Tracking question

[raymo]

I am surprised that in this age of technological wonders, nobody has come
up with a mount/system that can track well enough for long exposure astro
imaging out of the box, at a price that at least some amateurs could afford. There is a constant flow of posts from members with tracking problems, and I don't mean newbies, who will have at least initial problems. How much time
must you top imagers spend agonising over your PHD graphs, and trying to improve them?
The large professional observatories must surely be able to track very well
indeed, almost perfectly, so why is there not a much cheaper version of whatever they use to do it?
From a 50+ year manual guider.
raymo

[glend (Glen)]

Honestly i don't worry to much about it. My mount is on a pier and aligned pretty close to perfect. All i ever do is a 1 Star alignment in the area where i will be imagng then guide from there. No PEC, no drifting, nothing.

[raymo]

You're a lucky fella, I've got nowhere to put a pier, or leave my tripod set up.
raymo

[Atmos (Colin)]

This is exactly the reason that I have bought an ASA DDM60 raymo Should be arriving within the next month I hope! It does however not fall into the price range of the amateur market which is what you're looking for.

The next closest one I can think of is the 10 Micron mounts, these are virtually the same price as the DDM60 (for the same size). What allows both of these systems to work is closed loop absolute encoders, these on their own are very expensive items.

The difficulty comes from the fact that even if you have a "perfect" polar alignment, it doesn't work for every point in the sky due to the refractive index of the atmosphere. If you use any of the Bisque (Paramount) mounts, they can counteract some of this via T-Point with sufficiently large sky models.

One mount that has very little Periodic Error is the Friction Mount such as a Mesu 200.
http://www.mesu-optics.nl/mesu200_en.html

They fall into the medium price bracket and to some extent, do not have any gear system so they have a small error but it isn't periodic as such. Due to their size, very smooth curve which is very easy to guide out.

One of the problems that amateurs have is cost, to get something cheaply it has to be mass produced and there in lies one of the major issues. As a manufacturer you can make a LOT of parts at pretty good tolerances at a good price... OR you can make a small number of very high quality ones.

[glend (Glen)]

Raymo i was not being a smart a**, sorry.
I used to have some pavers set into my lawn properly aligned to true south for the tripod. They were leveled as well and the mount head set for my latitude. When i first did a proper alignment i marked the spot on each of the three pavers - a circle around the leg point, and drilled a hole there to locate the leg point next time. It work pretty well for a couple of years. I used a strap around my battery case and through an eye bolt screwed to the tripod centre bolt, when the strap was tight the tripod could not shift when slewing or during weight transfer. If you setup on a driveway the same should work just watch the levelling.

[Shiraz (Ray)]

I think it's coming Raymo - but it won't need a new mount. The new generation of low read noise cameras with subs as short as 10 seconds could mean that the imaging of the brighter objects will not require guiding or expensive mounts - just a big hard disk and a fast processor.

Colin has ordered the sort of mount technology that the pro's use - but I don't think that it is likely to be low cost in the near future.

[raymo]

Hi Colin, I'm not actually looking to purchase an up market solution to the
problem,[can't even afford a guide camera], I'm close to the end of my
viewing/ imaging time; I was really just thinking out loud, as it were.
I would have thought that the technology existed to produce a camera that
would not require accurate P.A., being able to respond close to
instantaneously to any movement of the guide star, but I suppose
atmospheric instability would cause the camera to chase its own rear end.
raymo

[Atmos (Colin)]

I didn't think that you were looking at a mount upgrade raymo, just that the easiest way of explaining the problems that need to be overcome is by giving examples of how they are being done currently

What Ray is mentioning is far easier to do on many levels than having a camera adjust for errors. The closest thing to what you mention raymo is the entry level adaptive optics (tilt/shift) glass plates.

[raymo]

Glen, I didn't think for one minute that you were. I wasn't even thinking
about P.A., just tracking. I also have marks on my pavers, and using
Darv I'm soon up and running. I have always weighted down lighter tripods,
but don't seem to have any problems with my 8" Newt and 80mm frac
+ finder, camera, and electric focuser, and D.I.Y. tube rotator, which is
almost at the mount's visual limit.
Hi Shiraz, Looks like it's all going to be too late for me, but exciting times
ahead.
Thanks everyone.
raymo

[Eden (Brett)]

Originally Posted by Shiraz

I think it's coming Raymo - but it won't need a new mount. The new generation of low read noise cameras with subs as short as 10 seconds could mean that the imaging of the brighter objects will not require guiding or expensive mounts - just a big hard disk and a fast processor.

Colin has ordered the sort of mount technology that the pro's use - but I don't think that it is likely to be low cost in the near future.

Could you be more specific? What sensors and from whom and when? CMOS or CCD based?

[Shiraz (Ray)]

Originally Posted by Eden

Could you be more specific? What sensors and from whom and when? CMOS or CCD based?

http://www.astrokraai.nl/dump/201605..._Kraaikamp.jpg (2000x1second subs)
http://www.cloudynights.com/topic/53...si1600mm-cool/

there is a thread running on the topic on IIS http://www.iceinspace.com.au/forum/s...d.php?t=144427 and more on CN. ZWO is the first cab off the rank with the new low noise cooled CMOS - just coming available now.

