Quickest imaging setup for field use?

[NickMorris]

I have to setup each and every night and was wondering which combination of medium duty mount and / or software has the fastest setup time.

This would be for long exposures and a very accurate polar alignment is required.

Clock starts when the tripod is placed and stops when the first faint fuzzy goto lands smack dead centre of the CCD.

Pointing models are allowed.

My HEQ-5 takes me about 5 mins to rough align but more like 1hr to accurately drift align.

Any exotic mount owners out there with super quick times?

Cheers

Nick

[RikM]

I have to set up each night as well. I use an explorer 150P with a Mono CCD and filters on an NEQ6 with a finderguider. I have foot pads set into the lawn so my starting point for PA is pretty close. I do a quick polarscope alignment and then a rapid drift align using PDH and the finderguider. This gets me close enough for 20 min subs and I am more or less limited by the local seeing rather than PA. I have all my cables in a loom so I just hang it by velcro then plug and play. I have the time down from opening the back door to getting the first sub underway in about 40 min. The scope doesn't cool much quicker than that, so taking an hour might actually be better.

[perfrej]

GM1000HPS is a safe bet in that respect.

1. Setup tripod and mount mount

2. Aim mount roughly at North

3. Run a model automatically with, say, five points

4. Adjust Alt/Az as per handset instructions

5. Clear model and run a 15-25 point one

After that, evertything is within a pixel or two of dead center for slews, and tracking is good for unguided imaging, possibly up to hour-long subs (not unlikely).

Total time to first fuzzie sub is less than 20 minutes plus exposure for said fuzzie sub. However, the fuzzie in question may suffer from tube currents due to lack of enough cool-down time...

The cool software needed to make this happen is available for free at http://astro.frejvall.se (but you do need Maxim and a full version of PinPoint)

/per

[NickMorris]

Thanks Guys,

Per, that sounds amazing! I have however for my sins been trying to stay on the Mac OSX platform up until now using The Sky X for control and Nebulosity/PHD for imaging. I don't suppose you fancy porting it over do you Are there other ways via the handset to build a model?

Do you know if the mount conforms closely enough to the LX200 protocol for the Sky X to control it?

I do love the sound of this alignment procedure, so totally automated apart from adjustment to alt/az. What form are the alt/az adjustment instructions from handset?

I am going to have a serious look at this, thanks

Nick

[perfrej]

Nick,

I have used the OS X platform for AP but it just doesn't get there. I don't like TheSky and there is no - absolutely no - automation software available. Dveloping tools on the OSX platform are not that hot either. I have developed several applications for Mac and iPad and the tools are just not as good as the ones on the other side. So, instead of porting me over, I suggest you take a serious look at the offerings on the Windows side... Besides, if you go 10Micron you can ditch PHD or any other guideing software. I haven't shot a single guided exposure since early last fall when I seriously started using my GM2000HPS.

Anyway, controlling a 10Micron mount from TheSky as an LX200 is definitely possible but that protocol, as such, lacks the precision that is available in the 10Micron mounts. This is by design, and you have to consider that it is a very old protocol and that the scopes that uses it natively (i.e. Meade) do not suffer from that lack of precision as they do not have it in the first place.

You can align via the handset using known stars, just like with any other mount. The results are the same but the procedure, oh, the procedure! Select star, slew to it, center in CCD, select next star... Imagine doing more than ten stars that way!

Note that even though you use a PC for controlling all the components involved in a plate solved model building process, the model is still stored in the mount and available without any differences when you use your mount without a computer.

The information that you get in "Align info" looks like this (from the virtual handset in Windows):

As you can see, I have a polar error of 39 arcseconds, and in order to correct that I should turn the knob that moves the mount to the left 0.01 turns. Needless to say, I am not going to touch it... Also, the mount tracks in both axis according to the model so there is no need for exact polar alignment.

My scope is a bit off in terms of cone error (ortho) and needs to be shimmed at the rear tube ring. The model is expected to deliver 6.1 arcseconds of pointing accuracy as well as tracking to the same level.

This model, which is now obsolete as I have taken the mount down for the summer (it's too light here - no stars), has given me several good images with 10 to 20 minute subs, all unguided.

/per

[ollypenrice]

For a different approach, software free, the Takahashi system is hard to beat. It doesn't require the mount to be even slightly level and uses a bubble level on RA, preset to your longitude, and a polar reticule like a planisphere, on which you set the date to the time. Polaris then goes in a little slot on the reticule. It probably takes one to two minutes to get a PA good enough for 30 minute subs. In an observatory one might do a more sophisticated alignment, though in reality I've never actually needed to do so. SInce our Tak mount is observatory based this super alignment routine is rather wasted!

In a system like the Skywatcher where levelling the mount calibrates the polar scope reticule one actually wastes a fair bit of time on this levelling. WHy Tak alone thought to put the bubble level in the right place is beyond me!

