashi mounts are in a league of their own and are very accurate (about 5 arcsecs PE as opposed to 20 or 30 for an EQ6.)

The iOptron IEQ45 is worth a look and they are making a very accurate version, they say. However, all the accuracy in the world depends on precise polar alignment...

I have seen a few Sphinx mounts and been seriously underwhelmed by them and by tales of customer service as well.

Olly

[rocketandroll]

Cheers all for the thoughts.

You already talked me in to buying one of the L series f2.8 lenses back in June remember Olly :-)

I have had some nice results from 1.5 - 2 minute subs with the Meg72 at f6 so if I can get a scope with a reducer down around the f5 or lower mark and no more than 500mm fl I am confident I could do a lot.

Hmmm.... well, still in two minds about which way to go. Maybe guiding is still a better option and I put up with the extra set-up time.

Tough to decide really :-s

Ben

Sent from my GT-I9100 using Tapatalk