Even an EQ3 with an add on RA motor and no guider, (or even a tracking Dob if the field rotation is not too bad) will probably do 1 second subs - and give perfect round stars.

[sil (Steve)]

Originally Posted by glend

I used to have some pavers set into my lawn properly aligned to true south for the tripod. They were leveled as well and the mount head set for my latitude. When i first did a proper alignment i marked the spot on each of the three pavers - a circle around the leg point, and drilled a hole there to locate the leg point next time. It work pretty well for a couple of years. I used a strap around my battery case and through an eye bolt screwed to the tripod centre bolt, when the strap was tight the tripod could not shift when slewing or during weight transfer. If you setup on a driveway the same should work just watch the levelling.

I did the same sort of thing for my CGEM DX mount when I was able to use it. HOles drilled and painted in my courtyard pavers for tripod leg points. Used a digital spririt level to adjust mount ALT angle and solar noon for AZ. Tripod has an immovable pin the mount can be tightened against via two adjustable bolts, so once I had established north south line I used a locking nut to fix one of the bolts hard against the pin, using the other to tighten. So I just needed to drag the tripod outside and legs in holes on ground, then put mount on top and its polar aligned off the bat in its home position.

[sil (Steve)]

Raymo, I agree with the sentiment of your original post. However I think a big sticking point is astrophotographers are a niche market requiring long term equipment whereas Instagrammers can and do change their "gear" (read phones) often. We're not a get rich quick opportunity for someone but there is promise in the TinyMOS Tiny1.

I don't see why we can't have a camera that outputs FITS files using internal processing to create a single file, registered and stacked from its own captures as it goes, so you could put it on a tripod or tracking mount and it just captures and adds to a stacked image on the fly with maybe the registration options of deekskystacker from a larger mosaic to a smaller cropped region using data from all shots (maybe to a half resolution size maybe so the camera just keeps grabbing frames to reach this goal). It could internally task bias and dark frames and do subtractions and an illuminated lens/body cap for flats and output a single processed FITS file maybe with Master flat/dark/bias layers optional too. Should be achievable to do something like that. with configurability for users who want tons of data to process down to users who just want a pretty jpg for facebook. built in filters not a problem either, my pocket camera has a built in ND filter.

if we're going to fantasise it should have a built in lens at least equal to the antique Hubble Space telescope, be weatherproof, pocket sized, take infrared/ xray imagery too, radio and spectrum data too for everything in shot, able to shoot galaxies and faint nebulosity during noon time sun in a thunderstorm.

[raymo]

Hi Sil, your first line answers my original question, why didn't I think of that?
It costs a lot of money to research and develop/manufacture advanced
technical gear for what? a tiny market place. Not much incentive is there.
raymo

[DavidTrap (David)]

David Malin said the 3.9m scope at Siding Springs had an autoguider system when he used to ride in the cage.

There are some encoder system that will reduce PE to almost nil. Have a read about SiTech controllers.

DT

[raymo]

Thank you David.
raymo

[OICURMT]

Originally Posted by raymo

I am surprised that in this age of technological wonders, nobody has come up with a mount/system that can track well enough for long exposure astro imaging out of the box, at a price that at least some amateurs could afford.
.
.
.
raymo

This is probably as close as your will come. http://www.iceinspace.com.au/41-751-0-0-1-0.html

[silv (Annette)]

Interesting new hardware perspective: reduce the required exposure time instead of perfecting the tracking?
And the box out of which we think gets smaller and smaller:
The Polarie, my Samyang 500mm 6.3, the ZWO CMOS ASI1600MM-Cool cam, 2 ballheads and a tripod = 4.5kg -

and *coughs* a recording laptop with multiple fast processors and fibre optic SAN access.

The SAN can help with reducing heating cost during winter

[Shiraz (Ray)]

Originally Posted by silv

Interesting new hardware perspective: reduce the required exposure time instead of perfecting the tracking?
And the box out of which we think gets smaller and smaller:
The Polarie, my Samyang 500mm 6.3, the ZWO CMOS ASI1600MM-Cool cam, 2 ballheads and a tripod = 4.5kg -

and *coughs* a recording laptop with multiple fast processors and fibre optic SAN access.

The SAN can help with reducing heating cost during winter

looks to like a way to overcome lots of problems that have traditionally been solved by throwing heaps of money at them. Your setup could possibly do very nicely.

maybe there are some ways around the processing issue:
- lots of fast cores and memory (I just got a second i7Q laptop for this task)
- subframe selection to optimise the field of view (only take what you really need)
- 8 bit data gathering (will give plenty of dynamic range if you have low read noise and take enough short subs)

[silv (Annette)]

yeah... good advice.
you do planetary imaging with video, right?
so all this is known terrain for you, anyway.

Actually through this thread I only just now started to consider trying video capture and processing. (AVCHD to AVI conversion on my Mac is where I'm currently at with the preliminary consideration.)