Olly

[Chris Rowland]

The biggest time seems to be drift aligning and something that will at least help with that is Celestron's All Star Polar align.

After doing a normal alignment you adjust the mount to centre a selected star in the main scope. Takes just a few extra minutes after the normal alignment.

I think it's good enough for imaging with just that but at least it gets you close enough that a drift align will take less time.

Chris

[Spikey]

I also have to set up and break down if I want to imgae and I use EQMOD's polar alignment routine to set the mount up before loading it with the scopes - this must take less than 5 minutes from start to finish, most of that time is me scrabbling about underneath the polarscope twiddling the adjustments.

I can get good guided subs in excess of 30 mins with this method and used exactly the same routine with my HEQ5.

I'd only bother drift aligning if I had a permanent setup in an observatory.

[perfrej]

Getting a Skywatcher or Takahashi mount reasonably polar aligned is a breeze. But on the other hand you are doomed to guide...

/per

[NickMorris]

Thanks for the replies,

I just looked up the price of a Tak EM-200 and it's similar to the 10 micron. Seems a bit of a no contest however the GM1000HPS only carries 25kg. Here's a question for Per or others:-

Is there a very marked difference (im sure the answer is yes) in using an AZ EQ-6GT with Maxim / Maxpoint or The Sky X / T-point modelling software and a GM1000HPS? Obviously the model would be run on a laptop rather than inside the mount firmware but could you image unguided with the aforementioned modelling software?

Thanks

Nick

[ollypenrice]

There is no doubt that the Tak is too expensive. I can't help on the other questions.

Olly

[Ben Ritchie]

For a different approach, software free, the Takahashi system is hard to beat. It doesn't require the mount to be even slightly level and uses a bubble level on RA, preset to your longitude, and a polar reticule like a planisphere, on which you set the date to the time. Polaris then goes in a little slot on the reticule. It probably takes one to two minutes to get a PA good enough for 30 minute subs.

I agree, the Tak mounts are brilliant for quick polar alignment - I used to use an NJP and setup was very simple. Great mount, if rather expensive

[perfrej]

Simple answer to the Skywatcher/Tpoint vs 10Micron question: no chance in a million years.

The 10Micron mounts have absolute encoders with rediculous resolution and can thus track in two axis. The SW mount doesn't have absolute encoders and can thus only track in Ra. So, TPoint, MaxPoint, EQMOD (all with good POINTING models) cannot do anything but improve your pointing.

Improving pointing is nice but not really the key issue as you plate solve and adjust anyway before exposure. The tracking is, however, the key issue, and in order to get dual axis tracking you need the encoders and software that understands how to use them. With encoders and dual axis tracking you get rid of two annoying issues: polar alignment dependency and guiding dependency.

It is a hard fact that once you see and try a mount that doesn't require guiding nor accurate polar alignment you can't go back. It is so beatifully simple to operate and delivers very consistant results. For the past nine months of operation, I have NEVER verified that I am spot on where I want to be, and I have lost very few subs. The latter has been due to my experimentation in model making software of too strong winds with the 190MN (19kg, big tube, nice sail).

So, nope.

And, for reference, try this with a Skywatcher... This is a crop of a one hour long sub - yes, single exposure, at focal length 1000mm taken with my Skywatcher 190MN on top of my balcony pier mounted GM2000HPS. M106, central region crop, NO GUIDING:

/per

[chrisshillito]

The SW mount doesn't have absolute encoders and can thus only track in Ra. So, TPoint, MaxPoint, EQMOD (all with good POINTING models) cannot do anything but improve your pointing.

There is nothing that prevents a skywatcher mount from being tracked in RA and DEC - it only needs the software to command it. Given the existance of a 'good' pointing model there is no reason why software can't be written to track through that model. Variable rate dual axis custom tracking is already a part of EQMOD and at some point I do plan extend this to allow model corrected tracking. However, the real problem I face with this is how to adapt PEC to work in an environment where both axis move at variable rates. Irrespective of the accuracy of polar alignment, PE is itself a reason why guiding is usualy necessary for long exposure imaging on skywatcher mounts.

Chris.

[Gonzo]

GM1000HPS is a safe bet in that respect.

At the price it goes for... it better be a safe bet lol

[perfrej]

Yes Chris, that is totally true. I have used EQMOD a lot and I like it. You should work on the dual axis tracking and I think that therein lies the future. I haven't looked deeper into EQMOD's modeling, but I am sure it is good enough to provide all the data needed for dual axis tracking. I still have an NEQ6 and will probably put it to use this fall when my two 10Micron mounts are at two different remote sites and my balcony pier is unoccupied. Let me know if you need some input and/or testing done.

/per

[NickMorris]

I suppose the limitation will always be the resolution of the encoders. You tell the mount where to point but without the encoder feedback, the firmware never knows for sure it is pointed exactly.....

Seems this has to be the way forward for mount technology?

Nick